Publications by year
In Press
Littlechild JA (In Press). Improving the ‘Tool Box’ for Robust Industrial Enzymes. Journal of Industrial Microbiology & Biotechnology
2022
Frustaci S (2022). A Whispering Gallery Mode based sensor platform for single enzyme real time conformational changes.
Abstract:
A Whispering Gallery Mode based sensor platform for single enzyme real time conformational changes
Understanding the conformational changes that occur in an enzyme during turnover is crucial for understanding biomolecular processes and for new rational drug discovery. Many single-molecule techniques have been developed in the past three decades, such as Förster resonance energy transfer, although powerful, these techniques have their limitations, for example, limited temporal resolution, or necessity for fluorescent labelling. In this study a new class of highly sensitive optical devices based on the whispering gallery mode sensor have been investigated and employed to track the conformational changes of a kinase enzyme in real time.
A thermostable Geobacillus stearothermophilus phosphoglycerate kinase enzyme has been used as model enzyme to prove that the optoplasmonic whispering gallery mode sensor can detect the conformational changes involved in enzyme turnover.
The enzyme was expressed and purified to a high degree of purity that was suitable for crystallographic studies as well as biochemical investigation. The purified enzyme has been used for kinetics and biophysical enzymatic characterisation. A reproducible protocol has been established to immobilise the enzyme onto gold nanoparticles in a defined orientation to track the conformational changes occurring on the sensor. The enzyme has been immobilised onto the gold nanoparticles using two different methods: through the his-tags introduced onto the recombinant enzyme and directly onto the gold through a surface cysteine residue introduced by site-directed mutagenesis. The kinase enzyme was found to retain activity using both methods.
To rationalise the observed conformational changes occurring during enzymatic turnover, the crystal structures of the native enzyme and its complexes with the substrate, and with substrate together with non-hydrolysable ATP, have been determined to high resolution, between 1.2 Å and 2 Å. Finally, for the first-time a real-time visualisation of the movement of the phosphoglycerate kinase during enzymatic turnover has been recorded. Repeating signals from the sensor were registered and only observed when both the substrate 3-phosphoglycerate and ATP are introduced with the enzyme into the sensor chamber. No signal is observed with the 3-phosphoglycerate alone or ATP alone or when 3-phosphoglycerate and a non-hydrolysable ATP analogue were used with the enzyme. The sensor system presented in this thesis shows potential for future fast, real-time, rapid throughput, lab-on-chip measurements for studying single enzymes.
Abstract.
Alcántara AR, DomĂnguez de MarĂa P, Littlechild JA, SchĂĽrmann M, Sheldon RA, Wohlgemuth R (2022). Biocatalysis as Key to Sustainable Industrial Chemistry.
ChemSusChem,
15(9).
Abstract:
Biocatalysis as Key to Sustainable Industrial Chemistry.
Invited for this month's cover is the Working Group Sustainable Chemistry of the European Society of Applied Biocatalysis (ESAB). The image shows the significant contributions of Biocatalysis to science, industry, society, and environment as a technology of first choice for Sustainable Chemistry in the 21st century. The Perspective itself is available at 10.1002/cssc.202102709.
Abstract.
Author URL.
Alcántara AR, DomĂnguez de MarĂa P, Littlechild JA, SchĂĽrmann M, Sheldon RA, Wohlgemuth R (2022). Biocatalysis as Key to Sustainable Industrial Chemistry.
ChemSusChem,
15(9).
Abstract:
Biocatalysis as Key to Sustainable Industrial Chemistry.
The role and power of biocatalysis in sustainable chemistry has been continuously brought forward step by step to its present outstanding position. The problem-solving capabilities of biocatalysis have been realized by numerous substantial achievements in biology, chemistry and engineering. Advances and breakthroughs in the life sciences and interdisciplinary cooperation with chemistry have clearly accelerated the implementation of biocatalytic synthesis in modern chemistry. Resource-efficient biocatalytic manufacturing processes have already provided numerous benefits to sustainable chemistry as well as customer-centric value creation in the pharmaceutical, food, flavor, fragrance, vitamin, agrochemical, polymer, specialty, and fine chemical industries. Biocatalysis can make significant contributions not only to manufacturing processes, but also to the design of completely new value-creation chains. Biocatalysis can now be considered as a key enabling technology to implement sustainable chemistry.
Abstract.
Author URL.
Wohlgemuth R, Littlechild J (2022). Complexity reduction and opportunities in the design, integration and intensification of biocatalytic processes for metabolite synthesis.
Frontiers in Bioengineering and Biotechnology,
10Abstract:
Complexity reduction and opportunities in the design, integration and intensification of biocatalytic processes for metabolite synthesis
The biosynthesis of metabolites from available starting materials is becoming an ever important area due to the increasing demands within the life science research area. Access to metabolites is making essential contributions to analytical, diagnostic, therapeutic and different industrial applications. These molecules can be synthesized by the enzymes of biological systems under sustainable process conditions. The facile synthetic access to the metabolite and metabolite-like molecular space is of fundamental importance. The increasing knowledge within molecular biology, enzyme discovery and production together with their biochemical and structural properties offers excellent opportunities for using modular cell-free biocatalytic systems. This reduces the complexity of synthesizing metabolites using biological whole-cell approaches or by classical chemical synthesis. A systems biocatalysis approach can provide a wealth of optimized enzymes for the biosynthesis of already identified and new metabolite molecules.
Abstract.
Wohlgemuth R, Littlechild J, Kim B-G (2022). Editorial: Systems biocatalysis for bioprocess design. Frontiers in Bioengineering and Biotechnology, 10
Alcántara AR, de MarĂa PD, Littlechild JA, SchĂĽrmann M, Sheldon RA, Wohlgemuth R (2022). Front Cover: Biocatalysis as Key to Sustainable Industrial Chemistry (ChemSusChem 9/2022). ChemSusChem, 15(9).
Alcántara AR, DomĂnguez de MarĂa P, Littlechild JA, SchĂĽrmann M, Sheldon RA, Wohlgemuth R (2022). Preface to Special Issue on Biocatalysis as Key to Sustainable Industrial Chemistry.
ChemSusChem,
15(9).
Abstract:
Preface to Special Issue on Biocatalysis as Key to Sustainable Industrial Chemistry.
In their Editorial for the Special Issue on Biocatalysis as Key to Sustainable Industrial Chemistry, Guest Editors Andrés Alcántara, Pablo Domínguez de María, Jennifer Littlechild, and Roland Wohlgemuth and their co-workers on the European Society of Applied Biocatalysis' (ESAB) Working Group on Sustainable Chemistry Martin Schürmann and Roger Sheldon discuss the Special Issue and the importance of biocatalysis in carrying out cutting-edge industrial chemistry in a sustainable way, as well as the future prospects for the field.
Abstract.
Author URL.
Sutter J-M, Mitchell DE, Schmidt M, Isupov MN, Littlechild JA, Schönheit P (2022). Substrate specificity of branched chain amino acid aminotransferases: the substitution of glycine to serine in the active site determines the substrate specificity for α-ketoglutarate. Frontiers in Catalysis, 2
Cutlan R (2022). Synthetic Biology for Green Chemistry: Building in Vivo Enzymatic Cascades Using Carboxylic Acid Reductases (CARs).
Abstract:
Synthetic Biology for Green Chemistry: Building in Vivo Enzymatic Cascades Using Carboxylic Acid Reductases (CARs)
Biocatalysis has a proven track record of offering replacements for individual chemical reactions with a lower environmental impact. Cascade reactions are an extension of biocatalysis; coupling a series of reactions to provide replacement for more than one chemical step. Herein, this thesis describes the engineering of a multi-enzyme cascade reaction for the production of phenylacetylcarbinol (PAC). Using a carboxylic acid reductase (CAR) from Mycobacterium phlei and a pyruvate decarboxylase from Acetobacter pasteurianus this thesis demonstrated a biocatalytic cascade reaction in which benzoic acid and pyruvate are converted into PAC. This cascade was combined with several other enzymes to recycle spent cofactors and deplete inhibitor by-products.
Furthermore, this thesis has highlighted the discovery of five putative enzymes; three ancestral CARs (AncCARs) and two thiamine diphosphate (ThDP) dependent enzymes. CARs typically have poor stability and thus limited tractability in industrial reactions. Within this study ancestral sequence reconstruction was performed on type I CARs. This is a developing engineering tool that can identify stabilizing and enzymatically neutral mutations throughout a protein. A combined algorithm approach was used to reconstruct functional ancestors of the Mycobacterial and Nocardial Type I CAR orthologues. Carboxylic acid reduction by Ancestral CARs was confirmed. Each showed a preference for aromatic carboxylic acids. AncCARs also showed improved tolerance to solvents, pH and in vivo-like salt-like conditions. Compared to well-studied extant CARs, AncCARs had a Tm up to 35 °C higher. Two ThDP enzymes were discovered using metagenomics. These were assessed in silico through homology modelling and docking simulations. Furthermore, this study has demonstrated the importance of each tool in the discovery of new enzymes from within the ThDP family. Our homology models were used in docking simulations with unique carboligation-like intermediates allowing a rationalization of the reactions and stereoisomerism of the products. Two functional enzymes ThDP enzymes were identified that are capable of producing PAC; one from Thermus thermophilus and another from bacterium HR16.
Abstract.
2021
De Rose SA, Kuprat T, Isupov MN, Reinhardt A, Schönheit P, Littlechild JA (2021). Biochemical and Structural Characterisation of a Novel D-Lyxose Isomerase from the Hyperthermophilic Archaeon Thermofilum sp.
Frontiers in Bioengineering and Biotechnology,
9Abstract:
Biochemical and Structural Characterisation of a Novel D-Lyxose Isomerase from the Hyperthermophilic Archaeon Thermofilum sp.
A novel D-lyxose isomerase has been identified within the genome of a hyperthermophilic archaeon belonging to the Thermofilum species. The enzyme has been cloned and over-expressed in Escherichia coli and biochemically characterised. This enzyme differs from other enzymes of this class in that it is highly specific for the substrate D-lyxose, showing less than 2% activity towards mannose and other substrates reported for lyxose isomerases. This is the most thermoactive and thermostable lyxose isomerase reported to date, showing activity above 95°C and retaining 60% of its activity after 60 min incubation at 80°C. This lyxose isomerase is stable in the presence of 50% (v/v) of solvents ethanol, methanol, acetonitrile and DMSO. The crystal structure of the enzyme has been resolved to 1.4–1.7 A. resolution in the ligand-free form and in complexes with both of the slowly reacting sugar substrates mannose and fructose. This thermophilic lyxose isomerase is stabilised by a disulfide bond between the two monomers of the dimeric enzyme and increased hydrophobicity at the dimer interface. These overall properties of high substrate specificity, thermostability and solvent tolerance make this lyxose isomerase enzyme a good candidate for potential industrial applications.
Abstract.
De Rose SA, Finnigan W, Harmer NJ, Littlechild JA, consortium TH, Bettina S, Christopher B, Christina S, Benjamin M, N. IM, et al (2021). Production of the Extremolyte Cyclic 2,3-Diphosphoglycerate Using Thermus thermophilus as a Whole-Cell Factory. Frontiers in Catalysis, 1
De Rose SA, Harmer N, Littlechild J (2021). Production of the extremolyte cyclic 2,3-diphosphoglycerate using Thermus thermophilus as a whole-cell factory.
Abstract:
Production of the extremolyte cyclic 2,3-diphosphoglycerate using Thermus thermophilus as a whole-cell factory
Osmolytes protect microbial cells against temperature, osmolarity and other stresses. The osmolyte cyclic 2,3-diphosphoglycerate, originally isolated from the thermophilic archaeon Methanothermus fervidus, naturally protects cellular proteins under extreme conditions. The biosynthetic pathway for cyclic 2,3-diphosphoglycerate has been introduced into the thermophilic bacterium Thermus thermophilus. The two enzymes in this synthetic pathway, 2-phosphoglycerate kinase and cyclic diphosphoglycerate synthetase, were incorporated into a newly designed modular BioBricks vector. The expression of this two-enzyme cascade resulted in the whole cell production of cyclic 2,3 diphosphoglycerate. In vivo production of cyclic 2,3-diphosphoglycerate was confirmed by mass spectrometry to a concentration up to 650 µM. This study demonstrates the feasibility of using this well studied thermophilic bacterium as a host in a whole-cell factory approach to produce cyclic 2,3 diphosphoglycerate. This raises the potential for commercialisation of cDPG for cosmetic and healthcare applications. Our work demonstrates the potential of Thermus thermophilus as an alternative host for other high value small organic molecules of industrial interest.
Abstract.
De Rose S, Harmer N, Littlechild J, Finnigan W (2021). Production of the extremolyte cyclic 2,3-diphosphoglycerate using Thermus thermophilus as a whole-cell factory- DATASET.
Nepogodiev D, Simoes JFF, Li E, Glasbey J, Picciochi M, Kamarajah SK, Gujjuri R, Bhangu A, Maryam A, Azab MA, et al (2021). SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study.
British Journal of Surgery,
108(9), 1056-1063.
Abstract:
SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study
Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: the primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.
Abstract.
Zhu C, Chen Y, Isupov MN, Littlechild JA, Sun L, Liu X, Wang Q, Gong H, Dong P, Zhang N, et al (2021). Structural Insights into a Novel Esterase from the East Pacific Rise and its Improved Thermostability by a Semirational Design. Journal of Agricultural and Food Chemistry, 69(3), 1079-1090.
2020
James P, Isupov MN, De Rose SA, Sayer C, Cole IS, Littlechild JA (2020). A ‘Split-Gene’ Transketolase from the Hyper-Thermophilic Bacterium Carboxydothermus hydrogenoformans: Structure and Biochemical Characterization. Frontiers in Microbiology, 11
K. Hussain K, Malavia D, M. Johnson E, Littlechild J, Winlove CP, Vollmer F, Gow NAR (2020). Biosensors and Diagnostics for Fungal Detection.
Journal of Fungi,
6(4), 349-349.
Abstract:
Biosensors and Diagnostics for Fungal Detection
Early detection is critical to the successful treatment of life-threatening infections caused by fungal pathogens, as late diagnosis of systemic infection almost always equates with a poor prognosis. The field of fungal diagnostics has some tests that are relatively simple, rapid to perform and are potentially suitable at the point of care. However, there are also more complex high-technology methodologies that offer new opportunities regarding the scale and precision of fungal diagnosis, but may be more limited in their portability and affordability. Future developments in this field are increasingly incorporating new technologies provided by the use of new format biosensors. This overview provides a critical review of current fungal diagnostics and the development of new biophysical technologies that are being applied for selective new sensitive fungal biosensors to augment traditional diagnostic methodologies.
Abstract.
Yilmazer B, Isupov MN, De Rose SA, Bulut H, Benninghoff JC, Binay B, Littlechild JA (2020). Structural insights into the NAD+-dependent formate dehydrogenase mechanism revealed from the NADH complex and the formate NAD+ ternary complex of the Chaetomium thermophilum enzyme. Journal of Structural Biology, 212(3), 107657-107657.
Wang Q, Jiang M, Isupov MN, Chen Y, Littlechild JA, Sun L, Wu X, Wang Q, Yang W, Chen L, et al (2020). The crystal structure of Arabidopsis BON1 provides insights into the copine protein family.
Plant J,
103(3), 1215-1232.
Abstract:
The crystal structure of Arabidopsis BON1 provides insights into the copine protein family.
The Arabidopsis thaliana BON1 gene product is a member of the evolutionary conserved eukaryotic calcium-dependent membrane-binding protein family. The copine protein is composed of two C2 domains (C2A and C2B) followed by a vWA domain. The BON1 protein is localized on the plasma membrane, and is known to suppress the expression of immune receptor genes and to positively regulate stomatal closure. The first structure of this protein family has been determined to 2.5-Å resolution and shows the structural features of the three conserved domains C2A, C2B and vWA. The structure reveals the third Ca2+ -binding region in C2A domain is longer than classical C2 domains and a novel Ca2+ binding site in the vWA domain. The structure of BON1 bound to Mn2+ is also presented. The binding of the C2 domains to phospholipid (PSF) has been modeled and provides an insight into the lipid-binding mechanism of the copine proteins. Furthermore, the selectivity of the separate C2A and C2B domains and intact BON1 to bind to different phospholipids has been investigated, and we demonstrated that BON1 could mediate aggregation of liposomes in response to Ca2+. These studies have formed the basis of further investigations into the important role that the copine proteins play in vivo.
Abstract.
Author URL.
Cutlan R, De Rose S, Isupov MN, Littlechild JA, Harmer NJ (2020). Using enzyme cascades in biocatalysis: Highlight on transaminases and carboxylic acid reductases. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 1868(2), 140322-140322.
2019
Finnigan W, Cutlan R, Snajdrova R, Adams J, Littlechild J, Harmer NJ (2019). Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts. ChemCatChem
finnigan W, Cutlan R, Snajdrova R, Adams J, Littlechild J, Harmer NJ (2019). Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts (dataset).
Finnigan W, Cutlan R, Snajdrova R, Adams JP, Littlechild JA, Harmer NJ (2019). Engineering a seven enzyme biotransformation using mathematical modelling and characterized enzyme parts.
Kalibala R (2019). Investigation into Human Erythrocyte Peroxiredoxin 2 : S-Nitrosation and Interaction with Haemoglobin.
Abstract:
Investigation into Human Erythrocyte Peroxiredoxin 2 : S-Nitrosation and Interaction with Haemoglobin
The most abundant intracellular protein in erythrocytes is haemoglobin (Hb) and the third most abundant protein is peroxiredoxin 2 (Prx2). Prx2 exists in both dimeric and decameric form; its dimeric form has two cysteines (Cys) redox active sites. The presence of the two redox-active Cys sites means that Prx2 possesses free thiols, which can react with reactive nitrogen species to form S-nitrosothiols. The function of Prx2 is not completely understood, although it is thought to be an antioxidant by virtue of its peroxidase activity. Prx2 may play a central role in protecting Hb against oxidative damage and mediating some of the key functions of Hb. Nitric oxide (NO) exerts numerous important physiological functions in biological systems including vasodilation in humans. Because of the short-lived nature of NO, S-nitrosothiols (RSNOs) are believed to act as stable NO carriers.
This study hypothesises a model highlighting possible interactions between NO and Hb, and the HbNO complex and Prx2. In this model, NO is produced upon nitrite reduction by deoxyHb, NO equivalents are transferred to the Cys residues of Prx2 forming S-nitrosoperoxiredoxin (Prx2-SNO). The proximity of Prx2 to Hb promotes S-nitrosothiol formation in Prx2 and avoids the scavenging of NO by Hb itself.
This study also describes the purification of the native hPrx2, and the over-expression and purification of hPrx2 in various forms, as well as the subsequent crystallisation and X-ray diffraction studies. The calibrated gel filtration column confirmed that hPrx2 is mainly produced in the decameric form. Purification of native hPrx2 isolated from human red blood cells (RBCs) was successfully achieved using FFQ Sepharose and gel filtration chromatography (Superdex 200). The recombinant hPrx2 DNA cloned in pET28q was transformed into a competent E.coli Rosetta Gami 2 cell line. The purified recombinant hPrx2 protein was achieved using nickel affinity and gel filtration column chromatography. S-nitrosated Prx2 (Prx2-SNO) was achieved by incubation of Prx2 with S-nitrosoglutathione (GSNO) under differing experimental conditions. The mixing of hPrx2 and Hb in various molar ratios, demonstrated a significant specific protein-protein interaction between a Prx2 decamer with an Hb tetramer. The complex binding results from size exclusion chromatography showed that decameric Prx2 bound to Hb in a 1:1 ratio.
This study also describes the post-modification of hPrx2 cysteine residues, and the nitration of tyrosine residues attained by the incubation of protein with GSNO. The incubation of the recombinant hPrx2 protein with GSNO altered the oligomeric state of hPrx2 into a dimer formation. The gas-phase chemiluminescence, gel filtration chromatography, Saville assay, Western-blot, UV-vis spectrophotometry and LC-MS/MS, confirmed the post-modifications of the protein residues.
This research reports the purification and characterization of the stable; native hPrx2, recombinant hPrx2, hPrx2-SNO, and SNO-Hb proteins necessary to perform the hypothesised interactions, to allow us to understand the transnitrosation process that could occur between hPrx2 and Hb. The study also describes the crystallisation conditions for hPrx2-Hb complex and the co-crystallisation conditions for hPrx2-SNO and [hPrx2-SNO]Hb complex
Abstract.
Jiang M, Sun L, Isupov MN, Littlechild JA, Wu X, Wang Q, Wang Q, Yang W, Wu Y (2019). Structural basis for the Target DNA recognition and binding by the MYB domain of phosphate starvation response 1.
FEBS J,
286(14), 2809-2821.
Abstract:
Structural basis for the Target DNA recognition and binding by the MYB domain of phosphate starvation response 1.
The phosphate starvation response 1 (PHR1) protein has a central role in mediating the response to phosphate starvation in plants. PHR1 is composed of a number of domains including a MYB domain involved with DNA binding and a coiled-coil domain proposed to be involved with dimer formation. PHR1 binds to the promoter of phosphate starvation-induced genes to control the levels of phosphate required for nutrition. Previous studies have shown that both the MYB domain and the coiled-coil domain of PHR1 are required for binding the target DNA. Here, we describe the crystal structure of the PHR1 MYB domain and two structures of its complex with the PHR1-binding DNA sequence (P1BS). Structural and isothermal titration calorimetry has been carried out showing that the MYB domain of PHR1 alone is sufficient for target DNA recognition and binding. Two copies of the PHR1 MYB domain bind to the same major groove of the P1BS DNA with few direct interactions between the individual MYB domains. In addition, the PHR1 MYB-P1BS DNA complex structures reveal amino acid residues involved in DNA recognition and binding. Mutagenesis of these residues results in lost or impaired ability of PHR1 MYB to bind to its target DNA. The results presented reveal the structural basis for DNA recognition by the PHR1 MYB domain and demonstrate that two PHR1 MYB domains attach to their P1BS DNA targeting sequence. DATABASE: Coordinates and structure factors have been deposited in the Protein Data Bank under accession codes 6J4K (PHR1 MYB), 6J4R (PHR1 MYB-R-P1BS), 6J5B (MYB-CC-R2-P1BS).
Abstract.
Author URL.
Isupov MN, James P, Littlechild JA (2019). Thermostable Branched-Chain Amino Acid Transaminases from the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization. Front. Bioeng. Biotechnol, 7, 7-7.
Isupov MN, Boyko KM, Sutter J-M, James P, Sayer C, Schmidt M, Schonheit P, Nikolaeva AY, Stekhanova TN, Mardanov AV, et al (2019). Thermostable Branched-Chain Amino Acid Transaminases from the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization (vol 7, 7, 2019).
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY,
7 Author URL.
Westlake A (2019). Thermostable Enzymes Important for Industrial Biotechnology.
Abstract:
Thermostable Enzymes Important for Industrial Biotechnology
The use of enzymes in technology is of increasing commercial interest due to their high catalytic efficiency and specificity and the lowering of manufacturing costs. Enzymes are also becoming more widely utilised because they are more environmentally friendly compared to chemical methods. Firstly, they carry out their reactions at ambient temperatures requiring less energy to achieve the high temperatures and pressures that many chemical methods require. Secondly, they can substitute for toxic chemical catalysts which need careful disposal. In this project two classes of enzymes of industrial interest from thermophiles were investigated, lactonase enzymes and 1-deoxy-D-xylulose 5-phosphate (DXP) synthases.
A quorum sensing lactonase from Vulcanisaeta moutnovskia, a thermoacidophilic anaerobic crenarchaeon, was expressed in high levels in an Escherichia coli host, then purified and characterised with a range of industrially relevant substrates. These enzymes are of industrial interest for water treatment and bioreactors for their ability to prevent biofilm formation in bacteria. This enzyme showed different specificity to another well characterised quorum sensing lactonase from a thermophilic crenarchaeon, Sulfolobus solfataricus. Crystals of the native enzyme were obtained. Structural examination revealed that the V. moutnovskia lactonase possesses an α-helix obstructing a hydrophobic channel near the active site, whereas the S. solfataricus lactonase has a flexible loop leaving the hydrophobic channel unrestricted. As a result the acyl chains of substrates interact with surface residues of the α-helix in V. moutnovskia lactonase rather than sitting in the channel, so its activity is no longer restricted to substrates with long acyl chains.
A gluconolactonase encoded by a thermophilic Planctomyces genome was cloned and expressed at high levels in an E. coli host, purified and successfully crystallised. The crystals had a space group of P 3 2 1 and diffracted to a resolution of 2.41 Å. This enzyme was intended to be used by an industrial partner for synthesis of metabolite standards for mass spectrometry and diagnostics. Attempts were made to clone, purify and express two other lactonases from thermophilic metagenomes obtained from terrestrial hot springs: an enol lactonase and a second quorum sensing lactonase. Homology modelling was used to create predicted structures for both of these enzymes. The quorum sensing lactonase showed a 2.5 Å difference in the position of a catalytic serine and a 3.1 Å difference in a catalytic histidine in comparison to a mesophilic homologue. The enol lactonase contained an aspartic acid in place of a catalytic serine found in a mesophilic homologue.
A DXP synthase from an anaerobic Gram-negative bacterium Thermovibrio ammonificans was successfully cloned, over-expressed and purified. Crystals were successfully produced although these diffracted only to low resolution. A DXP synthase from an anaerobic Gram-positive bacterium Carboxydothermus hydroformans was successfully cloned, however the protein was expressed primarily in the insoluble fraction. Homology models were made for these two enzymes. Both enzymes showed strong similarity with mesophilic DXP synthases in terms of tertiary structure and positions of active site residues. Visual analysis revealed an increase of 15-20 % in the number of hydrophobic interactions within the enzymes and a high proportion of charged residues at the dimer interface, which would confer increased thermostability. The hope was to obtain high resolution diffraction data to assist in understanding what allows these enzymes to utilise pyruvate as a substrate compared to transketolase, a related enzyme, which uses hydroxypyruvate.
Abstract.
Line K, Isupov MN, LaCourse EJ, Cutress DJ, Morphew RM, Brophy PM, Littlechild JA (2019). X-ray structure of Fasciola hepatica Sigma class glutathione transferase 1 reveals a disulfide bond to support stability in gastro-intestinal environment.
Scientific Reports,
9(1).
Abstract:
X-ray structure of Fasciola hepatica Sigma class glutathione transferase 1 reveals a disulfide bond to support stability in gastro-intestinal environment
Sigma class GST (Prostaglandin D synthase), FhGST-S1, is present in the excretory–secretory products (ES) of the liver fluke parasite Fasciola hepatica as cargo of extracellular vesicles (EVs) released by the parasite. FhGST-S1 has a well characterised role in the modulation of the immune response; a key fluke intercession that allows for establishment and development within their hosts. We have resolved the three-dimensional structure of FhGST-S1 in complex with its co-factor glutathione, in complex with a glutathione-cysteine adduct, and in a glutathione disulfide complex in order to initiate a research pipeline to mechanistically understand how FhGST-S1 functions within the host environment and to rationally design selective inhibitors. The overall fold of FhGST-S1 shows high structural similarity to other Sigma class GSTs. However, a unique interdomain disulfide bond was found in the FhGST-S1 which could stabilise the structure within the host gastro-intestinal environment. The position of the two domains of the protein with respect to each other is seen to be crucial in the formation of the active site cleft of the enzyme. The interdomain disulfide bond raises the possibility of oxidative regulation of the active site of this GST protein.
Abstract.
2018
Knight AR, Taylor EL, Lukaszewski R, Winyard PG (2018). A high-sensitivity electrochemiluminescence-based ELISA for the measurement of the oxidative stress biomarker, 3-nitrotyrosine, in human blood serum and cells. Free Radical Biology and Medicine
Wohlgemuth R, Littlechild J, Monti D, Schnorr K, van Rossum T, Siebers B, Menzel P, Kublanov IV, Rike AG, Skretas G, et al (2018). Discovering novel hydrolases from hot environments.
Biotechnol Adv,
36(8), 2077-2100.
Abstract:
Discovering novel hydrolases from hot environments.
Novel hydrolases from hot and other extreme environments showing appropriate performance and/or novel functionalities and new approaches for their systematic screening are of great interest for developing new processes, for improving safety, health and environment issues. Existing processes could benefit as well from their properties. The workflow, based on the HotZyme project, describes a multitude of technologies and their integration from discovery to application, providing new tools for discovering, identifying and characterizing more novel thermostable hydrolases with desired functions from hot terrestrial and marine environments. To this end, hot springs worldwide were mined, resulting in hundreds of environmental samples and thousands of enrichment cultures growing on polymeric substrates of industrial interest. Using high-throughput sequencing and bioinformatics, 15 hot spring metagenomes, as well as several sequenced isolate genomes and transcriptomes were obtained. To facilitate the discovery of novel hydrolases, the annotation platform Anastasia and a whole-cell bioreporter-based functional screening method were developed. Sequence-based screening and functional screening together resulted in about 100 potentially new hydrolases of which more than a dozen have been characterized comprehensively from a biochemical and structural perspective. The characterized hydrolases include thermostable carboxylesterases, enol lactonases, quorum sensing lactonases, gluconolactonases, epoxide hydrolases, and cellulases. Apart from these novel thermostable hydrolases, the project generated an enormous amount of samples and data, thereby allowing the future discovery of even more novel enzymes.
Abstract.
Author URL.
Ferrandi EE, Sayer C, De Rose SA, Guazzelli E, Marchesi C, Saneei V, Isupov MN, Littlechild JA, Monti D (2018). New thermophilic α/β class epoxide hydrolases found in metagenomes from hot environments.
Frontiers in Bioengineering and Biotechnology,
6(OCT).
Abstract:
New thermophilic α/β class epoxide hydrolases found in metagenomes from hot environments
Two novel epoxide hydrolases (EHs), Sibe-EH and CH65-EH, were identified in the metagenomes of samples collected in hot springs in Russia and China, respectively. The two α/β hydrolase superfamily fold enzymes were cloned, over-expressed in Escherichia coli, purified and characterized. The new EHs were active toward a broad range of substrates, and in particular, Sibe-EH was excellent in the desymmetrization of cis-2,3-epoxybutane producing the (2R,3R)-diol product with ee exceeding 99%. Interestingly these enzymes also hydrolyse (4R)-limonene-1,2-epoxide with Sibe-EH being specific for the trans isomer. The Sibe-EH is a monomer in solution whereas the CH65-EH is a dimer. Both enzymes showed high melting temperatures with the CH65-EH being the highest at 85°C retaining 80% of its initial activity after 3 h thermal treatment at 70°C making it the most thermal tolerant wild type epoxide hydrolase described. The Sibe-EH and CH65-EH have been crystallized and their structures determined to high resolution, 1.6 and 1.4 Å, respectively. The CH65-EH enzyme forms a dimer via its cap domains with different relative orientation of the monomers compared to previously described EHs. The entrance to the active site cavity is located in a different position in CH65-EH and Sibe-EH in relation to other known bacterial and mammalian EHs.
Abstract.
Petrova TE, Boyko KM, Nikolaeva AY, Stekhanova TN, Gruzdev EV, Mardanov AV, Stroilov VS, Littlechild JA, Popov VO, Bezsudnova EY, et al (2018). Structural characterization of geranylgeranyl pyrophosphate synthase GACE1337 from the hyperthermophilic archaeon Geoglobus acetivorans.
Extremophiles,
22(6), 877-888.
Abstract:
Structural characterization of geranylgeranyl pyrophosphate synthase GACE1337 from the hyperthermophilic archaeon Geoglobus acetivorans.
A novel type 1 geranylgeranyl pyrophosphate synthase GACE1337 has been identified within the genome of a newly identified hyperthermophilic archaeon Geoglobus acetivorans. The enzyme has been cloned and over-expressed in Escherichia coli. The recombinant enzyme has been biochemically and structurally characterized. It is able to catalyze the synthesis of geranylgeranyl pyrophosphate as a major product and of farnesyl pyrophosphate in smaller amounts, as measured by gas chromatography-mass spectrometry at an elevated temperature of 60 °C. Its ability to produce two products is consistent with the fact that GACE1337 is the only short-chain isoprenyl diphosphate synthase in G. acetivorans. Attempts to crystallize the enzyme were successful only at 37 °C. The three-dimensional structure of GACE1337 was determined by X-ray diffraction to 2.5 Å resolution. A comparison of its structure with those of related enzymes revealed that the Geoglobus enzyme has the features of both type I and type III geranylgeranyl pyrophosphate synthases, which allow it to regulate the product length. The active enzyme is a dimer and has three aromatic amino acids, two Phe, and a Tyr, located in the hydrophobic cleft between the two subunits. It is proposed that these bulky residues play a major role in the synthetic reaction by controlling the product elongation.
Abstract.
Author URL.
Isupov MN, Schröder E, Gibson RP, Beecher J, Donadio G, Saneei V, Dcunha SA, McGhie EJ, Sayer C, Davenport CF, et al (2018). The oxygenating constituent of 3,6-diketocamphane monooxygenase from the CAM plasmid of Pseudomonas putida: the first crystal structure of a type II Baeyer-Villiger monooxygenase. Corrigendum.
Acta Crystallogr D Struct Biol,
74(Pt 4).
Abstract:
The oxygenating constituent of 3,6-diketocamphane monooxygenase from the CAM plasmid of Pseudomonas putida: the first crystal structure of a type II Baeyer-Villiger monooxygenase. Corrigendum.
A statement is amended in the article by Isupov et al. [(2015). Acta Cryst. D71, 2344-2353].
Abstract.
Author URL.
Littlechild J (2018). Thermophilic enzymes for synthetic biology in vivo and in vitro cascades.
Author URL.
2017
Littlechild JA, Isupov MN (2017). Comments to Article by Willetts A. et al. Microorganisms 2016, 4, 38.
Microorganisms,
5(3).
Abstract:
Comments to Article by Willetts A. et al. Microorganisms 2016, 4, 38.
We would like to comment on recent work published in your journal in October 2016 by Willetts A. et al. [1].[. ].
Abstract.
Author URL.
Antranikian G, Suleiman M, Schäfers C, Adams MWW, Bartolucci S, Blamey JM, Birkeland N-K, Bonch-Osmolovskaya E, da Costa MS, Cowan D, et al (2017). Diversity of bacteria and archaea from two shallow marine hydrothermal vents from Vulcano Island.
Extremophiles,
21(4), 733-742.
Abstract:
Diversity of bacteria and archaea from two shallow marine hydrothermal vents from Vulcano Island.
To obtain new insights into community compositions of hyperthermophilic microorganisms, defined as having optimal growth temperatures of 80 °C and above, sediment and water samples were taken from two shallow marine hydrothermal vents (I and II) with temperatures of 100 °C at Vulcano Island, Italy. A combinatorial approach of denaturant gradient gel electrophoresis (DGGE) and metagenomic sequencing was used for microbial community analyses of the samples. In addition, enrichment cultures, growing anaerobically on selected polysaccharides such as starch and cellulose, were also analyzed by the combinatorial approach. Our results showed a high abundance of hyperthermophilic archaea, especially in sample II, and a comparable diverse archaeal community composition in both samples. In particular, the strains of the hyperthermophilic anaerobic genera Staphylothermus and Thermococcus, and strains of the aerobic hyperthermophilic genus Aeropyrum, were abundant. Regarding the bacterial community, ε-Proteobacteria, especially the genera Sulfurimonas and Sulfurovum, were highly abundant. The microbial diversity of the enrichment cultures changed significantly by showing a high dominance of archaea, particularly the genera Thermococcus and Palaeococcus, depending on the carbon source and the selected temperature.
Abstract.
Author URL.
de Rose SA, Novak H, Dowd A, Singh S, Lang DA, Littlechild J (2017). Stabilization of a lipolytic enzyme for commercial application.
Catalysts,
7(3).
Abstract:
Stabilization of a lipolytic enzyme for commercial application
Thermomyces lanouginosa lipase has been used to develop improved methods for carrier-free immobilization, the Cross-Linked Enzyme Aggregates (CLEAs), for its application in detergent products. An activator step has been introduced to the CLEAs preparation process with the addition of Tween 80 as activator molecule, in order to obtain a higher number of the individual lipase molecules in the “open lid” conformation prior to the cross-linking step. A terminator step has been introduced to quench the cross-linking reaction at an optimal time by treatment with an amine buffer in order to obtain smaller and more homogenous cross-linked particles. This improved immobilization method has been compared to a commercially available enzyme and has been shown to be made up of smaller and more homogenous particles with an average diameter of 1.85 ± 0.28 µm which are 129.7% more active than the free enzyme. The CLEAs produced show improved features for commercial applications such as an improved wash performance comparable with the free enzyme, improved stability to proteolysis and a higher activity after long-term storage.
Abstract.
2016
Finnigan W, Thomas A, Cromar H, Gough B, Snajdrova R, Adams JP, Littlechild JA, Harmer NJ (2016). Characterization of carboxylic acid reductases as enzymes in the toolbox for synthetic chemistry. ChemCatChem, in press
Zarafeta D, Kissas D, Sayer C, Gudbergsdottir SR, Ladoukakis E, Isupov MN, Chatziioannou A, Peng X, Littlechild JA, Skretas G, et al (2016). Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate.
PLoS One,
11(1).
Abstract:
Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate.
With the ultimate goal of identifying robust cellulases for industrial biocatalytic conversions, we have isolated and characterized a new thermostable and very halotolerant GH5 cellulase. This new enzyme, termed CelDZ1, was identified by bioinformatic analysis from the genome of a polysaccharide-enrichment culture isolate, initiated from material collected from an Icelandic hot spring. Biochemical characterization of CelDZ1 revealed that it is a glycoside hydrolase with optimal activity at 70°C and pH 5.0 that exhibits good thermostability, high halotolerance at near-saturating salt concentrations, and resistance towards metal ions and other denaturing agents. X-ray crystallography of the new enzyme showed that CelDZ1 is the first reported cellulase structure that lacks the defined sugar-binding 2 subsite and revealed structural features which provide potential explanations of its biochemical characteristics.
Abstract.
Author URL.
Littlechild J (2016). Novel enzymes from metagenomics.
Author URL.
sayer C, Finnigan W, Isupov MN, Levisson M, Kengen SWM, van der Oost J, Harmer NJ, Littlechild JA (2016). Structural and biochemical characterisation of Archaeoglobus fulgidus esterase reveals a bound CoA molecule in the vicinity of the active site.
Scientific Reports,
6, 25542-25542.
Abstract:
Structural and biochemical characterisation of Archaeoglobus fulgidus esterase reveals a bound CoA molecule in the vicinity of the active site
A new carboxyl esterase, AF-Est2, from the hyperthermophilic archaeon Archaeoglobus
fulgidus has been cloned, over-expressed in Escherichia coli and biochemically and
structurally characterized. The enzyme has high activity towards short- to medium-chain pnitrophenyl
carboxylic esters with optimal activity towards the valerate ester. The AF-Est2
has good solvent and pH stability and is very thermostable, showing no loss of activity after
incubation for 30 min at 80 °C. The 1.4 Å resolution crystal structure of AF-Est2 reveals
Coenzyme a (CoA) bound in the vicinity of the active site. Despite the presence of CoA
bound to the AF-Est2 this enzyme has no CoA thioesterase activity. The pantetheine group of
CoA partially obstructs the active site alcohol pocket suggesting that this ligand has a role in
regulation of the enzyme activity. A comparison with closely related α/β hydrolase fold
2
enzyme structures shows that the AF-Est2 has unique structural features that allow CoA
binding. A comparison of the structure of AF-Est2 with the human carboxyl esterase 1, which
has CoA thioesterase activity, reveals that CoA is bound to different parts of the core domain
in these two enzymes and approaches the active site from opposite directions.
Abstract.
2015
Littlechild JA (2015). Archaeal Enzymes and Applications in Industrial Biocatalysts.
Archaea,
2015, 1-10.
Abstract:
Archaeal Enzymes and Applications in Industrial Biocatalysts
Archaeal enzymes are playing an important role in industrial biotechnology. Many representatives of organisms living in “extreme” conditions, the so-called Extremophiles, belong to the archaeal kingdom of life. This paper will review studies carried by the Exeter group and others regarding archaeal enzymes that have important applications in commercial biocatalysis. Some of these biocatalysts are already being used in large scale industrial processes for the production of optically pure drug intermediates and amino acids and their analogues. Other enzymes have been characterised at laboratory scale regarding their substrate specificity and properties for potential industrial application. The increasing availability of DNA sequences from new archaeal species and metagenomes will provide a continuing resource to identify new enzymes of commercial interest using both bioinformatics and screening approaches.
Abstract.
Ferrandi EE, Sayer C, Isupov MN, Annovazzi C, Marchesi C, Iacobone G, Peng X, Bonch-Osmolovskaya E, Wohlgemuth R, Littlechild JA, et al (2015). Discovery and characterization of thermophilic limonene-1,2-epoxide hydrolases from hot spring metagenomic libraries.
FEBS J,
282(15), 2879-2894.
Abstract:
Discovery and characterization of thermophilic limonene-1,2-epoxide hydrolases from hot spring metagenomic libraries.
The epoxide hydrolases (EHs) represent an attractive option for the synthesis of chiral epoxides and 1,2-diols which are valuable building blocks for the synthesis of several pharmaceutical compounds. A metagenomic approach has been used to identify two new members of the atypical EH limonene-1,2-epoxide hydrolase (LEH) family of enzymes. These two LEHs (Tomsk-LEH and CH55-LEH) show EH activities towards different epoxide substrates, differing in most cases from those previously identified for Rhodococcus erythropolis (Re-LEH) in terms of stereoselectivity. Tomsk-LEH and CH55-LEH, both from thermophilic sources, have higher optimal temperatures and apparent melting temperatures than Re-LEH. The new LEH enzymes have been crystallized and their structures solved to high resolution in the native form and in complex with the inhibitor valpromide for Tomsk-LEH and poly(ethylene glycol) for CH55-LEH. The structural analysis has provided insights into the LEH mechanism, substrate specificity and stereoselectivity of these new LEH enzymes, which has been supported by mutagenesis studies.
Abstract.
Author URL.
Littlechild JA (2015). Enzymes from Extreme Environments and Their Industrial Applications.
Front Bioeng Biotechnol,
3Abstract:
Enzymes from Extreme Environments and Their Industrial Applications.
This article will discuss the importance of specific extremophilic enzymes for applications in industrial biotechnology. It will specifically address those enzymes that have applications in the area of biocatalysis. Such enzymes now play an important role in catalyzing a variety of chemical conversions that were previously carried out by traditional chemistry. The biocatalytic process is carried out under mild conditions and with greater specificity. The enzyme process does not result in the toxic waste that is usually produced in a chemical process that would require careful disposal. In this sense, the biocatalytic process is referred to as carrying out "green chemistry" which is considered to be environmentally friendly. Some of the extremophilic enzymes to be discussed have already been developed for industrial processes such as an l-aminoacylase and a γ-lactamase. The industrial applications of other extremophilic enzymes, including transaminases, carbonic anhydrases, dehalogenases, specific esterases, and epoxide hydrolases, are currently being assessed. Specific examples of these industrially important enzymes that have been studied in the authors group will be presented in this review.
Abstract.
Author URL.
Sayer C, Isupov MN, Bonch-Osmolovskaya E, Littlechild JA (2015). Structural studies of a thermophilic esterase from a new Planctomycetes species, Thermogutta terrifontis.
FEBS J,
282(15), 2846-2857.
Abstract:
Structural studies of a thermophilic esterase from a new Planctomycetes species, Thermogutta terrifontis.
Thermogutta terrifontis esterase (TtEst), a carboxyl esterase identified in the novel thermophilic bacterium T. terrifontis from the phylum Planctomycetes, has been cloned and over-expressed in Escherichia coli. The enzyme has been characterized biochemically and shown to have activity towards small p-nitrophenyl (pNP) carboxylic esters, with optimal activity for pNP-propionate. The enzyme retained 95% activity after incubation for 1 h at 80 °C. The crystal structures of the native TtEst and its complexes with the substrate analogue D-malate and the product acetate have been determined to high resolution. The bound ligands have allowed the identification of the carboxyl and alcohol binding pockets in the enzyme active site. Comparison of TtEst with structurally related enzymes provides insight into how differences in their catalytic activity can be rationalized based upon the properties of the amino acid residues in their active site pockets. The mutant enzymes L37A and L251A have been constructed to extend the substrate range of TtEst towards the larger butyrate and valerate pNP-esters. These mutant enzymes have also shown a significant increase in activity towards acetate and propionate pNP esters. A crystal structure of the L37A mutant was determined with the butyrate product bound in the carboxyl pocket of the active site. The mutant structure shows an expansion of the pocket that binds the substrate carboxyl group, which is consistent with the observed increase in activity towards pNP-butyrate.
Abstract.
Author URL.
Sayer C, Szabo Z, Isupov MN, Ingham C, Littlechild JA (2015). The Structure of a Novel Thermophilic Esterase from the Planctomycetes Species, Thermogutta terrifontis Reveals an Open Active Site Due to a Minimal 'Cap' Domain.
Front Microbiol,
6Abstract:
The Structure of a Novel Thermophilic Esterase from the Planctomycetes Species, Thermogutta terrifontis Reveals an Open Active Site Due to a Minimal 'Cap' Domain.
A carboxyl esterase (TtEst2) has been identified in a novel thermophilic bacterium, Thermogutta terrifontis from the phylum Planctomycetes and has been cloned and over-expressed in Escherichia coli. The enzyme has been characterized biochemically and shown to have activity toward small p-nitrophenyl (pNP) carboxylic esters with optimal activity for pNP-acetate. The enzyme shows moderate thermostability retaining 75% activity after incubation for 30 min at 70°C. The crystal structures have been determined for the native TtEst2 and its complexes with the carboxylic acid products propionate, butyrate, and valerate. TtEst2 differs from most enzymes of the α/β-hydrolase family 3 as it lacks the majority of the 'cap' domain and its active site cavity is exposed to the solvent. The bound ligands have allowed the identification of the carboxyl pocket in the enzyme active site. Comparison of TtEst2 with structurally related enzymes has given insight into how differences in their substrate preference can be rationalized based upon the properties of their active site pockets.
Abstract.
Author URL.
Isupov MN, Schröder E, Gibson RP, Beecher J, Donadio G, Saneei V, Dcunha SA, McGhie EJ, Sayer C, Davenport CF, et al (2015). The oxygenating constituent of 3,6-diketocamphane monooxygenase from the CAM plasmid of Pseudomonas putida: the first crystal structure of a type II Baeyer-Villiger monooxygenase.
Acta Crystallogr D Biol Crystallogr,
71(Pt 11), 2344-2353.
Abstract:
The oxygenating constituent of 3,6-diketocamphane monooxygenase from the CAM plasmid of Pseudomonas putida: the first crystal structure of a type II Baeyer-Villiger monooxygenase.
The three-dimensional structures of the native enzyme and the FMN complex of the overexpressed form of the oxygenating component of the type II Baeyer-Villiger 3,6-diketocamphane monooxygenase have been determined to 1.9 Å resolution. The structure of this dimeric FMN-dependent enzyme, which is encoded on the large CAM plasmid of Pseudomonas putida, has been solved by a combination of multiple anomalous dispersion from a bromine crystal soak and molecular replacement using a bacterial luciferase model. The orientation of the isoalloxazine ring of the FMN cofactor in the active site of this TIM-barrel fold enzyme differs significantly from that previously observed in enzymes of the bacterial luciferase-like superfamily. The Ala77 residue is in a cis conformation and forms a β-bulge at the C-terminus of β-strand 3, which is a feature observed in many proteins of this superfamily.
Abstract.
Author URL.
2014
Novak HR, Sayer C, Isupov MN, Gotz D, Spragg AM, Littlechild JA (2014). Biochemical and structural characterisation of a haloalkane dehalogenase from a marine Rhodobacteraceae.
FEBS Lett,
588(9), 1616-1622.
Abstract:
Biochemical and structural characterisation of a haloalkane dehalogenase from a marine Rhodobacteraceae.
A putative haloalkane dehalogenase has been identified in a marine Rhodobacteraceae and subsequently cloned and over-expressed in Escherichia coli. The enzyme has highest activity towards the substrates 1,6-dichlorohexane, 1-bromooctane, 1,3-dibromopropane and 1-bromohexane. The crystal structures of the enzyme in the native and product bound forms reveal a large hydrophobic active site cavity. A deeper substrate binding pocket defines the enzyme preference towards substrates with longer carbon chains. Arg136 at the bottom of the substrate pocket is positioned to bind the distal halogen group of extended di-halogenated substrates.
Abstract.
Author URL.
Kallnik V, Bunescu A, Sayer C, Bräsen C, Wohlgemuth R, Littlechild J, Siebers B (2014). Characterization of a phosphotriesterase-like lactonase from the hyperthermoacidophilic crenarchaeon Vulcanisaeta moutnovskia.
J Biotechnol,
190, 11-17.
Abstract:
Characterization of a phosphotriesterase-like lactonase from the hyperthermoacidophilic crenarchaeon Vulcanisaeta moutnovskia.
The phosphotriesterase-like lactonase (PLL) encoded by Vmut_2255 in the hyperthermoacidophilic crenarchaeon Vulcanisaeta moutnovskia (VmutPLL), represents the only hyperthermophilic PLL homologue identified so far in addition to the previously characterized thermophilic PLLs from Sulfolobus spp. The Vmut_2255 gene was cloned, heterologously expressed in Escherichia coli; the resultant protein purified and characterized as a 82kDa homodimer (36kDa subunits). The VmutPLL converted lactones and acyl-homoserine lactones (AHLs) with comparable activities. Towards organophosphates (OP) VmutPLL showed a promiscuous but significantly lower activity and only minor activity was observed with carboxylesters. The catalytic activity strictly depended on bivalent cations (Cd(2+)>Ni(2+)>Co(2+)>Mn(2+)>Zn(2+)). Furthermore, VmutPLL showed a pH optimum around 8.0, a temperature optimum of 80°C, and thermostability with a half-life of 26min at 90°C. In this work, the stereoselectivity of a PLL enzyme was investigated for the first time using enantiopure lactones. The VmutPLL showed a slight preference but not an exclusive specificity for the (R)-enantiomers of capro- and valerolactone. The high thermal stability as well as the broad substrate spectrum towards lactones, AHLs and OPs underlines the high biotechnological potential of VmutPLL.
Abstract.
Author URL.
Vivoli M, Novak HR, Littlechild JA, Harmer NJ (2014). Determination of Protein-ligand Interactions Using Differential Scanning Fluorimetry. Journal of Visualized Experiments(91).
Vivoli M, Novak HR, Littlechild JA, Harmer NJ (2014). Determination of protein-ligand interactions using differential scanning fluorimetry.
J Vis Exp(91).
Abstract:
Determination of protein-ligand interactions using differential scanning fluorimetry.
A wide range of methods are currently available for determining the dissociation constant between a protein and interacting small molecules. However, most of these require access to specialist equipment, and often require a degree of expertise to effectively establish reliable experiments and analyze data. Differential scanning fluorimetry (DSF) is being increasingly used as a robust method for initial screening of proteins for interacting small molecules, either for identifying physiological partners or for hit discovery. This technique has the advantage that it requires only a PCR machine suitable for quantitative PCR, and so suitable instrumentation is available in most institutions; an excellent range of protocols are already available; and there are strong precedents in the literature for multiple uses of the method. Past work has proposed several means of calculating dissociation constants from DSF data, but these are mathematically demanding. Here, we demonstrate a method for estimating dissociation constants from a moderate amount of DSF experimental data. These data can typically be collected and analyzed within a single day. We demonstrate how different models can be used to fit data collected from simple binding events, and where cooperative binding or independent binding sites are present. Finally, we present an example of data analysis in a case where standard models do not apply. These methods are illustrated with data collected on commercially available control proteins, and two proteins from our research program. Overall, our method provides a straightforward way for researchers to rapidly gain further insight into protein-ligand interactions using DSF.
Abstract.
Author URL.
Littlechild J, Isupov M (2014). Haloperoxidase enzymes as 'redox catalysts' important for industrial biocatalysis. In (Ed)
Recent Advances in Redox Active Plant and Microbial Products: from Basic Chemistry to Widespread Applications in Medicine and Agriculture, 425-446.
Abstract:
Haloperoxidase enzymes as 'redox catalysts' important for industrial biocatalysis
Abstract.
Littlechild J, Sayer C, Isupov M, Ward J, Littlechild J (2014). Structural studies on transaminase enzymes and applications in biocatalysis.
NEW BIOTECHNOLOGY,
31, S19-S19.
Author URL.
James P, Isupov MN, Sayer C, Saneei V, Berg S, Lioliou M, Kotlar HK, Littlechild JA (2014). The structure of a tetrameric α-carbonic anhydrase from Thermovibrio ammonificans reveals a core formed around intermolecular disulfides that contribute to its thermostability.
Acta Crystallogr D Biol Crystallogr,
70(Pt 10), 2607-2618.
Abstract:
The structure of a tetrameric α-carbonic anhydrase from Thermovibrio ammonificans reveals a core formed around intermolecular disulfides that contribute to its thermostability.
Carbonic anhydrase enzymes catalyse the reversible hydration of carbon dioxide to bicarbonate. A thermophilic Thermovibrio ammonificans α-carbonic anhydrase (TaCA) has been expressed in Escherichia coli and structurally and biochemically characterized. The crystal structure of TaCA has been determined in its native form and in two complexes with bound inhibitors. The tetrameric enzyme is stabilized by a unique core in the centre of the molecule formed by two intersubunit disulfides and a single lysine residue from each monomer that is involved in intersubunit ionic interactions. The structure of this core protects the intersubunit disulfides from reduction, whereas the conserved intrasubunit disulfides are not formed in the reducing environment of the E. coli host cytosol. When oxidized to mimic the environment of the periplasmic space, TaCA has increased thermostability, retaining 90% activity after incubation at 70°C for 1â€
h, making it a good candidate for industrial carbon-dioxide capture. The reduction of all TaCA cysteines resulted in dissociation of the tetrameric molecule into monomers with lower activity and reduced thermostability. Unlike other characterized α-carbonic anhydrases, TaCA does not display esterase activity towards p-nitrophenyl acetate, which appears to result from the increased rigidity of its protein scaffold.
Abstract.
Author URL.
Sayer C, Martinez-Torres RJ, Richter N, Isupov MN, Hailes HC, Littlechild JA, Ward JM (2014). The substrate specificity, enantioselectivity and structure of the (R)-selective amine : pyruvate transaminase from Nectria haematococca.
FEBS J,
281(9), 2240-2253.
Abstract:
The substrate specificity, enantioselectivity and structure of the (R)-selective amine : pyruvate transaminase from Nectria haematococca.
UNLABELLED: During the last decade the use of transaminases for the production of pharmaceutical and fine chemical intermediates has attracted a great deal of attention. Transaminases are versatile biocatalysts for the efficient production of amine intermediates and many have (S)-enantiospecificity. Transaminases with (R)-specificity are needed to expand the applications of these enzymes in biocatalysis. In this work we have identified a fungal putative (R)-specific transaminase from the Eurotiomycetes Nectria haematococca, cloned a synthetic version of this gene, demonstrated (R)-selective deamination of several substrates including (R)-α-methylbenzylamine, as well as production of (R)-amines, and determined its crystal structure. The crystal structures of the holoenzyme and the complex with an inhibitor gabaculine offer the first detailed insight into the structural basis for substrate specificity and enantioselectivity of the industrially important class of (R)-selective amine : pyruvate transaminases. DATABASE: the atomic coordinates and structure factors for the Nectria TAm in holoenzyme and gabaculine-bound forms have been deposited in the PDB as entries 4cmd and 4cmf respectively.
Abstract.
Author URL.
2013
Novak H, Littlechild J (2013). 4 Marine enzymes with applications for biosynthesis of fine chemicals. In (Ed) Marine Enzymes for Biocatalysis, 89-106.
Holley JE, Slonka J, Littlechild J, Gutowski NJ (2013). An investigation into the presence of pyroglutamyl peptidases in the Alzheimer's disease brain: relevance to pathology?.
JOURNAL OF NEUROLOGY,
260, S167-S167.
Author URL.
Littlechild JA (2013). Chapter 2 Protein structure and function. In (Ed) Introduction to Biological and Small Molecule Drug Research and Development, 57-79.
Novak HR, Sayer C, Panning J, Littlechild JA (2013). Characterisation of an L-haloacid dehalogenase from the marine psychrophile Psychromonas ingrahamii with potential industrial application.
Mar Biotechnol (NY),
15(6), 695-705.
Abstract:
Characterisation of an L-haloacid dehalogenase from the marine psychrophile Psychromonas ingrahamii with potential industrial application.
The recombinant L-haloacid dehalogenase from the marine bacterium Psychromonas ingrahamii has been cloned and over-expressed in Escherichia coli. It shows activity towards monobromoacetic (100 %), monochloroacetic acid (62 %), S-chloropropionic acid (42 %), S-bromopropionic acid (31 %), dichloroacetic acid (28 %) and 2-chlorobutyric acid (10 %), respectively. The L-haloacid dehalogenase has highest activity towards substrates with shorter carbon chain lengths (≤ C3), without preference towards a chlorine or bromine at the α-carbon position. Despite being isolated from a psychrophilic bacterium, the enzyme has mesophilic properties with an optimal temperature for activity of 45 °C. It retains above 70 % of its activity after being incubated at 65 °C for 90 min before being assayed at 25 °C. The enzyme is relatively stable in organic solvents as demonstrated by activity and thermal shift analysis. The V max and K m were calculated to be 0.6 μM min(-1) mg(-1) and 1.36 mM with monobromoacetic acid, respectively. This solvent-resistant and stable L-haloacid dehalogenase from P. ingrahamii has potential to be used as a biocatalyst in industrial processes.
Abstract.
Author URL.
Novak HR, Sayer C, Panning J, Littlechild JA (2013). Characterisation of an l-Haloacid Dehalogenase from the Marine Psychrophile Psychromonas ingrahamii with Potential Industrial Application.
Marine Biotechnology,
15(6), 695-705.
Abstract:
Characterisation of an l-Haloacid Dehalogenase from the Marine Psychrophile Psychromonas ingrahamii with Potential Industrial Application
The recombinant l-haloacid dehalogenase from the marine bacterium Psychromonas ingrahamii has been cloned and over-expressed in Escherichia coli. It shows activity towards monobromoacetic (100 %), monochloroacetic acid (62 %), S-chloropropionic acid (42 %), S-bromopropionic acid (31 %), dichloroacetic acid (28 %) and 2-chlorobutyric acid (10 %), respectively. The l-haloacid dehalogenase has highest activity towards substrates with shorter carbon chain lengths (≤C3), without preference towards a chlorine or bromine at the α-carbon position. Despite being isolated from a psychrophilic bacterium, the enzyme has mesophilic properties with an optimal temperature for activity of 45 °C. It retains above 70 % of its activity after being incubated at 65 °C for 90 min before being assayed at 25 °C. The enzyme is relatively stable in organic solvents as demonstrated by activity and thermal shift analysis. The V max and K m were calculated to be 0.6 μM min-1 mg-1 and 1.36 mM with monobromoacetic acid, respectively. This solvent-resistant and stable l-haloacid dehalogenase from P. ingrahamii has potential to be used as a biocatalyst in industrial processes. © 2013 Springer Science+Business Media New York.
Abstract.
Hill A, Littlechild J (2013). ChemInform Abstract: Oxidation. Haloperoxidases. ChemInform, 44(25), no-no.
Reid EL, Weynberg KD, Love J, Isupov MN, Littlechild JA, Wilson WH, Kelly SL, Lamb DC, Allen MJ (2013). Functional and structural characterisation of a viral cytochrome b5.
FEBS Lett,
587(22), 3633-3639.
Abstract:
Functional and structural characterisation of a viral cytochrome b5.
Cytochrome b5 is a ubiquitous electron transport protein. The sequenced viral OtV-2 genome, which infects Ostreococcus tauri, was predicted to encode a putative cytochrome b5 enzyme. Using purified OtV-2 cytochrome b5 we confirm this protein has identical spectral properties to purified human cytochrome b5 and additionally that the viral enzyme can substitute for yeast cytochrome b5 in yeast cytochrome P450 51 mediated sterol 14α-demethylation. The crystal structure of the OtV-2 cytochrome b5 enzyme reveals a single domain, comprising four β sheets, four α helices and a haem moiety, which is similar to that found in larger eukaryotic cytochrome proteins. As a product of a horizontal gene transfer event involving a subdomain of the host fumarate reductase-like protein, OtV-2 cytochrome b5 appears to have diverged in function and is likely to have evolved an entirely new role for the virus during infection. Indeed, lacking a hydrophobic C-terminal anchor, OtV-2 encodes the first cytosolic cytochrome b5 characterised. The lack of requirement for membrane attachment (in contrast to all other microsomal cytochrome b5s) may be a reflection of the small size of the host cell, further emphasizes the unique nature of this virus gene product and draws attention to the potential importance of cytochrome b5 metabolic activity at the extremes of cellular scale.
Abstract.
Author URL.
Novak HR, Sayer C, Isupov MN, Paszkiewicz K, Gotz D, Spragg AM, Littlechild JA (2013). Marine Rhodobacteraceae L-haloacid dehalogenase contains a novel His/Glu dyad that could activate the catalytic water.
FEBS J,
280(7), 1664-1680.
Abstract:
Marine Rhodobacteraceae L-haloacid dehalogenase contains a novel His/Glu dyad that could activate the catalytic water.
The putative L-haloacid dehalogenase gene (DehRhb) from a marine Rhodobacteraceae family was cloned and overexpressed in Escherichia coli. The DehRhb protein was shown to be an L-haloacid dehalogenase with highest activity towards brominated substrates with short carbon chains (≤ C3). The optimal temperature for enzyme activity was 55 °C, and the Vmax and Km were 1.75 μm·min(-1) ·mg(-1) of protein and 6.72 mm, respectively, when using monobromoacetic acid as a substrate. DehRhb showed moderate thermal stability, with a melting temperature of 67 °C. The enzyme demonstrated high tolerance to solvents, as shown by thermal shift experiments and solvent incubation assays. The DehRhb protein was crystallized and structures of the native, reaction intermediate and substrate-bound forms were determined. The active site of DehRhb had significant differences from previously studied L-haloacid dehalogenases. The asparagine and arginine residues shown to be essential for catalytic activity in other L-haloacid dehalogenases are not present in DehRhb. The histidine residue which replaces the asparagine residue in DehRhb was coordinated by a conformationally strained glutamate residue that replaces a conserved glycine. The His/Glu dyad is positioned for deprotonation of the catalytic water which attacks the ester bond in the reaction intermediate. The catalytic water in DehRhb is shifted by ~ 1.5 Å from its position in other L-haloacid dehalogenases. A similar His/Glu or Asp dyad is known to activate the catalytic water in haloalkane dehalogenases. The DehRhb enzyme represents a novel member within the L-haloacid dehalogenase family and it has potential to be used as a commercial biocatalyst.
Abstract.
Author URL.
Novak H, Littlechild J (2013). Marine enzymes with applications for biosynthesis of fine chemicals.
, 89-106.
Abstract:
Marine enzymes with applications for biosynthesis of fine chemicals
This chapter will discuss the application of enzymes to carry out biotransformation reactions for the synthesis of building blocks of new drugs within the fine chemicals industry. It will concentrate on the marine environment to discover novel enzymes that have applications in this important area of substainable chemistry. Marine enzymes that have been cloned and isolated from bacteria, archaea, macro algae and viruses will be used to illustrate specific examples and applications. These enzyme activities include haloperoxidases, dehalogenases, alcohol dehydrogenases, L-aminoacylases, proteases, esterases and lipases. The biochemical and structural studies on these marine enzymes will be described in relation to their mechanism of action and evolutionary diversity with regards to related enzymes. © 2013 Woodhead Publishing Limited. All rights reserved.
Abstract.
James PBC, sayer C, Novak H, Littlechild JA (2013). Mechanisms of Thermal Stability Adopted by Thermophilic Proteins and Their Use in White Biotechnology. In Littlechild JA, Satyanarayana T, Kawarabayasi Y (Eds.) Thermophilic Microbes in Environmental and Industrial Biotechnology, Springer Netherlands, 481-507.
Satyanarayana T, Littlechild J, Kawarabayasi Y (2013). Preface.
Littlechild JA (2013). Protein structure and function.
, 57-79.
Abstract:
Protein structure and function
This chapter covers the general features of protein structure and recent advances in structural bioinformatics. The importance of the three-dimensional structure of the protein target in order to understand its mechanism of action as an aid for drug design is illustrated by specific examples of enzyme inhibition, receptor interactions and drugs binding to structural proteins. The impact of proteomics and bioinformatics is stressed, while protein interactions with other proteins and different biological macromolecules are discussed. © 2013 Elsevier Ltd all rights reserved.
Abstract.
Sayer C, Isupov MN, Westlake A, Littlechild JA (2013). Structural studies of Pseudomonas and Chromobacterium ω-aminotransferases provide insights into their differing substrate specificity.
Acta Crystallogr D Biol Crystallogr,
69(Pt 4), 564-576.
Abstract:
Structural studies of Pseudomonas and Chromobacterium ω-aminotransferases provide insights into their differing substrate specificity.
The crystal structures and inhibitor complexes of two industrially important ω-aminotransferase enzymes from Pseudomonas aeruginosa and Chromobacterium violaceum have been determined in order to understand the differences in their substrate specificity. The two enzymes share 30% sequence identity and use the same amino acceptor, pyruvate; however, the Pseudomonas enzyme shows activity towards the amino donor β-alanine, whilst the Chromobacterium enzyme does not. Both enzymes show activity towards S-α-methylbenzylamine (MBA), with the Chromobacterium enzyme having a broader substrate range. The crystal structure of the P. aeruginosa enzyme has been solved in the holo form and with the inhibitor gabaculine bound. The C. violaceum enzyme has been solved in the apo and holo forms and with gabaculine bound. The structures of the holo forms of both enzymes are quite similar. There is little conformational difference observed between the inhibitor complex and the holoenzyme for the P. aeruginosa aminotransferase. In comparison, the crystal structure of the C. violaceum gabaculine complex shows significant structural rearrangements from the structures of both the apo and holo forms of the enzyme. It appears that the different rigidity of the protein scaffold contributes to the substrate specificity observed for the two ω-aminotransferases.
Abstract.
Author URL.
2012
Hill A, Littlechild J (2012). 7.15 Oxidation: Haloperoxidases.
,
7, 329-349.
Abstract:
7.15 Oxidation: Haloperoxidases
This chapter describes the different natural enzymes that have been discovered that can specifically halogenate organic compounds and that have applications in biotransformation reactions. Specific halogenation of a compound can change its chemical and biological properties. There are many naturally halogenated compounds that have been isolated from both marine and terrestrial environments and some examples are presented. Many of these compounds have properties that are of interest to the pharmaceutical industry since they have antibacterial or anticancer activities. This chapter summarizes the enzymes discovered to date and discusses their properties. They include heme haloperoxidases, nonheme iron-dependent halogenases, vanadium haloperoxidases, flavin-dependent haloperoxidases, noncofactor-containing bacterial haloperoxidases, S-adenosyl-. l-methionine-dependent chlorinases and fluorinases, and methyl halide transferases. These enzymes are unrelated structurally and use different mechanisms to achieve their chemical reactions. The known applications of well-studied enzymes are discussed alongside potential applications of more recently discovered enzymes for white biotechnology. © 2012 Elsevier Ltd. All rights reserved.
Abstract.
Fraser CS, Rubio-Cabezas O, Littlechild JA, Ellard S, Hattersley AT, Flanagan SE (2012). Amino acid properties may be useful in predicting clinical outcome in patients with Kir6.2 neonatal diabetes.
Eur J Endocrinol,
167(3), 417-421.
Abstract:
Amino acid properties may be useful in predicting clinical outcome in patients with Kir6.2 neonatal diabetes.
BACKGROUND: Mutations in the KCNJ11 gene, which encodes the Kir6.2 subunit of the β-cell K(ATP) channel, are a common cause of neonatal diabetes. The diabetes may be permanent neonatal diabetes mellitus (PNDM) or transient neonatal diabetes mellitus (TNDM), and in ≈ 20% of patients, neurological features are observed. A correlation between the position of the mutation in the protein and the clinical phenotype has previously been described; however, recently, this association has become less distinct with different mutations at the same residues now reported in patients with different diabetic and/or neurological phenotypes. METHODS: We identified from the literature, and our unpublished series, KCNJ11 mutations that affected residues harbouring various amino acid substitutions (AAS) causing differences in diabetic or neurological status. Using the Grantham amino acid scoring system, we investigated whether the difference in properties between the wild-type and the different AAS at the same residue could predict phenotypic severity. RESULTS: Pair-wise analysis demonstrated higher Grantham scores for mutations causing PNDM or diabetes with neurological features when compared with mutations affecting the same residue that causes TNDM (P=0.013) or diabetes without neurological features (P=0.016) respectively. In just five of the 25 pair-wise analyses, a lower Grantham score was observed for the more severe phenotype. In each case, the wild-type residue was glycine, the simplest amino acid. CONCLUSION: This study demonstrates the importance of the specific AAS in determining phenotype and highlights the potential utility of the Grantham score for predicting phenotypic severity for novel KCNJ11 mutations affecting previously mutated residues.
Abstract.
Author URL.
Sayer C, Bommer M, Isupov M, Ward J, Littlechild J (2012). Crystal structure and substrate specificity of the thermophilic serine:pyruvate aminotransferase from Sulfolobus solfataricus.
Acta Crystallographica Section D: Biological Crystallography,
68(7), 763-772.
Abstract:
Crystal structure and substrate specificity of the thermophilic serine:pyruvate aminotransferase from Sulfolobus solfataricus
The three-dimensional structure of the Sulfolobus solfataricus serine:pyruvate aminotransferase has been determined to 1.8 Å resolution. The structure of the protein is a homodimer that adopts the type I fold of pyridoxal 5′-phosphate (PLP)-dependent aminotransferases. The structure revealed the PLP cofactor covalently bound in the active site to the active-site lysine in the internal aldimine form. The structure of the S. solfataricus enzyme was also determined with an amino form of the cofactor pyridoxamine 5′-phosphate bound in the active site and in complex with gabaculine, an aminotransferase inhibitor. These structures showed the changes in the enzyme active site during the course of the catalytic reaction. A comparison of the structure of the S. solfataricus enzyme with that of the closely related alanine:glyoxylate aminotransferase has identified structural features that are proposed to be responsible for the differences in substrate specificity between the two enzymes. These results have been complemented by biochemical studies of the substrate specificity and thermostability of the S. solfataricus enzyme. © 2012 International Union of Crystallography. Printed in Singapore - all rights reserved.
Abstract.
Littlechild JA, Greenway G, Watts P, Hickey AM, Ngamsom B (2012). Immobilised Enzymes and Co-Factors.
Szabo-Taylor KE, Eggleton P, Turner CAL, Lo Faro ML, Tarr JM, Toth S, Whiteman M, Haigh RC, Littlechild JA, Winyard PG, et al (2012). Lymphocytes from rheumatoid arthritis patients have elevated levels of intracellular peroxiredoxin 2, and a greater frequency of cells with exofacial peroxiredoxin 2, compared with healthy human lymphocytes.
INTERNATIONAL JOURNAL OF BIOCHEMISTRY & CELL BIOLOGY,
44(8), 1223-1231.
Author URL.
Littlechild JA, Hill A (2012). Oxidation:Haloperoxidases. In Carreira EM, Yamamoto H (Eds.)
Comprehensive Chirality, Amsterdam: Elsevier, 329-349.
Abstract:
Oxidation:Haloperoxidases
Abstract.
2011
Reid EL, Worthy CA, Probert I, Ali ST, Love J, Napier J, Littlechild JA, Somerfield PJ, Allen MJ (2011). Coccolithophores: functional biodiversity, enzymes and bioprospecting.
Mar Drugs,
9(4), 586-602.
Abstract:
Coccolithophores: functional biodiversity, enzymes and bioprospecting.
Emiliania huxleyi is a single celled, marine phytoplankton with global distribution. As a key species for global biogeochemical cycling, a variety of strains have been amassed in various culture collections. Using a library consisting of 52 strains of E. huxleyi and an 'in house' enzyme screening program, we have assessed the functional biodiversity within this species of fundamental importance to global biogeochemical cycling, whilst at the same time determining their potential for exploitation in biocatalytic applications. Here, we describe the screening of E. huxleyi strains, as well as a coccolithovirus infected strain, for commercially relevant biocatalytic enzymes such as acid/alkali phosphodiesterase, acid/alkali phosphomonoesterase, EC1.1.1-type dehydrogenase, EC1.3.1-type dehydrogenase and carboxylesterase.
Abstract.
Author URL.
Littlechild JA (2011). Thermophilic archaeal enzymes and applications in biocatalysis.
Biochem Soc Trans,
39(1), 155-158.
Abstract:
Thermophilic archaeal enzymes and applications in biocatalysis.
Thermophilic enzymes have advantages for their use in commercial applications and particularly for the production of chiral compounds to produce optically pure pharmaceuticals. They can be used as biocatalysts in the application of 'green chemistry'. The thermophilic archaea contain enzymes that have already been used in commercial applications such as the L-aminoacylase from Thermococcus litoralis for the resolution of amino acids and amino acid analogues. This enzyme differs from bacterial L-aminoacylases and has similarities to carboxypeptidases from other archaeal species. An amidase/γ-lactamase from Sulfolobus solfataricus has been used for the production of optically pure γ-lactam, the building block for antiviral carbocyclic nucleotides. This enzyme has similarities to the bacterial signature amidase family. An alcohol dehydrogenase from Aeropyrum pernix has been used for the production of optically pure alcohols and is related to the zinc-containing eukaryotic alcohol dehydrogenases. A transaminase and a dehalogenase from Sulfolobus species have also been studied. The archaeal transaminase is found in a pathway for serine synthesis which is found only in eukaryotes and not in bacteria. It can be used for the asymmetric synthesis of homochiral amines of high enantioselective purity. The L-2-haloacid dehalogenase has applications both in biocatalysis and in bioremediation. All of these enzymes have increased thermostability over their mesophilic counterparts.
Abstract.
Author URL.
2010
Wilson RA, Gibson RP, Quispe CF, Littlechild JA, Talbot NJ (2010). An NADPH-dependent genetic switch regulates plant infection by the rice blast fungus.
Proc Natl Acad Sci U S A,
107(50), 21902-21907.
Abstract:
An NADPH-dependent genetic switch regulates plant infection by the rice blast fungus.
To cause rice blast disease, the fungus Magnaporthe oryzae breaches the tough outer cuticle of the rice leaf by using specialized infection structures called appressoria. These cells allow the fungus to invade the host plant and proliferate rapidly within leaf tissue. Here, we show that a unique NADPH-dependent genetic switch regulates plant infection in response to the changing nutritional and redox conditions encountered by the pathogen. The biosynthetic enzyme trehalose-6-phosphate synthase (Tps1) integrates control of glucose-6-phosphate metabolism and nitrogen source utilization by regulating the oxidative pentose phosphate pathway, the generation of NADPH, and the activity of nitrate reductase. We report that Tps1 directly binds to NADPH and, thereby, regulates a set of related transcriptional corepressors, comprising three proteins, Nmr1, Nmr2, and Nmr3, which can each bind NADP. Targeted deletion of any of the Nmr-encoding genes partially suppresses the nonpathogenic phenotype of a Δtps1 mutant. Tps1-dependent Nmr corepressors control the expression of a set of virulence-associated genes that are derepressed during appressorium-mediated plant infection. When considered together, these results suggest that initiation of rice blast disease by M. oryzae requires a regulatory mechanism involving an NADPH sensor protein, Tps1, a set of NADP-dependent transcriptional corepressors, and the nonconsuming interconversion of NADPH and NADP acting as signal transducer.
Abstract.
Author URL.
TAYLOR SJC, MCCAGUE R, WISDOM R, LEE C, DICKSON K, RUECROFT G, O'BRIEN F, LITTLECHILD J, BEVAN J, ROBERTS SM, et al (2010). ChemInform Abstract: Development of the Biocatalytic Resolution of 2â€Azabicyclo(2.2.1)hept†5â€enâ€3â€one as an Entry to Singleâ€Enantiomer Carbocyclic Nucleosides. ChemInform, 24(41), no-no.
Opperman DJ, Sewell BT, Litthauer D, Isupov MN, Littlechild JA, van Heerden E (2010). Crystal structure of a thermostable old yellow enzyme from Thermus scotoductus SA-01.
Biochem Biophys Res Commun,
393(3), 426-431.
Abstract:
Crystal structure of a thermostable old yellow enzyme from Thermus scotoductus SA-01.
Recent characterization of the chromate reductase (CrS) from the thermophile Thermus scotoductus SA-01 revealed this enzyme to be related to the Old Yellow Enzyme (OYE) family. Here, we report the structure of a thermostable OYE homolog in its holoform at 2.2A as well as its complex with p-hydroxybenzaldehyde (pHBA). The enzyme crystallized as octamers with the monomers showing a classical TIM barrel fold which upon dimerization yields the biologically active form of the protein. A sulfate ion is bound above the si-side of the non-covalently bound FMN cofactor in the oxidized solved structure but is displaced upon pHBA binding. The active-site architecture is highly conserved as with other members of this enzyme family. The pHBA in the CrS complex is positioned by hydrogen bonding to the two conserved catalytic-site histidines. The most prominent structural difference between CrS and other OYE homologs is the size of the "capping domain". Thermostabilization of the enzyme is achieved in part through increased proline content within loops and turns as well as increased intersubunit interactions through hydrogen bonding and complex salt bridge networks. CrS is able to reduce the C=C bonds of alpha,beta-unsaturated carbonyl compounds with a preference towards cyclic substrates however no activity was observed towards beta-substituted substrates. Mutational studies have confirmed the role of Tyr177 as the proposed proton donor although reduction could still occur at a reduced rate when this residue was mutated to phenylalanine.
Abstract.
Author URL.
Ngamsom B, Hickey AM, Greenway GM, Littlechild JA, Watts P, Wiles C (2010). Development of a high throughput screening tool for biotransformations utilising a thermophilic l-aminoacylase enzyme.
Journal of Molecular Catalysis B: Enzymatic,
63(1-2), 81-86.
Abstract:
Development of a high throughput screening tool for biotransformations utilising a thermophilic l-aminoacylase enzyme
Micro-reactors containing a monolith-immobilised thermophilic l-aminoacylase, from Thermococcus litoralis, have been developed for use in biotransformation reactions and a study has been carried out to investigate the stereospecificity and stability of the immobilised enzyme. The potential to use the developed micro-reactors as a tool for rapid screening of enzyme specificity was demonstrated, confirming that the l-aminoacylase showed a similar substrate specificity to that previously reported of the free enzyme. From this baseline, the technique was employed as a tool to evaluate potential unreported substrates with N-benzoyl- (l-threonine, l-leucine and l-arginine) and N-acetyl- (d,l-serine, d,l-leucine, l-tyrosine and l-lysine) protecting groups. The order of preferred substrates was found to be Phe > Thr > Leu > Arg for N-benzoyl substrates and Phe ≫ Ser > Leu > Met > Tyr > Trp for N-acetyl substrates. It was found that by using the micro-reactor a significantly smaller quantity of enzyme and substrates was required. It was shown that the micro-reactors were still operational in the presence of selected organic solvents, such as ethanol, methanol, acetone, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results indicated that a combination of a small amount of an appropriate solvent (5% DMSO) and a higher reaction temperature could be employed in biotransformations where substrate solubility was an issue. © 2009 Elsevier B.V. All rights reserved.
Abstract.
Szabo-Taylor KE, Lo Faro ML, Eggleton P, Turner CAL, Tarr JM, Haigh RC, Littlechild JA, Whiteman M, Winyard PG (2010). Peroxiredoxin 2 in Human Inflammatory Joint Disease.
Author URL.
Ngamsom B, Hickey AM, Greenway GM, Littlechild JA, McCreedy T, Watts P, Wiles C (2010). The development and evaluation of a conducting matrix for the electrochemical regeneration of the immobilised co-factor NAD(H) under continuous flow.
Org Biomol Chem,
8(10), 2419-2424.
Abstract:
The development and evaluation of a conducting matrix for the electrochemical regeneration of the immobilised co-factor NAD(H) under continuous flow.
Through the preparation of a novel controlled pore glass-poly(pyrrole) material we have developed a conducting support that is not only suitable for the co-immobilisation of enzymes and co-factors, but also enables the facile electrochemical regeneration of the co-factor during a reaction. Employing the selective reduction of (rac)-2-phenylpropionaldehyde to (S)-phenyl-1-propanol as a model, we have demonstrated the successful co-immobilisation of the HLADH enzyme and co-factor NAD(H); with incorporation of the material into a continuous flow reactor facilitating the in situ electrochemical regeneration of NAD(H) for in excess of 100 h. Using this approach we have developed a reagent-less, atom efficient system applicable to the cost-effective, continuous biosynthesis of chiral compounds.
Abstract.
Author URL.
Willies S, Isupov M, Littlechild J (2010). Thermophilic enzymes and their applications in biocatalysis: a robust aldo-keto reductase.
Environ Technol,
31(10), 1159-1167.
Abstract:
Thermophilic enzymes and their applications in biocatalysis: a robust aldo-keto reductase.
Extremophiles are providing a good source of novel robust enzymes for use in biocatalysis for the synthesis of new drugs. This is particularly true for the enzymes from thermophilic organisms which are more robust than their mesophilic counterparts to the conditions required for industrial bio-processes. This paper describes a new aldo-keto reductase enzyme from a thermophilic eubacteria, Thermotoga maritima which can be used for the production of primary alcohols. The enzyme has been cloned and over-expressed in Escherichia coli and has been purified and subjected to full biochemical characterization. The aldo-keto reductase can be used for production of primary alcohols using substrates including benzaldehyde, 1,2,3,6-tetrahydrobenzaldehyde and para-anisaldehyde. It is stable up to 80 degrees C, retaining over 60% activity for 5 hours at this temperature. The enzyme at pH 6.5 showed a preference for the forward, carbonyl reduction. The enzyme showed moderate stability with organic solvents, and retained 70% activity in 20% (v/v) isopropanol or DMSO. These properties are favourable for its potential industrial applications.
Abstract.
Author URL.
2009
Hickey AM, Ngamsom B, Wiles C, Greenway GM, Watts P, Littlechild JA (2009). A microreactor for the study of biotransformations by a cross-linked gamma-lactamase enzyme.
Biotechnol J,
4(4), 510-516.
Abstract:
A microreactor for the study of biotransformations by a cross-linked gamma-lactamase enzyme.
A (+)-gamma-lactamase was precipitated, cross-linked and the resulting solid crushed prior to immobilisation within a capillary column microreactor. The microreactor was subsequently used to study enzyme stability, activity, kinetics and substrate specificity. The thermophilic (+)-gamma-lactamase retained 100% of its initial activity at the assay temperature, 80 degrees C, for 6 h and retained 52% activity after 10 h, indicating the advantage of immobilisation. This high stability of the immobilised enzyme provided the advantage that it could be utilised to screen many compounds in the microreactor system. This advantage overcame the fact that the immobilisation process affected enzyme kinetics and activity, which was reduced (by 70%) compared to the free enzyme. In general, the enzyme displayed similar substrate specificity to that found in a previous study for the free enzyme; however, enhanced activity was seen towards one substrate, acrylamide. The system developed correlates well with the free enzyme in batch assay and indicates the suitability of the system for enzyme substrate screening, allowing a significant reduction in cost, due to the reduced amounts of enzyme, substrates and other assay constituents required.
Abstract.
Author URL.
Rye CA, Isupov MN, Lebedev AA, Littlechild JA (2009). Biochemical and structural studies of a L-haloacid dehalogenase from the thermophilic archaeon Sulfolobus tokodaii.
Extremophiles,
13(1), 179-190.
Abstract:
Biochemical and structural studies of a L-haloacid dehalogenase from the thermophilic archaeon Sulfolobus tokodaii.
Haloacid dehalogenases have potential applications in the pharmaceutical and fine chemical industry as well as in the remediation of contaminated land. The L: -2-haloacid dehalogenase from the thermophilic archaeon Sulfolobus tokodaii has been cloned and over-expressed in Escherichia coli and successfully purified to homogeneity. Here we report the structure of the recombinant dehalogenase solved by molecular replacement in two different crystal forms. The enzyme is a homodimer with each monomer being composed of a core-domain of a beta-sheet bundle surrounded by alpha-helices and an alpha-helical sub-domain. This fold is similar to previously solved mesophilic L: -haloacid dehalogenase structures. The monoclinic crystal form contains a putative inhibitor L: -lactate in the active site. The enzyme displays haloacid dehalogenase activity towards carboxylic acids with the halide attached at the C2 position with the highest activity towards chloropropionic acid. The enzyme is thermostable with maximum activity at 60 degrees C and a half-life of over 1 h at 70 degrees C. The enzyme is relatively stable to solvents with 25% activity lost when incubated for 1 h in 20% v/v DMSO.
Abstract.
Author URL.
Turner CA, Szabo KE, Haigh R, Tarr J, Littlechild JA, Eggleton P, Winyard PG (2009). EXPRESSION OF THE PEROXIREDOXIN-BASED ANTIOXIDANT SYSTEM IN PERIPHERAL BLOOD LYMPHOCYTES IN RHEUMATOID ARTHRITIS.
Author URL.
Gutowski NJ, Watson EL, Holley JE, Winyard PG, Littlechild JA (2009). Peroxiredoxin II: an antioxidant with therapeutic potential in multiple sclerosis?.
Author URL.
Szabo K, Gutowski NJ, Holley JE, Littlechild JA, Winyard P (2009). Redox Control in Human Disease with a Special Emphasis on the Peroxiredoxin-Based Antioxidant System. In Jacob C, Winyard PG (Eds.)
Redox signaling and regulation in biology and medicine, Vch Verlagsgesellschaft Mbh, 409-431.
Abstract:
Redox Control in Human Disease with a Special Emphasis on the Peroxiredoxin-Based Antioxidant System
Abstract.
Szabo KE, Line K, Eggleton P, Littlechild JA, Winyard P (2009). Structure and Function of the Human Peroxiredoxin-Based Antioxidant System:the Interplay between Peroxiredoxins,Thioredoxins,Thioredoxin Reductases,Sulfiredoxins and Sestrins. In Jacob C, Winyard PG (Eds.)
Redox signaling and regulation in biology and medicine, Vch Verlagsgesellschaft Mbh, 143-174.
Abstract:
Structure and Function of the Human Peroxiredoxin-Based Antioxidant System:the Interplay between Peroxiredoxins,Thioredoxins,Thioredoxin Reductases,Sulfiredoxins and Sestrins
Abstract.
Szabo KE, Line K, Eggleton P, Littlechild JA, Winyard PG (2009). Structure and function of the human peroxiredoxin-based antioxidant system: the interplay between peroxierdoxins, thioredoxins, thioredoxin reductases, sulfiredoxins and sestrins. In Jacob C, Winyard PG (Eds.) Redox Signaling and Regulation in Biology and Medicine, Weinheim, Germany: Wiley-VCH.
Willies SC, Isupov MN, Garman EF, Littlechild JA (2009). The binding of haem and zinc in the 1.9 a X-ray structure of Escherichia coli bacterioferritin.
J Biol Inorg Chem,
14(2), 201-207.
Abstract:
The binding of haem and zinc in the 1.9 a X-ray structure of Escherichia coli bacterioferritin.
The crystal structure of Escherichia coli bacterioferritin has been solved to 1.9 A, and shows the symmetrical binding of a haem molecule on the local twofold axis between subunits and a pair of metal atoms bound to each subunit at the ferroxidase centre. These metals have been identified as zinc by the analysis of the structure and X-ray data and confirmed by microfocused proton-induced X-ray emission experiments. For the first time the haem has been shown to be linked to both the internal and the external environments via a cluster of waters positioned above the haem molecule.
Abstract.
Author URL.
Littlechild J (2009). Thermophilic enzymes as stable biocatalysts.
NEW BIOTECHNOLOGY,
25, S108-S108.
Author URL.
Littlechild J, Garcia Rodriguez E, Isupov M (2009). Vanadium containing bromoperoxidase--insights into the enzymatic mechanism using X-ray crystallography.
J Inorg Biochem,
103(4), 617-621.
Abstract:
Vanadium containing bromoperoxidase--insights into the enzymatic mechanism using X-ray crystallography.
The X-ray crystal structure of the vanadium bromoperoxidase from the red algae Corallina pilulifera has been solved in the presence of the known substrates, phenol red and phloroglucinol. A putative substrate binding site has been observed in the active site channel of the enzyme. In addition bromide has been soaked into the crystals and it has been shown to bind unambiguously within the enzyme active site by using the technique of single anomalous dispersion. A specific leucine amino acid is seen to move towards the bromide ion in the wild-type enzyme to produce a hydrophobic environment within the active site. A mutant of the enzyme where arginine 397 has been changed to tryptophan, shows a different behaviour on bromide binding. These results have increased our understanding of the mechanism of the vanadium bromoperoxidases and have demonstrated that the substrate and bromide are specifically bound to the enzyme active site.
Abstract.
Author URL.
2008
Littlechild J (2008). Catalyst for improvement.
EBR - European Biopharmaceutical Review(SUMM), 27-32.
Abstract:
Catalyst for improvement
The use of enzymes in industrial bioprocesses is becoming increasingly important. This is partially driven by the pharmaceutical sector in the development of new therapeutic agents that are required to be enantiomerically pure compounds. Enzymes are able to carry out reactions using both regio- and stereo-specificity. Often drug molecules are large molecules with several chiral centres. The complexity of these molecules requires that their production by catalytic methods encompasses several enzymatic steps. These molecules can often be difficult to synthesise by conventional chemical synthesis, and frequently a combination of chemical and biocatalytic steps is used. One benefit to using enzymes is that the chemistry is carried out in an environmentally friendly manner with fewer toxic waste products that require careful disposal. The new drug molecules and intermediates produced by biocatalytic methods result in the production of new and safer products due to their homochirality. This is beneficial both to the general public and to the pharmaceutical companies.
Abstract.
Ward S, Macgowan A, Roberts S, Littlechild JA, Line K, Irving E, Donnelly S (2008). Derivatives of 18Beta-Glycyrrhetinic Acid.
Szabo K, Tarr J, Eggleton P, Line K, Ryan B, Aksu K, Akcay Y, Haigh R, Littlechild J, Winyard P, et al (2008). Extracellular peroxiredoxin II in rheumatoid arthritis and other autoimmune conditions.
Author URL.
Ngamsom B, Marle L, Hickey AM, Greenway GM, Watts P, McCreedy T, Littlechild JA (2008). Immobilisation of thermophilic enzymes within miniaturised flow reactors for biotransformations. AIChE Annual Meeting, Conference Proceedings
Line K, Isupov MN, Garcia-Rodriguez E, Maggioli G, Parra F, Littlechild JA (2008). The Fasciola hepatica thioredoxin: High resolution structure reveals two oxidation states.
Mol Biochem Parasitol,
161(1), 44-48.
Abstract:
The Fasciola hepatica thioredoxin: High resolution structure reveals two oxidation states.
The Fasciola hepatica thioredoxin protein structure has been determined to 1.45A resolution. This is the first example of a single crystal structure to show the active site cysteine residues in both the reduced and disulfide oxidised form. Consistent with this observation the process of oxidation appears to require very little rearrangement of the surrounding protein structure. The F. hepatica thioredoxin structure has been compared to other thioredoxin protein structures already known and is found to be highly conserved. The F. hepatica protein is most similar to that of the thioredoxin from its human and animal hosts but it resembles other parasitic thioredoxins with regard to having no additional cysteine residues and is therefore not regulated by transient disulfide bond formation as proposed for thioredoxins from higher eukaryotic species.
Abstract.
Author URL.
2007
Rye CA, Isupov MN, Lebedev AA, Littlechild JA (2007). An order-disorder twin crystal of L-2-haloacid dehalogenase from Sulfolobus tokodaii.
Acta Crystallogr D Biol Crystallogr,
63(Pt 8), 926-930.
Abstract:
An order-disorder twin crystal of L-2-haloacid dehalogenase from Sulfolobus tokodaii.
The L-2-haloacid dehalogenase enzymes catalyse the hydrolytic cleavage of a halogen from the C2 position of short-chain haloacids. The recombinant dehalogenase from the thermophilic archaeon Sulfolobus tokodaii has been cloned, overexpressed and purified to homogeneity. The 24 kDa enzyme was crystallized using the microbatch method in the monoclinic space group C2, with unit-cell parameters a = 127.6, b = 58.1, c = 51.2 A, beta = 97.2 degrees. Data were collected to 1.9 a resolution using synchrotron radiation and the structure was solved by molecular replacement. Analysis of the data and the preliminary refined model showed that the crystal was an order-disorder twin by reticular merohedry with a twin index of 10. It was possible to de-twin the experimental data utilizing the symmetry of the molecular layers from which the crystal is built.
Abstract.
Author URL.
Battershill C, Bavington C, Chahal S, Jaspars M, Littlechild J, Spragg AM (2007). Contributions of marine bioscience to industrial biotechology.
Industrial Biotechnology,
3(4), 304-313.
Abstract:
Contributions of marine bioscience to industrial biotechology
Industrial Biotechnology assembles international industry leaders to address current topics, in Roundtable Discussions. This issue's Roundtable focuses on marine industrial biotechnology. The Journal gratefully acknowledges the contributions of our panel of experts:.
Abstract.
Sayer C, Isupov MN, Littlechild JA (2007). Crystallization and preliminary X-ray diffraction analysis of omega-amino acid:pyruvate transaminase from Chromobacterium violaceum.
Acta Crystallogr Sect F Struct Biol Cryst Commun,
63(Pt 2), 117-119.
Abstract:
Crystallization and preliminary X-ray diffraction analysis of omega-amino acid:pyruvate transaminase from Chromobacterium violaceum.
The enzyme omega-transaminase catalyses the conversion of chiral omega-amines to ketones. The recombinant enzyme from Chromobacterium violaceum has been purified to homogeneity. The enzyme was crystallized from PEG 4000 using the microbatch method. Data were collected to 1.7 a resolution from a crystal belonging to the triclinic space group P1, with unit-cell parameters a = 58.9, b = 61.9, c = 63.9 A, alpha = 71.9, beta = 87.0, gamma = 74.6 degrees. Data were also collected to 1.95 a from a second triclinic crystal form. The structure has been solved using the molecular-replacement method.
Abstract.
Author URL.
Hickey AM, Marle L, McCreedy T, Watts P, Greenway GM, Littlechild JA (2007). Immobilization of thermophilic enzymes in miniaturized flow reactors.
Biochem Soc Trans,
35(Pt 6), 1621-1623.
Abstract:
Immobilization of thermophilic enzymes in miniaturized flow reactors.
The exploitation of enzymes for biotransformation reactions for the production of new and safer drug intermediates has been the focus of much research. While a number of enzymes are commercially available, their use in an industrial setting is often limited to reactions that are cost-effective and they are rarely investigated further. However, the development of miniaturized flow reactor technology has meant that the cost of such research, once considered cost- and time-inefficient, would be much less prohibitive. The use of miniaturized flow reactors for enzyme screening offers a number of advantages over batch enzyme assay systems. Since the assay is performed on a miniaturized scale, enzyme, substrate and cofactor quantities are significantly reduced, thus reducing the cost of laboratory-scale investigations. Since flow reactors use microfluidic systems, where the substrate and products flow out of the system, the problems of substrate inhibition and product inhibition encountered by some enzymes are avoided. Quite often, enzymes fulfil a single-use function in biotransformation processes; however, enzyme immobilization allows enzyme reuse and often helps to increase enzyme stability. We have used an aminoacylase enzyme with potential use for industrial biotransformation reactions and have successfully immobilized it in miniaturized flow reactors. This L-aminoacylase is from the thermophilic archaeon Thermococcus litoralis. Two approaches to enzyme immobilization have been examined, both involving enzyme cross-linking. The first reactor type has used monoliths, to which the enzyme was attached, and the second contained previously cross-linked enzyme trapped using frits, in the microfluidic channels. Two different microreactor designs were used in the investigation: microreactor chips for the monoliths and capillary flow reactors for the cross-linked enzyme. These systems allowed passage of the substrate and product through the system while retaining the aminoacylase enzyme performing the catalytic conversion. The enzyme has been successfully immobilized and used to produce stable biocatalytic microreactors that can be used repeatedly over a period of several months.
Abstract.
Author URL.
Littlechild JA, Guy J, Connelly S, Mallett L, Waddell S, Rye CA, Line K, Isupov M (2007). Natural methods of protein stabilization: thermostable biocatalysts.
Biochem Soc Trans,
35(Pt 6), 1558-1563.
Abstract:
Natural methods of protein stabilization: thermostable biocatalysts.
Enzymes that are naturally found in thermophilic and hyperthermophilic organisms are being used as robust biocatalysts in the fine chemical and pharmaceutical industries. They have important use in these industries due to their increased stability which is often required during commercial reaction conditions. The approach used in these studies is to learn how nature has managed to stabilize these proteins using a detailed knowledge of their biochemical properties and three-dimensional structures. This is illustrated with several different classes of enzyme that have been studied at Exeter. These include alcohol dehydrogenase, aminoacylase, pyroglutamyl carboxypeptidase, gamma-lactamase, dehalogenase and lysophospholipase.
Abstract.
Author URL.
Littlechild J (2007). Nature's catalysts for biosynthesis of natural products.
AMINO ACIDS,
33(3), XIV-XIV.
Author URL.
Watts P, McCreedy T, Marle L, Littlechild J, Hickey AM, Greenway GM (2007). ORGN 104-The use of immobilized thermophilic enzymes for organic synthesis in flow reactors.
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY,
234 Author URL.
Littlechild JA, Garcia-Rodriguez E, Coupe E, Watts A, Isupov M (2007). Structural Studies of Vanadium Haloperoxidases:Insight into Halide Specificity,Stability and Enzyme Mechanism. In Kustin K, Pessoa JC, Crans D (Eds.) Vanadium:The versatile Metal, Washington, USA: ACS, 136-147.
Coupe EE, Smyth MG, Fosberry AP, Hall RM, Littlechild JA (2007). The dodecameric vanadium-dependent haloperoxidase from the marine algae Corallina officinalis: cloning, expression, and refolding of the recombinant enzyme.
Protein Expr Purif,
52(2), 265-272.
Abstract:
The dodecameric vanadium-dependent haloperoxidase from the marine algae Corallina officinalis: cloning, expression, and refolding of the recombinant enzyme.
The dodecameric vanadium-dependent bromoperoxidase from Corallina officinalis has been cloned and over-expressed in Escherichia coli. However, the enzyme was found to be predominantly in the form of inclusion bodies. This protein presents a challenging target for refolding, both due to the size (768kDa) and quaternary structure (12x64kDa). Successful refolding conditions have been established which result in an increase in the final yield of active bromoperoxidase from 0.5mg to 40mg per litre of culture. The refolded protein has been characterised and compared to the native enzyme and was shown to be stable at temperatures of 80 degrees C, over a pH range 5.5-10 and in organic solvents such as ethanol, acetonitrile, methanol, and acetone. The novel refolding approach reported in this paper opens up the full potential of this versatile enzyme for use in large scale biotransformation studies.
Abstract.
Author URL.
Littlechild J, Garcia-Rodriguez E, Watts A, Coupe E, Isupov M (2007). The vanadium dependent bromoperoxidase enzymes:Insights into Mechanism and Applications gained from Structural Studies. In Aureliano M (Ed) Vanadium biochemistry, India: Signpost, 97-116.
Littlechild JA, Garcia-Rodriguez E, Watts A, Coupe E, Isupov M (2007). The vanadium dependent bromoperoxidase enzymes:Insights into Mechanism and Applications gained from Structural Studies. In Alves MA (Ed) Vanadium Biochemistry, India: Research Signpost, 97-116.
Wilson RA, Jenkinson JM, Gibson RP, Littlechild JA, Wang Z-Y, Talbot NJ (2007). Tps1 regulates the pentose phosphate pathway, nitrogen metabolism and fungal virulence. The EMBO Journal, 26(15), 3673-3685.
2006
Tapper S, Littlechild JA, Molard Y, Prokes I, Tucker JHR (2006). Anion binding tripodal receptors as structural models for the active site of vanadium haloperoxidases and acid phosphatases.
Supramolecular Chemistry,
18(1), 55-58.
Abstract:
Anion binding tripodal receptors as structural models for the active site of vanadium haloperoxidases and acid phosphatases
In an attempt to mimic the active sites of the anion-binding enzymes vanadium haloperoxidase and acid phosphatase, two tripodal receptors have been shown to bind phosphate and vanadate anions in organic solvents through H-bonding interactions. © 2006 Taylor & Francis.
Abstract.
Conklin PL, Gatzek S, Wheeler GL, Dowdle J, Raymond MJ, Rolinski S, Isupov M, Littlechild JA, Smirnoff N (2006). Arabidopsis thaliana VTC4 encodes L-galactose-1-P phosphatase, a plant ascorbic acid biosynthetic enzyme.
J Biol Chem,
281(23), 15662-15670.
Abstract:
Arabidopsis thaliana VTC4 encodes L-galactose-1-P phosphatase, a plant ascorbic acid biosynthetic enzyme.
In plants, a proposed ascorbate (vitamin C) biosynthesis pathway occurs via GDP-D-mannose (GDP-D-Man), GDP-L-galactose (GDP-L-Gal), and L-galactose. However, the steps involved in the synthesis of L-Gal from GDP-L-Gal in planta are not fully characterized. Here we present evidence for an in vivo role for L-Gal-1-P phosphatase in plant ascorbate biosynthesis. We have characterized a low ascorbate mutant (vtc4-1) of Arabidopsis thaliana, which exhibits decreased ascorbate biosynthesis. Genetic mapping and sequencing of the VTC4 locus identified a mutation (P92L) in a gene with predicted L-Gal-1-P phosphatase activity (At3g02870). Pro-92 is within a beta-bulge that is conserved in related myo-inositol monophosphatases. The mutation is predicted to disrupt the positioning of catalytic amino acid residues within the active site. Accordingly, L-Gal-1-P phosphatase activity in vtc4-1 was approximately 50% of wild-type plants. In addition, vtc4-1 plants incorporate significantly more radiolabel from [2-(3)H]Man into L-galactosyl residues suggesting that the mutation increases the availability of GDP-L-Gal for polysaccharide synthesis. Finally, a homozygous T-DNA insertion line, which lacks a functional At3g02870 gene product, is also ascorbate-deficient (50% of wild type) and deficient in L-Gal-1-P phosphatase activity. Genetic complementation tests revealed that the insertion mutant and VTC4-1 are alleles of the same genetic locus. The significantly lower ascorbate and perturbed L-Gal metabolism in vtc4-1 and the T-DNA insertion mutant indicate that L-Gal-1-P phosphatase plays a role in plant ascorbate biosynthesis. The presence of ascorbate in the T-DNA insertion mutant suggests there is a bypass to this enzyme or that other pathways also contribute to ascorbate biosynthesis.
Abstract.
Author URL.
Littlechild J, Garcia-Rodriguez E, Isupov M (2006). INOR 398-Crystallization studies of vanadium haloperoxidases: Insights into halide specificity and enzyme mechanism.
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY,
232 Author URL.
2005
Garcia-Rodriguez E, Ohshiro T, Aibara T, Izumi Y, Littlechild J (2005). Enhancing effect of calcium and vanadium ions on thermal stability of bromoperoxidase from Corallina pilulifera.
J Biol Inorg Chem,
10(3), 275-282.
Abstract:
Enhancing effect of calcium and vanadium ions on thermal stability of bromoperoxidase from Corallina pilulifera.
Bromoperoxidase from the macro-alga Corallina pilulifera is an enzyme that possesses vanadate in the catalytic center, and shows a significant thermostability and stability toward organic solvents. The structural analysis of the recombinant enzyme overexpressed in yeast revealed that it contains one calcium atom per subunit. This has been confirmed by inductively coupled plasma emission spectrometry experiments. The study of the effect of metal ions on the apo-enzyme stability has shown that the calcium ion significantly increased the enzyme stability. In addition, vanadate also increased the thermostability and strontium and magnesium ions had similar effects as calcium. The holo-enzyme shows high stability in a range of organic solvents. The effect of the different ions and solvents on the structure of the enzyme has been studied by circular dichroism experiments. The high stability of the enzyme in the presence of organic solvents is useful for its application as a biocatalyst.
Abstract.
Author URL.
Littlechild J (2005). Nature's catalysts and their applications in the pharmaceutical industry.
EBR - European Biopharmaceutical Review(AUTUMN), 64-68.
Abstract:
Nature's catalysts and their applications in the pharmaceutical industry
Enzymes that are found naturally in micro-organisms and seaweeds are being used as robust biocatalysts in the fine chemical and pharmaceutical industries. Knowledge of their biochemical properties and 3D structures has proved invaluable in understanding their mechanisms and optimising their commercial use.
Abstract.
Connelly S, Line K, Isupov MN, Littlechild JA (2005). Synthesis and characterisation of a ligand that forms a stable tetrahedral intermediate in the active site of the Aureobacterium species (-) gamma-lactamase.
Org Biomol Chem,
3(18), 3260-3262.
Abstract:
Synthesis and characterisation of a ligand that forms a stable tetrahedral intermediate in the active site of the Aureobacterium species (-) gamma-lactamase.
The crystal structure of a (-) gamma-lactamase from an Aureobacterium species showed a molecule bound covalently to the active site serine residue. This enzyme complex represented the first structure of a stably bound tetrahedral intermediate for an alpha/beta hydrolase fold enzyme. The structural elucidation of tetrahedral intermediates is important for the understanding of enzymatic mechanism, substrate recognition and enzyme inhibition. In this paper, we report the synthesis and subsequent characterisation of (3aR,7aS)-3a,4,7,7a-tetrahydrobenzo-[1,3]-dioxol-2-one (BD1), the molecule modelled into the Aureobacterium (-) gamma-lactamase active site. This molecule has been confirmed to be an inhibitor and to be displaced from the enzyme by the racemic gamma-lactam substrate.
Abstract.
Author URL.
2004
Taylor IN, Brown RC, Bycroft M, King G, Littlechild JA, Lloyd MC, Praquin C, Toogood HS, Taylor SJC (2004). Application of thermophilic enzymes in commercial biotransformation processes.
Abstract:
Application of thermophilic enzymes in commercial biotransformation processes.
Abstract.
Author URL.
Clark DS, Ball P, Littlechild JA, Rice DW, Halle B (2004). Characteristics of nearly dry enzymes in organic solvents: Implications for biocatalysis in the absence of water.
Philosophical Transactions of the Royal Society B: Biological Sciences,
359(1448), 1299-1307.
Abstract:
Characteristics of nearly dry enzymes in organic solvents: Implications for biocatalysis in the absence of water
We have examined enzymes in nearly anhydrous organic solvents spanning a wide range of dielectric constants using a combination of electron paramagnetic resonance (EPR) spectroscopy, molecular dynamics simulations, high-pressure kinetic studies and the electrostatic model of Kirkwood. This approach enabled us to investigate the relationship between catalytic activity, protein flexibility and solvent polarity for an enzymatic reaction proceeding through a highly polar transition state in the near absence of water. Further insights into water-protein interactions and the involvement of water in enzyme structure and function have been obtained by EPR and multinuclear nuclear magnetic resonance studies of enzymes suspended and immobilized in organic solvents with and without added water. In these systems, correlations were observed between the water content and enzyme activity, flexibility, and active-site polarity, although the structural properties of suspended and immobilized enzymes differed markedly. These results have helped to elucidate the role of water in molecular events at the enzymic active site leading to improved biocatalysis in low-water environments.
Abstract.
Brice DC, Bryant JA, Dambrauskas G, Drury SC, Littlechild JA (2004). Cloning and expression of cytosolic phosphoglycerate kinase from pea (Pisum sativum L.).
J Exp Bot,
55(398), 955-956.
Abstract:
Cloning and expression of cytosolic phosphoglycerate kinase from pea (Pisum sativum L.).
In common with several other respiratory and photosynthetic enzymes, a sub-population of cytosolic phosphoglycerate kinase (PGK) occurs in the nucleus in pea leaves and shoots. The full-length cDNA encoding pea cytosolic PGK has been cloned and sequenced, revealing not only the PGK 'signature' but also a nuclear localization signal (NLS). A translational fusion of PGK and GFP was used to transform tobacco BY-2 cells resulting in GFP locating to the cell nuclei.
Abstract.
Author URL.
Isupov MN, Brindley AA, Hollingsworth EJ, Murshudov GN, Vagin AA, Littlechild JA (2004). Crystallization and preliminary X-ray diffraction studies of a fungal hydrolase from Ophiostoma novo-ulmi.
Acta Crystallogr D Biol Crystallogr,
60(Pt 10), 1879-1882.
Abstract:
Crystallization and preliminary X-ray diffraction studies of a fungal hydrolase from Ophiostoma novo-ulmi.
Dutch elm disease fungus Ophiostoma novo-ulmi contains a hydrolase activity which catalyses the resolution of racemic ethyl naproxen to the corresponding acid. The recombinant enzyme has been crystallized by the vapour-diffusion method in two crystal forms. The crystals of the first form belong to space group P2(1)2(1)2, with unit-cell parameters a = 115.9, b = 174.4, c = 62.1 A. The enzyme also crystallizes in space group P2(1)2(1)2, with unit-cell parameters a = 72.9, b = 212.7, c = 61.7 A. Synchrotron data have been collected for both crystal forms to 2.6 and 2.3 A, respectively. A molecular-replacement solution has been found using a remote starting model of a bacterial esterase (23% sequence identity) for both crystal forms. Multicrystal averaging has resulted in interpretable electron-density maps.
Abstract.
Author URL.
Littlechild JA, Guy JE, Isupov MN (2004). Hyperthermophilic dehydrogenase enzymes.
Abstract:
Hyperthermophilic dehydrogenase enzymes.
Abstract.
Author URL.
Ohshiro T, Littlechild J, Garcia-Rodriguez E, Isupov MN, Iida Y, Kobayashi T, Izumi Y (2004). Modification of halogen specificity of a vanadium-dependent bromoperoxidase.
Protein Sci,
13(6), 1566-1571.
Abstract:
Modification of halogen specificity of a vanadium-dependent bromoperoxidase.
The halide specificity of vanadium-dependent bromoperoxidase (BPO) from the marine algae, Corallina pilulifera, has been changed by a single amino acid substitution. The residue R397 has been substituted by the other 19 amino acids. The mutant enzymes R397W and R397F showed significant chloroperoxidase (CPO) activity as well as BPO activity. These mutant enzymes were purified and their properties were investigated. The maximal velocities of CPO activities of the R397W and R397F enzymes were 31.2 and 39.2 units/mg, and the K(m) values for Cl(-) were 780 mM and 670 mM, respectively. Unlike the native enzyme, both mutant enzymes were inhibited by NaN(3). In the case of the R397W enzyme, the incorporation rate of vanadate into the active site was low, compared with the R397F and the wild-type enzyme. These results supported the existence of a specific halogen binding site within the catalytic cleft of vanadium haloperoxidases.
Abstract.
Author URL.
Rand RP, Ho MW, Littlechild JA, Finney JL, Cupane A, Engberts JBFN (2004). Probing the role of water in protein conformation and function.
Philosophical Transactions of the Royal Society B: Biological Sciences,
359(1448), 1277-1285.
Abstract:
Probing the role of water in protein conformation and function
Life began in a bath of water and has never escaped it. Cellular function has forced the evolution of many mechanisms ensuring that cellular water concentration has never changed significantly. To free oneself of any conceptual distinction among all small molecules, solutes and solvents, means that experiments to probe water's specific role in molecular function can be designed like any classical chemical reaction. Such an 'osmotic stress' strategy will be described in general and for an enzyme, hexokinase. Water behaves like a reactant that competes with glucose in binding to hexokinase, and modulates its conformational change and activity. This 'osmotic stress' strategy, now applied to many very different systems, shows that water plays a significant role, energetically, in most macromolecular reactions. It can be required to fill obligatory space, it dominates nearest non-specific interactions between large surfaces, it can be a reactant modulating conformational change; all this in addition to its more commonly perceived static role as an integral part of stereospecific intramolecular structure.
Abstract.
Littlechild JA, Isupov MN, Line K (2004). The crystal structure of a (-)?-lactamase from an Aureobacterium species reveals a tetrahedral intermediate in the active site. Journal of Molecular Biology, 338(3), 519-532.
Toogood HS, Brown RC, Line K, Keene PA, Taylor SJC, McCague R, Littlechild JA (2004). The use of a thermostable signature amidase in the resolution of the bicyclic synthon (rac)-γ-lactam.
Tetrahedron,
60(3), 711-716.
Abstract:
The use of a thermostable signature amidase in the resolution of the bicyclic synthon (rac)-Îł-lactam
The resolution of the bicyclic synthon (rac)-γ-lactam (2-azabicyclo[2.2.1]hept-5-en-3-one) is an important step in the synthesis of a group of chemotherapuetic agents known as carbocyclic nucleosides. The archaeon Sulfolobus solfataricus MT4 produces a thermostable γ-lactamase that has a high sequence homology to the signature amidase family of enzymes. It shows similar inhibition patterns of amidases towards benzonitrile, phenylmethylsulfonyl fluoride and heavy metals such as Hg2+, and is activated by thiol reagents. The enzyme selectively cleaves the (+)-enantiomer from a racemic mix of γ-lactam. It also exhibits general amidase activity by cleaving linear and branched aliphatic and aromatic amides. The enzyme catalyses the synthesis of benzoic hydrazide from benzamide preferentially to benzamide cleavage in the presence of excess hydrazine. This enzyme has potential for use in industrial biotransformations in the production of both carbocyclic nucleosides and hydrazides. © 2003 Published by Elsevier Ltd.
Abstract.
Halling PJ, Finney JL, Ho MW, Franks F, Littlechild JA (2004). What can we learn by studying enzymes in non-aqueous media?.
Philosophical Transactions of the Royal Society B: Biological Sciences,
359(1448), 1287-1297.
Abstract:
What can we learn by studying enzymes in non-aqueous media?
What is the role of water in enzyme structure and function? One approach to answers should come from studies in which the amount of water present is a variable. In the absence of bulk liquid water, effective monitoring of enzyme action requires an alternative fluid medium through which substrates and products may be transported. The past 20 years have seen quite extensive study of enzyme behaviour when reactants are transferred via a bulk phase that is an organic liquid, a supercritical fluid or a gas. Some lipases, at least, remain highly active with only a few, if any, residual water molecules. Many enzymes seem to require larger amounts of water, but still not a liquid water phase. There are hysteresis effects on both the amount of bound water and the observed catalytic activity. Increasing hydration promotes mobility of the enzyme molecule, as revealed by various techniques, and there are correlations with catalytic activity. There are other plausible roles for hydration, such as opening up proton conduction pathways.
Abstract.
2003
Whitcher CS, Littlechild JA, Woodley JM (2003). Application of a Baeyer-Villiger monooxygenase from cunninghamella echinulata NRRL 3655.
Author URL.
Guy JE, Isupov MN, Littlechild JA (2003). Crystallization and preliminary X-ray diffraction studies of a novel alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix.
Acta Crystallogr D Biol Crystallogr,
59(Pt 1), 174-176.
Abstract:
Crystallization and preliminary X-ray diffraction studies of a novel alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix.
A novel alcohol dehydrogenase enzyme has been cloned from the hyperthermophilic archaeon Aeropyrum pernix and overexpressed in Escherichia coli. This zinc-containing enzyme has been crystallized by the sitting-drop vapour-diffusion method using PEG 600 as precipitant. The crystals diffract to 1.5 a resolution and belong to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 100.7, b = 103.2, c = 67.5 A. The asymmetric unit contains two enzyme monomers. Two synchrotron data sets have been collected: one at a wavelength near the absorption edge of zinc and one at a remote wavelength. Three strong zinc-ion positions were visible in the anomalous Patterson map. Two additional weaker zinc ions have been identified by anomalous Fourier synthesis.
Abstract.
Author URL.
Watts, A. Giles, G.I. Fry, F.H. (2003). Metal and Redox Regulation of Cysteine Protein Function. Chemistry and Biology, 10, 677-693.
Littlechild JA, Garcia-Rodriguez E (2003). Structural studies on the dodecameric vanadium bromoperoxidase from Corallina species. Coordination Chemistry Reviews, 237(1-2), 65-76.
Littlechild JA, Guy JE, Isupov MN (2003). The Structure of an Alcohol Dehydrogenase from the Hyperthermophilic Archaeon Aeropyrum pernix. Journal of Molecular Biology, 331(5), 1041-1051.
2002
Watts AB, Beecher J, Whitcher CS, Littlechild JA (2002). A method for screening Baeyer-Villiger monooxygenase activity against monocyclic ketones.
Biocatalysis and Biotransformation,
20(3), 209-215.
Abstract:
A method for screening Baeyer-Villiger monooxygenase activity against monocyclic ketones
The assay for Baeyer-Villiger monooxygenase (BVMO) enzyme activity has relied to date on the spectrophotometric change observed on the oxidation of the nicotinamide cofactor during the enzymatic reaction. By analogy to the cyclohexanol catabolic pathway of Acinetobacter calcoaceticus NCIMB 9871, we have developed a specific colorimetric screening method that utilises an esterase to cleave the lactone that is formed in the BVMO reaction. When carried out in a non-buffered or weakly buffered system the resultant change in pH can be visually detected. This allows the rapid assaying and screening of BVMO enzymes. This has been demonstrated with cyclohexanone monooxygenase from A. calcoaceticus. The resultant colour change has been visualised with washed cell suspensions, individual bacterial colonies on Petri dishes and with semi-purified recombinant enzyme utilising Linbro dishes.
Abstract.
Toogood HS, Hollingsworth EJ, Brown RC, Taylor IN, Taylor SJC, McCague R, Littlechild JA (2002). A thermostable L-aminoacylase from Thermococcus litoralis: cloning, overexpression, characterization, and applications in biotransformations.
Extremophiles,
6(2), 111-122.
Abstract:
A thermostable L-aminoacylase from Thermococcus litoralis: cloning, overexpression, characterization, and applications in biotransformations.
A thermostable L-aminoacylase from Thermococcus litoralis was cloned, sequenced, and overexpressed in Escherichia coli. The enzyme is a homotetramer of 43 kDa monomers and has an 82% sequence identity to an aminoacylase from Pyrococcus horikoshii and 45% sequence identity to a carboxypeptidase from Sulfolobus solfataricus. It contains one cysteine residue that is highly conserved among aminoacylases. Cell-free extracts of the recombinant enzyme were characterized and were found to have optimal activity at 85 degrees C in Tris-HCl at pH 8.0. The recombinant enzyme is thermostable, with a half-life of 25 h at 70 degrees C. Aminoacylase inhibitors, such as mono-tert-butyl malonate, had only a slight effect on activity. The enzyme was partially inhibited by EDTA and p-hydroxymercuribenzoate, suggesting that the cysteine residue and a metal ion are important, but not essential, for activity. Addition of Zn2+ and Co2+ to the apoenzyme increased the enzyme activity, whereas Sn4+ and Cu2+ almost completely abolished enzyme activity. The enzyme was most specific for substrates containing N-benzoyl- or N-chloroacetyl-amino acids. preferring substrates containing hydrophobic, uncharged, or weakly charged amino acids such as phenylalanine, methionine, and cysteine.
Abstract.
Author URL.
Hollingsworth EJ, Isupov MN, Littlechild JA (2002). Crystallization and preliminary X-ray diffraction analysis of L-aminoacylase from the hyperthermophilic archaeon Thermococcus litoralis.
Acta Crystallogr D Biol Crystallogr,
58(Pt 3), 507-510.
Abstract:
Crystallization and preliminary X-ray diffraction analysis of L-aminoacylase from the hyperthermophilic archaeon Thermococcus litoralis.
The enzyme L-aminoacylase catalyses the hydrolysis of N-acyl-L-amino acids from peptides or proteins. The recombinant enzyme from the hyperthermophilic archaeon Thermococcus litoralis has been purified to homogeneity. This zinc-containing enzyme has been crystallized from ammonium sulfate using the sitting-drop vapour-diffusion method. The crystals diffract to 2.8 a resolution and belong to the rhombohedral space group R32, with unit-cell parameters a = b = 102.4, c = 178.5 A, gamma = 120 degrees in a hexagonal lattice setting. The asymmetric unit contains one enzyme monomer, containing a single zinc ion. Two synchrotron data sets have been collected at a remote wavelength and at the maximum f'wavelength for zinc. This has allowed the position of the metal to be identified in anomalous Patterson maps.
Abstract.
Author URL.
Littlechild J (2002). Extremely versatile systems. Trends in Biotechnology, 20(8).
Gloyn AL, Noordam K, Willemsen MA, Watts AB, Littlechild JA, Ellard S, Hatterlsey AT (2002). Familial hyperinsulinism caused by a novel activating glucokinase mutation.
DIABETES,
51, A260-A260.
Author URL.
Toogood HS, Taylor IN, Brown RC, Taylor SJC, McCague R, Littlechild JA (2002). Immobilisation of the thermostable L-aminoacylase from Thermococcus litoralis to generate a reusable industrial biocatalyst.
Biocatalysis and Biotransformation,
20(4), 241-249.
Abstract:
Immobilisation of the thermostable L-aminoacylase from Thermococcus litoralis to generate a reusable industrial biocatalyst
A thermostable archaeal L-aminoacylase from Thermococcus litoralis has been used in immobilisation trials to optimise its application in industrial biotransformation reactions. Immobilisation techniques used included direct adsorption and crosslinking of the enzyme onto solid supports, bioencapsulation, and covalent bonding onto a variety of activated matrices. The most successful immobilisation methods were covalent binding of the enzyme onto glyoxyl-Sepharose and Amberlife XAD7. These methods yielded an average of 15 and 80 mg of protein bound per gram of support (wet weight for glyoxyl-Sepharose), respectively, with nearly 80% activity recovery in both cases. Enzyme immobilised onto glyoxyl-agarose was stabilised 106-fold under aqueous conditions and 142-fold in 100% acetonitrile when activity was measured after 24h at 90°C. A column bioreactor containing the recombinant L-aminoacylase immobilised onto Sepharose beads was constructed with the substrate, N-acetyl-DL-Trp, continuously flowing at 60°C for 10 days. No loss of activity was detected over five days, with 32% activity remaining after 40 days at 60°C. These results show the potential of the use of immobilised L-aminoacylase in biotransformation reactions for the production of fine chemicals.
Abstract.
Littlechild J, Garcia-Rodriguez E, Dalby A, Isupov M (2002). Structural and functional comparisons between vanadium haloperoxidase and acid phosphatase enzymes.
J Mol Recognit,
15(5), 291-296.
Abstract:
Structural and functional comparisons between vanadium haloperoxidase and acid phosphatase enzymes.
The crystallographic structures of both the vanadium chloroperoxidase and bromoperoxidase enzymes have been determined with either vanadium or phosphate bound at their active site. The amino acids that are involved in phosphate binding in the acid phosphatase enzymes and those that are coordinated to vanadium in the haloperoxidases appear to be conserved between the two classes of enzyme. The detailed active site architecture for enzymes that recognize and use either vanadium or phosphate will be discussed in relation to their proposed enzymatic mechanism.
Abstract.
Author URL.
2001
Qi JF, Isupov MN, Littlechild JA, Anderson LE (2001). Chloroplast glyceraldehyde-3-P dehydrogenase contains a single disulfide bond located in the C-terminal extension to the B subunit.
BIOCHEMISTRY,
40(29), 8615-8615.
Author URL.
Qi JF, Isupov MN, Littlechild JA, Anderson LE (2001). Chloroplast glyceraldehyde-3-P dehydrogenase contains a single disulfide bond located in the C-terminal extension to the B subunit.
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY,
222, U121-U121.
Author URL.
Littlechild JA, Anderson LE, Isupov MN, Qi JF (2001). Chloroplast glyceraldehydes-3-phosphate dehydrogenase contains a single disulfide bond located in the C-terminal extension to the B subunit. Journal of Biological Chemistry, 276(38), 35247-35252.
Harris JR, Schröder E, Isupov MN, Scheffler D, Kristensen P, Littlechild JA, Vagin AA, Meissner U (2001). Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography.
Biochim Biophys Acta,
1547(2), 221-234.
Abstract:
Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography.
The decameric human erythrocyte protein torin is identical to the thiol-specific antioxidant protein-II (TSA-II), also termed peroxiredoxin-II (Prx-II). Single particle analysis from electron micrographs of Prx-II molecules homogeneously orientated across holes in the presence of a thin film of ammonium molybdate and trehalose has facilitated the production of a >/=20 a 3-D reconstruction by angular reconstitution that emphasises the D5 symmetry of the ring-like decamer. The X-ray structure for Prx-II was fitted into the transmission electron microscopic reconstruction by molecular replacement. The surface-rendered transmission electron microscopy (TEM) reconstruction correlates well with the solvent-excluded surface of the X-ray structure of the Prx-II molecule. This provides confirmation that transmission electron microscopy of negatively stained specimens, despite limited resolution, has the potential to reveal a valid representation of surface features of protein molecules. 2-D crystallisation of the Prx-II protein on mica as part of a TEM study resulted in the formation of a p2 crystal form with parallel linear arrays of stacked rings. This latter 2-D form correlates well with that observed from the 2.7 a X-ray structure of Prx-II solved from a new orthorhombic 3-D crystal form.
Abstract.
Author URL.
Gonsalvez IS, Isupov MN, Littlechild JA (2001). Crystallization and preliminary X-ray analysis of a gamma-lactamase.
Acta Crystallogr D Biol Crystallogr,
57(Pt 2), 284-286.
Abstract:
Crystallization and preliminary X-ray analysis of a gamma-lactamase.
An enzyme from Comomonas acidovorans has been isolated that is specific for the stereospecific hydrolysis of (+)gamma-lactam. This so-called (+)gamma-lactamase has important applications in biotransformation reactions. The enzyme has been crystallized by vapour-phase diffusion using polyethylene glycol 4000 as a precipitant. Addition of a detergent, beta-octylglucoside, was found to be essential for obtaining diffraction-quality crystals. The crystals grow in the space group P1, with unit-cell parameters a = 63.0, b = 93.2, c = 152.4 A, alpha = 104.3, beta = 92.6, gamma = 108.5 degrees, and diffract to 2 a resolution using synchrotron radiation. Native data from these crystals have been collected to 2.4 A.
Abstract.
Author URL.
Turner NA, Gaskin DJ, Yagnik AT, Littlechild JA, Vulfson EN (2001). Enantioselectivity of recombinant Rhizomucor miehei lipase in the ring opening of oxazolin-5(4H)-ones.
Protein Eng,
14(4), 269-278.
Abstract:
Enantioselectivity of recombinant Rhizomucor miehei lipase in the ring opening of oxazolin-5(4H)-ones.
Enantioselectivity of enzyme catalysis is often rationalized via active site models. These models are constructed on the basis of comparing the enantiomeric excess of product observed in a series of reactions which are conducted with a range of homologous substrates, typically carrying various side chain substitutions. Surprisingly the practical application of these simple but informative 'pocket size' models has been rarely tested in genetic engineering experiments. In this paper we report the construction, purification and enantioselectivity of two recombinant Rhizomucor miehei lipases which were designed to check the validity of such a model in reactions of ring opening of oxazolin-5(4H)-ones.
Abstract.
Author URL.
Littlechild JA, Isupov M (2001). Glyceraldehyde-3-phosphate dehydrogenase from Sulfolobus solfataricus.
Methods Enzymol,
331, 105-117.
Author URL.
Crowhurst G, McHarg J, Littlechild JA (2001). Phosphoglycerate kinases from bacteria and archaea.
Methods Enzymol,
331, 90-104.
Author URL.
Singleton MR, Littlechild JA (2001). Pyrrolidone carboxylpeptidase from Thermococcus litoralis.
Methods Enzymol,
330, 394-403.
Author URL.
Littlechild J, Isupov M, Garcia E (2001). Structural studies on the dodecameric vanadium containing bromoperoxidase from Corallina officinalis.
JOURNAL OF INORGANIC BIOCHEMISTRY,
86(1), 67-67.
Author URL.
Dalby AR, Tolan DR, Littlechild JA (2001). The structure of human liver fructose-1,6-bisphosphate aldolase.
Acta Crystallogr D Biol Crystallogr,
57(Pt 11), 1526-1533.
Abstract:
The structure of human liver fructose-1,6-bisphosphate aldolase.
The X-ray crystallographic structure of the human liver isozyme of fructose-1,6-bisphosphate aldolase has been determined by molecular replacement using a tetramer of the human muscle isozyme as a search model. The liver aldolase (B isozyme) crystallized in space group C2, with unit-cell parameters a = 291.1, b = 489.8, c = 103.4 A, alpha = 90, beta = 103.6, gamma = 90 degrees. These large unit-cell parameters result from the presence of 18 subunits in the asymmetric unit: four catalytic tetramers and a dimer from a fifth tetramer positioned on the twofold crystallographic axis. This structure provides further insight into the factors affecting isozyme specificity. It reveals small differences in secondary structure that occur in regions previously determined to be isozyme specific. Two of these regions are at the solvent-exposed enzyme surface away from the active site of the enzyme. The most significant changes are in the flexible C-terminal region of the enzyme, where there is an insertion of an extra alpha-helix. Point mutations of the human liver aldolase are responsible for the disease hereditary fructose intolerance. Sequence information is projected onto the new crystal structure in order to indicate how these mutations bring about reduced enzyme activity and affect structural stability.
Abstract.
Author URL.
2000
Gonsalvez IS, Littlechild JA, Isupov M, Taylor SJ, Brown R (2000). Characterisation and preliminary crystallographic studies of a novel γ-lactamase enzyme used in the synthesis of an anti-HIV drug.
Gonsalvez IS, Littlechild JA, Taylor S, Brown R (2000). Characterisation of a novel γ-lactamase enzyme used in the synthesis of an anti-HIV drug. Biochemical Society Transactions, 28(3), a75-a75.
Hollingsworth EJ, Brown R, Isupov MN, Taylor S, Littlechild JA (2000). Cloning, Expression & Purification of a Thermostable Aminoacylase from <i>Thermococcus litoralis</i>.
Singleton MR, Taylor SJ, Parrat JS, Littlechild JA (2000). Cloning, expression, and characterization of pyrrolidone carboxyl peptidase from the archaeon Thermococcus litoralis.
Extremophiles,
4(5), 297-303.
Abstract:
Cloning, expression, and characterization of pyrrolidone carboxyl peptidase from the archaeon Thermococcus litoralis.
The gene encoding pyrrolidone carboxyl peptidase (Pcp) has been cloned from the hyperthermophilic archaeon Thermococcus litoralis. The recombinant enzyme has been expressed in Escherichia coli, purified, and characterized. The T. litoralis Pcp demonstrates strong sequence homology to previously characterized bacterial Pcps. Some investigations have been carried out on enzyme substrate specificity and stability.
Abstract.
Author URL.
Schröder E, Littlechild JA, Lebedev AA, Errington N, Vagin AA, Isupov MN (2000). Crystal structure of decameric 2-Cys peroxiredoxin from human erythrocytes at 1.7 a resolution.
Structure,
8(6), 605-615.
Abstract:
Crystal structure of decameric 2-Cys peroxiredoxin from human erythrocytes at 1.7 a resolution.
BACKGROUND: the peroxiredoxins (Prxs) are an emerging family of multifunctional enzymes that exhibit peroxidase activity in vitro, and in vivo participate in a range of cellular processes known to be sensitive to reactive oxygen species. Thioredoxin peroxidase B (TPx-B), a 2-Cys type II Prx from erythrocytes, promotes potassium efflux and down-regulates apoptosis and the recruitment of monocytes by endothelial tissue. RESULTS: the crystal structure of human decameric TPx-B purified from erythrocytes has been determined to 1.7 [corrected)] a resolution. The structure is a toroid comprising five dimers linked end-on through predominantly hydrophobic interactions, and is proposed to represent an intermediate in the in vivo reaction cycle. In the crystal structure, Cys51, the site of peroxide reduction, is oxidised to cysteine sulphinic acid. The residue Cys172, lies approximately 10 a away from Cys51 [corrected]. CONCLUSIONS: the oxidation of Cys51 appears to have trapped the structure into a stable decamer, as confirmed by sedimentation analysis. A comparison with two previously reported dimeric Prx structures reveals that the catalytic cycle of 2-Cys Prx requires significant conformational changes that include the unwinding of the active-site helix and the movement of four loops. It is proposed that the stable decamer forms in vivo under conditions of oxidative stress. Similar decameric structures of TPx-B have been observed by electron microscopy, which show the protein associated with the erythrocyte membrane.
Abstract.
Author URL.
Schroder E, Littlechild JA, Lebedev AA, Errington N, Vagin AA, Isupov MN (2000). Crystal structure of decameric 2-Cys peroxiredoxin from human erythrocytes at 1.7 angstrom resolution (vol 8, pg 605, 2000).
STRUCTURE,
8(12), U5-U5.
Author URL.
Isupov MN, Dalby AR, Brindley AA, Izumi Y, Tanabe T, Murshudov GN, Littlechild JA (2000). Crystal structure of dodecameric vanadium-dependent bromoperoxidase from the red algae Corallina officinalis.
J Mol Biol,
299(4), 1035-1049.
Abstract:
Crystal structure of dodecameric vanadium-dependent bromoperoxidase from the red algae Corallina officinalis.
The three-dimensional structure of the vanadium bromoperoxidase protein from the marine red macroalgae Corallina officinalis has been determined by single isomorphous replacement at 2.3 a resolution. The enzyme subunit is made up of 595 amino acid residues folded into a single alpha+beta domain. There are 12 bromoperoxidase subunits, arranged with 23-point group symmetry. A cavity is formed by the N terminus of each subunit in the centre of the dodecamer. The subunit fold and dimer organisation of the Cor. officinalis vanadium bromoperoxidase are similar to those of the dimeric enzyme from the brown algae Ascophyllum nodosum, with which it shares 33 % sequence identity. The different oligomeric state of the two algal enzymes seems to reflect separate mechanisms of adaptation to harsh environmental conditions and/or to chemically active substrates and products. The residues involved in the vanadate binding are conserved between the two algal bromoperoxidases and the vanadium chloroperoxidase from the fungus Curvularia inaequalis. However, most of the other residues forming the active-site cavity are different in the three enzymes, which reflects differences in the substrate specificity and stereoselectivity of the reaction. A dimer of the Cor. officinalis enzyme partially superimposes with the two-domain monomer of the fungal enzyme.
Abstract.
Author URL.
Schröder E, Littlechild JA, Lebedev AA, Isupov MN (2000). Structure and mechanism of decameric 2-cys peroxiredoxin from human erythrocytes.
Schröder E, Lebedev AA, Isupov MN, Littlechild JA (2000). Structure and mechanism of human decameric 2-cys peroxiredoxin.
Bourne PC, Isupov MN, Littlechild JA (2000). The atomic-resolution structure of a novel bacterial esterase.
Structure,
8(2), 143-151.
Abstract:
The atomic-resolution structure of a novel bacterial esterase.
BACKGROUND: a novel bacterial esterase that cleaves esters on halogenated cyclic compounds has been isolated from an Alcaligenes species. This esterase 713 is encoded by a 1062 base pair gene. The presence of a leader sequence of 27 amino acids suggests that this enzyme is exported from the cytosol. Esterase 713 has been over-expressed in Agrobacterium without this leader sequence. Its amino acid sequence shows no significant homology to any known protein sequence. RESULTS: the crystal structure of esterase 713 has been determined by multiple isomorphous replacement and refined to 1. 1 a resolution. The subunits of this dimeric enzyme comprise a single domain with an alpha/beta hydrolase fold. The catalytic triad has been identified as Ser206-His298-Glu230. The acidic residue of the catalytic triad (Glu230) is located on the beta6 strand of the alpha/beta hydrolase fold, whereas most other alpha/beta hydrolase enzymes have the acidic residue located on the beta7 strand. The oxyanion hole is formed by the mainchain nitrogens of Cys71 and Gln207 as identified by the binding of a substrate analogue, (S)-7-iodo-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1, 4-benzodiazepine-2-acetic acid. Cys71 forms a disulphide bond with the neighbouring Cys72. CONCLUSIONS: Despite negligible sequence homology, esterase 713 has structural similarities to a number of other esterases and lipases. Residues of the oxyanion hole were confirmed by structural comparison with Rhizomucor miehei lipase. It is proposed that completion of a functional active site requires the formation of the disulphide bond between adjacent residues Cys71 and Cys72 on export of the esterase into the oxidising environment of the periplasmic space.
Abstract.
Author URL.
Charron C, Talfournier F, Isupov MN, Littlechild JA, Branlant G, Vitoux B, Aubry A (2000). The crystal structure of d-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Methanothermus fervidus in the presence of NADP(+) at 2.1 a resolution.
J Mol Biol,
297(2), 481-500.
Abstract:
The crystal structure of d-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Methanothermus fervidus in the presence of NADP(+) at 2.1 a resolution.
The crystal structure of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the archaeon Methanothermus fervidus has been solved in the holo form at 2.1 a resolution by molecular replacement. Unlike bacterial and eukaryotic homologous enzymes which are strictly NAD(+)-dependent, GAPDH from this organism exhibits a dual-cofactor specificity, with a marked preference for NADP(+) over NAD(+). The present structure is the first archaeal GAPDH crystallized with NADP(+). GAPDH from M. fervidus adopts a homotetrameric quaternary structure which is topologically similar to that observed for its bacterial and eukaryotic counterparts. Within the cofactor-binding site, the positively charged side-chain of Lys33 decisively contributes to NADP(+) recognition through a tight electrostatic interaction with the adenosine 2'-phosphate group. Like other GAPDHs, GAPDH from archaeal sources binds the nicotinamide moiety of NADP(+) in a syn conformation with respect to the adjacent ribose and so belongs to the B-stereospecific class of oxidoreductases. Stabilization of the syn conformation is principally achieved through hydrogen bonding of the carboxamide group with the side-chain of Asp171, a structural feature clearly different from what is observed in all presently known GAPDHs from bacteria and eukaryotes. Within the catalytic site, the reported crystal structure definitively confirms the essential role previously assigned to Cys140 by site-directed mutagenesis studies. In conjunction with new mutation results reported in this paper, inspection of the crystal structure gives reliable evidence for the direct implication of the side-chain of His219 in the catalytic mechanism. M. fervidus grows optimally at 84 degrees C with a maximal growth temperature of 97 degrees C. The paper includes a detailed comparison of the present structure with four other homologous enzymes extracted from mesophilic as well as thermophilic organisms. Among the various phenomena related to protein thermostabilization, reinforcement of electrostatic and hydrophobic interactions as well as a more efficient molecular packing appear to be essentially promoted by the occurrence of two additional alpha-helices in the archaeal GAPDHs. The first one, named alpha4, is located in the catalytic domain and participates in the enzyme architecture at the quaternary structural level. The second one, named alphaJ, occurs at the C terminus and contributes to the molecular packing within each monomer by filling a peripherical pocket in the tetrameric assembly.
Abstract.
Author URL.
1999
Isupov MN, Dalby AR, Brindley AA, Littlechild JA (1999). CRYSTAL STRUCTURE OF THE VANADIUM DEPENDENT HALOPEROXIDASE FROM C. OFFICINALIS.
Author URL.
Dalby A, Dauter Z, Littlechild JA (1999). Crystal structure of human muscle aldolase complexed with fructose 1,6-bisphosphate: mechanistic implications.
Protein Sci,
8(2), 291-297.
Abstract:
Crystal structure of human muscle aldolase complexed with fructose 1,6-bisphosphate: mechanistic implications.
Fructose 1,6-bisphosphate aldolase catalyzes the reversible cleavage of fructose 1,6-bisphosphate and fructose 1-phosphate to dihydroxyacetone phosphate and either glyceraldehyde 3-phosphate or glyceraldehyde, respectively. Catalysis involves the formation of a Schiff's base intermediate formed at the epsilon-amino group of Lys229. The existing apo-enzyme structure was refined using the crystallographic free-R-factor and maximum likelihood methods that have been shown to give improved structural results that are less subject to model bias. Crystals were also soaked with the natural substrate (fructose 1,6-bisphosphate), and the crystal structure of this complex has been determined to 2.8 A. The apo structure differs from the previous Brookhaven-deposited structure (1ald) in the flexible C-terminal region. This is also the region where the native and complex structures exhibit differences. The conformational changes between native and complex structure are not large, but the observed complex does not involve the full formation of the Schiff's base intermediate, and suggests a preliminary hydrogen-bonded Michaelis complex before the formation of the covalent complex.
Abstract.
Author URL.
Isupov MN, Fleming TM, Dalby AR, Crowhurst GS, Bourne PC, Littlechild JA (1999). Crystal structure of the glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus.
J Mol Biol,
291(3), 651-660.
Abstract:
Crystal structure of the glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus.
The enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the archaea shows low sequence identity (16-20%) with its eubacterial and eukaryotic counterparts. The crystal structure of the apo GAPDH from Sulfolobus solfataricus has been determined by multiple isomorphous replacement at 2.05 a resolution. The enzyme has several differences in secondary structure when compared with eubacterial GAPDHs, with an overall increase in the number of alpha-helices. There is a relocation of the active-site residues within the catalytic domain of the enzyme. The thermostability of the S. solfataricus enzyme can be attributed to a combination of an ion pair cluster and an intrasubunit disulphide bond.
Abstract.
Author URL.
Schröder E, Isupov MN, Naran A, Littlechild JA (1999). Crystallization and preliminary X-ray analysis of human thioredoxin peroxidase-B from red blood cells.
Acta Crystallogr D Biol Crystallogr,
55(Pt 2), 536-538.
Abstract:
Crystallization and preliminary X-ray analysis of human thioredoxin peroxidase-B from red blood cells.
Two different crystal forms of human thioredoxin peroxidase-B have been grown by vapour diffusion using polyethylene glycol 400 as a precipitant. Monoclinic P21 crystals were grown from freshly purified protein, whilst orthorhombic P212121 crystals were grown from purified protein that had been stored in ammonium sulfate, but otherwise under the same conditions. The diffraction from both crystal forms was observed to extend to beyond 2.0 a resolution using synchrotron radiation. Complete native data sets to 1.8 and 3. 7 a have been collected from the monoclinic and orthorhombic crystals, respectively.
Abstract.
Author URL.
Charron C, Talfournier F, Isupov MN, Branlant G, Littlechild JA, Vitoux B, Aubry A (1999). Crystallization and preliminary X-ray diffraction studies of D-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Methanothermus fervidus.
Acta Crystallogr D Biol Crystallogr,
55(Pt 7), 1353-1355.
Abstract:
Crystallization and preliminary X-ray diffraction studies of D-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Methanothermus fervidus.
The homotetrameric holo-D-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Methanothermus fervidus has been crystallized in the presence of NADP+ using the hanging-drop vapour-diffusion method. Crystals grew from a solution containing 2-methyl-2,4-pentanediol and magnesium acetate. A native data set has been collected to 2.1 a using synchrotron radiation and cryocooling. Diffraction data have been processed in the orthorhombic system (space group P21212) with unit-cell dimensions a = 136.7, b = 153.3, c = 74.9 a and one tetramer per asymmetric unit.
Abstract.
Author URL.
Singleton MR, Isupov MN, Littlechild JA (1999). Crystallization and preliminary X-ray diffraction studies of pyrrolidone carboxyl peptidase from the hyperthermophilic archaeon Thermococcus litoralis.
Acta Crystallogr D Biol Crystallogr,
55(Pt 3), 702-703.
Abstract:
Crystallization and preliminary X-ray diffraction studies of pyrrolidone carboxyl peptidase from the hyperthermophilic archaeon Thermococcus litoralis.
Pyrrolidone carboxyl peptidase from the hyperthermophilic archaeon Thermococcus litoralis has been crystallized in a form suitable for X-ray diffraction from ammonium sulfate or ammonium dihydrogen orthophosphate using the vapour-phase diffusion method. Crystals from both precipitants are of the orthorhombic space group P21212 with unit-cell dimensions a = 94.06, b = 149.06, c = 73.54 A. A complete data set to 2.8 a resolution has been collected from crystals grown from ammonium sulfate.
Abstract.
Author URL.
Bourne PC, Isupov MN, Littlechild JA (1999). Crystallization and preliminary x-ray diffraction studies of a novel bacterial esterase.
Acta Crystallogr D Biol Crystallogr,
55(Pt 4), 915-917.
Abstract:
Crystallization and preliminary x-ray diffraction studies of a novel bacterial esterase.
A novel bacterial esterase has been crystallized in two forms suitable for X-ray diffraction studies. Crystals have been obtained by vapour-phase diffusion at 290 K using ammonium sulfate as precipitant. The first crystals grew in space group C2 with unit-cell parameters a = 134.7, b = 55.8, c = 110.3 A, beta = 125.1 degrees. A monoclinic data set has been collected to 2.0 a resolution. Microseeding yielded a second crystal form which grew in space group P212121 with unit-cell parameters a = 57.1, b = 115.4, c = 130.4 A. Native data from these crystals have been collected to 1.6 a resolution. A molecular envelope has been determined using an uranyl acetate derivative for phase calculation.
Abstract.
Author URL.
Littlechild J (1999). Haloperoxidases and their role in biotransformation reactions.
Curr Opin Chem Biol,
3(1), 28-34.
Abstract:
Haloperoxidases and their role in biotransformation reactions.
The past year has seen further structural characterisation of both nonmetal and vanadium haloperoxidase enzymes to add to that already known for the haem- and vanadium-containing enzymes. Exploitation of these enzymes for halogenation, sulfoxidation, epoxidation, oxidation of indoles and other biotransformations has increased as more information on their catalytic mechanism has been obtained.
Abstract.
Author URL.
McHarg J, Kelly SM, Price NC, Cooper A, Littlechild JA (1999). Site-directed mutagenesis of proline 204 in the 'hinge' region of yeast phosphoglycerate kinase.
Eur J Biochem,
259(3), 939-945.
Abstract:
Site-directed mutagenesis of proline 204 in the 'hinge' region of yeast phosphoglycerate kinase.
Site-specific mutants have been produced in order to investigate the role of proline 204 in the 'hinge' region of yeast phosphoglycerate kinase (PGK). This totally conserved proline has been shown to be the only cis-proline in the high resolution crystal structures of yeast, B. stearothermophilus, T. brucei and T. maritima PGK, and may therefore have a role in the independent folding of the two domains or in the 'hinge' bending of the molecule during catalysis. The residue was replaced by a histidine (Pro204His) and a phenylalanine (Pro204Phe), and the resulting proteins characterised by differential scanning calorimetry (DSC), circular dichroism (CD), tryptophan fluorescence emission and kinetic analysis. Although the secondary and tertiary structure of the Pro204His protein is generally similar to that of the wild-type enzyme as assessed by CD, the enzyme is less stable to heat and guanidinium chloride denaturation than the wild-type. In the denaturation experiments two transitions were observed for both the wild-type and the Pro204His mutant, as have been previously reported for yeast PGK [Missiakas, D. Betton, J.M. Minard, P. & Yon, J.M. (1990) Biochemistry 29, 8683-8689]. The first transition is accompanied by an increase in fluorescence intensity leading to a hyperfluorescent state, followed by the second, corresponding to a decrease in fluorescence intensity. However, for the Pro204His mutant, the first transition proceeded at lower concentrations of guanidinium chloride and the second transition proceeded to the same extent as for the wild-type protein, suggesting that sequence-distant interactions are more rapidly disrupted in this mutant enzyme than in the wild-type enzyme, while sequence-local interactions are disrupted in a similar way. The Michaelis constants (K(m)) for both 3-phospho-D-glycerate and ATP are increased only by three or fourfold, which confirms that, as expected, the substrate binding sites are largely unaffected by the mutation. However, the turnover and efficiency of the Pro204His mutant is severely impaired, indicating that the mechanism of 'hinge' bending is hindered. The Pro204Phe enzyme was shown to be significantly less well folded than the wild-type and Pro204His enzymes, with considerable loss of both secondary and tertiary structure. It is proposed that the proline residue at 204 in the 'hinge' region of PGK plays a role in the stability and catalytic mechanism of the enzyme.
Abstract.
Author URL.
Crowhurst GS, Dalby AR, Isupov MN, Campbell JW, Littlechild JA (1999). Structure of a phosphoglycerate mutase:3-phosphoglyceric acid complex at 1.7 A.
Acta Crystallogr D Biol Crystallogr,
55(Pt 11), 1822-1826.
Abstract:
Structure of a phosphoglycerate mutase:3-phosphoglyceric acid complex at 1.7 A.
The crystal structure of the tetrameric glycolytic enzyme phosphoglycerate mutase from the yeast Saccharomyces cerevisiae has been determined to 1.7 a resolution in complex with the sugar substrate. The difference map indicates that 3-phosphoglycerate is bound at the base of a 12 a cleft, positioning C2 of the substrate within 3.5 a of the primary catalytic residue, histidine 8.
Abstract.
Author URL.
Bourne PC, Isupov MN, Littlechild JA (1999). THE ATOMIC RESOLUTION (1.15 angstrom) STRUCTURE OF a NOVEL BACTERIAL ESTERASE.
Author URL.
Schroder E, Isupov MI, Littlechild JA (1999). X-RAY STRUCTURAL STUDIES WITH HUMAN THIOREDOXIN PEROXIDASE.
Author URL.
Isupov MN, Lebedev AA, Harutyunyan EH, Antson FA, Wilson KS, Dodson GG, Zakomirdina LN, Littlechild JA, Dementieva IS (1999). X-RAY STUDIES OF TRYPTOPHANASE.
Author URL.
Crowhurst G, Isupov MN, Littlechild JA (1999). X-RAY STUDIES OF TWO GLYCOLYTIC ENZYMES FROM THE ARCHAEON SULFOLOBUS SOLFATARICUS.
Author URL.
Singleton M, Isupov M, Littlechild J (1999). X-ray structure of pyrrolidone carboxyl peptidase from the hyperthermophilic archaeon Thermococcus litoralis.
Structure,
7(3), 237-244.
Abstract:
X-ray structure of pyrrolidone carboxyl peptidase from the hyperthermophilic archaeon Thermococcus litoralis.
BACKGROUND: Pyrrolidone carboxyl peptidases (pcps) are a group of exopeptidases responsible for the hydrolysis of N-terminal pyroglutamate residues from peptides and proteins. The bacterial and archaeal pcps are members of a conserved family of cysteine proteases. The pcp from the hyperthermophilic archaeon Thermococcus litoralis is more thermostable than the bacterial enzymes with which it has up to 40% sequence identity. The pcp activity in archaea and eubacteria is proposed to be involved in detoxification processes and in nutrient metabolism; eukaryotic counterparts of the enzyme are involved in the processing of biologically active peptides. RESULTS: the crystal structure of pcp has been determined by multiple isomorphous replacement techniques at 1.73 a resolution and refined to an R factor of 18.7% (Rfree = 21.4%). The enzyme is a homotetramer of single open alpha/beta domain subunits, with a prominent hydrophobic core formed from loops coming together from each monomer. The active-site residues have been identified as a Cys143-His167-Glu80 catalytic triad. Structural homology to enzymes of different specificity and mechanism has been identified. CONCLUSIONS: the Thermococcus pcp has no sequence or structural homology with other members of the cysteine protease family. It does, however, show considerable similarities to other hydrolytic enzymes of widely varying substrate specificity and mechanism, suggesting that they are the products of divergent evolution from a common ancestor. The enhanced thermostability of the T. litoralis pcp may arise from hydrophobic interactions between the subunits and the presence of intersubunit disulphide bridges.
Abstract.
Author URL.
1998
Fleming TM, Jones CE, Piper PW, Cowan DA, Isupov MN, Littlechild JA (1998). Characterization, crystallization and preliminary X-ray investigation of glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus.
Acta Crystallogr D Biol Crystallogr,
54(Pt 4), 671-674.
Abstract:
Characterization, crystallization and preliminary X-ray investigation of glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus.
Recombinant Sulfolobus solfataricus glyceraldehyde-3-phosphate dehydrogenase has been purified and found to be a tetramer of 148 kDa. The enzyme shows dual cofactor specificity and uses NADP+ in preference to NAD+. The sequence has been compared with other GAPDH proteins including those from other archaeal sources. The purified protein has been crystallized from ammonium sulfate to produce crystals that diffract to 2.4 a with a space group of P43212 or P41212. A native data set has been collected to 2.4 a using synchrotron radiation and cryocooling.
Abstract.
Author URL.
McGhie EJ, Isupov MN, Schröder E, Littlechild JA (1998). Crystallization and preliminary X-ray diffraction studies of the oxygenating subunit of 3,6-diketocamphane monooxygenase from Pseudomonas putida.
Acta Crystallogr D Biol Crystallogr,
54(Pt 5), 1035-1038.
Abstract:
Crystallization and preliminary X-ray diffraction studies of the oxygenating subunit of 3,6-diketocamphane monooxygenase from Pseudomonas putida.
The oxygenating constituent of the 3,6-diketocamphane monooxygenase isozyme from Pseudomonas putida NCIMB 10007 has been crystallized under two different conditions. Crystals were initially grown from polyethylene glycol (PEG) 8000 and sodium acetate using the vapour-phase diffusion method. The crystals were of orthorhombic P212121 space group, with cell dimensions a = 55.8, b = 94.5 and c = 163.7 a and diffracted to 2.8 a resolution. More recently, improved crystals, which diffracted beyond 2 A, have been grown from ammonium sulfate. These crystals also belong to the orthorhombic P212121 space group, with cell dimensions of a = 54.6, b = 93.2 and c = 154. 1 A. A full native data set to 2.5 a resolution has been collected from the ammonium sulfate grown crystals.
Abstract.
Author URL.
Brindley AA, Dalby AR, Isupov MN, Littlechild JA (1998). Preliminary X-ray analysis of a new crystal form of the vanadium-dependent bromoperoxidase from Corallina officinalis.
Acta Crystallogr D Biol Crystallogr,
54(Pt 3), 454-457.
Abstract:
Preliminary X-ray analysis of a new crystal form of the vanadium-dependent bromoperoxidase from Corallina officinalis.
A new crystal form of the vanadium-dependent bromoperoxidase from Corallina officinalis has been obtained. The crystals exhibit a 'teardrop' morphology and are grown from 2 M ammonium dihydrogen phosphate pH and diffract to beyond 1.7 a resolution. They are in tetragonal space group P4222 with unit-cell dimensions of a = b = 201.9, c = 178.19 A, alpha = beta = gamma = 90 degrees. A 2.3 a resolution native data set has been collected at the Hamburg Synchrotron. A mercury derivative data set has also been collected, and the heavy-atom positions have been determined. The self-rotation function and the positions of the heavy atoms are consistent with the molecule being a dodecamer with local 23 symmetry.
Abstract.
Author URL.
Crowhurst GS, Isupov MN, Fleming T, Littlechild JA (1998). Two glycolytic enzymes from Sulfolobus solfataricus.
Author URL.
1997
Lewis G, Bevan J, Rawas A, McMichael P, Wisdom R, McCague R, Watson H, Littlechild J (1997). Crystallization and preliminary X-ray studies on Candida cylindracea lipase.
Acta Crystallogr D Biol Crystallogr,
53(Pt 3), 348-351.
Abstract:
Crystallization and preliminary X-ray studies on Candida cylindracea lipase.
As part of the programme to understand the mechanism and specificity of lipase enzymes used in biotransformation reactions, the lipase from Candida cylindracea has been purified and crystallized. This lipase has been widely used by organic chemists for hydrolysis and esterification reactions. Crystals were obtained using polyethylene glycol 6000 as a precipitant and grew to 0.6 mm in the maximum dimension. The enzyme crystallized in the space group P2(1) with unit-cell dimensions a = 94.3, b = 117.0, and c = 114.2 a with beta = 109.2 degrees. Calculations indicate that there are four molecules in the asymmetric unit. The crystals diffract to at least 2.5 a resolution and the structure has been solved by molecular replacement using the lipase from Geotrichum candidum as a search model.
Abstract.
Author URL.
Yagnik AT, Littlechild JA, Turner NJ (1997). Molecular modelling studies of substrate binding to the lipase from Rhizomucor miehei.
J Comput Aided Mol Des,
11(3), 256-264.
Abstract:
Molecular modelling studies of substrate binding to the lipase from Rhizomucor miehei.
Lipase enzymes have found increasingly widespread use, especially in biotransformation reactions in organic synthesis. Due to their efficiency and high enantioselectivity, they can be employed in a variety of reactions to carry out asymmetric hydrolyses, esterifications and transesterifications. However, the reasons for their stereospecificity have not been fully correlated with the enzyme structure. Employing molecular modelling techniques and existing experimental data, a transesterification reaction using Rhizomucor miehei lipase was studied. The results indicate that the major controlling factor for this reaction is hydrophobic in nature, providing support for previous literature hypotheses. In addition, computational experiments suggest that the origin of enantioselectivity is the formation of essential hydrogen bonds in and around the catalytic triad of active site residues. Only one enantiomer of the substrate is able to form these hydrogen bonds during the formation of the first tetrahedral transition state.
Abstract.
Author URL.
Bentley PA, Kroutil W, Littlechild JA, Roberts SM (1997). Preparation of polyamino acid catalysts for use in Julia asymmetric epoxidation.
Chirality,
9(2), 198-202.
Abstract:
Preparation of polyamino acid catalysts for use in Julia asymmetric epoxidation
This article describes improvements in the Julia asymmetric epoxidation reaction. The oligopeptides needed for the study were synthesised from N- carboxyanhydrides (NCAs) employing various initiators, such as water, 1,3- diaminopropane (DAP), and cross-linked aminomethylpolystyrene (CLAMPS) 1.
Abstract.
Fleming T, Littlechild J (1997). Sequence and structural comparison of thermophilic phosphoglycerate kinases with a mesophilic equivalent.
Comp Biochem Physiol a Physiol,
118(3), 439-451.
Abstract:
Sequence and structural comparison of thermophilic phosphoglycerate kinases with a mesophilic equivalent.
The monomeric glycolytic enzyme phosphoglycerate kinase (PGK) has been used as a model system to study protein thermostability. The primary sequence of this enzyme has been elucidated from 47 species to date. Although only 42 amino acids are totally conserved, most of which line the active site cleft, the protein is structurally conserved. This is achieved by making conservative changes to maintain the same secondary and tertiary folds. The crystal structures of 5 PGK enzymes have been solved by X-ray diffraction methods. This paper seeks to use the available information to understand protein thermostability. Although some general mechanisms to increase stability can be determined, different species have adopted a variety of subtle additive changes to achieve greater protein stability. Comparisons have been directly made between the PGK enzyme from yeast, the moderate thermophilic bacterium Bacillus stearothermophilus, the hyperthermophilic bacteria Thermus thermophilus, Thermotoga maritima, and the hyperthermophilic archaea Sulpholobus solfataricus and Methanothermus fervidus.
Abstract.
Author URL.
Isupov MN, Obmolova G, Butterworth S, BadetDenisot MA, Badet B, Polikarpov I, Littlechild JA, Teplyakov A (1997). Substrate binding is required for assembly of the active conformation of the catalytic site in Ntn amidotransferases: Evidence from the 1.8 angstrom crystal structure of the glutaminase domain of glucosamine 6-phosphate synthase (vol 4, pg 801, 1996).
STRUCTURE,
5(5), 723-723.
Author URL.
1996
Dalby A, Rush C, Willetts A, Davies G, Dauter Z, Littlechild J (1996). ANALYSIS OF THE VANADIUM DEPENDENT HALOPEROXIDASE FROM CORALLINA OFFICINALIS.
Author URL.
Lilly MD, Chauhan R, French C, Gyamerah M, Hobbs GR, Humphrey A, Isupov M, Littlechild JA, Mitra RK, Morris KG, et al (1996). Carbon-carbon bond synthesis: the impact of rDNA technology on the production and use of E. coli transketolase.
Abstract:
Carbon-carbon bond synthesis: the impact of rDNA technology on the production and use of E. coli transketolase
Abstract.
Piper PW, Emson C, Jones CE, Cowan DA, Fleming TM, Littlechild JA (1996). Complementation of a pgk deletion mutation in Saccharomyces cerevisiae with expression of the phosphoglycerate-kinase gene from the hyperthermophilic Archaeon Sulfolobus solfataricus.
Curr Genet,
29(6), 594-596.
Abstract:
Complementation of a pgk deletion mutation in Saccharomyces cerevisiae with expression of the phosphoglycerate-kinase gene from the hyperthermophilic Archaeon Sulfolobus solfataricus.
The gene encoding phosphoglycerate kinase (PGK) from the Archaeon Sulfolobus solfataricus, an organism growing optimally at 87 degrees C, was inserted into a yeast expression vector under the control of the galactose-inducible GAL1 yeast promoter. This vector was then transformed into a pgk::TRP1 yeast mutant, a strain inhibited for growth on galactose or glucose due to its lack of PGK enzyme. Slow-growing transformants were obtained on galactose plates at 37 degrees C, but not 28 degrees C. These transformants contained low levels of transcripts of the heterologous gene and low amounts of thermostable PGK activity. Weak expression of the hyperthermophile gene in yeast, a mesophile, therefore enabled complementation of the yeast pgk defect at 37 degrees C but not at 28 degrees C.
Abstract.
Author URL.
Dalby A, Rawas A, Watson HC, Littlechild JA (1996). Crystallisation and preliminary x-ray diffraction studies on human liver aldolase.
Protein and Peptide Letters,
3(3), 207-212.
Abstract:
Crystallisation and preliminary x-ray diffraction studies on human liver aldolase
Human liver aldolase has been crystallised from an over-expressed protein in the space group I212121 with unit cell dimensions a = 189.0 Å, b = 59.5 Å and c = 155.2 Å, α = β = γ = 90°. The structure has been solved by molecular replacement at 3.8 Å resolution using human muscle aldolase as an initial model.
Abstract.
Brabban AD, Littlechild J, Wisdom R (1996). Stereospecific γ-lactamase activity in a Pseudomonas fluorescens species.
Journal of Industrial Microbiology,
16(1), 8-14.
Abstract:
Stereospecific Îł-lactamase activity in a Pseudomonas fluorescens species
Twenty five environmental isolates enriched for their ability to grow on N-acetylphenylalanine as sole carbon source were investigated for their hydrolytic action on (+)γ-lactam (2-azabicyclo[2.2.1]hept-5-en-3-one). Strain CMC 3060, a mucoidal Gram-negative rod identified as a strain of Pseudomonas fluorescens, produced high levels of (+)lactamase, and was subsequently found to produce two distinct intracellular enantiomer-selective γ-lactamases, one for each isomer. The (+)lactamase was produced constitutively whereas the (-)lactamase was produced only in the presence of the substrate. The (+)lactamase was stable when stored as a frozen cell paste but unstable as a protein solution, losing activity during purification and storage. This enzyme was highly selective for the (+)lactam and showed no activity against a wide range of similar compounds. By use of rapid purification techniques and the inclusion of protease inhibitors and protein stabilisers, the (+)lactamase was purified to homogeneity by FPLC and found to be a monomer of molecular weight 61000 Da.
Abstract.
Mcharg J, Littlechild JA (1996). Studies with inhibitors of the glycolytic enzyme phosphoglycerate kinase for potential treatment of cardiovascular and respiratory disorders.
J Pharm Pharmacol,
48(2), 201-205.
Abstract:
Studies with inhibitors of the glycolytic enzyme phosphoglycerate kinase for potential treatment of cardiovascular and respiratory disorders.
Inhibition of the glycolytic enzyme phosphoglycerate kinase (PGK) in erythrocyte cells could provide a method of treatment for cardiovascular and respiratory disorders. The product of the reaction catalysed by PGK, 1,3-diphosphoglycerate, is converted by another enzyme in erythrocytes to 2,3-diphosphoglycerate, which is an allosteric effector of haemoglobin. For this reason, a series of fluoro-phosphonate inhibitors have been tested for their potency in detailed inhibition kinetic experiments with yeast PGK. The results were analysed by Lineweaver-Burk and Dixon plots and Ki values obtained. Two fluorophosphonates were found to be inhibitory and both have an electron rich mid-chain functionality, which is thought to provide electrons for hydrogen bonding to residues in the triose binding site of the enzyme. It is postulated that either the fluorine or mid-chain moieties of the analogues are binding to Asp23 and Asn25 residues in the so called 'basic patch' area of the triose site. These residues are shown to bind to the D-hydroxyl moiety on the C2 of the true substrate, 3-phosphoglycerate, in the high-resolution crystal structure of pig muscle PGK co-crystallized with 3-phosphoglycerate.
Abstract.
Author URL.
Dalby A, Littlechild JA (1996). Studies with type I aldolase to understand fructose intolerance and combat parasitic disease.
J Pharm Pharmacol,
48(2), 214-217.
Abstract:
Studies with type I aldolase to understand fructose intolerance and combat parasitic disease.
A structural study of the type I aldolases has been carried out to examine the isozyme specificity of these enzymes and the potential for designing specific inhibitors. Natural mutations in these aldolase enzymes are associated with haemolytic anaemia and fructose intolerance. It has also been proposed that inhibition of the parasitic version of the enzyme may provide a new lead in the design of drugs against malaria and sleeping sickness. X-ray crystallographic data is used with molecular modelling techniques to investigate the structural properties of these enzymes.
Abstract.
Author URL.
Isupov MN, Obmolova G, Butterworth S, Badet-Denisot MA, Badet B, Polikarpov I, Littlechild JA, Teplyakov A (1996). Substrate binding is required for assembly of the active conformation of the catalytic site in Ntn amidotransferases: evidence from the 1.8 a crystal structure of the glutaminase domain of glucosamine 6-phosphate synthase.
Structure,
4(7), 801-810.
Abstract:
Substrate binding is required for assembly of the active conformation of the catalytic site in Ntn amidotransferases: evidence from the 1.8 a crystal structure of the glutaminase domain of glucosamine 6-phosphate synthase.
BACKGROUND: Amidotransferases use the amide nitrogen of glutamine in a number of important biosynthetic reactions. They are composed of a glutaminase domain, which catalyzes the hydrolysis of glutamine to glutamate and ammonia, and a synthetase domain, catalyzing amination of the substrate. To gain insight into the mechanism of nitrogen transfer, we examined the structure of the glutaminase domain of glucosamine 6-phosphate synthase (GLMS). RESULTS: the crystal structures of the enzyme complexed with glutamate and with a competitive inhibitor, Glu-hydroxamate, have been determined to 1.8 a resolution. The protein fold has structural homology to other members of the superfamily of N-terminal nucleophile (Ntn) hydrolases, being a sandwich of antiparallel beta sheets surrounded by two layers of alpha helices. CONCLUSIONS: the structural homology between the glutaminase domain of GLMS and that of PRPP amidotransferase (the only other Ntn amidotransferase whose structure is known) indicates that they may have diverged from a common ancestor. Cys1 is the catalytic nucleophile in GLMS, and the nucleophilic character of its thiol group appears to be increased through general base activation by its own alpha-amino group. Cys1 can adopt two conformations, one active and one inactive; glutamine binding locks the residue in a predetermined conformation. We propose that when a nitrogen acceptor is present Cys1 is kept in the active conformation, explaining the phenomenon of substrate-induced activation of the enzyme, and that Arg26 is central in this coupling.
Abstract.
Author URL.
McGhie EJ, Littlechild JA (1996). The purification and crystallisation of 2,5-diketocamphane 1,2 monooxygenase and 3,6-diketocamphane 1,6 monooxygenase from Pseudomonas putida NCIMB 10007.
McGhie EJ, Littlechild JA (1996). The purification and crystallisation of 2,5-diketocamphane 1,2-monooxygenase and 3,6-diketocamphane 1,6-monooxygenase from Pseudomonas putida NCIMB 10007.
Biochem Soc Trans,
24(1).
Author URL.
Fleming TM, Jones CE, Piper PW, Cowan DA, Adams MWW, Littlechild JA (1996). The purification and crystallisation of phosphoglycerate kinase from the hyperthermophilic eubacterium thermotoga maritima.
Protein and Peptide Letters,
3(3), 213-218.
Abstract:
The purification and crystallisation of phosphoglycerate kinase from the hyperthermophilic eubacterium thermotoga maritima
Two phosphoglycerate kinase enzymes have been purified from the hyperthermophilic eubacterium Thermotoga maritima. One has been shown to be monomeric with a MW of 41 kDa, whilst the other, in contrast to other phosphoglycerate kinases that have been studied, is seen to be tetrameric by gel filtration, with a subunit MW of 70 kDa by SDS PAGE. The tetrameric PGK is a fusion protein with triose phosphate isomerase and has been crystallised from ammonium sulphate in the presence of the triose sugar substrate 3-phosphoglycerate.
Abstract.
1995
Jones CE, Fleming TM, Piper PW, Littlechild JA, Cowan DA (1995). Cloning and sequencing of a gene from the archaeon Pyrococcus furiosus with high homology to a gene encoding phosphoenolpyruvate synthetase from Escherichia coli.
Gene,
160(1), 101-103.
Abstract:
Cloning and sequencing of a gene from the archaeon Pyrococcus furiosus with high homology to a gene encoding phosphoenolpyruvate synthetase from Escherichia coli.
A gene from the hyperthermophilic archaeon Pyrococcus furiosus, strain Vc1 (DSM 3638), contains an 817-amino-acid open reading frame which shows 42% identity to the phosphoenolpyruvate (PEP) synthetase of Escherichia coli. This putative P. furiosus PEP synthetase is slightly larger than the E. coli enzyme, the region between residues 58 and 89 being absent from the latter.
Abstract.
Author URL.
Littlechild J, Turner N, Hobbs G, Lilly M, Rawas A, Watson H (1995). Crystallization and preliminary X-ray crystallographic data with Escherichia coli transketolase.
Acta Crystallogr D Biol Crystallogr,
51(Pt 6), 1074-1076.
Abstract:
Crystallization and preliminary X-ray crystallographic data with Escherichia coli transketolase.
The Escherichia coli enzyme transketolase, a dimeric protein of 2 x 70 kDa (662 amino acids) has been prepared from an overexpression system in E. coli. The purified enzyme has been crystallized from PIPES buffer pH 6.4 and ammonium sulfate. The crystals which grow as large plates diffract to greater than 1.9 A, resolution and are of the space group P2(1)2(1)2(1) with unit-cell dimensions of a = 74.6, b = 125.6 and c = 151.0 A, (Z = 8 with one transketolase dimer in the asymmetric unit). The structure has been solved by molecular replacement using the yeast transketolase enzyme structure as a search model. The enzyme is being used for large-scale biotransformations using various aldehydes and hydroxypyruvate as substrates.
Abstract.
Author URL.
Rush C, Willetts A, Davies G, Dauter Z, Watson H, Littlechild J (1995). Purification, crystallisation and preliminary X-ray analysis of the vanadium-dependent haloperoxidase from Corallina officinalis.
FEBS Lett,
359(2-3), 244-246.
Abstract:
Purification, crystallisation and preliminary X-ray analysis of the vanadium-dependent haloperoxidase from Corallina officinalis.
The vanadium-dependent haloperoxidase from the seaweed Corallina officinalis has been purified to homogeneity and crystallised. The protein is reported to be a hexamer of 12 x 64,000 Da, contains no haem, and is dependent on vanadium for activity. The crystals are grown from polyethylene glycol (PEG) 6,000 and 0.4 M potassium chloride. They are stable and diffract to better than 2 a resolution. They are of a cubic space group I23 (or 12(1)3) with cell dimensions a = b = c = 310 A.
Abstract.
Author URL.
Jones CE, Fleming TM, Cowan DA, Littlechild JA, Piper PW (1995). The phosphoglycerate kinase and glyceraldehyde-3-phosphate dehydrogenase genes from the thermophilic archaeon Sulfolobus solfataricus overlap by 8-bp. Isolation, sequencing of the genes and expression in Escherichia coli.
Eur J Biochem,
233(3), 800-808.
Abstract:
The phosphoglycerate kinase and glyceraldehyde-3-phosphate dehydrogenase genes from the thermophilic archaeon Sulfolobus solfataricus overlap by 8-bp. Isolation, sequencing of the genes and expression in Escherichia coli.
The overlapping genes encoding phosphoglycerate kinase (PGK) and glyceraldehyde-3-phosphate dehydrogenase (GraP-DH) from the hyperthermophilic archaeon Sulfolobus solfataricus have been cloned and sequenced. PCR primers based on highly conserved regions of different PGK sequences were used to isolate an internal region of the pgk gene. This was then used to screen a genomic library to isolate the full length pgk gene. A 2.5-kb BglII fragment of S. solfataricus DNA contained both the pgk gene and the gap gene immediately downstream. Unexpectedly, the pgk and gap genes were found to overlap by 8 bp, with the initiation codon of the gap gene preceding the termination codon of the pgk gene. Evidence that the two genes are co-transcribed was obtained by Northern-blot analysis. The S. solfataricus PGK amino acid sequence shows 43% and 45% identity to the PGK sequences of the Archaea Methanobacterium bryantii and Methanothermus fervidus, respectively. High level expression of the S. solfataricus PGK and GraP-DH in Escherichia coli was achieved, with heat treatment at 80 degrees C proving an effective first step in the purification of these recombinant enzymes from extracts of the E. coli host. Purified recombinant S. solfataricus PGK and GraP-DH showed half lives of 39 min and 17 h, respectively, at 80 degrees C. Unlike bacterial GraP-DH enzymes, S. solfataricus GraP-DH was able to use both NAD+ and NADP+ as cofactors, but exhibited a marked preference for NADP+.
Abstract.
Author URL.
1994
Davies GJ, Gamblin SJ, Littlechild JA, Dauter Z, Wilson KS, Watson HC (1994). Structure of the ADP complex of the 3-phosphoglycerate kinase from Bacillus stearothermophilus at 1.65 A.
Acta Crystallogr D Biol Crystallogr,
50(Pt 2), 202-209.
Abstract:
Structure of the ADP complex of the 3-phosphoglycerate kinase from Bacillus stearothermophilus at 1.65 A.
The structure of the ADP complex of the enzyme 3-phosphoglycerate kinase (PGK, E.C. 2.7.2.3) from Bacillus stearothermophilus NCA-1503 has been determined by the method of molecular replacement. The structure has been refined to an R factor of 0.16 for all data between 10.0 and 1.65 a resolution, using data collected on the Hendrix-Lentfer imaging plate at the EMBL outstation in Hamburg. The r.m.s. deviations from stereochemical ideality are 0.010 and 0.011 a for bonds and planes, respectively. Although crystallized in the presence of the nucleotide product MgATP, the high-resolution structure reveals the bound nucleotide to be MgADP reflecting the low intrinsic ATPase activity of PGK. Although the two domains of this enzyme are found to be some 4.5 degrees closer together than is found in the yeast and horse-muscle apo-enzyme structures, this structure represents the 'open' rather than the 'closed', catalytically competent form, of the enzyme.
Abstract.
Author URL.
1993
Littlechild JA, Watson HC (1993). A data-based reaction mechanism for type I fructose bisphosphate aldolase.
Trends Biochem Sci,
18(2), 36-39.
Abstract:
A data-based reaction mechanism for type I fructose bisphosphate aldolase.
The structures of three type I fructose-1,6-bisphosphate aldolases have been determined and the common residues surrounding the Schiff base-forming Lys residue located. Armed with this information, it is now possible to propose a mechanism for this ubiquitous enzyme which is consistent with the recorded biochemical data. An interesting, but by no means mandatory, feature of the reaction mechanism is that catalysis can proceed without exchange with the solvent.
Abstract.
Author URL.
Taylor SJ, McCague R, Wisdom R, Lee C, Dickson K, Ruecroft G, O'Brien F, Littlechild J, Bevan J, Roberts SM, et al (1993). Development of the biocatalytic resolution of 2-azabicyclo[2.2.1]hept-5-en-3-one as an entry to single-enantiomer carbocyclic nucleosides.
Tetrahedron: Asymmetry,
4(6), 1117-1128.
Abstract:
Development of the biocatalytic resolution of 2-azabicyclo[2.2.1]hept-5-en-3-one as an entry to single-enantiomer carbocyclic nucleosides
For the resolution of the bicyclic lactam 2-azabicyclo[2.2.1]hept-5-en-3-one, efficient whole cell biocatalysts have been identified and from these, enzymes (lactamases) have been isolated. While the two enzymes obtained act on different enantiomers of the lactam, either can be used in scaleable processes to obtain synthons for carbocyclic nucleosides having the natural configuration. © 1993.
Abstract.
BARBER MD, GAMBLIN SJ, WATSON HC, LITTLECHILD JA (1993). SITE-DIRECTED MUTAGENESIS OF YEAST PHOSPHOGLYCERATE KINASE - ARGININE-65, ARGININE-121 AND ARGININE-168.
FEBS LETTERS,
320(3), 193-197.
Author URL.
Vellieux FM, Hajdu J, Verlinde CL, Groendijk H, Read RJ, Greenhough TJ, Campbell JW, Kalk KH, Littlechild JA, Watson HC, et al (1993). Structure of glycosomal glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma brucei determined from Laue data.
Proc Natl Acad Sci U S A,
90(6), 2355-2359.
Abstract:
Structure of glycosomal glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma brucei determined from Laue data.
The three-dimensional structure of glycosomal glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.12.1.12] from the sleeping-sickness parasite Trypanosoma brucei was solved by molecular replacement at 3.2-A resolution with an x-ray data set collected by the Laue method. For data collection, three crystals were exposed to the polychromatic synchrotron x-ray beam for a total of 20.5 sec. The structure was solved by using the Bacillus stearothermophilus enzyme model [Skarzyński, T. Moody, P. C. E. & Wonacott, A. J. (1987) J. Mol. Biol. 193, 171-187] with a partial data set which was 37% complete. The crystals contain six subunits per asymmetric unit, which allowed us to overcome the absence of > 60% of the reflections by 6-fold density averaging. After molecular dynamics refinement, the current molecular model has an R factor of 17.6%. Comparing the structure of the trypanosome enzyme with that of the homologous human muscle enzyme, which was determined at 2.4-A resolution, reveals important structural differences in the NAD binding region. These are of great interest for the design of specific inhibitors of the parasite enzyme.
Abstract.
Author URL.
Davies GJ, Gamblin SJ, Littlechild JA, Watson HC (1993). The structure of a thermally stable 3-phosphoglycerate kinase and a comparison with its mesophilic equivalent.
Proteins,
15(3), 283-289.
Abstract:
The structure of a thermally stable 3-phosphoglycerate kinase and a comparison with its mesophilic equivalent.
The structure of the phosphoglycerate kinase (PGK) from Bacillus stearothermophilus, a moderate thermophile, has been determined and compared with that of its mesophilic equivalent from yeast. The Bacillus enzyme structure was solved by molecular replacement and improved using constrained rigid-body, molecular dynamics and conventional refinement procedures. The refinement residual, calculated using all the measured data between 8 and 1.65 A, is 0.18(1). The stereo chemical deviations of the final model from ideality are 0.01 a for both bonds and planes. The mid-point temperatures of the Bacillus and yeast enzymes are 67 and 53 degrees C, respectively. Differential scanning calorimetry indicates that the energy difference (delta delta G) between the mesophilic and thermophilic enzymes is of the order of 5 kcal mol-1 at room temperature. The structure comparison indicates that the features most likely to be responsible for the increased thermal stability of the Bacillus enzyme are the increased internal hydrophobicity, additional ion pairs, and better alpha-helix stability resulting from the removal of helix destabilizing residues and extra helix-dipole/helix side chain ionic interactions.
Abstract.
Author URL.
1992
Joao HC, Williams RJ, Littlechild JA, Nagasuma R, Watson HC (1992). An investigation of large inhibitors binding to phosphoglycerate kinase and their effect on anion activation.
Eur J Biochem,
205(3), 1077-1088.
Abstract:
An investigation of large inhibitors binding to phosphoglycerate kinase and their effect on anion activation.
This study extends, to a series of larger anions, our earlier investigation of the interaction of the trypanocidal drug suramin and other small negatively charged molecules with yeast phosphoglycerate kinase. 1H-NMR structural studies of phosphoglycerate kinase in the presence of varying concentrations of these large molecules (designed to mimic, at one end, the anionic charge distribution in the substrate 3-phosphoglycerate, while possibly being able to interact across the cleft of the enzyme) including inositol 1,4,5-triphosphate, 4-amino-6-trichloroethenyl-1,3- benzenedisulphonamide, gallic acid and sulphasalazine are described. The anion activation and/or inhibition of the enzyme by these molecules are also reported. Evidence that binding to the general anion site in the 'basic patch' region of the protein may be responsible for either the activating or inhibiting effects, while binding at the hydrophobic (catalytic) site leads to inhibition only is presented. A reaction scheme which explains these observations is given.
Abstract.
Author URL.
Walker PA, Joâo HC, Littlechild JA, Williams RJ, Watson HC (1992). Characterisation of yeast phosphoglycerate kinase modified by mutagenesis at residue 21.
Eur J Biochem,
207(1), 29-37.
Abstract:
Characterisation of yeast phosphoglycerate kinase modified by mutagenesis at residue 21.
Site-directed mutagenesis has been used to produce mutant forms of yeast phosphoglycerate kinase in which the conserved active-site residue, Arg21, has been replaced by a methionine or a lysine. Kinetic results obtained using these mutant enzymes show that their Km for both 3-phospho-D-glycerate and ATP are significantly different from those recorded for the wild-type enzyme. The Vmax for the lysine mutant is reduced by a factor of two from that of the wild-type enzyme whereas the Vmax for the methionine mutant is reduced more than sevenfold. A very clean electron-density-difference map shows little, if any, evidence of a structural change associated with the C-terminal domain, although resonances in the NMR spectra associated with the ATP-binding site (C-terminal domain) are also affected by the mutation as one might expect from the kinetic results. The NMR data show that binding at both the 3-phospho-D-glycerate and the non-productive ATP-binding site (associated with the N-terminal domain) are affected in the mutant in a way which is different to that associated with the wild-type enzyme. These results, taken together with the X-ray and kinetic data, indicate that the non-productive ATP-binding site and the activating anion-binding site are both associated with the basic patch region of yeast phosphoglycerate kinase.
Abstract.
Author URL.
Eisenberg D, Perutz MF, Buckingham AD, Graf L, Thornton J, Blow DM, Fersht AR, Karplus M, Johnson LN, Rippmann F, et al (1992). General discussion. Faraday Discussions, 93, 107-129.
Davies GJ, Gamblin SJ, Littlechild JA, Watson HC (1992). Purification, crystallization and preliminary X-ray analysis of the 3-phosphoglycerate kinase from Bacillus stearothermophilus.
J Mol Biol,
227(4), 1263-1264.
Abstract:
Purification, crystallization and preliminary X-ray analysis of the 3-phosphoglycerate kinase from Bacillus stearothermophilus.
As part of a programme investigating the molecular basis of thermal stability in proteins we have isolated and characterized the thermally stable 3-phosphoglycerate kinase (PGK) from Bacillus stearothermophilus NCA 1503. The B. stearothermophilus PGK has been crystallized in a form suitable for X-ray diffraction analysis. Crystals which diffract to greater than 1.8 a resolution have been grown in the presence of the nucleotide substrate, MgATP, using polyethylene glycol (PEG 600) as a precipitant. The best crystals have been obtained using "seeding" techniques and are monoclinic, space group P2(1), with cell dimensions a = 40.5 A, b = 74.0 A, c = 68.5 a and beta = 99.8 degrees.
Abstract.
Author URL.
Littlechild JA (1992). Structure and function. Nature, 359(6394), 448-449.
1991
Graham HC, Williams RJ, Littlechild JA, Watson HC (1991). A proton-NMR study of a site-directed mutation (His388----Glu) in the interdomain region of yeast phosphoglycerate kinase. Implications for domain movement.
Eur J Biochem,
196(2), 261-269.
Abstract:
A proton-NMR study of a site-directed mutation (His388----Glu) in the interdomain region of yeast phosphoglycerate kinase. Implications for domain movement.
Proton NMR has been used to study a site-directed mutant of yeast phosphoglycerate kinase in which the interdomain residue His388 has been replaced by a glutamine residue. Using 1H-NMR spectroscopy, it was found that 3-phosphoglycerate binding to the mutant protein induces different conformational effects to those observed for the wild-type enzyme. These differences are not only located at the 3-phosphoglycerate binding site but are also seen as long-range effects at the surface of the protein. Measurements of the Kd for 3-phosphoglycerate from the NMR experiments show that the mutant enzyme has a 30-times reduced affinity for this substrate as compared with the wild-type enzyme. These data are consistent with the suggestion that an aromatic residue at position 388 plays an important role in the proposed hinge-bending mechanism.
Abstract.
Author URL.
Gamblin SJ, Davies GJ, Grimes JM, Jackson RM, Littlechild JA, Watson HC (1991). Activity and specificity of human aldolases.
J Mol Biol,
219(4), 573-576.
Abstract:
Activity and specificity of human aldolases.
The structure of the type I fructose 1,6-bisphosphate aldolase from human muscle has been extended from 3 a to 2 a resolution. The improvement in the resulting electron density map is such that the 20 or so C-terminal residues, known to be associated with activity and isozyme specificity, have been located. The side-chain of the Schiff's base-forming lysine 229 is located towards the centre of an eight-stranded beta-barrel type structure. The C-terminal "tail" extends from the rim of the beta-barrel towards lysine 229, thus forming part of the active site of the enzyme. This structural arrangement appears to explain the difference in activity and specificity of the three tissue-specific human aldolases and helps with our understanding of the type I aldolase reaction mechanism.
Abstract.
Author URL.
Littlechild JA (1991). Protein crystallization: Magical or logical: can we establish some general rules?.
Journal of Physics D: Applied Physics,
24(2), 111-118.
Abstract:
Protein crystallization: Magical or logical: can we establish some general rules?
The systematic-type studies carried out on small molecule crystallization are of limited use when dealing with proteins. The reasons for this are that proteins have a much higher molecular weight, typically ranging from 10000 to 250000 daltons and are of lower symmetry than small molecules. Protein crystals are ’soft’ and sensitive to small changes in external conditions since they have a high solvent content. There are small binding energies between protein molecules in the crystal lattice. This means that there are a large number of potential attachment sites which are almost as favourable as the small number of specific sites through which the ordered array is formed. Despite these problems, some general rules have been established and procedures devised that can be followed when attempting to crystallize a new protein. These rules and procedures are illustrated by using specific examples of crystals grown from monomeric and multisubunit proteins isolated from a variety of bacterial and animal sources. © 1991 IOP Publishing Ltd.
Abstract.
Davies GJ, Littlechild JA, Watson HC, Hall L (1991). Sequence and expression of the gene encoding 3-phosphoglycerate kinase from Bacillus stearothermophilus.
Gene,
109(1), 39-45.
Abstract:
Sequence and expression of the gene encoding 3-phosphoglycerate kinase from Bacillus stearothermophilus.
The structural gene (pgk) encoding 3-phosphoglycerate (PGK) from Bacillus stearothermophilus NCA1503, has been cloned in Escherichia coli and its complete nucleotide sequence determined. The gene consists of an open reading frame corresponding to a protein of 394 amino acids (aa) (calculated Mr 42,703) and, in common with other prokaryotic pgk genes, is preceded by the structural gene encoding glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Constructs containing the B. stearothermophilus pgk gene and its flanking sequences in the high-copy plasmid, pUC9, co-express both PGK and GAPDH at high levels in transformed E. coli cells, typically producing PGK at levels of up to 30% of the soluble cell protein. The deduced aa sequence of B. stearothermophilus PGK is compared with those of the mesophilic (yeast) and extreme thermophilic (Thermus thermophilus) enzymes since the crystal structure of these PGKs are known or are in the process of being determined. Changes in the sequences of the three enzymes, as they appear to relate to the enhancement of thermal stability, are discussed.
Abstract.
Author URL.
1990
Watson HC, Littlechild JA (1990). Isoenzymes of phosphoglycerate kinase: evolutionary conservation of the structure of this glycolytic enzyme.
Author URL.
Minard P, Bowen DJ, Hall L, Littlechild JA, Watson HC (1990). Site-directed mutagenesis of aspartic acid 372 at the ATP binding site of yeast phosphoglycerate kinase: over-expression and characterization of the mutant enzyme.
Protein Eng,
3(6), 515-521.
Abstract:
Site-directed mutagenesis of aspartic acid 372 at the ATP binding site of yeast phosphoglycerate kinase: over-expression and characterization of the mutant enzyme.
A new phosphoglycerate kinase over-expression vector, pYE-PGK, has been constructed which greatly facilitates the insertion and removal of mutant enzyme genes by cleavage at newly introduced BamHI sites. This vector has been used to prepare mutant protein in appreciable (100 mg) quantities for use in kinetic, crystallographic and NMR experiments. Aspartate 372 is an invariant amino acid residue in genes known to code for a functionally active PGK. The function of this acidic residue appears to be to help desolvate the magnesium ion complexed with either ADP or ATP when this substrate binds to the enzyme. Both crystallographic and nuclear magnetic resonance experiments show that the replacement of the residue with asparagine has only minimal effects on the overall structure. The substitution of the charged carboxyl group with that of the neutral amide affects the binding of the nucleotide substrate as predicted but not, as might have been expected, the binding of 3-phosphoglycerate. The overall velocity of the enzymic reaction (Vmax) is reduced 10-fold by the substitution of aspartic acid 372 by an asparagine residue (D372N). This reduction in Vmax is considerably less than one would expect from its known position within the structure of the enzyme. This result therefore poses questions about our understanding of charged groups at the active centres of enzymes and of the reason for their apparent conservation.
Abstract.
Author URL.
Gamblin SJ, Cooper B, Millar JR, Davies GJ, Littlechild JA, Watson HC (1990). The crystal structure of human muscle aldolase at 3.0 a resolution.
FEBS Lett,
262(2), 282-286.
Abstract:
The crystal structure of human muscle aldolase at 3.0 a resolution.
The three-dimensional structure of fructose-1,6-bisphosphate aldolase from human muscle has been determined at 3.0 a resolution by X-ray crystallography. The active protein is a tetramer of 4 identical subunits each of which is composed of an eight-stranded alpha/beta-barrel structure. The lysine residue responsible for Schiff base formation with the substrate is located near the centre of the barrel in the middle of the sixth beta-strand. While the overall topology of the alpha/beta-barrel is very similar to those found in several other enzymes, the distribution of charged residues inside the core of the barrel seems distinct. The quaternary fold of human muscle aldolase uses interfacial regions also involved in the subunit association of other alpha/beta-barrel proteins found in glycolysis, but exploits these regions in a manner not seen previously.
Abstract.
Author URL.
1989
Fairbrother WJ, Walker PA, Minard P, Littlechild JA, Watson HC, Williams RJ (1989). NMR analysis of site-specific mutants of yeast phosphoglycerate kinase. An investigation of the triose-binding site.
Eur J Biochem,
183(1), 57-67.
Abstract:
NMR analysis of site-specific mutants of yeast phosphoglycerate kinase. An investigation of the triose-binding site.
Site-specific mutants of yeast phosphoglycerate kinase have been produced in order to investigate the roles of the 'basic-patch' residues, arginine 168 and histidine 170. The fully-conserved residue, arginine 168, has been replaced with a lysine (R168K) and a methionine (R168M) residue, while the non-conserved histidine 170 has been replaced with an aspartate (H170D). Comparison of the 500-MHz 1H-NMR spectra of the mutant proteins with that of wild-type phosphoglycerate kinase shows that the overall fold of the mutants remains essentially unaltered from that of the native enzyme. Results of NOE experiments indicate that there are only very minor changes in structure in the vicinity of the mutations. These mutations have also led to firm sequence-specific resonance assignments to histidines 62, 167 and 170. NMR studies of 3-phosphoglycerate binding show that decreasing the positive charge in the sequence 168-170 reduces the binding of this substrate (by about 15-fold and 4-fold for mutants R168M and H170D respectively). Mutant R168K binds 3-phosphoglycerate with an affinity about twofold less than that of the native enzyme. Significantly, the activity of mutant H170D, measured at saturating substrate concentrations, is unchanged from that of the wild-type enzyme. This indicates that this residue is not of major importance in the binding or reaction of 3-phosphoglycerate. The observation is in agreement with results obtained for the wild-type enzyme, which indicate that 3-phosphoglycerate interacts most strongly with histidine 62 and least strongly with histidine 170, as would be predicted from the X-ray crystal structure. Substitution of positively charged arginine 168 with neutral methionine (or positively charged lysine) does not cause a detectable change in the pKa values of the neighbouring histidine groups, in as much as they remain below 3. The results reported here indicate that the observed reduction in catalytic efficiency relates less to direct electrostatic effects than to the mutants' inability to undergo 3-phosphoglycerate-induced conformational changes.
Abstract.
Author URL.
Fairbrother WJ, Hall L, Littlechild JA, Walker PA, Watson HC, Williams RJ (1989). Site-directed mutagenesis of histidine 62 in the 'basic patch' region of yeast phosphoglycerate kinase.
FEBS Lett,
258(2), 247-250.
Abstract:
Site-directed mutagenesis of histidine 62 in the 'basic patch' region of yeast phosphoglycerate kinase.
Site-directed mutagenesis has been used to produce a mutant form of yeast phosphoglycerate kinase (PGK) in which the 'basic patch' residue His 62 has been replaced by a glutamine residue. Using 1H-NMR spectroscopy, it was found that 3-phosphoglycerate (3-PG) binding to the mutant protein induces the same conformational effects as for wild-type PGK, although the affinity was reduced by 2- to 3-fold. Kinetic studies show both Km for 3-PG and Vmax to be increased by approximately 2-fold relative to the wild-type enzyme. These data are consistent with the suggestion that His 62 assists in the binding of the substrate to the enzyme.
Abstract.
Author URL.
Walker PA, Littlechild JA, Hall L, Watson HC (1989). Site-directed mutagenesis of yeast phosphoglycerate kinase. The 'basic-patch' residue arginine 168.
Eur J Biochem,
183(1), 49-55.
Abstract:
Site-directed mutagenesis of yeast phosphoglycerate kinase. The 'basic-patch' residue arginine 168.
There is evidence, some of it of questionable authenticity, which suggests that phosphoglycerate kinase takes up a more compact form following the binding of substrates. Using this evidence it has been assumed that a conformational rearrangement is required for phosphoryl transfer to occur and that this is brought about by moving the enzyme's two domains towards each other. In order to test this hypothesis we have modified, by site-directed mutagenesis, an arginine residue thought to be involved in stabilising the transition-state intermediate. Although some 1.3 nm away from the site of phosphoryl transfer, as seen in the crystallographically determined structure, the substitution of arginine 168 by lysine (R168K) more than halves the specific activity of the enzyme. Substituting the arginine with a methionine (R168M) reduces activity further, but not completely, thus proving that the charge associated with this residue is not essential for catalytic activity. Both mutations raise the Michaelis constants (Km) for ATP and glycerate 3-phosphate. The largest change is observed with the triose substrate and the methionine mutant, suggesting that the primary function of arginine 168 is to influence the environment of this substrate. The effect on activity of adding sulphate to R168K and R168M mutant enzyme has also been investigated. The sulphate activation effect at low substrate concentrations is reduced for the methionine substitution but almost abolished for the lysine substitution. The most reasonable explanation of all these findings is that, in the wild-type enzyme, the guanidinium group of arginine 168 forms a hydrogen bond with one of the triose substrate's C1 oxygens. This steric arrangement would not be possible in the 'open form' of this enzyme as observed in the crystal structure.
Abstract.
Author URL.
1988
Wilson HR, Williams RJ, Littlechild JA, Watson HC (1988). NMR analysis of the interdomain region of yeast phosphoglycerate kinase.
Eur J Biochem,
170(3), 529-538.
Abstract:
NMR analysis of the interdomain region of yeast phosphoglycerate kinase.
Previous proton and phosphorus nuclear magnetic resonance studies with yeast phosphoglycerate kinase have been extended using a higher-resolution spectrometer and a greater variety of binding agents. The new study shows that, apart from a few isolated mobile side chains distributed over the protein surface, there is a mobile section of phosphoglycerate kinase associated with the inter-domain region of the molecule. This region gives relatively well resolved resonances which are quite distinct from those originating from the remainder of the protein. This suggests that the molecule fluctuates between many states including several open or substrate binding forms in addition to the closed and supposedly catalytically competent form of the enzyme. The occupancy of these states appears to be affected by several anions including sulphate, phosphate and cobalticyanide, as well as substrates and their analogues.
Abstract.
Author URL.
Bowen D, Littlechild JA, Fothergill JE, Watson HC, Hall L (1988). Nucleotide sequence of the phosphoglycerate kinase gene from the extreme thermophile Thermus thermophilus. Comparison of the deduced amino acid sequence with that of the mesophilic yeast phosphoglycerate kinase.
Biochem J,
254(2), 509-517.
Abstract:
Nucleotide sequence of the phosphoglycerate kinase gene from the extreme thermophile Thermus thermophilus. Comparison of the deduced amino acid sequence with that of the mesophilic yeast phosphoglycerate kinase.
Using oligonucleotide probes derived from amino acid sequencing information, the structural gene for phosphoglycerate kinase from the extreme thermophile, Thermus thermophilus, was cloned in Escherichia coli and its complete nucleotide sequence determined. The gene consists of an open reading frame corresponding to a protein of 390 amino acid residues (calculated Mr 41,791) with an extreme bias for G or C (93.1%) in the codon third base position. Comparison of the deduced amino acid sequence with that of the corresponding mesophilic yeast enzyme indicated a number of significant differences. These are discussed in terms of the unusual codon bias and their possible role in enhanced protein thermal stability.
Abstract.
Author URL.
FAIRBROTHER WJ, HALL L, LITTLECHILD JA, WALKER PA, WATSON HC, WILLIAMS RJP (1988). PROBING THE 3-PHOSPHOGLYCERATE-BINDING SITE OF YEAST PHOSPHOGLYCERATE KINASE USING SITE-SPECIFIC MUTANTS AND H-1 NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPY.
BIOCHEMICAL SOCIETY TRANSACTIONS,
16(5), 724-725.
Author URL.
1987
FAIRBROTHER WJ, HALL L, LITTLECHILD J, MINARD P, WATSON HC, WILLIAMS RJP (1987). ANION BINDING STUDY OF YEAST PHOSPHOGLYCERATE KINASE BY NMR AND SITE-SPECIFIC MUTAGENESIS.
PROTEIN ENGINEERING,
1(3), 261-261.
Author URL.
FAIRBROTHER WJ, HALL L, LITTLECHILD JA, MINARD P, WATSON HC, WILLIAMS RJP (1987). ANION BINDING STUDY OF YEAST PHOSPHOGLYCERATE KINASE BY NUCLEAR-MAGNETIC-RESONANCE AND SITE-SPECIFIC MUTAGENESIS.
BIOCHEMICAL SOCIETY TRANSACTIONS,
15(5), 868-869.
Author URL.
BOWEN D, DAVIES G, GAMBLIN S, HALL L, LITTLECHILD J, WATSON HC (1987). PHOSPHOGLYCERATE KINASE - a TEST-BED SYSTEM FOR THE STUDY OF PROTEIN THERMOSTABILITY.
PROTEIN ENGINEERING,
1(3), 242-242.
Author URL.
Littlechild JA, Davies GJ, Gamblin SJ, Watson HC (1987). Phosphoglycerate kinase from the extreme thermophile Thermus thermophilus Crystallization and preliminary X-ray data.
FEBS Letters,
225(1-2), 123-126.
Abstract:
Phosphoglycerate kinase from the extreme thermophile Thermus thermophilus Crystallization and preliminary X-ray data
The glycolytic enzyme phosphoglycerate kinase has been prepared from the extreme thermophile Thermus thermophilus. In contrast to its eukaryote equivalents (yeast and horse muscle) this prokaryotic enzyme crystallizes from ammonium sulphate in the presence of nucleotide substrates. These crystals are of a form and size well suited to high resolution X-ray diffraction study using rotation camera techniques. © 1987.
Abstract.
MINARD P, WALKER P, BOWEN D, DAVIES G, LITTLECHILD J, HALL L, WATSON HC (1987). THE USE OF SITE-DIRECTED MUTAGENESIS TO STUDY THE GLYCOLYTIC ENZYME PHOSPHOGLYCERATE KINASE.
PROTEIN ENGINEERING,
1(3), 260-260.
Author URL.
Littlechild J, Malcolm A, Paterakis K, Ackermann I, Dijk J (1987). The tertiary structure of salt-extracted ribosomal proteins from Escherichia coli as studied by proton magnetic resonance spectroscopy and limited proteolysis experiments.
Biochim Biophys Acta,
913(2), 245-255.
Abstract:
The tertiary structure of salt-extracted ribosomal proteins from Escherichia coli as studied by proton magnetic resonance spectroscopy and limited proteolysis experiments.
Ribosomal proteins from Escherichia coli have been isolated by a mild purification procedure. Their tertiary structure has been explored by two techniques, proton magnetic resonance and limited proteolysis. A number of proteins when subjected to limited proteolysis produce resistant fragments in good yields. In most cases this does not depend on the specificity of the enzyme used. The proteins S15, S16, S17 and L30 are not degraded at all, whereas a few proteins are very susceptible to proteolysis. 1H-NMR experiments show that the majority of the ribosomal proteins have a uniquely folded tertiary structure. This is particularly pronounced in the four proteins mentioned above which resist proteolysis. In general, a good agreement is observed between the degree of proteolytic resistance and the amount of folding indicated by NMR spectroscopy. Similar studies on a few ribosomal proteins purified under denaturing conditions show that, in contrast, these protein preparations are not structurally homogeneous and that they contain a mixture of denatured and renatured molecules. The results are interpreted in terms of a compactly folded tertiary structure for the four proteinase-resistant proteins while the majority of the other proteins appear to have two domains, one compactly folded and resistant to proteinase and the other flexible and susceptible to proteolysis. A few proteins seem to have a completely flexible structure and can therefore be easily degraded.
Abstract.
Author URL.
1986
Crout DHG, Littlechild J, Morrey SM (1986). Acetoin metabolism: Stereochemistry of the acetoin produced by the pyruvate decarboxylase of wheat germ and by the α-acetolactate decarboxylase of Klebsiella aerogenes.
Journal of the Chemical Society, Perkin Transactions 1, 105-108.
Abstract:
Acetoin metabolism: Stereochemistry of the acetoin produced by the pyruvate decarboxylase of wheat germ and by the α-acetolactate decarboxylase of Klebsiella aerogenes
Acetoin (3-hydroxybutan-2-one) (1) produced from pyruvate and acetaldehyde by the pyruvate decarboxylase of wheat germ consists of a mixture of enantiomers with the (S)-(+)-isomer preponderating. With pyruvate alone as substrate, racemic acetoin is produced. Acetoin produced from pyruvate by the sequential action of the acetohydroxy acid synthetase and α-acetolactate decarboxylase of Klebsiella aerogenes consists solely of the (R)-(-)-isomer.
Abstract.
LITTLECHILD JA (1986). THE TYPE-II RESTRICTION ENZYMES HGIAI AND TAQI - PURIFICATION AND PROPERTIES.
BIOCHEMICAL SOCIETY TRANSACTIONS,
14(2), 268-268.
Author URL.
Dijk J, Littlechild JA, Freund AM, Pouyet J, Daune M, Provencher SW (1986). The secondary structure of salt-extracted ribosomal proteins from Escherichia coli as studied by circular dichroic spectroscopy.
Biochim Biophys Acta,
874(2), 227-234.
Abstract:
The secondary structure of salt-extracted ribosomal proteins from Escherichia coli as studied by circular dichroic spectroscopy.
Ribosomal proteins from Escherichia coli MRE600 have been obtained by a new, mild purification procedure. This involves extraction of the subunits with salt followed by chromatographic fractionation in the presence of salt. The use of urea or other denaturing agents and conditions is avoided. A survey of the secondary structure of the 30 S and 50 S proteins, as observed by circular dichroic spectroscopy, is presented. The spectra have been analysed by a new procedure which uses a library of 16 circular dichroic spectra of proteins with a known three-dimensional structure. This method provides a more reliable analysis, especially of the contribution from beta-sheet. The results show that most of the 30 S proteins have a high alpha-helix content, whereas the 50 S proteins are more diverse. The latter group shows a larger contribution from beta-sheet. The data presented here are compared with those already published for a number of proteins which were, with one exception, prepared in the presence of urea. In most cases we find higher alpha-helix and beta-sheet values for the salt-extracted proteins than for the corresponding urea-treated proteins. In those cases, however, where special care was taken to renature the urea-treated proteins agreement is found to within the expected experimental error. The results show that salt-extracted ribosomal proteins have a well-defined secondary structure with a relatively small contribution from unordered structure.
Abstract.
Author URL.
1984
Stöffler-Meilicke M, Epe B, Woolley P, Lotti M, Littlechild J, Stöffler G (1984). Location of protein S4 on the small ribosomal subunit of E. coli and B. stearothermophilus with protein- and hapten-specific antibodies.
Mol Gen Genet,
197(1), 8-18.
Abstract:
Location of protein S4 on the small ribosomal subunit of E. coli and B. stearothermophilus with protein- and hapten-specific antibodies.
In spite of considerable effort there is still serious disagreement in the literature about the question of whether epitopes of ribosomal protein S4 are accessible for antibody binding on the intact small ribosomal subunit. We have attempted to resolve this issue using three independent approaches: (i) a re-investigation of the exposure and the location of epitopes of ribosomal protein S4 on the surface of the 30S subunit and 30S core particles of the E. coli ribosome, including rigorous controls of antibody specificity, (ii) a similar investigation of protein S4 from Bacillus stearothermophilus and (iii) the labelling of residue Cys-31 of E. coli S4 with a fluorescein derivative the accessibility of which towards a fluorescein-specific antibody was demonstrated directly by fluorimetry. In each of the three cases the antigen (E. coli S4, B. stearothermophilus S4 or fluorescein) was found to reside on the small lobe.
Abstract.
Author URL.
Crout DHG, Littlechild J, Mitchell MB, Morrey SM (1984). Stereochemistry of the decarboxylation of α-acetolactate (2-hydroxy-2-methyl-3-oxobutanoate) by the acetolactate decarboxylase of Klebsiella aerogenes.
Journal of the Chemical Society, Perkin Transactions 1, 2271-2276.
Abstract:
Stereochemistry of the decarboxylation of α-acetolactate (2-hydroxy-2-methyl-3-oxobutanoate) by the acetolactate decarboxylase of Klebsiella aerogenes
[3-14C]-α-Acetolactate ([3-14C]-2-hydroxy-2- methyl-3-oxobutanoate) was synthesised and subjected to enzymatic decarboxylation by the acetolactate decarboxylase from Klebsiella pneumoniae. Degradation of the acetoin produced showed that the radioactivity was largely confined to the acetyl component. Together with previous results, this proves that during decarboxylation the carboxy group of α-acetolactate is replaced regiospecifically by hydrogen and that this process takes place with overall inversion of configuration.
Abstract.
1983
Paterakis K, Littlechild J, Woolley P (1983). Structural and functional studies on protein S20 from the 30-S subunit of the Escherichia coli ribosome.
Eur J Biochem,
129(3), 543-548.
Abstract:
Structural and functional studies on protein S20 from the 30-S subunit of the Escherichia coli ribosome.
Fragments resistant to proteolysis have been obtained from the ribosomal protein S20. They provide evidence for a structural domain stretching from the middle of the protein to its C terminus. With the exception of a large fragment of this protein lacking only 14 residues at the N terminus, all fragments had lost their ability to bind to 16-S rRNA. The protein in the S20. 16-S-RNA complex was highly protected against enzymic digestion, indicating that the entire protein is involved in interaction with the nucleic acid. Circular dichroism showed a high alpha helix content (36%) for the intact protein and a low alpha helix content (2%) for the large fragment. Intrinsic fluorescence studies demonstrated that the single tyrosine residue in protein S20 is exposed to the solvent in the intact protein and is not exposed in the S20. 16-S-RNA complex. Irreversible thermal denaturation of the protein was followed by fluorescence of the tyrosine and was found between 50 degrees C and 70 degrees C.
Abstract.
Author URL.
1982
Epe B, Woolley P, Steinhäuser KG, Littlechild J (1982). Distance measurement by energy transfer: the 3' end of 16-S RNA and proteins S4 and S17 of the ribosome of Escherichia coli.
Eur J Biochem,
129(1), 211-219.
Abstract:
Distance measurement by energy transfer: the 3' end of 16-S RNA and proteins S4 and S17 of the ribosome of Escherichia coli.
Escherichia coli ribosomal proteins S4 and S17 were specifically labelled at their thiol groups with the acetylaminoethyl-dansyl and/or bimane fluorophores. Each formed a complex with 16-S RNA and, when the other 30-S ribosomal proteins were added, a complete 30-S subunit with at least partial activity. If the 3' end of the RNA was also labelled (with fluorescein) then the distance between the two fluorophores could be measured by Förster-type energy transfer. The result for S4 was 6.0 nm (60 A) in the ribonucleoprotein complex and 5.6 nm (56 A) in the 30-S subunit, and for S17 6.3 nm (63 A) in the complex and 6.2 nm (62 A) in the subunit. There is no evidence for a major change in the relative disposition of the 3' and 5' ends of the 16-S RNA during formation of the 30-S subunit. Sources of error are discussed, including the question of multiple labelling. In order to measure more accurately the extent of energy transfer a procedure based upon enzymic digestion was developed and is detailed in this paper.
Abstract.
Author URL.
Wirth R, Littlechild J, Böck A (1982). Ribosomal protein S20 purified under mild conditions almost completely inhibits its own translation.
Mol Gen Genet,
188(1), 164-166.
Abstract:
Ribosomal protein S20 purified under mild conditions almost completely inhibits its own translation.
The efficiency of ribosomal protein S20 to act as repressor of its own synthesis in an in vitro system was found to depend greatly on the procedures employed to purify this protein. Whilst conventionally purified r-protein S20 inhibited its own synthesis by some 30%, up to 90% inhibition was observed if "milder" purification conditions were used. Evidence is presented that the latter preparation shows also a higher binding affinity to 16S rRNA.
Abstract.
Author URL.
Paterakis K, Littlechild J (1982). Structural domains of ribosomal protein S8 and their relationship to ribosomal RNA binding.
FEBS Lett,
149(2), 328-333.
Abstract:
Structural domains of ribosomal protein S8 and their relationship to ribosomal RNA binding.
Escherichia coli ribosomal protein S8 has been subjected to mild proteolytic digestion in order to search for structural domains within the protein [1]. A characteristic fragment produced in high yield after chymotrypsin treatment has been located with the protein sequence. Circular dichroism has shown this domain to be rich in alpha helix. However, the fragment loses its ability to bind to 16S rRNA as does a similar fragment produced by trypsin cleavage. The intact protein is required for rRNA binding and is highly protected against proteolytic digestion when bound to the RNA.
Abstract.
Author URL.
1981
Georgalis Y, Giri L, Littlechild JA (1981). Physical studies on the ribosomal protein S2 from the Escherichia coli 30S.
Biochemistry,
20(5), 1061-1064.
Abstract:
Physical studies on the ribosomal protein S2 from the Escherichia coli 30S.
The protein S2 has been isolated from the 30S subunit of Escherichia coli A19 ribosomes [Littlechild, J. & Malcolm, A.L. (1978) Biochemistry 17, 3363-3369]. This salt-extracted protein is soluble and does not aggregate at salt concentrations of 0.3-0.4 M as used under reconstitution conditions. This differs from the S2 protein extracted by the acetic acid and urea method. The molecular weight from sedimentation equilibrium was found to be 29 200, and the protein was found to have a S0(20,w) value of 2.36S. The apparent specific volume at 20 degrees C was 0.726 mL.g(-1), and the D0(20,2) was 7.37 x 10(-7) cm(2)s(-1). The value for intrinsic viscosity was found to be 6.42 mL.g(-1). An axial ratio of (5-6):1 for a prolate ellipsoid of revolution was estimated by using these parameters. The circular dichroism and proton magnetic resonance studies show that protein S2 has both substantial amounts of alpha helix and beta-pleated sheet in solution and appears as a "folded" protein and not a random coil structure.
Abstract.
Author URL.
Pawlik RT, Littlechild J, Pon C, Gualerzi C (1981). Purification and properties of Escherichia coli translational initiation factors. Biochemistry International, 2(4), 421-428.
1980
LITTLECHILD JA, MALCOLM AL, SOWDEN BK (1980). COMPARATIVE STUDIES ON THE 30S RIBOSOMAL-PROTEINS FROM ESCHERICHIA-COLI AND BACILLUS-STEAROTHERMOPHILUS.
EUROPEAN JOURNAL OF CELL BIOLOGY,
22(1), 133-133.
Author URL.
Littlechild J (1980). Proton magnetic resonance studies of Escherichia coli ribosomal protein S16.
FEBS Lett,
111(1), 51-55.
Author URL.
LITTLECHILD JA, PATERAKIS K (1980). STRUCTURAL STABILITY OF SEVERAL PROTEINS ISOLATED FROM THE 30S-RIBOSOMAL SUBUNIT OF ESCHERICHIA-COLI.
EUROPEAN JOURNAL OF CELL BIOLOGY,
22(1), 132-132.
Author URL.
1979
Littlechild J, Morrison CA, Bradbury EM (1979). Proton magnetic resonance studies of Escherichia coli ribosomal protein S4 and a C-terminal fragment of this protein.
FEBS Lett,
104(1), 90-94.
Author URL.
Dijk J, Littlechild J (1979). Purification of ribosomal proteins from Escherichia coli under nondenaturing conditions.
Methods Enzymol,
59, 481-502.
Author URL.
1978
Khechinashvili NN, Koteliansky VE, Gogia ZV, Littlechild J, Dijk J (1978). A heat denaturation study of several ribosomal proteins from Escherichia coli by scanning microcalorimetry. FEBS Letters, 95(2), 270-272.
Khechinashvili NN, Koteliansky VE, Gogia ZV, Littlechild J, Dijk J (1978). A heat denaturation study of several ribosomal proteins from Escherichia coli by scanning microcalorimetry.
FEBS Lett,
95(2), 270-272.
Author URL.
Littlechild JA, Malcolm AL (1978). A new method for the purification of 30S ribosomal proteins from Escherichia coli using nondenaturing conditions.
Biochemistry,
17(16), 3363-3369.
Abstract:
A new method for the purification of 30S ribosomal proteins from Escherichia coli using nondenaturing conditions.
A new method for the purification of Escherichia coli (A19) 30S ribosomal proteins has been developed that avoids the use of denaturing conditions such as urea, acetic acid, and lyophilization. In this way the majority of the proteins from the small ribosomal subunit can be obtained in 5--100 mg quantities and at greater than or equal to 90% purity. This has been achieved by the initial "splitting" of the proteins into two main groups with LiCl followed by fractionating on ion-exchange and gel-filtration columns, in the absence of urea and in the presence of salt. The proteins prepared by this nondenaturing procedure were soluble at high ionic strength and less soluble, being aggregated, at low salt concentrations. This behavior was exactly the opposite of that exhibited by proteins prepared with methods using denaturing conditions. These new methods have enabled additional ribosomal RNA-binding proteins to be found and potential protein-proteins complexes to be isolated. Preliminary evidence that these proteins may retain a more native structure is presented.
Abstract.
Author URL.
OSTERBERG R, SJOBERG B, LILJAS A, GARRETT RA, LITTLECHILD J (1978). SMALL-ANGLE X-RAY-SCATTERING STUDY OF COMPLEXES OF INDIVIDUAL COMPONENTS FROM ESCHERICHIA-COLI RIBOSOMES.
JOURNAL OF APPLIED CRYSTALLOGRAPHY,
11(OCT), 487-487.
Author URL.
Österberg R, Sjöberg B, Littlechild J (1978). Small-angle X-ray scattering study of the proteins S1, S8, S15, S16, S20 from Escherichia coli ribosomes. FEBS Letters, 93(1), 115-119.
Osterberg R, Sjöberg B, Garrett RA, Littlechild J (1978). Small-angle X-ray titration of the complex formed between the ribosomal protein S4 and its 16S binding site, S4-RNA: a central core in the 30S subunit.
Nucleic Acids Res,
5(10), 3579-3587.
Abstract:
Small-angle X-ray titration of the complex formed between the ribosomal protein S4 and its 16S binding site, S4-RNA: a central core in the 30S subunit.
X-ray scattering titrations at 21 degree C and in ribosomal reconstitution buffer indicate that the S4-RNA and the protein S4 from a 1:1 complex with a stability constant, log K approximately 6.5. When the complex forms, there is only a limited change in the scattering curve indicating that S4-RNA essentially retains its conformation during the complex formation. The increase in the gyration radius as a result of the complex formation, delta R = 4 +/- 3 A, as well as the experimental scattering curve of the complex can be explained by models where the protein S4 is supposed to interact with the periphery of the S4-RNA.
Abstract.
Author URL.
1977
Giri L, Littlechild J, Dijk J (1977). Hydrodynamic studies on the Escherichia coli robosomal proteins S8 and L6, prepared by two different methods.
FEBS Lett,
79(2), 238-244.
Author URL.
Morrison CA, Bradbury EM, Littlechild J, Dijk J (1977). Proton magnetic resonance studies to compare Escherichia coli ribosomal proteins prepared by two different methods.
FEBS Lett,
83(2), 348-352.
Author URL.
Österberg R, Sjöberg B, Garrett RA, Littlechild J (1977). Small-angle X-ray scattering study of the 16 S RNA binding protein S4 from Escherichia coli ribosomes. FEBS Letters, 73(1), 22-24.
Osterberg R, Sjöberg B, Garrett RA, Littlechild J (1977). Small-angle x-ray scattering study of the 16S RNA binding protein S4 from Escherichia coli ribosomes.
FEBS Lett,
73(1), 25-28.
Author URL.
Dijk J, Littlechild J, Garrett RA (1977). The RNA binding properties of "native" protein-protein complexes isolated from the Escherichia coli ribosome.
FEBS Lett,
77(2), 295-300.
Author URL.
Littlechild J, Dijk J, Garrett RA (1977). The identification of new RNA-binding proteins in the Escherichia coli ribosome.
FEBS Lett,
74(2), 292-294.
Author URL.
1973
Littlechild J (1973). Nuclease contaminant of a batch of lysozyme used for ribosome extraction: cleavage of Escherichia coli 23S rRNA into two specific fragments.
Anal Biochem,
55(2), 634-636.
Author URL.
Littlechild J, Spencer M (1973). Stability and homogeneity of preparations of ribosomal particles from Escherichia coli.
Biochemistry,
12(16), 3102-3108.
Author URL.