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Muduli S, Karmakar S, Mishra S. Conformational Dynamics in Corynebacterium glutamicum Diaminopimelate Epimerase: Insights from Ligand Parameterization, Atomistic Simulation, and Markov State Modeling. J Chem Inf Model 2024; 64:4250-4262. [PMID: 38701175 DOI: 10.1021/acs.jcim.4c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
The microbial enzyme diaminopimelate epimerase (DapF), a vital enzyme in the lysine biosynthetic pathway, catalyzes the conversion of L, L-diaminopimelate (L, L-DAP) to D, L-diaminopimelate (D, L-DAP) using a catalytic cysteine dyad with one cysteine in thiol state and another in thiolate. Under oxidizing conditions, the catalytic cysteines of apo DapF form a disulfide bond that alters the structure and function of DapF. Given its potential as a target for antimicrobial resistance treatments, understanding DapF's functional dynamics is imperative. In the present work, we employ microsecond-scale all-atom molecular dynamics simulations of product-bound DapF and apo-DapF under oxidized and reduced conditions. We employ a polarized charge model for the ligand and the active site residues, which was necessary to preserve the electrostatic environment in the active site and retain the ligand in the active site. The product-bound DapF and apo-DapF in oxidized and reduced conditions exhibit a closed, semi-open, and open conformation, respectively, as identified using the internal coordinates of the dimeric enzyme and the principal component analysis. The conformational switch is guided by the dynamic catalytic (DC) loop, loop II, and loop III movements in the active site. The time scale of the close-to-open conformational transition is estimated to be 0.8 μs through Markov state modeling (MSM) and transition path theory (TPT). The present study explains the role of various active site residues and loops in ligand binding and protein dynamics in the DapF enzyme under different redox conditions. Such information will be helpful in future inhibitor design studies targeting the DapF enzyme.
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Affiliation(s)
- Sunita Muduli
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Soumyajit Karmakar
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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2
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Singh S, Praveen A, Khanna SM. Computational Modelling, Functional Characterization and Molecular Docking to Lead Compounds of Bordetella pertussis Diaminopimelate Epimerase. Appl Biochem Biotechnol 2023; 195:6675-6693. [PMID: 36913098 DOI: 10.1007/s12010-023-04413-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2023] [Indexed: 03/14/2023]
Abstract
Bordetella pertussis, the causative agent of whooping cough, is an opportunistic virulent bacterial pathogen that is resistant to a wide range of antibiotics due to a variety of resistance mechanisms. Looking at the increasing number of infections caused by B. pertussis and its resistance to diverse antibiotics, it is essential to develop alternative strategies to fight against B. pertussis. Diaminopimelate epimerase (DapF) is an important enzyme of the lysine biosynthesis pathway in B. pertussis that catalyzes the formation of meso-2, 6-diaminoheptanedioate (meso-DAP), which is an important step in lysine metabolism. Therefore, Bordetella pertussis diaminopimelate epimerase (DapF) becomes an ideal target for antimicrobial drug development. In the present study, computational modelling, functional characterization, binding studies, and docking studies of BpDapF with lead compounds were carried out using different in silico tools. In silico prediction results in the secondary structure, 3-D structure analysis, and protein-protein interaction analysis of BpDapF. Docking studies further showed the respective amino acid residues for ligands in the phosphate‑binding loop of BpDapF play a vital role in the formation of H‑bonds with these ligands. The site where the ligand was bound is a deep groove, which is regarded as the binding cavity of the protein. Biochemical studies indicated that Limonin (binding energy - 8.8 kcal/mol), Ajmalicine (binding energy - 8.7 kcal/mol), Clinafloxacin (binding energy - 8.3 kcal/mol), Dexamethasone (binding energy - 8.2 kcal/mol), and Tetracycline (binding energy - 8.1 kcal/mol) exhibited promising binding towards the drug target DapF of B. pertussis in comparison with the binding between other drugs and act as the potential inhibitors of BpDapF that eventually can reduce the catalytic activity of BpDapF.
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Affiliation(s)
- Shilpy Singh
- Department of Biotechnology and Microbiology, School of Sciences, Noida International University, Gautam Budh Nagar, U.P, 203201, India
| | - Afsana Praveen
- Department of Biotechnology and Microbiology, School of Sciences, Noida International University, Gautam Budh Nagar, U.P, 203201, India
| | - Suruchi M Khanna
- Mangalmay Institute of Management and Technology, Greater Noida, U.P, 201310, India.
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3
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Bearne SL. Design and evaluation of substrate-product analog inhibitors for racemases and epimerases utilizing a 1,1-proton transfer mechanism. Methods Enzymol 2023; 690:397-444. [PMID: 37858537 DOI: 10.1016/bs.mie.2023.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Racemases and epimerases catalyze the inversion of stereochemistry at asymmetric carbon atoms to generate stereoisomers that often play important roles in normal and pathological physiology. Consequently, there is interest in developing inhibitors of these enzymes for drug discovery. A strategy for the rational design of substrate-product analog (SPA) inhibitors of racemases and epimerases utilizing a direct 1,1-proton transfer mechanism is elaborated. This strategy assumes that two groups on the asymmetric carbon atom remain fixed at active-site binding determinants, while the hydrogen and third, motile group move during catalysis, with the latter potentially traveling between an R- and S-pocket at the active site. SPAs incorporate structural features of the substrate and product, often with geminal disubstitution on the asymmetric carbon atom to simultaneously present the motile group to both the R- and S-pockets. For racemases operating on substrates bearing three polar groups (glutamate, aspartate, and serine racemases) or with compact, hydrophobic binding pockets (proline racemase), substituent motion is limited and the design strategy furnishes inhibitors with poor or modest binding affinities. The approach is most successful when substrates have a large, motile hydrophobic group that binds at a plastic and/or capacious hydrophobic site. Potent inhibitors were developed for mandelate racemase, isoleucine epimerase, and α-methylacyl-CoA racemase using the SPA inhibitor design strategy, exhibiting binding affinities ranging from substrate-like to exceeding that of the substrate by 100-fold. This rational approach for designing inhibitors of racemases and epimerases having the appropriate active-site architectures is a useful strategy for furnishing compounds for drug development.
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Affiliation(s)
- Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada; Department of Chemistry, Dalhousie University, Halifax, NS, Canada.
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4
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Abstract
Many enzymes that show a large specificity in binding the enzymatic transition state with a higher affinity than the substrate utilize substrate binding energy to drive protein conformational changes to form caged substrate complexes. These protein cages provide strong stabilization of enzymatic transition states. Using part of the substrate binding energy to drive the protein conformational change avoids a similar strong stabilization of the Michaelis complex and irreversible ligand binding. A seminal step in the development of modern enzyme catalysts was the evolution of enzymes that couple substrate binding to a conformational change. These include enzymes that function in glycolysis (triosephosphate isomerase), the biosynthesis of lipids (glycerol phosphate dehydrogenase), the hexose monophosphate shunt (6-phosphogluconate dehydrogenase), and the mevalonate pathway (isopentenyl diphosphate isomerase), catalyze the final step in the biosynthesis of pyrimidine nucleotides (orotidine monophosphate decarboxylase), and regulate the cellular levels of adenine nucleotides (adenylate kinase). The evolution of enzymes that undergo ligand-driven conformational changes to form active protein-substrate cages is proposed to proceed by selection of variants, in which the selected side chain substitutions destabilize a second protein conformer that shows compensating enhanced binding interactions with the substrate. The advantages inherent to enzymes that incorporate a conformational change into the catalytic cycle provide a strong driving force for the evolution of flexible protein folds such as the TIM barrel. The appearance of these folds represented a watershed event in enzyme evolution that enabled the rapid propagation of enzyme activities within enzyme superfamilies.
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Affiliation(s)
- John P Richard
- Department of Chemistry, University at Buffalo, the State University of New York, Buffalo, New York 14260-3000, United States
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Lloyd MD, Yevglevskis M, Nathubhai A, James TD, Threadgill MD, Woodman TJ. Racemases and epimerases operating through a 1,1-proton transfer mechanism: reactivity, mechanism and inhibition. Chem Soc Rev 2021; 50:5952-5984. [PMID: 34027955 PMCID: PMC8142540 DOI: 10.1039/d0cs00540a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Indexed: 12/12/2022]
Abstract
Racemases and epimerases catalyse changes in the stereochemical configurations of chiral centres and are of interest as model enzymes and as biotechnological tools. They also occupy pivotal positions within metabolic pathways and, hence, many of them are important drug targets. This review summarises the catalytic mechanisms of PLP-dependent, enolase family and cofactor-independent racemases and epimerases operating by a deprotonation/reprotonation (1,1-proton transfer) mechanism and methods for measuring their catalytic activity. Strategies for inhibiting these enzymes are reviewed, as are specific examples of inhibitors. Rational design of inhibitors based on substrates has been extensively explored but there is considerable scope for development of transition-state mimics and covalent inhibitors and for the identification of inhibitors by high-throughput, fragment and virtual screening approaches. The increasing availability of enzyme structures obtained using X-ray crystallography will facilitate development of inhibitors by rational design and fragment screening, whilst protein models will facilitate development of transition-state mimics.
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Affiliation(s)
- Matthew D Lloyd
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Maksims Yevglevskis
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK. and CatSci Ltd., CBTC2, Capital Business Park, Wentloog, Cardiff CF3 2PX, UK
| | - Amit Nathubhai
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK. and University of Sunderland, School of Pharmacy & Pharmaceutical Sciences, Sciences Complex, Sunderland SR1 3SD, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK and School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, People's Republic of China
| | - Michael D Threadgill
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK. and Institute of Biological, Environmental & Rural Sciences, Aberystwyth University, Aberystwyth SY23 3BY, UK
| | - Timothy J Woodman
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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Singh H, Das S, Yadav J, Srivastava VK, Jyoti A, Kaushik S. In silico prediction, molecular docking and binding studies of acetaminophen and dexamethasone to Enterococcus faecalis diaminopimelate epimerase. J Mol Recognit 2021; 34:e2894. [PMID: 33719110 DOI: 10.1002/jmr.2894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/18/2021] [Accepted: 02/05/2021] [Indexed: 11/11/2022]
Abstract
Enterococcus faecalis (E. faecalis) is a Gram-positive coccoid, non-sporulating, facultative anaerobic, multidrug resistance bacterium responsible for almost 65% to 80% of all enterococcal nosocomial infections. It usually causes infective endocarditis, urinary tract and surgical wound infections. The increase in E. faecalis resistance to conventionally available antibiotic has rekindled intense interest in developing useful antibacterial drugs. In E. faecalis, diaminopimelate epimerase (DapF) is involved in the lysine biosynthetic pathway. The product of this pathway is precursors of peptidoglycan synthesis, which is a component of bacterial cell wall. Also, because mammals lack this enzyme, consequently E. faecalis diaminopimelate epimerase (EfDapF) represents a potential target for developing novel class of antibiotics. In this regard, we have successfully cloned, overexpressed the gene encoding DapF in BL-21(DE3) and purified with Ni-NTA Agarose resin. In addition to this, binding studies were performed using fluorescence spectroscopy in order to confirm the bindings of the identified lead compounds (acetaminophen and dexamethasone) with EfDapF. Docking studies revealed that acetaminophen found to make hydrogen bonds with Asn72 and Asn13 while dexamethasone interacted by forming hydrogen bonds with Asn205 and Glu223. Thus, biochemical studies indicated acetaminophen and dexamethasone, as potential inhibitors of EfDapF and eventually can reduce the catalytic activity of EfDapF.
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Affiliation(s)
- Harpreet Singh
- Amity Institute of Biotechnology, Amity University, Jaipur, Rajasthan, India
| | - Satyajeet Das
- Amity Institute of Biotechnology, Amity University, Jaipur, Rajasthan, India
| | - Jyoti Yadav
- Amity Institute of Biotechnology, Amity University, Jaipur, Rajasthan, India
| | | | - Anupam Jyoti
- Amity Institute of Biotechnology, Amity University, Jaipur, Rajasthan, India
| | - Sanket Kaushik
- Amity Institute of Biotechnology, Amity University, Jaipur, Rajasthan, India
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7
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Hall CJ, Lee M, Boarder MP, Mangion AM, Gendall AR, Panjikar S, Perugini MA, Soares da Costa TP. Differential lysine-mediated allosteric regulation of plant dihydrodipicolinate synthase isoforms. FEBS J 2021; 288:4973-4986. [PMID: 33586321 DOI: 10.1111/febs.15766] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/16/2021] [Accepted: 02/12/2021] [Indexed: 12/31/2022]
Abstract
Lysine biosynthesis in plants occurs via the diaminopimelate pathway. The first committed and rate-limiting step of this pathway is catalysed by dihydrodipicolinate synthase (DHDPS), which is allosterically regulated by the end product, l-lysine (lysine). Given that lysine is a common nutritionally limiting amino acid in cereal crops, there has been much interest in probing the regulation of DHDPS. Interestingly, knockouts in Arabidopsis thaliana of each isoform (AtDHDPS1 and AtDHDPS2) result in different phenotypes, despite the enzymes sharing > 85% protein sequence identity. Accordingly, in this study, we compared the catalytic activity, lysine-mediated inhibition and structures of both A. thaliana DHDPS isoforms. We found that although the recombinantly produced enzymes have similar kinetic properties, AtDHDPS1 is 10-fold more sensitive to lysine. We subsequently used X-ray crystallography to probe for structural differences between the apo- and lysine-bound isoforms that could account for the differential allosteric inhibition. Despite no significant changes in the overall structures of the active or allosteric sites, we noted differences in the rotamer conformation of a key allosteric site residue (Trp116) and proposed that this could result in differences in lysine dissociation. Microscale thermophoresis studies supported our hypothesis, with AtDHDPS1 having a ~ 6-fold tighter lysine dissociation constant compared to AtDHDPS2, which agrees with the lower half minimal inhibitory concentration for lysine observed. Thus, we highlight that subtle differences in protein structures, which could not have been predicted from the primary sequences, can have profound effects on the allostery of a key enzyme involved in lysine biosynthesis in plants. DATABASES: Structures described are available in the Protein Data Bank under the accession numbers 6VVH and 6VVI.
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Affiliation(s)
- Cody J Hall
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Mihwa Lee
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Matthew P Boarder
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Alexandra M Mangion
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Anthony R Gendall
- Department of Animal, Plant and Soil Sciences, AgriBio, La Trobe University, Bundoora, Australia.,Australian Research Council Research Hub for Medicinal Agriculture, AgriBio, La Trobe University, Bundoora, Australia
| | - Santosh Panjikar
- Australian Synchrotron, ANSTO, Clayton, Australia.,Department of Molecular Biology and Biochemistry, Monash University, Melbourne, Australia
| | - Matthew A Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Tatiana P Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
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8
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Bearne SL. Through the Looking Glass: Chiral Recognition of Substrates and Products at the Active Sites of Racemases and Epimerases. Chemistry 2020; 26:10367-10390. [DOI: 10.1002/chem.201905826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/09/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Stephen L. Bearne
- Department of Biochemistry & Molecular BiologyDepartment of ChemistryDalhousie University Halifax, Nova Scotia B3H 4R2 Canada
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9
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Oda K, Shimotani N, Kuroda T, Matoba Y. Crystal structure of an N ω-hydroxy-L-arginine hydrolase found in the D-cycloserine biosynthetic pathway. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2020; 76:506-514. [PMID: 32496212 DOI: 10.1107/s2059798320004908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/06/2020] [Indexed: 11/10/2022]
Abstract
DcsB, one of the enzymes encoded in the D-cycloserine (D-CS) biosynthetic gene cluster, displays a high sequence homology to arginase, which contains two manganese ions in the active site. However, DcsB hydrolyzes Nω-hydroxy-L-arginine, but not L-arginine, to supply hydroxyurea for the biosynthesis of D-CS. Here, the crystal structure of DcsB was determined at a resolution of 1.5 Å using anomalous scattering from the manganese ions. In the crystal structure, DscB generates an artificial dimer created by the open and closed forms. Gel-filtration analysis demonstrated that DcsB is a monomeric protein, unlike arginase, which forms a trimeric structure. The active center containing the binuclear manganese cluster differs between DcsB and arginase. In DcsB, one of the ligands of the MnA ion is a cysteine, while the corresponding residue in arginase is a histidine. In addition, DcsB has no counterpart to the histidine residue that acts as a general acid/base during the catalytic reaction of arginase. The present study demonstrates that DcsB has a unique active site that differs from that of arginase.
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Affiliation(s)
- Kosuke Oda
- Department of Virology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Natsuki Shimotani
- Department of Microbiology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Teruo Kuroda
- Department of Microbiology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yasuyuki Matoba
- Department of Microbiology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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10
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Schmitz RA, Dietl A, Müller M, Berben T, Op den Camp HJM, Barends TRM. Structure of the 4-hydroxy-tetrahydrodipicolinate synthase from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV and the phylogeny of the aminotransferase pathway. Acta Crystallogr F Struct Biol Commun 2020; 76:199-208. [PMID: 32356521 PMCID: PMC7193512 DOI: 10.1107/s2053230x20005294] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/15/2020] [Indexed: 11/10/2022] Open
Abstract
The enzyme 4-hydroxy-tetrahydrodipicolinate synthase (DapA) is involved in the production of lysine and precursor molecules for peptidoglycan synthesis. In a multistep reaction, DapA converts pyruvate and L-aspartate-4-semialdehyde to 4-hydroxy-2,3,4,5-tetrahydrodipicolinic acid. In many organisms, lysine binds allosterically to DapA, causing negative feedback, thus making the enzyme an important regulatory component of the pathway. Here, the 2.1 Å resolution crystal structure of DapA from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV is reported. The enzyme crystallized as a contaminant of a protein preparation from native biomass. Genome analysis reveals that M. fumariolicum SolV utilizes the recently discovered aminotransferase pathway for lysine biosynthesis. Phylogenetic analyses of the genes involved in this pathway shed new light on the distribution of this pathway across the three domains of life.
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Affiliation(s)
- Rob A. Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Andreas Dietl
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Melanie Müller
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Tom Berben
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Huub J. M. Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Thomas R. M. Barends
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
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Fischer C, Ahn YC, Vederas JC. Catalytic mechanism and properties of pyridoxal 5'-phosphate independent racemases: how enzymes alter mismatched acidity and basicity. Nat Prod Rep 2020; 36:1687-1705. [PMID: 30994146 DOI: 10.1039/c9np00017h] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Covering: up to March 2019 Amino acid racemases and epimerases are key enzymes that invert the configuration of common amino acids and supply many corresponding d-isomers in living organisms. Some d-amino acids are inherently bioactive, whereas others are building blocks for important biomolecules, for example lipid II, the bacterial cell wall precursor. Peptides containing them have enhanced proteolytic stability and can act as important recognition elements in mammalian systems. Selective inhibition of certain amino acid racemases (e.g. glutamate racemase) is believed to offer a promising target for new antibacterial drugs effective against pathogens resistant to current antibiotics. Many amino acid racemases employ imine formation with pyridoxal phosphate (PLP) as a cofactor to accelerate the abstraction of the alpha proton. However, the group reviewed herein achieves racemization of free amino acids without the use of cofactors or metals, and uses a thiol/thiolate pair for deprotonation and reprotonation. All bacteria and higher plants contain such enzymes, for example diaminopimelate epimerase, which is required for lysine biosynthesis in these organisms. This process cannot be accomplished without an enzyme catalyst as the acidities of a thiol and the substrate α-hydrogen are inherently mismatched by at least 10 orders of magnitude. This review describes the structural and mechanistic studies on PLP-independent racemases and the evolving view of key enzymatic machinery that accomplishes these remarkable transformations.
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Affiliation(s)
- Conrad Fischer
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2.
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12
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Witkin KR, Vance NR, Caldwell C, Li Q, Yu L, Spies MA. An Atomistic Understanding of Allosteric Inhibition of Glutamate Racemase: a Dampening of Native Activation Dynamics. ChemMedChem 2020; 15:376-384. [PMID: 31876113 PMCID: PMC7337235 DOI: 10.1002/cmdc.201900642] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/11/2019] [Indexed: 11/07/2022]
Abstract
Glutamate racemases (GR) are members of the family of bacterial enzymes known as cofactor-independent racemases and epimerases and catalyze the stereoinversion of glutamate. D-amino acids are universally important for the proper construction of viable bacterial cell walls, and thus have been repeatedly validated as attractive targets for novel antimicrobial drug design. Significant aspects of the mechanism of this challenging stereoinversion remain unknown. The current study employs a combination of MD and QM/MM computational approaches to show that the GR from H. pylori must proceed via a pre-activation step, which is dependent on the enzyme's flexibility. This mechanism is starkly different from previously proposed mechanisms. These findings have immediate pharmaceutical relevance, as the H. pylori GR enzyme is a very attractive allosteric drug target. The results presented in this study offer a distinctly novel understanding of how AstraZeneca's lead series of inhibitors cripple the H. pylori GR's native motions, via prevention of this critical chemical pre-activation step. Our experimental studies, using SPR, fluorescence and NMR WaterLOGSY, show that H. pylori GR is not inhibited by the uncompetitive mechanism originally put forward by Lundqvist et al.. The current study supports a deep connection between native enzyme motions and chemical reactivity, which has strong relevance to the field of allosteric drug discovery.
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Affiliation(s)
- Katie R Witkin
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutics and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, 52246, USA
| | - Nicholas R Vance
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutics and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, 52246, USA
| | - Colleen Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52246, USA
| | - Quinn Li
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52246, USA
| | - Liping Yu
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52246, USA
- NMR Core Facility, Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52246, USA
| | - M Ashley Spies
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutics and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, 52246, USA
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52246, USA
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13
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Du J, Guo S, Sun J, Shu S. Proteomic and physiological analyses reveal the role of exogenous spermidine on cucumber roots in response to Ca(NO 3) 2 stress. PLANT MOLECULAR BIOLOGY 2018; 97:1-21. [PMID: 29633167 DOI: 10.1007/s11103-018-0721-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/20/2018] [Indexed: 05/14/2023]
Abstract
The mechanism of exogenous Spd-induced Ca(NO3)2 stress tolerance in cucumber was studied by proteomics and physiological analyses. Protein-protein interaction network revealed 13 key proteins involved in Spd-induced Ca(NO3)2 stress resistance. Ca(NO3)2 stress is one of the major reasons for secondary salinization that limits cucumber plant development in greenhouse. The conferred protective role of exogenous Spd on cucumber in response to Ca(NO3)2 stress cues involves changes at the cellular and physiological levels. To investigate the molecular foundation of exogenous Spd in Ca(NO3)2 stress tolerance, a proteomic approach was performed in our work. After a 9 days period of Ca(NO3)2 stress and/or exogenous Spd, 71 differential protein spots were confidently identified. The resulting proteins were enriched in seven different categories of biological processes, including protein metabolism, carbohydrate and energy metabolism, ROS homeostasis and stress defense, cell wall related, transcription, others and unknown. Protein metabolism (31.2%), carbohydrate and energy metabolism (15.6%), ROS homeostasis and stress defense (32.5%) were the three largest functional categories in cucumber root and most of them were significantly increased by exogenous Spd. The Spd-responsive protein interaction network revealed 13 key proteins, whose accumulation changes could be critical for Spd-induced resistance; all 13 proteins were upregulated by Spd at transcriptional and protein levels in response to Ca(NO3)2 stress. Furthermore, accumulation of antioxidant enzymes, non-enzymatic antioxidant and polyamines, along with reduction of H2O2 and MDA, were detected after exogenous Spd application during Ca(NO3)2 stress. The results of these proteomic and physiological analyses in cucumber root may facilitate a better understanding of the underlying mechanism of Ca(NO3)2 stress tolerance mediated by exogenous Spd.
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Affiliation(s)
- Jing Du
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
- Taizhou Research Institute, Jiangsu Academy Agricultural Sciences, Taizhou, 225300, People's Republic of China
| | - Shirong Guo
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
| | - Jin Sun
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Sheng Shu
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
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14
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Liechti G, Singh R, Rossi PL, Gray MD, Adams NE, Maurelli AT. Chlamydia trachomatis dapF Encodes a Bifunctional Enzyme Capable of Both d-Glutamate Racemase and Diaminopimelate Epimerase Activities. mBio 2018; 9:e00204-18. [PMID: 29615498 PMCID: PMC5885031 DOI: 10.1128/mbio.00204-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/16/2018] [Indexed: 02/03/2023] Open
Abstract
Peptidoglycan is a sugar/amino acid polymer unique to bacteria and essential for division and cell shape maintenance. The d-amino acids that make up its cross-linked stem peptides are not abundant in nature and must be synthesized by bacteria de novo d-Glutamate is present at the second position of the pentapeptide stem and is strictly conserved in all bacterial species. In Gram-negative bacteria, d-glutamate is generated via the racemization of l-glutamate by glutamate racemase (MurI). Chlamydia trachomatis is the leading cause of infectious blindness and sexually transmitted bacterial infections worldwide. While its genome encodes a majority of the enzymes involved in peptidoglycan synthesis, no murI homologue has ever been annotated. Recent studies have revealed the presence of peptidoglycan in C. trachomatis and confirmed that its pentapeptide includes d-glutamate. In this study, we show that C. trachomatis synthesizes d-glutamate by utilizing a novel, bifunctional homologue of diaminopimelate epimerase (DapF). DapF catalyzes the final step in the synthesis of meso-diaminopimelate, another amino acid unique to peptidoglycan. Genetic complementation of an Escherichia coli murI mutant demonstrated that Chlamydia DapF can generate d-glutamate. Biochemical analysis showed robust activity, but unlike canonical glutamate racemases, activity was dependent on the cofactor pyridoxal phosphate. Genetic complementation, enzymatic characterization, and bioinformatic analyses indicate that chlamydial DapF shares characteristics with other promiscuous/primordial enzymes, presenting a potential mechanism for d-glutamate synthesis not only in Chlamydia but also numerous other genera within the Planctomycetes-Verrucomicrobiae-Chlamydiae superphylum that lack recognized glutamate racemases.IMPORTANCE Here we describe one of the last remaining "missing" steps in peptidoglycan synthesis in pathogenic Chlamydia species, the synthesis of d-glutamate. We have determined that the diaminopimelate epimerase (DapF) encoded by Chlamydia trachomatis is capable of carrying out both the epimerization of DAP and the pyridoxal phosphate-dependent racemization of glutamate. Enzyme promiscuity is thought to be the hallmark of early microbial life on this planet, and there is currently an active debate as to whether "moonlighting enzymes" represent primordial evolutionary relics or are a product of more recent reductionist evolutionary pressures. Given the large number of Chlamydia species (as well as members of the Planctomycetes-Verrucomicrobiae-Chlamydiae superphylum) that possess DapF but lack homologues of MurI, it is likely that DapF is a primordial isomerase that functions as both racemase and epimerase in these organisms, suggesting that specialized d-glutamate racemase enzymes never evolved in these microbes.
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Affiliation(s)
- George Liechti
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Raghuveer Singh
- Emerging Pathogens Institute and Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
| | - Patricia L Rossi
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Miranda D Gray
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Nancy E Adams
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Anthony T Maurelli
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Emerging Pathogens Institute and Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
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15
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Ahn YC, Fischer C, van Belkum MJ, Vederas JC. PLP-independent racemization: mechanistic and mutational studies ofO-ureidoserine racemase (DcsC). Org Biomol Chem 2018; 16:1126-1133. [DOI: 10.1039/c7ob03013d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Site-specific mutagenesis and inhibition ofO-ureidoserine racemase reveals mechanistic insights in the unique PLP-independent bioenzymatic racemization of amino acids.
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Affiliation(s)
- Yeong-Chan Ahn
- Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - Conrad Fischer
- Department of Chemistry
- University of Alberta
- Edmonton
- Canada
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16
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Sagong HY, Kim KJ. Structural basis for redox sensitivity in Corynebacterium glutamicum diaminopimelate epimerase: an enzyme involved in l-lysine biosynthesis. Sci Rep 2017; 7:42318. [PMID: 28176858 PMCID: PMC5296763 DOI: 10.1038/srep42318] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/06/2017] [Indexed: 01/07/2023] Open
Abstract
Diaminopimelate epimerase (DapF) is one of the crucial enzymes involved in l-lysine biosynthesis, where it converts l,l-diaminopimelate (l,l-DAP) into d,l-DAP. DapF is also considered as an attractive target for the development of antibacterial drugs. Here, we report the crystal structure of DapF from Corynebacterium glutamicum (CgDapF). Structures of CgDapF obtained under both oxidized and reduced conditions reveal that the function of CgDapF is regulated by redox-switch modulation via reversible disulfide bond formation between two catalytic cysteine residues. Under oxidized condition, two catalytic cysteine residues form a disulfide bond; these same cysteine residues exist in reduced form under reduced condition. Disulfide bond formation also induces a subsequent structural change in the dynamic catalytic loop at the active site, which results in open/closed conformational change at the active site. We also determined the crystal structure of CgDapF in complex with its product d,l-DAP, and elucidated how the enzyme recognizes its substrate l,l-DAP as a substrate. Moreover, the structure in complex with the d,l-DAP product reveals that CgDapF undergoes a large open/closed domain movement upon substrate binding, resulting in a completely buried active site with the substrate bound.
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Affiliation(s)
- Hye-Young Sagong
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daehak-ro 80, Buk-ku, Daegu 702-701, Korea
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daehak-ro 80, Buk-ku, Daegu 702-701, Korea,
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17
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Waltman PH, Guo J, Reistetter EN, Purvine S, Ansong CK, van Baren MJ, Wong CH, Wei CL, Smith RD, Callister SJ, Stuart JM, Worden AZ. Identifying Aspects of the Post-Transcriptional Program Governing the Proteome of the Green Alga Micromonas pusilla. PLoS One 2016; 11:e0155839. [PMID: 27434306 PMCID: PMC4951065 DOI: 10.1371/journal.pone.0155839] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/05/2016] [Indexed: 11/18/2022] Open
Abstract
Micromonas is a unicellular motile alga within the Prasinophyceae, a green algal group that is related to land plants. This picoeukaryote (<2 μm diameter) is widespread in the marine environment but is not well understood at the cellular level. Here, we examine shifts in mRNA and protein expression over the course of the day-night cycle using triplicated mid-exponential, nutrient replete cultures of Micromonas pusilla CCMP1545. Samples were collected at key transition points during the diel cycle for evaluation using high-throughput LC-MS proteomics. In conjunction, matched mRNA samples from the same time points were sequenced using pair-ended directional Illumina RNA-Seq to investigate the dynamics and relationship between the mRNA and protein expression programs of M. pusilla. Similar to a prior study of the marine cyanobacterium Prochlorococcus, we found significant divergence in the mRNA and proteomics expression dynamics in response to the light:dark cycle. Additionally, expressional responses of genes and the proteins they encoded could also be variable within the same metabolic pathway, such as we observed in the oxygenic photosynthesis pathway. A regression framework was used to predict protein levels from both mRNA expression and gene-specific sequence-based features. Several features in the genome sequence were found to influence protein abundance including codon usage as well as 3’ UTR length and structure. Collectively, our studies provide insights into the regulation of the proteome over a diel cycle as well as the relationships between transcriptional and translational programs in the widespread marine green alga Micromonas.
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Affiliation(s)
- Peter H. Waltman
- University of California at Santa Cruz, Baskin School of Engineering, Santa Cruz, California, 95064, United States of America
| | - Jian Guo
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
| | - Emily Nahas Reistetter
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
| | - Samuel Purvine
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352, United States of America
| | - Charles K. Ansong
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352, United States of America
| | - Marijke J. van Baren
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
| | - Chee-Hong Wong
- U.S. Department of Energy (DOE) Joint Genome Institute (JGI), Walnut Creek, California, 94598, United States of America
| | - Chia-Lin Wei
- U.S. Department of Energy (DOE) Joint Genome Institute (JGI), Walnut Creek, California, 94598, United States of America
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352, United States of America
| | - Stephen J. Callister
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352, United States of America
- * E-mail: (SJC); (JMS); (AZW)
| | - Joshua M. Stuart
- University of California at Santa Cruz, Baskin School of Engineering, Santa Cruz, California, 95064, United States of America
- * E-mail: (SJC); (JMS); (AZW)
| | - Alexandra Z. Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
- University of California Santa Cruz, Department of Ocean Sciences, Santa Cruz, California, 95064, United States of America
- Integrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto, Canada, M5G 1Z8
- * E-mail: (SJC); (JMS); (AZW)
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18
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Discovery of a novel amino acid racemase through exploration of natural variation in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2015; 112:11726-31. [PMID: 26324904 DOI: 10.1073/pnas.1503272112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Plants produce diverse low-molecular-weight compounds via specialized metabolism. Discovery of the pathways underlying production of these metabolites is an important challenge for harnessing the huge chemical diversity and catalytic potential in the plant kingdom for human uses, but this effort is often encumbered by the necessity to initially identify compounds of interest or purify a catalyst involved in their synthesis. As an alternative approach, we have performed untargeted metabolite profiling and genome-wide association analysis on 440 natural accessions of Arabidopsis thaliana. This approach allowed us to establish genetic linkages between metabolites and genes. Investigation of one of the metabolite-gene associations led to the identification of N-malonyl-D-allo-isoleucine, and the discovery of a novel amino acid racemase involved in its biosynthesis. This finding provides, to our knowledge, the first functional characterization of a eukaryotic member of a large and widely conserved phenazine biosynthesis protein PhzF-like protein family. Unlike most of known eukaryotic amino acid racemases, the newly discovered enzyme does not require pyridoxal 5'-phosphate for its activity. This study thus identifies a new d-amino acid racemase gene family and advances our knowledge of plant d-amino acid metabolism that is currently largely unexplored. It also demonstrates that exploitation of natural metabolic variation by integrating metabolomics with genome-wide association is a powerful approach for functional genomics study of specialized metabolism.
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19
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Richard JP, Amyes TL, Goryanova B, Zhai X. Enzyme architecture: on the importance of being in a protein cage. Curr Opin Chem Biol 2014; 21:1-10. [PMID: 24699188 DOI: 10.1016/j.cbpa.2014.03.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/01/2014] [Indexed: 11/30/2022]
Abstract
Substrate binding occludes water from the active sites of many enzymes. There is a correlation between the burden to enzymatic catalysis of deprotonation of carbon acids and the substrate immobilization at solvent-occluded active sites for ketosteroid isomerase (KSI--small burden, substrate pKa=13), triosephosphate isomerase (TIM, substrate pKa≈18) and diaminopimelate epimerase (DAP epimerase, large burden, substrate pKa≈29) catalyzed reaction. KSI binds substrates at a surface cleft, TIM binds substrate at an exposed 'cage' formed by closure of flexible loops; and, DAP epimerase binds substrate in a tight cage formed by an 'oyster-like' clamping motion of protein domains. Directed evolution of a solvent-occluded active site at a designed protein catalyst of the Kemp elimination reaction is discussed.
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Affiliation(s)
- John P Richard
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA.
| | - Tina L Amyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
| | - Bogdana Goryanova
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
| | - Xiang Zhai
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
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20
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A compendium of cyclic sugar amino acids and their carbocyclic and heterocyclic nitrogen analogues. Amino Acids 2013; 45:613-89. [DOI: 10.1007/s00726-013-1521-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/21/2013] [Indexed: 12/19/2022]
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21
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Hor L, Peverelli MG, Perugini MA, Hutton CA. A new robust kinetic assay for DAP epimerase activity. Biochimie 2013; 95:1949-53. [PMID: 23838343 DOI: 10.1016/j.biochi.2013.06.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/28/2013] [Indexed: 11/30/2022]
Abstract
DAP epimerase is the penultimate enzyme in the lysine biosynthesis pathway. The most versatile assay for DAP epimerase catalytic activity employs a coupled DAP epimerase-DAP dehydrogenase enzyme system with a commercial mixture of DAP isomers as substrate. DAP dehydrogenase converts meso-DAP to THDP with concomitant reduction of NADP(+) to NADPH. We show that at high concentrations, accumulation of NADPH results in inhibition of DAPDH, resulting in spurious kinetic data. A new assay has been developed employing DAP decarboxylase that allows the reliable characterisation of DAP epimerase enzyme kinetics.
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Affiliation(s)
- Lilian Hor
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
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22
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Hor L, Dobson RCJ, Downton MT, Wagner J, Hutton CA, Perugini MA. Dimerization of bacterial diaminopimelate epimerase is essential for catalysis. J Biol Chem 2013; 288:9238-48. [PMID: 23426375 DOI: 10.1074/jbc.m113.450148] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diaminopimelate (DAP) epimerase is involved in the biosynthesis of meso-DAP and lysine, which are important precursors for the synthesis of peptidoglycan, housekeeping proteins, and virulence factors in bacteria. Accordingly, DAP epimerase is a promising antimicrobial target. Previous studies report that DAP epimerase exists as a monomeric enzyme. However, we show using analytical ultracentrifugation, X-ray crystallography, and enzyme kinetic analyses that DAP epimerase from Escherichia coli exists as a functional dimer in solution and the crystal state. Furthermore, the 2.0-Å X-ray crystal structure of the E. coli DAP epimerase dimer shows for the first time that the enzyme exists in an open, active conformation. The importance of dimerization was subsequently probed by using site-directed mutagenesis to generate a monomeric mutant (Y268A). Our studies show that Y268A is catalytically inactive, thus demonstrating that dimerization of DAP epimerase is essential for catalysis. Molecular dynamics simulations indicate that the DAP epimerase monomer is inherently more flexible than the dimer, suggesting that dimerization optimizes protein dynamics to support function. Our findings offer insight into the development of novel antimicrobial agents targeting the dimeric antibiotic target DAP epimerase.
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Affiliation(s)
- Lilian Hor
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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23
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Park JS, Lee WC, Song JH, Kim SI, Lee JC, Cheong C, Kim HY. Purification, crystallization and preliminary X-ray crystallographic analysis of diaminopimelate epimerase from Acinetobacter baumannii. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 69:42-4. [PMID: 23295484 DOI: 10.1107/s1744309112048506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 11/26/2012] [Indexed: 11/10/2022]
Abstract
The meso isomer of diaminopimelate (meso-DAP) is a biosynthetic precursor of L-lysine in bacteria and plants, and is a key component of the peptidoglycan layer in the cell walls of Gram-negative and some Gram-positive bacteria. Diaminopimelate epimerase (DapF) is a pyridoxal-5'-phosphate-independent racemase which catalyses the interconversion of (6S,2S)-2,6-diaminopimelic acid (LL-DAP) and meso-DAP. In this study, DapF from Acinetobacter baumannii was overexpressed in Escherichia coli strain SoluBL21, purified and crystallized using a vapour-diffusion method. A native crystal diffracted to a resolution of 1.9 Å and belonged to space group P3(1) or P3(2), with unit-cell parameters a = b = 74.91, c = 113.35 Å, α = β = 90, γ = 120°. There were two molecules in the asymmetric unit.
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Affiliation(s)
- Jeong Soon Park
- Division of Magnetic Resonance, Korea Basic Science Institute, 804-1 Yangcheong-ri, Ochang, Chungbuk 363-883, Republic of Korea
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24
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Pitscheider M, Mäusbacher N, Sieber SA. Antibiotic activity and target discovery of three-membered natural product-derived heterocycles in pathogenic bacteria. Chem Sci 2012. [DOI: 10.1039/c2sc20290e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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25
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Dietrich D, van Belkum MJ, Vederas JC. Characterization of DcsC, a PLP-independent racemase involved in the biosynthesis of d-cycloserine. Org Biomol Chem 2012; 10:2248-54. [DOI: 10.1039/c2ob06864h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Fan C, Vederas JC. Synthesis and structure–activity relationships of o-sulfonamido-arylhydrazides as inhibitors of ll-diaminopimelate aminotransferase (ll-DAP-AT). Org Biomol Chem 2012; 10:5815-9. [DOI: 10.1039/c2ob00040g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Conti P, Tamborini L, Pinto A, Blondel A, Minoprio P, Mozzarelli A, De Micheli C. Drug Discovery Targeting Amino Acid Racemases. Chem Rev 2011; 111:6919-46. [DOI: 10.1021/cr2000702] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paola Conti
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Lucia Tamborini
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Andrea Pinto
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Arnaud Blondel
- Institut Pasteur, Unité de Bioinformatique Structurale, CNRS-URA 2185, Département de Biologie Structurale et Chimie, 25 rue du Dr. Roux, 75724 Paris, France
| | - Paola Minoprio
- Institut Pasteur, Laboratoire des Processus Infectieux à Trypanosoma; Département d’Infection et Epidémiologie; 25 rue du Dr. Roux, 75724 Paris, France
| | - Andrea Mozzarelli
- Dipartimento di Biochimica e Biologia Molecolare, via G. P. Usberti 23/A, 43100 Parma, Italy
- Istituto di Biostrutture e Biosistemi, viale Medaglie d’oro, Roma, Italy
| | - Carlo De Micheli
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
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28
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Synthesis of new functionalized aziridine-2- and azetidine-3-carboxylic acid derivatives of potential interest for biological and foldameric applications. Amino Acids 2011; 41:541-58. [DOI: 10.1007/s00726-011-0879-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 03/01/2011] [Indexed: 10/18/2022]
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29
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Fan C, Clay MD, Deyholos MK, Vederas JC. Exploration of inhibitors for diaminopimelate aminotransferase. Bioorg Med Chem 2010; 18:2141-2151. [DOI: 10.1016/j.bmc.2010.02.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 01/31/2010] [Accepted: 02/02/2010] [Indexed: 10/19/2022]
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30
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Hor L, Dobson RCJ, Dogovski C, Hutton CA, Perugini MA. Crystallization and preliminary X-ray diffraction analysis of diaminopimelate epimerase from Escherichia coli. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:37-40. [PMID: 20057066 PMCID: PMC2805532 DOI: 10.1107/s1744309109047708] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 11/11/2009] [Indexed: 11/10/2022]
Abstract
Diaminopimelate (DAP) epimerase (EC 5.1.1.7) catalyzes the penultimate step of lysine biosynthesis in bacteria and plants, converting L,L-diaminopimelate to meso-diaminopimelate. Here, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DAP epimerase from Escherichia coli are presented. Crystals were obtained in space group P4(1)2(1)2 and diffracted to 2.0 A resolution, with unit-cell parameters a = b = 89.4, c = 179.6 A. Molecular replacement was conducted using Bacillus anthracis DAP epimerase as a search model and showed the presence of two molecules in the asymmetric unit, with an initial R(free) of 0.456 and R(work) of 0.416.
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Affiliation(s)
- Lilian Hor
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, The University of Melbourne, Parkville, Victoria 3010, Australia
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Craig A. Hutton
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Matthew A. Perugini
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, The University of Melbourne, Parkville, Victoria 3010, Australia
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