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de Munnik M, Lang PA, Calvopiña K, Rabe P, Brem J, Schofield CJ. Biochemical and crystallographic studies of L,D-transpeptidase 2 from Mycobacterium tuberculosis with its natural monomer substrate. Commun Biol 2024; 7:1173. [PMID: 39294212 PMCID: PMC11410929 DOI: 10.1038/s42003-024-06785-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 08/27/2024] [Indexed: 09/20/2024] Open
Abstract
The essential L,D-transpeptidase of Mycobacterium tuberculosis (LdtMt2) catalyses the formation of 3 → 3 cross-links in cell wall peptidoglycan and is a target for development of antituberculosis therapeutics. Efforts to inhibit LdtMt2 have been hampered by lack of knowledge of how it binds its substrate. To address this gap, we optimised the isolation of natural disaccharide tetrapeptide monomers from the Corynebacterium jeikeium bacterial cell wall through overproduction of the peptidoglycan sacculus. The tetrapeptides were used in binding / turnover assays and biophysical studies on LdtMt2. We determined a crystal structure of wild-type LdtMt2 reacted with its natural substrate, the tetrapeptide monomer of the peptidoglycan layer. This structure shows formation of a thioester linking the catalytic cysteine and the donor substrate, reflecting an intermediate in the transpeptidase reaction; it informs on the mode of entrance of the donor substrate into the LdtMt2 active site. The results will be useful in design of LdtMt2 inhibitors, including those based on substrate binding interactions, a strategy successfully employed for other nucleophilic cysteine enzymes.
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Affiliation(s)
- Mariska de Munnik
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK
| | - Pauline A Lang
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK
| | - Karina Calvopiña
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK
| | - Patrick Rabe
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK
| | - Jürgen Brem
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK
- Enzymology and Applied Biocatalysis Research Center, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
| | - Christopher J Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, Oxford, UK.
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2
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Huang LD, Gou XY, Yang MJ, Li MJ, Chen SN, Yan J, Liu XX, Sun AH. Peptidoglycan biosynthesis-associated enzymatic kinetic characteristics and β-lactam antibiotic inhibitory effects of different Streptococcus pneumoniae penicillin-binding proteins. Int J Biol Macromol 2024; 254:127784. [PMID: 37949278 DOI: 10.1016/j.ijbiomac.2023.127784] [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] [Received: 05/24/2023] [Revised: 09/15/2023] [Accepted: 10/28/2023] [Indexed: 11/12/2023]
Abstract
Penicillin-binding proteins (PBPs) include transpeptidases, carboxypeptidases, and endopeptidases for biosynthesis of peptidoglycans in the cell wall to maintain bacterial morphology and survival in the environment. Streptococcus pneumoniae expresses six PBPs, but their enzymatic kinetic characteristics and inhibitory effects on different β-lactam antibiotics remain poorly understood. In this study, all the six recombinant PBPs of S. pneumoniae displayed transpeptidase activity with different substrate affinities (Km = 1.56-9.11 mM) in a concentration-dependent manner, and rPBP3 showed a greater catalytic efficiency (Kcat = 2.38 s-1) than the other rPBPs (Kcat = 3.20-7.49 × 10-2 s-1). However, only rPBP3 was identified as a carboxypeptidase (Km = 8.57 mM and Kcat = 2.57 s-1). None of the rPBPs exhibited endopeptidase activity. Penicillin and cefotaxime inhibited the transpeptidase and carboxypeptidase activity of all the rPBPs but imipenem did not inhibited the enzymatic activities of rPBP3. Except for the lack of binding of imipenem to rPBP3, penicillin, cefotaxime, and imipenem bound to all the other rPBPs (KD = 3.71-9.35 × 10-4 M). Sublethal concentrations of penicillin, cefotaxime, and imipenem induced a decrease of pneumococcal pbps-mRNA levels (p < 0.05). These results indicated that all six PBPs of S. pneumoniae are transpeptidases, while only PBP3 is a carboxypeptidase. Imipenem has no inhibitory effect on pneumococcal PBP3. The pneumococcal genes for encoding endopeptidases remain to be determined.
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Affiliation(s)
- Li-Dan Huang
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China; Yiwu Central Blood Station, Yiwu, Zhejiang 322000, PR China
| | - Xiao-Yu Gou
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China
| | - Mei-Juan Yang
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China; The First Hospital of Putian City, Putian, Fujian 351100, PR China
| | - Meng-Jie Li
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China
| | - Sui-Ning Chen
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China
| | - Jie Yan
- Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China
| | - Xiao-Xiang Liu
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China.
| | - Ai-Hua Sun
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310053, PR China.
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3
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Bertonha AF, Silva CCL, Shirakawa KT, Trindade DM, Dessen A. Penicillin-binding protein (PBP) inhibitor development: A 10-year chemical perspective. Exp Biol Med (Maywood) 2023; 248:1657-1670. [PMID: 38030964 PMCID: PMC10723023 DOI: 10.1177/15353702231208407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Abstract
Bacterial cell wall formation is essential for cellular survival and morphogenesis. The peptidoglycan (PG), a heteropolymer that surrounds the bacterial membrane, is a key component of the cell wall, and its multistep biosynthetic process is an attractive antibacterial development target. Penicillin-binding proteins (PBPs) are responsible for cross-linking PG stem peptides, and their central role in bacterial cell wall synthesis has made them the target of successful antibiotics, including β-lactams, that have been used worldwide for decades. Following the discovery of penicillin, several other compounds with antibiotic activity have been discovered and, since then, have saved millions of lives. However, since pathogens inevitably become resistant to antibiotics, the search for new active compounds is continuous. The present review highlights the ongoing development of inhibitors acting mainly in the transpeptidase domain of PBPs with potential therapeutic applications for the development of new antibiotic agents. Both the critical aspects of the strategy, design, and structure-activity relationships (SAR) are discussed, covering the main published articles over the last 10 years. Some of the molecules described display activities against main bacterial pathogens and could open avenues toward the development of new, efficient antibacterial drugs.
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Affiliation(s)
- Ariane F Bertonha
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, Brazil
| | - Caio C L Silva
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, Brazil
| | - Karina T Shirakawa
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, Brazil
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, Brazil
| | - Daniel M Trindade
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, Brazil
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, Brazil
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France
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4
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Flanders PL, Contreras-Martel C, Brown NW, Shirley JD, Martins A, Nauta KN, Dessen A, Carlson EE, Ambrose EA. Combined Structural Analysis and Molecular Dynamics Reveal Penicillin-Binding Protein Inhibition Mode with β-Lactones. ACS Chem Biol 2022; 17:3110-3120. [PMID: 36173746 PMCID: PMC10057605 DOI: 10.1021/acschembio.2c00503] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
β-Lactam antibiotics comprise one of the most widely used therapeutic classes to combat bacterial infections. This general scaffold has long been known to inhibit bacterial cell wall biosynthesis by inactivating penicillin-binding proteins (PBPs); however, bacterial resistance to β-lactams is now widespread, and new strategies are urgently needed to target PBPs and other proteins involved in bacterial cell wall formation. A key requirement in the identification of strategies to overcome resistance is a deeper understanding of the roles of the PBPs and their associated proteins during cell growth and division, such as can be obtained with the use of selective chemical probes. Probe development has typically depended upon known PBP inhibitors, which have historically been thought to require a negatively charged moiety that mimics the C-terminus of the PBP natural peptidoglycan substrate, d-Ala-d-Ala. However, we have identified a new class of β-lactone-containing molecules that interact with PBPs, often in an isoform-specific manner, and do not incorporate this C-terminal mimetic. Here, we report a series of structural biology experiments and molecular dynamics simulations that we utilized to evaluate specific binding modes of this novel PBP inhibitor class. In this work, we obtained <2 Å resolution X-ray structures of four β-lactone probes bound to PBP1b from Streptococcus pneumoniae. Despite their diverging recognition modes beyond the site of covalent modification, these four probes all efficiently labeled PBP1b, as well as other PBPs from S. pneumoniae. From these structures, we analyzed protein-ligand interactions and characterized the β-lactone-bound active sites using in silico mutagenesis and molecular dynamics. Our approach has clarified the dynamic interaction profile in this series of ligands, expanding the understanding of PBP inhibitor binding.
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Affiliation(s)
- Parker L Flanders
- Department of Medicinal Chemistry, University of Minnesota, 208 Harvard Street SE, Minneapolis, Minnesota 55454, United States
| | - Carlos Contreras-Martel
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France
| | - Nathaniel W Brown
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota, 208 Harvard Street SE, Minneapolis, Minnesota 55454, United States
| | - Alexandre Martins
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France
| | - Kelsie N Nauta
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Andréa Dessen
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France.,Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas 13084-971, São Paulo, Brazil
| | - Erin E Carlson
- Department of Medicinal Chemistry, University of Minnesota, 208 Harvard Street SE, Minneapolis, Minnesota 55454, United States.,Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.,Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55454, United States.,Department of Pharmacology, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55454, United States
| | - Elizabeth A Ambrose
- Department of Medicinal Chemistry, University of Minnesota, 208 Harvard Street SE, Minneapolis, Minnesota 55454, United States.,Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455, United States
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5
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Santos RAND, Abdel-Nour J, McAuley C, Moore SC, Fegan N, Fox EM. Clostridium perfringens associated with dairy farm systems show diverse genotypes. Int J Food Microbiol 2022; 382:109933. [PMID: 36166891 DOI: 10.1016/j.ijfoodmicro.2022.109933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/08/2022] [Accepted: 09/13/2022] [Indexed: 10/14/2022]
Abstract
Clostridium perfringens is a bacterial species of importance to both public and animal health. Frequently found in food system environments, it presents a risk to food animal health such as dairy herds, and may cross contaminate associated ingredients or food products, with potential to cause sporadic and outbreaks of disease in human populations, including gastroenteric illness. In this study, we characterized C. perfringens isolated from bovine, caprine, and ovine dairy farm systems (n = 8, 11 and 4, respectively). Isolates were phenotypically screened for antimicrobial sensitivity profiling, and subjected to whole genome sequencing to elucidate related genetic markers, as well as examine virulence gene markers, mobile genetic elements, and other features. Both toxin type A and type D isolates were identified (78 % and 22 % of isolates, respectively), including 20 novel sequence types. Resistance to clindamycin was most prevalent among antibiotics screened (30 %), followed by erythromycin (13 %), then penicillin and tetracycline (4 %), although an additional 3 isolates were non-susceptible to tetracycline. Most isolates harboured plasmids, which mobilised virulence markers such as etx, cpb2, and resistance markers tetA(P), tetB(P), and erm(Q), on conjugative plasmids. The presence of type D isolates on caprine farms emphasizes the need for control efforts to prevent infection and potential enterotoxemia. Clostridium perfringens enterotoxin (cpe) was not identified, suggesting lower risk of gastrointestinal illness from contaminated foods, the presence of other virulence and antimicrobial resistance markers suggests farm hygiene remains an important consideration to help ensure food safety of associated dairy foods produced.
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Affiliation(s)
| | | | - Cathy McAuley
- CSIRO Agriculture and Food, Werribee, VIC 3030, Australia
| | - Sean C Moore
- CSIRO Agriculture and Food, Cooper Plains, QLD 4108, Australia
| | - Narelle Fegan
- CSIRO Agriculture and Food, Cooper Plains, QLD 4108, Australia
| | - Edward M Fox
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK.
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6
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Siziani D, Ziani BEC, Abdi Y, Bensouilah N, Boutemeur-Kheddis B, Ziani C, Boukkena L, Hamdi M, Talhi O, Bachari K, Silva AM. Multicomponent synthesis of pyranonicotinonitrile and chromene-3-carbonitrile: Studies on bioactivities and molecular docking. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Park M, Sutherland JB, Rafii F. β-Lactam resistance development affects binding of penicillin-binding proteins (PBPs) of Clostridium perfringens to the fluorescent penicillin, BOCILLIN FL. Anaerobe 2020; 62:102179. [PMID: 32088319 DOI: 10.1016/j.anaerobe.2020.102179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 01/11/2023]
Abstract
Alteration in the binding of bacterial penicillin-binding proteins (PBPs) to β-lactams is important in the development of drug resistance. The PBPs of wild type Clostridium perfringens ATCC 13124 and three β-lactam-resistant mutants were compared for the ability to bind to a fluorescent penicillin, BOCILLIN FL. The binding of the high molecular weight protein PBP1, a transpeptidase, to BOCILLIN FL was reduced in all of the resistant strains. In contrast, the binding of BOCILLIN FL to a low molecular weight protein, PBP6, a D-alanyl-d-alanine carboxypeptidase that was more abundant in all three resistant strains, was substantially increased. A competition assay with β-lactams reduced the binding of all of the PBPs, including PBP6, to BOCILLIN FL. β-Lactams enhanced transcription of the putative gene for PBP6 in both wild type and resistant strains. This is the first report showing that mutations in a high molecular weight PBP and overexpression of a low molecular weight PBP in resistant C. perfringens strains affected their binding to β-lactams.
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Affiliation(s)
- Miseon Park
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 71602, USA
| | - John B Sutherland
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 71602, USA
| | - Fatemeh Rafii
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 71602, USA.
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8
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Penicillin-binding proteins: evergreen drug targets. Curr Opin Pharmacol 2014; 18:112-9. [DOI: 10.1016/j.coph.2014.09.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023]
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9
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van Berkel SS, Nettleship JE, Leung IKH, Brem J, Choi H, Stuart DI, Claridge TDW, McDonough MA, Owens RJ, Ren J, Schofield CJ. Binding of (5S)-penicilloic acid to penicillin binding protein 3. ACS Chem Biol 2013; 8:2112-6. [PMID: 23899657 DOI: 10.1021/cb400200h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
β-Lactam antibiotics react with penicillin binding proteins (PBPs) to form relatively stable acyl-enzyme complexes. We describe structures derived from the reaction of piperacillin with PBP3 (Pseudomonas aeruginosa) including not only the anticipated acyl-enzyme complex but also an unprecedented complex with (5S)-penicilloic acid, which was formed by C-5 epimerization of the nascent (5R)-penicilloic acid product. Formation of the complex was confirmed by solution studies, including NMR. Together, these results will be useful in the design of new PBP inhibitors and raise the possibility that noncovalent PBP inhibition by penicilloic acids may be of clinical relevance.
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Affiliation(s)
- Sander S. van Berkel
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - Joanne E. Nettleship
- Oxford Protein
Production Facility
U.K., Research Complex at Harwell, Rutherford Appleton Laboratory Harwell, Science and Innovation Campus, Oxfordshire
OX11 0FA, U.K
- Division of
Structural Biology, University of Oxford, Henry Wellcome Building for Genomic
Medicine, Oxford OX3 7BN, U.K
| | - Ivanhoe K. H. Leung
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - Jürgen Brem
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - Hwanho Choi
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - David I. Stuart
- Division of
Structural Biology, University of Oxford, Henry Wellcome Building for Genomic
Medicine, Oxford OX3 7BN, U.K
| | - Timothy D. W. Claridge
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - Michael A. McDonough
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1
3TA, U.K
| | - Raymond J. Owens
- Oxford Protein
Production Facility
U.K., Research Complex at Harwell, Rutherford Appleton Laboratory Harwell, Science and Innovation Campus, Oxfordshire
OX11 0FA, U.K
- Division of
Structural Biology, University of Oxford, Henry Wellcome Building for Genomic
Medicine, Oxford OX3 7BN, U.K
| | - Jingshan Ren
- Division of
Structural Biology, University of Oxford, Henry Wellcome Building for Genomic
Medicine, Oxford OX3 7BN, U.K
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10
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Lecoq L, Bougault C, Hugonnet JE, Veckerlé C, Pessey O, Arthur M, Simorre JP. Dynamics induced by β-lactam antibiotics in the active site of Bacillus subtilis L,D-transpeptidase. Structure 2012; 20:850-61. [PMID: 22579252 DOI: 10.1016/j.str.2012.03.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 02/29/2012] [Accepted: 03/05/2012] [Indexed: 11/18/2022]
Abstract
β-lactams inhibit peptidoglycan polymerization by acting as suicide substrates of essential d,d-transpeptidases. Bypass of these enzymes by unrelated l,d-transpeptidases results in β-lactam resistance, although carbapenems remain unexpectedly active. To gain insight into carbapenem specificity of l,d-transpeptidases (Ldts), we solved the nuclear magnetic resonance (NMR) structures of apo and imipenem-acylated Bacillus subtilis Ldt and show that the cysteine nucleophile is present as a neutral imidazole-sulfhydryl pair in the substrate-free enzyme. NMR relaxation dispersion does not reveal any preexisting conformational exchange in the apoenzyme, and change in flexibility is not observed upon noncovalent binding of β-lactams (K(D) > 37.5 mM). In contrast, covalent modification of active cysteine by both carbapenems and 2-nitro-5-thiobenzoate induces backbone flexibility that does not result from disruption of the imidazole-sulfhydryl proton interaction or steric hindrance. The chemical step of the reaction determines enzyme specificity since no differences in drug affinity were observed.
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Affiliation(s)
- Lauriane Lecoq
- CEA, DSV, Institut de Biologie Structurale (IBS), Grenoble F-38027, France
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11
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Nemmara VV, Dzhekieva L, Sarkar KS, Adediran SA, Duez C, Nicholas RA, Pratt RF. Substrate specificity of low-molecular mass bacterial DD-peptidases. Biochemistry 2011; 50:10091-101. [PMID: 22029692 DOI: 10.1021/bi201326a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bacterial DD-peptidases or penicillin-binding proteins (PBPs) catalyze the formation and regulation of cross-links in peptidoglycan biosynthesis. They are classified into two groups, the high-molecular mass (HMM) and low-molecular mass (LMM) enzymes. The latter group, which is subdivided into classes A-C (LMMA, -B, and -C, respectively), is believed to catalyze DD-carboxypeptidase and endopeptidase reactions in vivo. To date, the specificity of their reactions with particular elements of peptidoglycan structure has not, in general, been defined. This paper describes the steady-state kinetics of hydrolysis of a series of specific peptidoglycan-mimetic peptides, representing various elements of stem peptide structure, catalyzed by a range of LMM PBPs (the LMMA enzymes, Escherichia coli PBP5, Neisseria gonorrhoeae PBP4, and Streptococcus pneumoniae PBP3, and the LMMC enzymes, the Actinomadura R39 dd-peptidase, Bacillus subtilis PBP4a, and N. gonorrhoeae PBP3). The R39 enzyme (LMMC), like the previously studied Streptomyces R61 DD-peptidase (LMMB), specifically and rapidly hydrolyzes stem peptide fragments with a free N-terminus. In accord with this result, the crystal structures of the R61 and R39 enzymes display a binding site specific to the stem peptide N-terminus. These are water-soluble enzymes, however, with no known specific function in vivo. On the other hand, soluble versions of the remaining enzymes of those noted above, all of which are likely to be membrane-bound and/or associated in vivo and have been assigned particular roles in cell wall biosynthesis and maintenance, show little or no specificity for peptides containing elements of peptidoglycan structure. Peptidoglycan-mimetic boronate transition-state analogues do inhibit these enzymes but display notable specificity only for the LMMC enzymes, where, unlike peptide substrates, they may be able to effectively induce a specific active site structure. The manner in which LMMA (and HMM) DD-peptidases achieve substrate specificity, both in vitro and in vivo, remains unknown.
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Affiliation(s)
- Venkatesh V Nemmara
- Department of Chemistry, Wesleyan University, Lawn Avenue, Middletown, Connecticut 06459, USA
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12
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Contreras-Martel C, Amoroso A, Woon ECY, Zervosen A, Inglis S, Martins A, Verlaine O, Rydzik AM, Job V, Luxen A, Joris B, Schofield CJ, Dessen A. Structure-guided design of cell wall biosynthesis inhibitors that overcome β-lactam resistance in Staphylococcus aureus (MRSA). ACS Chem Biol 2011; 6:943-51. [PMID: 21732689 DOI: 10.1021/cb2001846] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
β-Lactam antibiotics have long been a treatment of choice for bacterial infections since they bind irreversibly to Penicillin-Binding Proteins (PBPs), enzymes that are vital for cell wall biosynthesis. Many pathogens express drug-insensitive PBPs rendering β-lactams ineffective, revealing a need for new types of PBP inhibitors active against resistant strains. We have identified alkyl boronic acids that are active against pathogens including methicillin-resistant S. aureus (MRSA). The crystal structures of PBP1b complexed to 11 different alkyl boronates demonstrate that in vivo efficacy correlates with the mode of inhibitor side chain binding. Staphylococcal membrane analyses reveal that the most potent alkyl boronate targets PBP1, an autolysis system regulator, and PBP2a, a low β-lactam affinity enzyme. This work demonstrates the potential of boronate-based PBP inhibitors for circumventing β-lactam resistance and opens avenues for the development of novel antibiotics that target Gram-positive pathogens.
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Affiliation(s)
| | - Ana Amoroso
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Esther C. Y. Woon
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Astrid Zervosen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Steven Inglis
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Olivier Verlaine
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Anna M. Rydzik
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | | | - André Luxen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Bernard Joris
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
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13
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Iqbal A, Clifton IJ, Chowdhury R, Ivison D, Domene C, Schofield CJ. Structural and biochemical analyses reveal how ornithine acetyl transferase binds acidic and basic amino acid substrates. Org Biomol Chem 2011; 9:6219-25. [PMID: 21796301 DOI: 10.1039/c1ob05554b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural and biochemical analyses reveal how ornithine acetyl-transferases catalyse the reversible transfer of an acetyl-group from a basic (ornithine) to an acidic (glutamate) amino acid by employing a common mechanism involving an acetyl-enzyme intermediate but using different side chain binding modes.
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Affiliation(s)
- Aman Iqbal
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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Bobba S, Gutheil WG. Multivariate geometrical analysis of catalytic residues in the penicillin-binding proteins. Int J Biochem Cell Biol 2011; 43:1490-9. [PMID: 21740978 DOI: 10.1016/j.biocel.2011.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/04/2011] [Accepted: 06/22/2011] [Indexed: 12/11/2022]
Abstract
Penicillin-binding proteins (PBPs) are bacterial enzymes involved in the final stages of cell wall biosynthesis, and are targets of the β-lactam antibiotics. They can be subdivided into essential high-molecular-mass (HMM) and non-essential low-molecular-mass (LMM) PBPs, and further divided into subclasses based on sequence homologies. PBPs can catalyze transpeptidase or hydrolase (carboxypeptidase and endopeptidase) reactions. The PBPs are of interest for their role in bacterial cell wall biosynthesis, and as mechanistically interesting enzymes which can catalyze alternative reaction pathways using the same catalytic machinery. A global catalytic residue comparison seemed likely to provide insight into structure-function correlations within the PBPs. More than 90 PBP structures were aligned, and a number (40) of active site geometrical parameters extracted. This dataset was analyzed using both univariate and multivariate statistical methods. Several interesting relationships were observed. (1) Distribution of the dihedral angle for the SXXK-motif Lys side chain (DA_1) was bimodal, and strongly correlated with HMM/transpeptidase vs LMM/hydrolase classification/activity (P<0.001). This structural feature may therefore be associated with the main functional difference between the HMM and LMM PBPs. (2) The distance between the SXXK-motif Lys-NZ atom and the Lys/His-nitrogen atom of the (K/H)T(S)G-motif was highly conserved, suggesting importance for PBP function, and a possibly conserved role in the catalytic mechanism of the PBPs. (3) Principal components-based cluster analysis revealed several distinct clusters, with the HMM Class A and B, LMM Class C, and LMM Class A K15 PBPs forming one "Main" cluster, and demonstrating a globally similar arrangement of catalytic residues within this group.
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Affiliation(s)
- Sudheer Bobba
- Division of Pharmaceutical Sciences, University of Missouri-Kansas City, Kansas City, MO 64108, United States
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15
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Bridging cell wall biosynthesis and bacterial morphogenesis. Curr Opin Struct Biol 2010; 20:749-55. [DOI: 10.1016/j.sbi.2010.09.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/17/2010] [Accepted: 09/29/2010] [Indexed: 11/17/2022]
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Gautam A, Vyas R, Tewari R. Peptidoglycan biosynthesis machinery: a rich source of drug targets. Crit Rev Biotechnol 2010; 31:295-336. [PMID: 21091161 DOI: 10.3109/07388551.2010.525498] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The range of antibiotic therapy for the control of bacterial infections is becoming increasingly limited because of the rapid rise in multidrug resistance in clinical bacterial isolates. A few diseases, such as tuberculosis, which were once thought to be under control, have re-emerged as serious health threats. These problems have resulted in intensified research to look for new inhibitors for bacterial pathogens. Of late, the peptidoglycan (PG) layer, the most important component of the bacterial cell wall has been the subject of drug targeting because, first, it is essential for the survivability of eubacteria and secondly, it is absent in humans. The last decade has seen tremendous inputs in deciphering the 3-D structures of the PG biosynthetic enzymes. Many inhibitors against these enzymes have been developed using virtual and high throughput screening techniques. This review discusses the mechanistic and structural properties of the PG biosynthetic enzymes and inhibitors developed in the last decade.
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Affiliation(s)
- Ankur Gautam
- Department of Biotechnology, Panjab University, Chandigarh, India
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Manzano C, Izoré T, Job V, Di Guilmi AM, Dessen A. Sortase activity is controlled by a flexible lid in the pilus biogenesis mechanism of gram-positive pathogens. Biochemistry 2009; 48:10549-57. [PMID: 19810750 DOI: 10.1021/bi901261y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pili are surface-linked virulence factors that play key roles in infection establishment in a variety of pathogenic species. In Gram-positive pathogens, pilus formation requires the action of sortases, dedicated transpeptidases that covalently associate pilus building blocks. In Streptococcus pneumoniae, a major human pathogen, all genes required for pilus formation are harbored in a single pathogenicity islet which encodes three structural proteins (RrgA, RrgB, RrgC) and three sortases (SrtC-1, SrtC-2, SrtC-3). RrgB forms the backbone of the streptococcal pilus, to which minor pilins RrgA and RrgC are covalently associated. SrtC-1 is the main sortase involved in polymerization of the RrgB fiber and displays a lid which encapsulates the active site, a feature present in all pilus-related sortases. In this work, we show that catalysis by SrtC-1 proceeds through a catalytic triad constituted of His, Arg, and Cys and that lid instability affects protein fold and catalysis. In addition, we show by thermal shift analysis that lid flexibility can be stabilized by the addition of substrate-like peptides, a feature shared by other periplasmic transpeptidases. We also report the characterization of a trapped acyl-enzyme intermediate formed between SrtC-1 and RrgB. The presence of lid-encapsulated sortases in the pilus biogenesis systems in many Gram-positive pathogens points to a common mechanism of substrate recognition and catalysis that should be taken into consideration in the development of sortase inhibitors.
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Affiliation(s)
- Clothilde Manzano
- Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075 (CEA, CNRS, UJF), 41 rue Jules Horowitz, F-38027 Grenoble, France
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Shi Q, Meroueh SO, Fisher JF, Mobashery S. Investigation of the mechanism of the cell wall DD-carboxypeptidase reaction of penicillin-binding protein 5 of Escherichia coli by quantum mechanics/molecular mechanics calculations. J Am Chem Soc 2008; 130:9293-303. [PMID: 18576637 PMCID: PMC6993461 DOI: 10.1021/ja801727k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Penicillin-binding protein 5 (PBP 5) of Escherichia coli hydrolyzes the terminal D-Ala-D-Ala peptide bond of the stem peptides of the cell wall peptidoglycan. The mechanism of PBP 5 catalysis of amide bond hydrolysis is initial acylation of an active site serine by the peptide substrate, followed by hydrolytic deacylation of this acyl-enzyme intermediate to complete the turnover. The microscopic events of both the acylation and deacylation half-reactions have not been studied. This absence is addressed here by the use of explicit-solvent molecular dynamics simulations and ONIOM quantum mechanics/molecular mechanics (QM/MM) calculations. The potential-energy surface for the acylation reaction, based on MP2/6-31+G(d) calculations, reveals that Lys47 acts as the general base for proton abstraction from Ser44 in the serine acylation step. A discrete potential-energy minimum for the tetrahedral species is not found. The absence of such a minimum implies a conformational change in the transition state, concomitant with serine addition to the amide carbonyl, so as to enable the nitrogen atom of the scissile bond to accept the proton that is necessary for progression to the acyl-enzyme intermediate. Molecular dynamics simulations indicate that transiently protonated Lys47 is the proton donor in tetrahedral intermediate collapse to the acyl-enzyme species. Two pathways for this proton transfer are observed. One is the direct migration of a proton from Lys47. The second pathway is proton transfer via an intermediary water molecule. Although the energy barriers for the two pathways are similar, more conformers sample the latter pathway. The same water molecule that mediates the Lys47 proton transfer to the nitrogen of the departing D-Ala is well positioned, with respect to the Lys47 amine, to act as the hydrolytic water in the deacylation step. Deacylation occurs with the formation of a tetrahedral intermediate over a 24 kcal x mol(-1) barrier. This barrier is approximately 2 kcal x mol(-1) greater than the barrier (22 kcal x mol(-1)) for the formation of the tetrahedral species in acylation. The potential-energy surface for the collapse of the deacylation tetrahedral species gives a 24 kcal x mol(-1) higher energy species for the product, signifying that the complex would readily reorganize and pave the way for the expulsion of the product of the reaction from the active site and the regeneration of the catalyst. These computational data dovetail with the knowledge on the reaction from experimental approaches.
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Affiliation(s)
- Qicun Shi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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