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Kollár L, Grabrijan K, Hrast Rambaher M, Bozovičar K, Imre T, Ferenczy GG, Gobec S, Keserű GM. Boronic acid inhibitors of penicillin-binding protein 1b: serine and lysine labelling agents. J Enzyme Inhib Med Chem 2024; 39:2305833. [PMID: 38410950 PMCID: PMC10901194 DOI: 10.1080/14756366.2024.2305833] [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: 08/29/2023] [Accepted: 01/08/2024] [Indexed: 02/28/2024] Open
Abstract
Penicillin-binding proteins (PBPs) contribute to bacterial cell wall biosynthesis and are targets of antibacterial agents. Here, we investigated PBP1b inhibition by boronic acid derivatives. Chemical starting points were identified by structure-based virtual screening and aliphatic boronic acids were selected for further investigations. Structure-activity relationship studies focusing on the branching of the boron-connecting carbon and quantum mechanical/molecular mechanical simulations showed that reaction barrier free energies are compatible with fast reversible covalent binding and small or missing reaction free energies limit the inhibitory activity of the investigated boronic acid derivatives. Therefore, covalent labelling of the lysine residue of the catalytic dyad was also investigated. Compounds with a carbonyl warhead and an appropriately positioned boronic acid moiety were shown to inhibit and covalently label PBP1b. Reversible covalent labelling of the catalytic lysine by imine formation and the stabilisation of the imine by dative N-B bond is a new strategy for PBP1b inhibition.
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Affiliation(s)
- Levente Kollár
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
| | | | | | | | - Tímea Imre
- MS Metabolomics Research Group, Research Centre for Natural Sciences, Budapest, Hungary
| | - György G Ferenczy
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
| | - Stanislav Gobec
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - György M Keserű
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
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2
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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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3
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Fisher JF, Mobashery S. β-Lactams from the Ocean. Mar Drugs 2023; 21:86. [PMID: 36827127 PMCID: PMC9963991 DOI: 10.3390/md21020086] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/27/2023] Open
Abstract
The title of this essay is as much a question as it is a statement. The discovery of the β-lactam antibiotics-including penicillins, cephalosporins, and carbapenems-as largely (if not exclusively) secondary metabolites of terrestrial fungi and bacteria, transformed modern medicine. The antibiotic β-lactams inactivate essential enzymes of bacterial cell-wall biosynthesis. Moreover, the ability of the β-lactams to function as enzyme inhibitors is of such great medical value, that inhibitors of the enzymes which degrade hydrolytically the β-lactams, the β-lactamases, have equal value. Given this privileged status for the β-lactam ring, it is therefore a disappointment that the exemplification of this ring in marine secondary metabolites is sparse. It may be that biologically active marine β-lactams are there, and simply have yet to be encountered. In this report, we posit a second explanation: that the value of the β-lactam to secure an ecological advantage in the marine environment might be compromised by its close structural similarity to the β-lactones of quorum sensing. The steric and reactivity similarities between the β-lactams and the β-lactones represent an outside-of-the-box opportunity for correlating new structures and new enzyme targets for the discovery of compelling biological activities.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry & Biochemistry, 354 McCourtney Hall, University of Note Dame, Notre Dame, IN 46656-5670, USA
| | - Shahriar Mobashery
- Department of Chemistry & Biochemistry, 354 McCourtney Hall, University of Note Dame, Notre Dame, IN 46656-5670, USA
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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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Kumar V, Viviani SL, Ismail J, Agarwal S, Bonomo RA, van den Akker F. Structural analysis of the boronic acid β-lactamase inhibitor vaborbactam binding to Pseudomonas aeruginosa penicillin-binding protein 3. PLoS One 2021; 16:e0258359. [PMID: 34653211 PMCID: PMC8519428 DOI: 10.1371/journal.pone.0258359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial resistance (AMR) mediated by β-lactamases is the major and leading cause of resistance to penicillins and cephalosporins among Gram-negative bacteria. β-Lactamases, periplasmic enzymes that are widely distributed in the bacterial world, protect penicillin-binding proteins (PBPs), the major cell wall synthesizing enzymes, from inactivation by β-lactam antibiotics. Developing novel PBP inhibitors with a non-β-lactam scaffold could potentially evade this resistance mechanism. Based on the structural similarities between the evolutionary related serine β-lactamases and PBPs, we investigated whether the potent β-lactamase inhibitor, vaborbactam, could also form an acyl-enzyme complex with Pseudomonas aeruginosa PBP3. We found that this cyclic boronate, vaborbactam, inhibited PBP3 (IC50 of 262 μM), and its binding to PBP3 increased the protein thermal stability by about 2°C. Crystallographic analysis of the PBP3:vaborbactam complex reveals that vaborbactam forms a covalent bond with the catalytic S294. The amide moiety of vaborbactam hydrogen bonds with N351 and the backbone oxygen of T487. The carboxyl group of vaborbactam hydrogen bonds with T487, S485, and S349. The thiophene ring and cyclic boronate ring of vaborbactam form hydrophobic interactions, including with V333 and Y503. The active site of the vaborbactam-bound PBP3 harbors the often observed ligand-induced formation of the aromatic wall and hydrophobic bridge, yet the residues involved in this wall and bridge display much higher temperature factors compared to PBP3 structures bound to high-affinity β-lactams. These insights could form the basis for developing more potent novel cyclic boronate-based PBP inhibitors to inhibit these targets and overcome β-lactamases-mediated resistance mechanisms.
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Affiliation(s)
- Vijay Kumar
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Samantha L. Viviani
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jeeda Ismail
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Shreya Agarwal
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert A. Bonomo
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stokes Cleveland Veteran’s Affairs Medical Center Research Service, Cleveland, Ohio, United States of America
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America
- VA Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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A novel tricyclic β-lactam exhibiting potent antibacterial activities against carbapenem-resistant Enterobacterales: Synthesis and structure-activity-relationships. Bioorg Med Chem 2021; 46:116343. [PMID: 34450571 DOI: 10.1016/j.bmc.2021.116343] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 11/22/2022]
Abstract
A series of tricyclic β-lactams were synthesized and evaluated for in vitro antibacterial activities against carbapenem-resistant Enterobacterales (CREs). Starting from a reported tricyclic β-lactam that combined the cephalosporin skeleton having a γ-lactone ring with a carboxylic acid group, which was reported as a unique partial structure of Lactivicin, we identified the compound which shows potent antibacterial activities against all tested CREs by introducing sulfoxide. In addition, the sulfoxide-introduced tricyclic β-lactam also shows a strong therapeutic efficacy in the neutropenic mouse lung infection model. These results indicate that the tricyclic β-lactam skeleton will show sufficient therapeutic performance in clinical use and therefore can serve as a scaffold in the search for new antibacterial agents against CREs.
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7
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de Felício R, Ballone P, Bazzano CF, Alves LFG, Sigrist R, Infante GP, Niero H, Rodrigues-Costa F, Fernandes AZN, Tonon LAC, Paradela LS, Costa RKE, Dias SMG, Dessen A, Telles GP, da Silva MAC, Lima AODS, Trivella DBB. Chemical Elicitors Induce Rare Bioactive Secondary Metabolites in Deep-Sea Bacteria under Laboratory Conditions. Metabolites 2021; 11:metabo11020107. [PMID: 33673148 PMCID: PMC7918856 DOI: 10.3390/metabo11020107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023] Open
Abstract
Bacterial genome sequencing has revealed a vast number of novel biosynthetic gene clusters (BGC) with potential to produce bioactive natural products. However, the biosynthesis of secondary metabolites by bacteria is often silenced under laboratory conditions, limiting the controlled expression of natural products. Here we describe an integrated methodology for the construction and screening of an elicited and pre-fractionated library of marine bacteria. In this pilot study, chemical elicitors were evaluated to mimic the natural environment and to induce the expression of cryptic BGCs in deep-sea bacteria. By integrating high-resolution untargeted metabolomics with cheminformatics analyses, it was possible to visualize, mine, identify and map the chemical and biological space of the elicited bacterial metabolites. The results show that elicited bacterial metabolites correspond to ~45% of the compounds produced under laboratory conditions. In addition, the elicited chemical space is novel (~70% of the elicited compounds) or concentrated in the chemical space of drugs. Fractionation of the crude extracts further evidenced minor compounds (~90% of the collection) and the detection of biological activity. This pilot work pinpoints strategies for constructing and evaluating chemically diverse bacterial natural product libraries towards the identification of novel bacterial metabolites in natural product-based drug discovery pipelines.
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Affiliation(s)
- Rafael de Felício
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Patricia Ballone
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institute of Biology, University of Campinas (UNICAMP), Campinas 13083-862, SP, Brazil
| | - Cristina Freitas Bazzano
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institute of Computing (IC), University of Campinas (UNICAMP), Campinas 13083-852, SP, Brazil;
| | - Luiz F. G. Alves
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Renata Sigrist
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Gina Polo Infante
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Henrique Niero
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institute of Biology, University of Campinas (UNICAMP), Campinas 13083-862, SP, Brazil
| | - Fernanda Rodrigues-Costa
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institute of Biology, University of Campinas (UNICAMP), Campinas 13083-862, SP, Brazil
| | - Arthur Zanetti Nunes Fernandes
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institute of Biology, University of Campinas (UNICAMP), Campinas 13083-862, SP, Brazil
| | - Luciane A. C. Tonon
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Luciana S. Paradela
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Renna Karoline Eloi Costa
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Sandra Martha Gomes Dias
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CNRS, CEA, F-38000 Grenoble, France
| | - Guilherme P. Telles
- Institute of Computing (IC), University of Campinas (UNICAMP), Campinas 13083-852, SP, Brazil;
| | - Marcus Adonai Castro da Silva
- School of Sea, Science and Technology, University of Vale do Itajaí (Univali), Itajaí 88302-202, SC, Brazil; (M.A.C.d.S.); (A.O.d.S.L.)
| | - Andre Oliveira de Souza Lima
- School of Sea, Science and Technology, University of Vale do Itajaí (Univali), Itajaí 88302-202, SC, Brazil; (M.A.C.d.S.); (A.O.d.S.L.)
| | - Daniela Barretto Barbosa Trivella
- Brazilian Biosciences National Laboratory (LNBio), National Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil; (R.d.F.); (P.B.); (C.F.B.); (L.F.G.A.); (R.S.); (G.P.I.); (H.N.); (F.R.-C.); (A.Z.N.F.); (L.A.C.T.); (L.S.P.); (R.K.E.C.); (S.M.G.D.); (A.D.)
- Correspondence: ; Tel.: +55-19-3517-5055
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Krajnc A, Lang PA, Panduwawala TD, Brem J, Schofield CJ. Will morphing boron-based inhibitors beat the β-lactamases? Curr Opin Chem Biol 2019; 50:101-110. [PMID: 31004962 PMCID: PMC6591701 DOI: 10.1016/j.cbpa.2019.03.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 01/13/2023]
Abstract
The β-lactams remain the most important antibacterials, but their use is increasingly compromised by resistance, importantly by β-lactamases. Although β-lactam and non-β-lactam inhibitors forming stable acyl-enzyme complexes with nucleophilic serine β-lactamases (SBLs) are widely used, these are increasingly susceptible to evolved SBLs and do not inhibit metallo-β-lactamases (MBLs). Boronic acids and boronate esters, especially cyclic ones, can potently inhibit both SBLs and MBLs. Vaborbactam, a monocyclic boronate, is approved for clinical use, but its β-lactamase coverage is limited. Bicyclic boronates rapidly react with SBLs and MBLs forming stable enzyme-inhibitor complexes that mimic the common anionic high-energy tetrahedral intermediates in SBL/MBL catalysis, as revealed by crystallography. The ability of boronic acids to 'morph' between sp2 and sp3 hybridisation states may help enable potent inhibition. There is limited structure-activity relationship information on the (bi)cyclic boronate inhibitors compared to β-lactams, hence scope for creativity towards new boron-based β-lactamase inhibitors/antibacterials.
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Affiliation(s)
- Alen Krajnc
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Pauline A Lang
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Tharindi D Panduwawala
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Jürgen Brem
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Christopher J Schofield
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom.
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9
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Das N, Madhavan J, Selvi A, Das D. An overview of cephalosporin antibiotics as emerging contaminants: a serious environmental concern. 3 Biotech 2019; 9:231. [PMID: 31139546 PMCID: PMC6534636 DOI: 10.1007/s13205-019-1766-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/16/2019] [Indexed: 01/21/2023] Open
Abstract
Antibiotics have been categorized as emerging pollutants due to their indiscriminate usage, continuous input and persistence in various environmental matrices even at lower concentrations. Cephalosporins are the broad-spectrum antibiotics of β-lactam family. Owing to its enormous production and consumption, it is reported as the second most prescribed antibiotic classes in Europe. The cephalosporin wastewater contains toxic organic compounds, inorganic salts, and active pharmaceutical ingredients (API) which pose a potential threat to the organisms in the environment. Therefore, removal of cephalosporin antibiotics from the environment has become mandatory as it contributes to increase in the level of chemical oxygen demand (COD), causing toxicity of the effluent and production of cephalosporin-resistant microbes. So far, several processes have been reported for degradation/removal of cephalosporins from the environment. A number of individual studies have been published within the last decade covering the various aspects of antibiotics. However, a detailed compilation on cephalosporin antibiotics as an emerging environmental contaminant is still lacking. Hence, the present review intends to highlight the current ecological scenario with respect to distribution, toxicity, degradation, various remediation technologies, and the regulatory aspects concerning cephalosporins. The latest successful technologies for cephalosporin degradation/removal discussed in this review will help researchers for a better understanding of the nature and persistence of cephalosporins in the environment along with the risks associated with their existence. The research thrust discussed in this review will also evoke new technologies to be attempted by the future researchers to develop sustainable options to remediate cephalosporin-contaminated environments.
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Affiliation(s)
- Nilanjana Das
- Bioremediation Laboratory, School of Bio Sciences and Technology, VIT, Vellore, Tamilnadu 632014 India
| | - Jagannathan Madhavan
- Solar Energy Lab, Department of Chemistry, Thiruvalluvar University, Serkadu, Vellore, Tamilnadu 632115 India
| | - Adikesavan Selvi
- Environmental Molecular Microbiology Research Laboratory, Department of Biotechnology, Thiruvalluvar University, Serkadu, Vellore, Tamilnadu 632115 India
| | - Devlina Das
- Department of Biotechnology, PSG College of Technology, Coimbatore, Tamilnadu India
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10
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Synthetic sideromycins (skepticism and optimism): selective generation of either broad or narrow spectrum Gram-negative antibiotics. Biometals 2019; 32:425-451. [PMID: 30919118 DOI: 10.1007/s10534-019-00192-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 03/20/2019] [Indexed: 02/07/2023]
Abstract
New or repurposed antibiotics are desperately needed since bacterial resistance has risen to essentially all of our current antibiotics, and few new antibiotics have been developed over the last several decades. A primary cause of drug resistance is the overuse of antibiotics that can result in alteration of microbial permeability, alteration of drug target binding sites, induction of enzymes that destroy antibiotics (i.e., β-lactamases) and even induction of efflux mechanisms. Research efforts are described that are designed to determine if the known critical dependence of iron assimilation by microbes for growth and virulence can be exploited for the development of new approaches to antibiotic therapy. Iron recognition and active transport relies on the biosyntheses and use of microbe-selective iron chelating compounds called siderophores. Several natural siderophore-antibiotic conjugates (sideromycins) have been discovered and studied. The natural sideromycins consist of an iron binding siderophore linked to a warhead that exerts antibiotic activity once assimilated by targeted bacteria. Inspired these natural conjugates, a combination of chemical syntheses, microbiological and biochemical studies have been used to generate semi-synthetic and totally synthetic sideromycin analogs. The results demonstrate that siderophores and analogs can be used for iron transport-mediated drug delivery ("Trojan Horse" antibiotics or sideromycins) and induction of iron limitation/starvation (development of new agents to block iron assimilation). While several examples illustrate that this approach can generate microbe selective antibiotics that are active in vitro, the scope and limitations of this approach, especially related to development of resistance, siderophore based molecular recognition requirements, appropriate linker and drug choices, will be described.
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11
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Liu Y, Zhang X, Zhang J, Hu C. Construction of a Quantitative Structure Activity Relationship (QSAR) Model to Predict the Absorption of Cephalosporins in Zebrafish for Toxicity Study. Front Pharmacol 2019; 10:31. [PMID: 30761002 PMCID: PMC6361752 DOI: 10.3389/fphar.2019.00031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/11/2019] [Indexed: 12/17/2022] Open
Abstract
Cephalosporins are beta-lactam antibiotics that are widely used in China. Five generations of cephalosporins have been introduced in clinical practice to date; moreover, some new candidates are also undergoing clinical evaluations. To improve the success rates of new drug development, we need to have a comprehensive understanding about the relationship between the structure of cephalosporins and the toxicity that it induces at an early stage. In the cephalosporins toxicity study using zebrafish, the drug absorption is a key point. In this study, we determined the absorption of cephalosporins in zebrafish during toxicity test. The internal concentrations of 19 cephalosporins in zebrafish were determined using a developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Furthermore, a quantitative structure-activity relationship (QSAR) model was established by multilinear regression; moreover, it was used to predict the absorption of cephalosporins in zebrafish. During leave-one-out cross-validation, a satisfactory performance was obtained with a predictive ability (q 2) of 0.839. The prediction ability of the model was further confirmed when the predictive ability (q 2) was 0.859 in external prediction. The best QSAR model, which was based on five molecular descriptors, exhibited a promising predictive performance and robustness. In experiments involving drug toxicity, the developed QSAR model was used to estimate internal concentrations of cephalosporins. Thus, the toxicity results were correlated with the internal concentration of the drug within the larvae. The developed model served as a new powerful tool in zebrafish toxicity tests.
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Affiliation(s)
- Ying Liu
- National Institutes for Food and Drug Control, Beijing, China
| | - Xia Zhang
- National Institutes for Food and Drug Control, Beijing, China
| | - Jingpu Zhang
- Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Changqin Hu
- National Institutes for Food and Drug Control, Beijing, China
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12
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Miyachiro MM, Contreras-Martel C, Dessen A. Penicillin-Binding Proteins (PBPs) and Bacterial Cell Wall Elongation Complexes. Subcell Biochem 2019; 93:273-289. [PMID: 31939154 DOI: 10.1007/978-3-030-28151-9_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The bacterial cell wall is the validated target of mainstream antimicrobials such as penicillin and vancomycin. Penicillin and other β-lactams act by targeting Penicillin-Binding Proteins (PBPs), enzymes that play key roles in the biosynthesis of the main component of the cell wall, the peptidoglycan. Despite the spread of resistance towards these drugs, the bacterial cell wall continues to be a major Achilles' heel for microbial survival, and the exploration of the cell wall formation machinery is a vast field of work that can lead to the development of novel exciting therapies. The sheer complexity of the cell wall formation process, however, has created a significant challenge for the study of the macromolecular interactions that regulate peptidoglycan biosynthesis. New developments in genetic and biochemical screens, as well as different aspects of structural biology, have shed new light on the importance of complexes formed by PBPs, notably within the cell wall elongation machinery. This chapter summarizes structural and functional details of PBP complexes involved in the periplasmic and membrane steps of peptidoglycan biosynthesis with a focus on cell wall elongation. These assemblies could represent interesting new targets for the eventual development of original antibacterials.
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Affiliation(s)
- Mayara M Miyachiro
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, Brazil
| | - Carlos Contreras-Martel
- Univ Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Bacterial Pathogenesis Group, Grenoble, France
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, Brazil. .,Univ Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Bacterial Pathogenesis Group, Grenoble, France.
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13
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Qian J, Han Y, Li J, Zhang J, Hu C. Toxic effect prediction of cefatirizine amidine sodium and its impurities by structure-toxicity relationship of cephalosporins. Toxicol In Vitro 2017; 46:137-147. [PMID: 28963076 DOI: 10.1016/j.tiv.2017.09.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 08/26/2017] [Accepted: 09/21/2017] [Indexed: 11/30/2022]
Abstract
The three-dimensional (3D) structure-toxicity relationship of cephalosporins was explored by computing the most stable conformations of 33 kinds of cephalosporins in aqueous solution and using the teratogenicity and lethality of these compounds obtained in zebrafish embryo toxicity testing to evaluate their toxic effects. The toxic effect of cefatirizine amidine sodium, a novel cephalosporin which has finished preclinical study, was investigated. It is thought that the teratogenic effect of the triazine ring at the C-3 position is the main toxic effect of cefatirizine amidine. In addition, cefatirizine amidine is no more toxic than cefathiamidine and ceftriaxone. The results of the zebrafish embryo toxicity test combined with gene expression microarray technology were consistent with the prediction. The toxic effects of some potential process-related impurities of cefatirizine amidine were also predicted.
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Affiliation(s)
- Jianqin Qian
- National Institutes for Food and Drug Control, 100050 Beijing, China; ZheJiang Institute for Food and Drug Control, 310000 Hangzhou, Zhejiang, China
| | - Ying Han
- National Institutes for Food and Drug Control, 100050 Beijing, China; Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, 100050 Beijing, China
| | - Jin Li
- National Institutes for Food and Drug Control, 100050 Beijing, China
| | - Jingpu Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, 100050 Beijing, China.
| | - Changqin Hu
- National Institutes for Food and Drug Control, 100050 Beijing, China.
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14
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Sideromimic Modification of Lactivicin Dramatically Increases Potency against Extensively Drug-Resistant Stenotrophomonas maltophilia Clinical Isolates. Antimicrob Agents Chemother 2016; 60:4170-5. [PMID: 27139464 DOI: 10.1128/aac.00371-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/24/2016] [Indexed: 01/09/2023] Open
Abstract
Acetamido derivatives of the naturally antibacterial non-β-lactam lactivicin (LTV) have improved activity against their penicillin binding protein targets and reduced hydrolysis by β-lactamases, but penetration into Gram-negative bacteria is still relatively poor. Here we report that modification of the LTV lactone with a catechol-type siderophore increases potency 1,000-fold against Stenotrophomonas maltophilia, a species renowned for its insusceptibility to antimicrobials. The MIC90 of modified lactone compound 17 (LTV17) against a global collection of extensively drug-resistant clinical S. maltophilia isolates was 0.063 μg · ml(-1) Sideromimic modification does not reduce the ability of LTVs to induce production of the L1 and L2 β-lactamases in S. maltophilia and does not reduce the rate at which LTVs are hydrolyzed by L1 or L2. We conclude, therefore, that lactivicin modification with a siderophore known to be preferentially used by S. maltophilia substantially increases penetration via siderophore uptake. LTV17 has the potential to be developed as a novel antimicrobial for treatment of infections by S. maltophilia More generally, our work shows that sideromimic modification in a species-targeted manner might prove useful for the development of narrow-spectrum antimicrobials that have reduced collateral effects.
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15
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Wang DY, Abboud MI, Markoulides MS, Brem J, Schofield CJ. The road to avibactam: the first clinically useful non-β-lactam working somewhat like a β-lactam. Future Med Chem 2016; 8:1063-84. [PMID: 27327972 DOI: 10.4155/fmc-2016-0078] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Avibactam, which is the first non-β-lactam β-lactamase inhibitor to be introduced for clinical use, is a broad-spectrum serine β-lactamase inhibitor with activity against class A, class C, and, some, class D β-lactamases. We provide an overview of efforts, which extend to the period soon after the discovery of the penicillins, to develop clinically useful non-β-lactam compounds as antibacterials, and, subsequently, penicillin-binding protein and β-lactamase inhibitors. Like the β-lactam inhibitors, avibactam works via a mechanism involving covalent modification of a catalytically important nucleophilic serine residue. However, unlike the β-lactam inhibitors, avibactam reacts reversibly with its β-lactamase targets. We discuss chemical factors that may account for the apparently special nature of β-lactams and related compounds as antibacterials and β-lactamase inhibitors, including with respect to resistance. Avenues for future research including non-β-lactam antibacterials acting similarly to β-lactams are discussed.
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Affiliation(s)
| | | | | | - Jürgen Brem
- Department of Chemistry, University of Oxford, UK
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16
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Choi H, Paton RS, Park H, Schofield CJ. Investigations on recyclisation and hydrolysis in avibactam mediated serine β-lactamase inhibition. Org Biomol Chem 2016; 14:4116-28. [PMID: 27072755 PMCID: PMC4847122 DOI: 10.1039/c6ob00353b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/04/2016] [Indexed: 01/13/2023]
Abstract
β-Lactams inhibit penicillin-binding proteins (PBPs) and serine β-lactamases by acylation of a nucleophilic active site serine. Avibactam is approved for clinical use in combination with ceftazidime, and is a breakthrough non β-lactam β-lactamase inhibitor also reacting via serine acylation. Molecular dynamics (MD) and quantum chemical calculations on avibactam-mediated inhibition of a clinically relevant cephalosporinase reveal that recyclisation of the avibactam derived carbamoyl complex is favoured over hydrolysis. In contrast, we show that analogous recyclisation in β-lactam mediated inhibition is disfavoured. Avibactam recyclisation is promoted by a proton shuttle, a 'structural' water protonating the nucleophilic serine, and stabilization of the negative charge developed on aminocarbonyl oxygen. The results imply the potential of calculations for distinguishing between bifurcating pathways during inhibition and in generating hypotheses for predicting resistance. The inability of β-lactams to undergo recyclisation may be an Achilles heel, but one that can be addressed by suitably functionalized reversibly binding inhibitors.
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Affiliation(s)
- Hwanho Choi
- Department of Bioscience and Biotechnology, Sejong University, 209 Neungdong-ro, Kwangjin-gu, Seoul 143-747, Korea. and Chemical Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Robert S Paton
- Chemical Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Hwangseo Park
- Department of Bioscience and Biotechnology, Sejong University, 209 Neungdong-ro, Kwangjin-gu, Seoul 143-747, Korea.
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17
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Šink R, Kotnik M, Zega A, Barreteau H, Gobec S, Blanot D, Dessen A, Contreras-Martel C. Crystallographic Study of Peptidoglycan Biosynthesis Enzyme MurD: Domain Movement Revisited. PLoS One 2016; 11:e0152075. [PMID: 27031227 PMCID: PMC4816537 DOI: 10.1371/journal.pone.0152075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 03/08/2016] [Indexed: 11/30/2022] Open
Abstract
The biosynthetic pathway of peptidoglycan, an essential component of bacterial cell wall, is a well-recognized target for antibiotic development. Peptidoglycan precursors are synthesized in the bacterial cytosol by various enzymes including the ATP-hydrolyzing Mur ligases, which catalyze the stepwise addition of amino acids to a UDP-MurNAc precursor to yield UDP-MurNAc-pentapeptide. MurD catalyzes the addition of D-glutamic acid to UDP-MurNAc-L-Ala in the presence of ATP; structural and biochemical studies have suggested the binding of the substrates with an ordered kinetic mechanism in which ligand binding inevitably closes the active site. In this work, we challenge this assumption by reporting the crystal structures of intermediate forms of MurD either in the absence of ligands or in the presence of small molecules. A detailed analysis provides insight into the events that lead to the closure of MurD and reveals that minor structural modifications contribute to major overall conformation alterations. These novel insights will be instrumental in the development of new potential antibiotics designed to target the peptidoglycan biosynthetic pathway.
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Affiliation(s)
- Roman Šink
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia
| | - Miha Kotnik
- Lek Pharmaceuticals d. d., Verovškova 57, Ljubljana, Slovenia
| | - Anamarija Zega
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia
| | - Hélène Barreteau
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
| | - Stanislav Gobec
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia
| | - Didier Blanot
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
| | - Andréa Dessen
- Univ. Grenoble Alpes, Institut de Biologie Structurale, Grenoble, France
- CNRS, IBS, Grenoble, France
- CEA, IBS, Grenoble, France
- Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, São Paulo, Brazil
| | - Carlos Contreras-Martel
- Univ. Grenoble Alpes, Institut de Biologie Structurale, Grenoble, France
- CNRS, IBS, Grenoble, France
- CEA, IBS, Grenoble, France
- * E-mail:
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18
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Glycosyltransferases and Transpeptidases/Penicillin-Binding Proteins: Valuable Targets for New Antibacterials. Antibiotics (Basel) 2016; 5:antibiotics5010012. [PMID: 27025527 PMCID: PMC4810414 DOI: 10.3390/antibiotics5010012] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/27/2016] [Accepted: 02/03/2016] [Indexed: 12/29/2022] Open
Abstract
Peptidoglycan (PG) is an essential macromolecular sacculus surrounding most bacteria. It is assembled by the glycosyltransferase (GT) and transpeptidase (TP) activities of multimodular penicillin-binding proteins (PBPs) within multiprotein complex machineries. Both activities are essential for the synthesis of a functional stress-bearing PG shell. Although good progress has been made in terms of the functional and structural understanding of GT, finding a clinically useful antibiotic against them has been challenging until now. In contrast, the TP/PBP module has been successfully targeted by β-lactam derivatives, but the extensive use of these antibiotics has selected resistant bacterial strains that employ a wide variety of mechanisms to escape the lethal action of these antibiotics. In addition to traditional β-lactams, other classes of molecules (non-β-lactams) that inhibit PBPs are now emerging, opening new perspectives for tackling the resistance problem while taking advantage of these valuable targets, for which a wealth of structural and functional knowledge has been accumulated. The overall evidence shows that PBPs are part of multiprotein machineries whose activities are modulated by cofactors. Perturbation of these systems could lead to lethal effects. Developing screening strategies to take advantage of these mechanisms could lead to new inhibitors of PG assembly. In this paper, we present a general background on the GTs and TPs/PBPs, a survey of recent issues of bacterial resistance and a review of recent works describing new inhibitors of these enzymes.
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19
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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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20
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Starr J, Brown MF, Aschenbrenner L, Caspers N, Che Y, Gerstenberger BS, Huband M, Knafels JD, Lemmon MM, Li C, McCurdy SP, McElroy E, Rauckhorst MR, Tomaras AP, Young JA, Zaniewski RP, Shanmugasundaram V, Han S. Siderophore Receptor-Mediated Uptake of Lactivicin Analogues in Gram-Negative Bacteria. J Med Chem 2014; 57:3845-55. [DOI: 10.1021/jm500219c] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Jeremy Starr
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Matthew F. Brown
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Lisa Aschenbrenner
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Nicole Caspers
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Ye Che
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Brian S. Gerstenberger
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Michael Huband
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - John D. Knafels
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - M. Megan Lemmon
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Chao Li
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Sandra P. McCurdy
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Eric McElroy
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Mark R. Rauckhorst
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Andrew P. Tomaras
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Jennifer A. Young
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Richard P. Zaniewski
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Veerabahu Shanmugasundaram
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
| | - Seungil Han
- Medicinal Chemistry, ⧧Computational Chemistry, §Antibacterials Research
Unit, and ¶Structural Biology, Pfizer Global Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
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21
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Bacterial cell division proteins as antibiotic targets. Bioorg Chem 2014; 55:27-38. [PMID: 24755375 DOI: 10.1016/j.bioorg.2014.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 11/21/2022]
Abstract
Proteins involved in bacterial cell division often do not have a counterpart in eukaryotic cells and they are essential for the survival of the bacteria. The genetic accessibility of many bacterial species in combination with the Green Fluorescence Protein revolution to study localization of proteins and the availability of crystal structures has increased our knowledge on bacterial cell division considerably in this century. Consequently, bacterial cell division proteins are more and more recognized as potential new antibiotic targets. An international effort to find small molecules that inhibit the cell division initiating protein FtsZ has yielded many compounds of which some are promising as leads for preclinical use. The essential transglycosylase activity of peptidoglycan synthases has recently become accessible to inhibitor screening. Enzymatic assays for and structural information on essential integral membrane proteins such as MraY and FtsW involved in lipid II (the peptidoglycan building block precursor) biosynthesis have put these proteins on the list of potential new targets. This review summarises and discusses the results and approaches to the development of lead compounds that inhibit bacterial cell division.
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22
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Nikolaidis I, Favini-Stabile S, Dessen A. Resistance to antibiotics targeted to the bacterial cell wall. Protein Sci 2014; 23:243-59. [PMID: 24375653 DOI: 10.1002/pro.2414] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 12/21/2013] [Accepted: 12/23/2013] [Indexed: 11/10/2022]
Abstract
Peptidoglycan is the main component of the bacterial cell wall. It is a complex, three-dimensional mesh that surrounds the entire cell and is composed of strands of alternating glycan units crosslinked by short peptides. Its biosynthetic machinery has been, for the past five decades, a preferred target for the discovery of antibacterials. Synthesis of the peptidoglycan occurs sequentially within three cellular compartments (cytoplasm, membrane, and periplasm), and inhibitors of proteins that catalyze each stage have been identified, although not all are applicable for clinical use. A number of these antimicrobials, however, have been rendered inactive by resistance mechanisms. The employment of structural biology techniques has been instrumental in the understanding of such processes, as well as the development of strategies to overcome them. This review provides an overview of resistance mechanisms developed toward antibiotics that target bacterial cell wall precursors and its biosynthetic machinery. Strategies toward the development of novel inhibitors that could overcome resistance are also discussed.
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Affiliation(s)
- I Nikolaidis
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 6 rue Jules Horowitz, 38027, Grenoble, France; Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Grenoble, France; Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France; Bijvoet Center for Biomolecular Research, Department of Biochemistry of Membranes, Utrecht University, Utrecht, The Netherlands
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Lopp M, Paju A, Oja K, Matkevitš K, Lumi P, Järving I, Pehk T. Asymmetric Synthesis of Tertiary 2-Substituted 5-Oxotetrahydrofuran-2-carboxylic Acids. HETEROCYCLES 2014. [DOI: 10.3987/com-13-s(s)28] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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24
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Abstract
The gliding Gram-negative Lysobacter bacteria are emerging as a promising source of new bioactive natural products. These ubiquitous freshwater and soil microorganisms are fast growing, simple to use and maintain, and genetically amenable for biosynthetic engineering. This Highlight reviews a group of biologically active and structurally distinct natural products from the genus Lysobacter, with a focus on their biosyntheses. Although Lysobacter sp. are known as prolific producers of bioactive natural products, detailed molecular mechanistic studies of their enzymatic assembly have been surprisingly scarce. We hope to provide a snapshot of the important work done on the lysobacterial natural products and to provide useful information for future biosynthetic engineering of novel antibiotics in Lysobacter.
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Affiliation(s)
- Yunxuan Xie
- Department of Chemistry, University of Nebraska-Lincoln, NE 68588, USA
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25
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Hamed RB, Gomez-Castellanos JR, Henry L, Ducho C, McDonough MA, Schofield CJ. The enzymes of β-lactam biosynthesis. Nat Prod Rep 2013; 30:21-107. [DOI: 10.1039/c2np20065a] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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26
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Zervosen A, Zapun A, Frère JM. Inhibition of Streptococcus pneumoniae penicillin-binding protein 2x and Actinomadura R39 DD-peptidase activities by ceftaroline. Antimicrob Agents Chemother 2013; 57:661-3. [PMID: 23147739 PMCID: PMC3535952 DOI: 10.1128/aac.01593-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/04/2012] [Indexed: 11/20/2022] Open
Abstract
Although the rate of acylation of a penicillin-resistant form of Streptococcus pneumoniae penicillin-binding protein 2x (PBP2x) by ceftaroline is 80-fold lower than that of its penicillin-sensitive counterpart, it remains sufficiently high (k(2)/K = 12,600 M(-1) s(-1)) to explain the sensitivity of the penicillin-resistant strain to this new cephalosporin. Surprisingly, the Actinomadura R39 DD-peptidase is not very sensitive to ceftaroline.
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Affiliation(s)
- Astrid Zervosen
- Centre de Recherches du Cyclotron, Université de Liège, Sart-Tilman, Liège, Belgium.
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27
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Abstract
The synthesis of the bacterial peptidoglycan has been recognized for over 50 years as fertile ground for antibacterial discovery. Initially, empirical screening of natural products for inhibition of bacterial growth detected many chemical classes of antibiotics whose specific mechanisms of action were eventually dissected and defined. Of the nontoxic antibiotics discovered, most were found to be inhibitors of either protein synthesis or cell wall synthesis, which led to more directed screening for inhibitors of these pathways. Directed screening and design programs for cell wall inhibitors have been undertaken since the 1960s. In that time it has become clear that, while certain steps and intermediates have yielded selective inhibitors and are established targets, other potential targets have not yielded inhibitors whose antibacterial activity is proven to be solely due to that inhibition. Why has this search been so problematic? Are the established targets still worth pursuing? This review will attempt to answer these and other questions and evaluate the viability of targets related to peptidoglycan synthesis.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, LLC, Springfield, New Jersey 07081, USA.
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28
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Oldfield CJ, Xue B, Van YY, Ulrich EL, Markley JL, Dunker AK, Uversky VN. Utilization of protein intrinsic disorder knowledge in structural proteomics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:487-98. [PMID: 23232152 DOI: 10.1016/j.bbapap.2012.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 12/02/2012] [Accepted: 12/03/2012] [Indexed: 12/01/2022]
Abstract
Intrinsically disordered proteins (IDPs) and proteins with long disordered regions are highly abundant in various proteomes. Despite their lack of well-defined ordered structure, these proteins and regions are frequently involved in crucial biological processes. Although in recent years these proteins have attracted the attention of many researchers, IDPs represent a significant challenge for structural characterization since these proteins can impact many of the processes in the structure determination pipeline. Here we investigate the effects of IDPs on the structure determination process and the utility of disorder prediction in selecting and improving proteins for structural characterization. Examination of the extent of intrinsic disorder in existing crystal structures found that relatively few protein crystal structures contain extensive regions of intrinsic disorder. Although intrinsic disorder is not the only cause of crystallization failures and many structured proteins cannot be crystallized, filtering out highly disordered proteins from structure-determination target lists is still likely to be cost effective. Therefore it is desirable to avoid highly disordered proteins from structure-determination target lists and we show that disorder prediction can be applied effectively to enrich structure determination pipelines with proteins more likely to yield crystal structures. For structural investigation of specific proteins, disorder prediction can be used to improve targets for structure determination. Finally, a framework for considering intrinsic disorder in the structure determination pipeline is proposed.
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Affiliation(s)
- Christopher J Oldfield
- Center for Computational Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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29
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Development of new drugs for an old target: the penicillin binding proteins. Molecules 2012; 17:12478-505. [PMID: 23095893 PMCID: PMC6268044 DOI: 10.3390/molecules171112478] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/05/2012] [Accepted: 10/17/2012] [Indexed: 11/16/2022] Open
Abstract
The widespread use of β-lactam antibiotics has led to the worldwide appearance of drug-resistant strains. Bacteria have developed resistance to β-lactams by two main mechanisms: the production of β-lactamases, sometimes accompanied by a decrease of outer membrane permeability, and the production of low-affinity, drug resistant Penicillin Binding Proteins (PBPs). PBPs remain attractive targets for developing new antibiotic agents because they catalyse the last steps of the biosynthesis of peptidoglycan, which is unique to bacteria, and lies outside the cytoplasmic membrane. Here we summarize the “current state of the art” of non-β-lactam inhibitors of PBPs, which have being developed in an attempt to counter the emergence of β-lactam resistance. These molecules are not susceptible to hydrolysis by β-lactamases and thus present a real alternative to β-lactams. We present transition state analogs such as boronic acids, which can covalently bind to the active serine residue in the catalytic site. Molecules containing ring structures different from the β-lactam-ring like lactivicin are able to acylate the active serine residue. High throughput screening methods, in combination with virtual screening methods and structure based design, have allowed the development of new molecules. Some of these novel inhibitors are active against major pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and thus open avenues new for the discovery of novel antibiotics.
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30
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Hakenbeck R, Brückner R, Denapaite D, Maurer P. Molecular mechanisms of β-lactam resistance in Streptococcus pneumoniae. Future Microbiol 2012; 7:395-410. [PMID: 22393892 DOI: 10.2217/fmb.12.2] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alterations in the target enzymes for β-lactam antibiotics, the penicillin-binding proteins (PBPs), have been recognized as a major resistance mechanism in Streptococcus pneumoniae. Mutations in PBPs that confer a reduced affinity to β-lactams have been identified in laboratory mutants and clinical isolates, and document an astounding variability of sites involved in this phenotype. Whereas point mutations are selected in the laboratory, clinical isolates display a mosaic structure of the affected PBP genes, the result of interspecies gene transfer and recombination events. Depending on the selective β-lactam, different combinations of PBP genes and mutations within are involved in conferring resistance, and astoundingly in non-PBP genes as well.
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Affiliation(s)
- Regine Hakenbeck
- Department of Microbiology, University of Kaiserslautern, Paul Ehrlich Strasse 23, D-67663 Kaiserslautern, Germany.
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31
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Zervosen A, Bouillez A, Herman A, Amoroso A, Joris B, Sauvage E, Charlier P, Luxen A. Synthesis and evaluation of boronic acids as inhibitors of Penicillin Binding Proteins of classes A, B and C. Bioorg Med Chem 2012; 20:3915-24. [PMID: 22579615 DOI: 10.1016/j.bmc.2012.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/05/2012] [Accepted: 04/07/2012] [Indexed: 10/28/2022]
Abstract
In response to the widespread use of β-lactam antibiotics bacteria have evolved drug resistance mechanisms that include the production of resistant Penicillin Binding Proteins (PBPs). Boronic acids are potent β-lactamase inhibitors and have been shown to display some specificity for soluble transpeptidases and PBPs, but their potential as inhibitors of the latter enzymes is yet to be widely explored. Recently, a (2,6-dimethoxybenzamido)methylboronic acid was identified as being a potent inhibitor of Actinomadura sp. R39 transpeptidase (IC(50): 1.3 μM). In this work, we synthesized and studied the potential of a number of acylaminomethylboronic acids as inhibitors of PBPs from different classes. Several derivatives inhibited PBPs of classes A, B and C from penicillin sensitive strains. The (2-nitrobenzamido)methylboronic acid was identified as a good inhibitor of a class A PBP (PBP1b from Streptococcus pneumoniae, IC(50) = 26 μM), a class B PBP (PBP2xR6 from Streptococcus pneumoniae, IC(50) = 138 μM) and a class C PBP (R39 from Actinomadura sp., IC(50) = 0.6 μM). This work opens new avenues towards the development of molecules that inhibit PBPs, and eventually display bactericidal effects, on distinct bacterial species.
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Affiliation(s)
- Astrid Zervosen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart-Tilman, B-4000 Liège, Belgium.
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32
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Dzhekieva L, Kumar I, Pratt RF. Inhibition of Bacterial DD-Peptidases (Penicillin-Binding Proteins) in Membranes and in Vivo by Peptidoglycan-Mimetic Boronic Acids. Biochemistry 2012; 51:2804-11. [DOI: 10.1021/bi300148v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Liudmila Dzhekieva
- Department of Chemistry, Wesleyan University, Lawn Avenue, Middletown, Connecticut 06459,
United
States
| | - Ish Kumar
- School of Natural
Sciences, Fairleigh Dickinson University, Teaneck, New Jersey 07666, United States
| | - R. F. Pratt
- Department of Chemistry, Wesleyan University, Lawn Avenue, Middletown, Connecticut 06459,
United
States
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33
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Gersch M, Kreuzer J, Sieber SA. Electrophilic natural products and their biological targets. Nat Prod Rep 2012; 29:659-82. [DOI: 10.1039/c2np20012k] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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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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35
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Inglis SR, Strieker M, Rydzik AM, Dessen A, Schofield CJ. A boronic-acid-based probe for fluorescence polarization assays with penicillin binding proteins and β-lactamases. Anal Biochem 2011; 420:41-7. [PMID: 21925482 DOI: 10.1016/j.ab.2011.08.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 11/28/2022]
Abstract
Penicillin binding proteins (PBPs) and β-lactamases are involved in interactions with β-lactam antibiotics connected with both antibacterial activity and mediation of bacterial β-lactam resistance. Current methods for identifying inhibitors of PBPs and β-lactamases can be inefficient and are often not suitable for studying weakly and/or reversibly binding compounds. Therefore, improved ligand binding assays for PBPs and β-lactamases are needed. We report the development of a fluorescence polarization (FP) assay for PBPs and "serine" β-lactamases using a boronic-acid-based, reversibly binding "tracer." The tracer was designed based on a crystal structure of a covalent complex between a boronic acid and PBP1b from Streptococcus pneumoniae. The tracer bound to three different PBPs with modest affinity (K(d)=4-12 μM) and more tightly to the TEM1 serine β-lactamase (K(d)=109 nM). β-Lactams and other boronic acids were able to displace the tracer in competition assays. These results indicate that fluorescent boronic acids are suited to serve as reversibly binding tracers in FP-based assays with PBPs and β-lactamases and potentially with other related enzymes.
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Affiliation(s)
- Steven R Inglis
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, 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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Zervosen A, Herman R, Kerff F, Herman A, Bouillez A, Prati F, Pratt RF, Frère JM, Joris B, Luxen A, Charlier P, Sauvage E. Unexpected Tricovalent Binding Mode of Boronic Acids within the Active Site of a Penicillin-Binding Protein. J Am Chem Soc 2011; 133:10839-48. [DOI: 10.1021/ja200696y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | - Fabio Prati
- Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
| | - R. F. Pratt
- Department of Chemistry, Wesleyan University, Middletown, Connecticut 06459, United States
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Turk S, Verlaine O, Gerards T, Živec M, Humljan J, Sosič I, Amoroso A, Zervosen A, Luxen A, Joris B, Gobec S. New noncovalent inhibitors of penicillin-binding proteins from penicillin-resistant bacteria. PLoS One 2011; 6:e19418. [PMID: 21573060 PMCID: PMC3090393 DOI: 10.1371/journal.pone.0019418] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 03/29/2011] [Indexed: 11/18/2022] Open
Abstract
Background Penicillin-binding proteins (PBPs) are well known and validated targets for antibacterial therapy. The most important clinically used inhibitors of PBPs β-lactams inhibit transpeptidase activity of PBPs by forming a covalent penicilloyl-enzyme complex that blocks the normal transpeptidation reaction; this finally results in bacterial death. In some resistant bacteria the resistance is acquired by active-site distortion of PBPs, which lowers their acylation efficiency for β-lactams. To address this problem we focused our attention to discovery of novel noncovalent inhibitors of PBPs. Methodology/Principal Findings Our in-house bank of compounds was screened for inhibition of three PBPs from resistant bacteria: PBP2a from Methicillin-resistant Staphylococcus aureus (MRSA), PBP2x from Streptococcus pneumoniae strain 5204, and PBP5fm from Enterococcus faecium strain D63r. Initial hit inhibitor obtained by screening was then used as a starting point for computational similarity searching for structurally related compounds and several new noncovalent inhibitors were discovered. Two compounds had promising inhibitory activities of both PBP2a and PBP2x 5204, and good in-vitro antibacterial activities against a panel of Gram-positive bacterial strains. Conclusions We found new noncovalent inhibitors of PBPs which represent important starting points for development of more potent inhibitors of PBPs that can target penicillin-resistant bacteria.
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Affiliation(s)
- Samo Turk
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Olivier Verlaine
- Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Thomas Gerards
- Laboratory of Organic Chemistry, University of Liège, Liège, Belgium
| | - Matej Živec
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Jan Humljan
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
- Lek Pharmaceuticals d.d., Mengeš, Slovenia
| | - Izidor Sosič
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Ana Amoroso
- Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Astrid Zervosen
- Laboratory of Organic Chemistry, University of Liège, Liège, Belgium
| | - André Luxen
- Laboratory of Organic Chemistry, University of Liège, Liège, Belgium
| | - Bernard Joris
- Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Stanislav Gobec
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
- * E-mail:
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39
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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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40
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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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41
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Brown T, Charlier P, Herman R, Schofield CJ, Sauvage E. Structural basis for the interaction of lactivicins with serine beta-lactamases. J Med Chem 2010; 53:5890-4. [PMID: 20593835 DOI: 10.1021/jm100437u] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lactivicin (LTV) is a natural non-beta-lactam antibiotic that inhibits penicillin-binding proteins and serine beta-lactamases. A crystal structure of a BS3-LTV complex reveals that, as for its reaction with PBPs, LTV reacts with the nucleophilic serine and that cycloserine and lactone rings of LTV are opened. This structure, together with reported structures of PBP1b with lactivicins, provides a basis for developing improved lactivicin-based gamma-lactam antibiotics.
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Affiliation(s)
- Tom Brown
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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42
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Lowther J, Yard BA, Johnson KA, Carter LG, Bhat VT, Raman MCC, Clarke DJ, Ramakers B, McMahon SA, Naismith JH, Campopiano DJ. Inhibition of the PLP-dependent enzyme serine palmitoyltransferase by cycloserine: evidence for a novel decarboxylative mechanism of inactivation. MOLECULAR BIOSYSTEMS 2010; 6:1682-93. [PMID: 20445930 PMCID: PMC3670083 DOI: 10.1039/c003743e] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cycloserine (CS, 4-amino-3-isoxazolidone) is a cyclic amino acid mimic that is known to inhibit many essential pyridoxal 5'-phosphate (PLP)-dependent enzymes. Two CS enantiomers are known; D-cycloserine (DCS, also known as Seromycin) is a natural product that is used to treat resistant Mycobacterium tuberculosis infections as well as neurological disorders since it is a potent NMDA receptor agonist, and L-cycloserine (LCS) is a synthetic enantiomer whose usefulness as a drug has been hampered by its inherent toxicity arising through inhibition of sphingolipid metabolism. Previous studies on various PLP-dependent enzymes revealed a common mechanism of inhibition by both enantiomers of CS; the PLP cofactor is disabled by forming a stable 3-hydroxyisoxazole/pyridoxamine 5'-phosphate (PMP) adduct at the active site where the cycloserine ring remains intact. Here we describe a novel mechanism of CS inactivation of the PLP-dependent enzyme serine palmitoyltransferase (SPT) from Sphingomonas paucimobilis. SPT catalyses the condensation of l-serine and palmitoyl-CoA, the first step in the de novo sphingolipid biosynthetic pathway. We have used a range of kinetic, spectroscopic and structural techniques to postulate that both LCS and DCS inactivate SPT by transamination to form a free pyridoxamine 5'-phosphate (PMP) and beta-aminooxyacetaldehyde that remain bound at the active site. We suggest this occurs by ring opening of the cycloserine ring followed by decarboxylation. Enzyme kinetics show that inhibition is reversed by incubation with excess PLP and that LCS is a more effective SPT inhibitor than DCS. UV-visible spectroscopic data, combined with site-directed mutagenesis, suggest that a mobile Arg(378) residue is involved in cycloserine inactivation of SPT.
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Affiliation(s)
- Jonathan Lowther
- EaStChem, School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, Scotland, UK
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Kluge AF, Petter RC. Acylating drugs: redesigning natural covalent inhibitors. Curr Opin Chem Biol 2010; 14:421-7. [PMID: 20457000 DOI: 10.1016/j.cbpa.2010.03.035] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 02/18/2010] [Accepted: 03/26/2010] [Indexed: 11/26/2022]
Abstract
Structural modification of naturally occurring beta-lactams and beta-lactones is a highly effective strategy for generating drugs for treating bacterial infections, cancer, obesity, and hyperlipidemia. These drugs acylate catalytic amino acids (serine, threonine, or cysteine) in enzyme targets such as penicillin-binding proteins (PBPs), beta-lactamases, lipases, HMG-CoA reductase, fatty acid synthetase, and the 20S proteasome. Optimally performing drugs combine features of high target affinity, chemoselective reactivity, and high stability of the acylated target protein. This review provides a perspective on these two classes of acylating agents and summarizes recent advances in mechanism and structure-based design of acylating drugs.
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Affiliation(s)
- Arthur F Kluge
- Avila Therapeutics, 100 Beaver Street, Waltham, MA 02453, USA
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Inglis SR, Zervosen A, Woon ECY, Gerards T, Teller N, Fischer DS, Luxen A, Schofield CJ. Synthesis and evaluation of 3-(dihydroxyboryl)benzoic acids as D,D-carboxypeptidase R39 inhibitors. J Med Chem 2009; 52:6097-106. [PMID: 19731939 DOI: 10.1021/jm9009718] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Penicillin binding proteins (PBPs) catalyze steps in the biosynthesis of bacterial cell walls and are the targets for the beta-lactam antibiotics. Non-beta-lactam based antibiotics that target PBPs are of interest because bacteria have evolved resistance to the beta-lactam antibiotics. Boronic acids have been developed as inhibitors of the mechanistically related serine beta-lactamases and serine proteases; however, they have not been explored extensively as PBP inhibitors. Here we report aromatic boronic acid inhibitors of the D,D-carboxypeptidase R39 from Actinomadura sp. strain. Analogues of an initially identified inhibitor [3-(dihydroxyboryl)benzoic acid 1, IC(50) 400 microM] were prepared via routes involving pinacol boronate esters, which were deprotected via a two-stage procedure involving intermediate trifluorborate salts that were hydrolyzed to provide the free boronic acids. 3-(Dihydroxyboryl)benzoic acid analogues containing an amide substituent in the meta, but not ortho position were up to 17-fold more potent inhibitors of the R39 PBP and displayed some activity against other PBPs. These compounds may be useful for the development of even more potent boronic acid based PBP inhibitors with a broad spectrum of antibacterial activity.
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Miguet L, Zervosen A, Gerards T, Pasha FA, Luxen A, Distèche-Nguyen M, Thomas A. Discovery of new inhibitors of resistant Streptococcus pneumoniae penicillin binding protein (PBP) 2x by structure-based virtual screening. J Med Chem 2009; 52:5926-36. [PMID: 19746934 DOI: 10.1021/jm900625q] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Penicillin binding proteins (PBPs) are involved in the biosynthesis of the peptidoglycan layer constitutive of the bacterial envelope. They have been targeted for more than half a century by extensively derived molecular scaffolds of penicillins and cephalosporins. Streptococcus pneumoniae resists the antibiotic pressure by inducing highly mutated PBPs that can no longer bind the beta-lactam containing agents. To find inhibitors of PBP2x from Streptococcus pneumoniae (spPBP2x) with novel chemical scaffold so as to circumvent the resistance problems, a hierarchical virtual screening procedure was performed on the NCI database containing approximately 260000 compounds. The calculations involved ligand-based pharmacophore mapping studies and molecular docking simulations in a homology model of spPBP2x from the highly resistant strain 5204. A total of 160 hits were found, and 55 were available for experimental tests. Three compounds harboring two novel chemical scaffolds were identified as inhibitors of the resistant strain 5204-spPBP2x at the micromolar range.
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Affiliation(s)
- Laurence Miguet
- Laboratoire de Dynamique Moleculaire, Institut de Biologie Structurale Jean-Pierre Ebel (CEA/CNRS/UJF), Grenoble, France
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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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Lemaire S, Fuda C, Van Bambeke F, Tulkens PM, Mobashery S. Restoration of susceptibility of methicillin-resistant Staphylococcus aureus to beta-lactam antibiotics by acidic pH: role of penicillin-binding protein PBP 2a. J Biol Chem 2008; 283:12769-76. [PMID: 18337244 DOI: 10.1074/jbc.m800079200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a global scourge, and treatment options are becoming limited. The MRSA phenotype reverts to that of beta-lactam-sensitive S. aureus when bacteria are grown at pH 5.0 in broth and, more importantly from a medical perspective (protracted, relapsing infections), after phagocytosis by macrophages, where the bacteria thrive in the acidic environment of phagolysosomes. The central factor for the MRSA phenotype is the function of the penicillin-binding protein (PBP) 2a, which maintains transpeptidase activity while being poorly inhibited by beta-lactams because of a closed conformation of its active site. We document herein by binding, acylation/deacylation kinetics, and circular dichroism spectroscopy with purified PBP 2a that at acidic pH (i) beta-lactams interact with PBP 2a more avidly; (ii) the non-covalent pre-acylation complex exhibits a lower dissociation constant and an increased rate of acyl-enzyme formation (first-order rate constant) without change in hydrolytic deacylation rate; and (iii) PBP 2a undergoes a conformational change in the presence of the antibiotic consistent with the opening of the active site from the closed conformation. These observations argue that PBP 2a most likely evolved for its physiological function at pH 7 or higher by adopting a closed conformation, which is not maintained at acidic pH. Although at the organism level the effect of acidic pH on other biological processes in MRSA could not be discounted, our report should provide the impetus for closer examination of the properties of PBP 2a at low pH and thereby identifying novel points of intervention in combating this problematic organism.
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Affiliation(s)
- Sandrine Lemaire
- Unité de Pharmacologie Cellulaire et Moléculaire, Université Catholique de Louvain, B-1200 Brussels, Belgium.
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Trapping of an Acyl–Enzyme Intermediate in a Penicillin-binding Protein (PBP)-catalyzed Reaction. J Mol Biol 2008; 376:405-13. [DOI: 10.1016/j.jmb.2007.10.066] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/01/2007] [Accepted: 10/26/2007] [Indexed: 10/22/2022]
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Holzgrabe U. Lactivicin – ein Antibiotikum gegen Penicillin-resistente Pneumokokken. ACTA ACUST UNITED AC 2007; 36:421-2. [DOI: 10.1002/pauz.200790103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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