1
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Tolbatov I, Marrone A. Auranofin Targeting the NDM-1 Beta-Lactamase: Computational Insights into the Electronic Configuration and Quasi-Tetrahedral Coordination of Gold Ions. Pharmaceutics 2023; 15:pharmaceutics15030985. [PMID: 36986846 PMCID: PMC10057648 DOI: 10.3390/pharmaceutics15030985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Recently, the well-characterized metallodrug auranofin has been demonstrated to restore the penicillin and cephalosporin sensitivity in resistant bacterial strains via the inhibition of the NDM-1 beta-lactamase, which is operated via the Zn/Au substitution in its bimetallic core. The resulting unusual tetrahedral coordination of the two ions was investigated via the density functional theory calculations. By assessing several charge and multiplicity schemes, coupled with on/off constraining the positions of the coordinating residues, it was demonstrated that the experimental X-ray structure of the gold-bound NDM-1 is consistent with either Au(I)-Au(I) or Au(II)-Au(II) bimetallic moieties. The presented results suggest that the most probable mechanism for the auranofin-based Zn/Au exchange in NDM-1 includes the early formation of the Au(I)-Au(I) system, superseded by oxidation yielding the Au(II)-Au(II) species bearing the highest resemblance to the X-ray structure.
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Affiliation(s)
- Iogann Tolbatov
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Paisos Catalans 16, 43007 Tarragona, Spain
| | - Alessandro Marrone
- Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
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2
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Hinchliffe P, Calvopiña K, Rabe P, Mojica M, Schofield C, Dmitrienko G, Bonomo R, Vila A, Spencer J. Interactions of hydrolyzed β-lactams with the L1 metallo-β-lactamase: Crystallography supports stereoselective binding of cephem/carbapenem products. J Biol Chem 2023; 299:104606. [PMID: 36924941 PMCID: PMC10148155 DOI: 10.1016/j.jbc.2023.104606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 03/15/2023] Open
Abstract
L1 is a dizinc subclass B3 metallo-β-lactamase (MBL) that hydrolyzes most β-lactam antibiotics and is a key resistance determinant in the Gram-negative pathogen Stenotrophomonas maltophilia, an important cause of nosocomial infections in immunocompromised patients. L1 is not usefully inhibited by MBL inhibitors in clinical trials, underlying the need for further studies on L1 structure and mechanism. We describe kinetic studies and crystal structures of L1 in complex with hydrolyzed β-lactams from the penam (mecillinam), cephem (cefoxitin/cefmetazole) and carbapenem (tebipenem, doripenem and panipenem) classes. Despite differences in their structures, all the β-lactam-derived products hydrogen bond to Tyr33, Ser221 and Ser225 and are stabilized by interactions with a conserved hydrophobic pocket. The carbapenem products were modelled as Δ1-imines, with (2S)-stereochemistry. Their binding mode is determined by the presence of a 1β-methyl substituent: the Zn-bridging hydroxide either interacts with the C-6 hydroxyethyl group (1β-hydrogen-containing carbapenems), or is displaced by the C-6 carboxylate (1β-methyl-containing carbapenems). Unexpectedly, the mecillinam product is a rearranged N-formyl amide rather than penicilloic acid, with the N-formyl oxygen interacting with the Zn-bridging hydroxide. NMR studies imply mecillinam rearrangement can occur non-enzymatically in solution. Cephem-derived imine products are bound with (3R)-stereochemistry and retain their 3' leaving groups, likely representing stable endpoints, rather than intermediates, in MBL-catalyzed hydrolysis. Our structures show preferential complex formation by carbapenem- and cephem-derived species protonated on the equivalent (β) faces, and so identify interactions that stabilize diverse hydrolyzed antibiotics. These results may be exploited in developing antibiotics, and β-lactamase inhibitors, that form long-lasting complexes with dizinc MBLs.
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Affiliation(s)
- Philip Hinchliffe
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Karina Calvopiña
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Patrick Rabe
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - MariaF Mojica
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; CWRU-Cleveland VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA; Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH; Grupo de Resistencia Antimicrobiana y Epidemiología Hospitalaria, Universidad El Bosque, Bogotá, Colombia
| | - ChristopherJ Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - GaryI Dmitrienko
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada; School of Pharmacy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - RobertA Bonomo
- CWRU-Cleveland VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA; Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH; Departments of Medicine, Biochemistry, Pharmacology, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH
| | - AlejandroJ Vila
- CWRU-Cleveland VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA; Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina; Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom.
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3
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Wilamowski M, Sherrell DA, Kim Y, Lavens A, Henning RW, Lazarski K, Shigemoto A, Endres M, Maltseva N, Babnigg G, Burdette SC, Srajer V, Joachimiak A. Time-resolved β-lactam cleavage by L1 metallo-β-lactamase. Nat Commun 2022; 13:7379. [PMID: 36450742 PMCID: PMC9712583 DOI: 10.1038/s41467-022-35029-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Serial x-ray crystallography can uncover binding events, and subsequent chemical conversions occurring during enzymatic reaction. Here, we reveal the structure, binding and cleavage of moxalactam antibiotic bound to L1 metallo-β-lactamase (MBL) from Stenotrophomonas maltophilia. Using time-resolved serial synchrotron crystallography, we show the time course of β-lactam hydrolysis and determine ten snapshots (20, 40, 60, 80, 100, 150, 300, 500, 2000 and 4000 ms) at 2.20 Å resolution. The reaction is initiated by laser pulse releasing Zn2+ ions from a UV-labile photocage. Two metal ions bind to the active site, followed by binding of moxalactam and the intact β-lactam ring is observed for 100 ms after photolysis. Cleavage of β-lactam is detected at 150 ms and the ligand is significantly displaced. The reaction product adjusts its conformation reaching steady state at 2000 ms corresponding to the relaxed state of the enzyme. Only small changes are observed in the positions of Zn2+ ions and the active site residues. Mechanistic details captured here can be generalized to other MBLs.
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Affiliation(s)
- M Wilamowski
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
- Department of General Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology of Jagiellonian University, 30387, Krakow, Poland
| | - D A Sherrell
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Y Kim
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - A Lavens
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - R W Henning
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL, 60637, USA
| | - K Lazarski
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - A Shigemoto
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - M Endres
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA
| | - N Maltseva
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA
| | - G Babnigg
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA
| | - S C Burdette
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - V Srajer
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL, 60637, USA
| | - A Joachimiak
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, 60667, USA.
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
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4
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Chen C, Oelschlaeger P, Wang D, Xu H, Wang Q, Wang C, Zhao A, Yang KW. Structure and Mechanism-Guided Design of Dual Serine/Metallo-Carbapenemase Inhibitors. J Med Chem 2022; 65:5954-5974. [PMID: 35420040 DOI: 10.1021/acs.jmedchem.2c00213] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Serine/metallo-carbapenemase-coproducing pathogens, often referred to as "superbugs", are a significant clinical problem. They hydrolyze nearly all available β-lactam antibiotics, especially carbapenems considered as last-resort antibiotics, seriously endangering efficacious antibacterial treatment. Despite the continuous global spread of carbapenem resistance, no dual-action inhibitors are available in therapy. This Perspective is the first systematic investigation of all chemotypes, modes of inhibition, and crystal structures of dual serine/metallo-carbapenemase inhibitors. An overview of the key strategy for designing dual serine/metallo-carbapenemase inhibitors and their mechanism of action is provided, as guiding rules for the development of clinically available dual inhibitors, coadministrated with carbapenems, to overcome the carbapenem resistance issue.
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Affiliation(s)
- Cheng Chen
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, P. R. China
| | - Peter Oelschlaeger
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East Second Street, Pomona 91766, California, United States
| | - Dongmei Wang
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, P. R. China
| | - Hao Xu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310030, P. R. China
| | - Qian Wang
- Department of Clinical Laboratory, The First Affiliated Hospital of Henan University of Chinese Medicine, Jinshui District 450046, Zhengzhou, P. R. China
| | - Cheng Wang
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, P. R. China
| | - Aiguo Zhao
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, P. R. China
| | - Ke-Wu Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, P. R. China
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5
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Bahr G, González LJ, Vila AJ. Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design. Chem Rev 2021; 121:7957-8094. [PMID: 34129337 PMCID: PMC9062786 DOI: 10.1021/acs.chemrev.1c00138] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.
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Affiliation(s)
- Guillermo Bahr
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Lisandro J. González
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
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6
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Levina EO, Khrenova MG. Metallo-β-Lactamases: Influence of the Active Site Structure on the Mechanisms of Antibiotic Resistance and Inhibition. BIOCHEMISTRY (MOSCOW) 2021; 86:S24-S37. [PMID: 33827398 DOI: 10.1134/s0006297921140030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The review focuses on bacterial metallo-β-lactamases (MβLs) responsible for the inactivation of β-lactams and associated antibiotic resistance. The diversity of the active site structure in the members of different MβL subclasses explains different mechanisms of antibiotic hydrolysis and should be taken into account when searching for potential MβL inhibitors. The review describes the features of the antibiotic inactivation mechanisms by various MβLs studied by X-ray crystallography, NMR, kinetic measurements, and molecular modeling. The mechanisms of enzyme inhibition for each MβL subclass are discussed.
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Affiliation(s)
- Elena O Levina
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow, 119071, Russia
| | - Maria G Khrenova
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow, 119071, Russia. .,Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
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7
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Palacios AR, Rossi MA, Mahler GS, Vila AJ. Metallo-β-Lactamase Inhibitors Inspired on Snapshots from the Catalytic Mechanism. Biomolecules 2020; 10:E854. [PMID: 32503337 PMCID: PMC7356002 DOI: 10.3390/biom10060854] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/31/2020] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
β-Lactam antibiotics are the most widely prescribed antibacterial drugs due to their low toxicity and broad spectrum. Their action is counteracted by different resistance mechanisms developed by bacteria. Among them, the most common strategy is the expression of β-lactamases, enzymes that hydrolyze the amide bond present in all β-lactam compounds. There are several inhibitors against serine-β-lactamases (SBLs). Metallo-β-lactamases (MBLs) are Zn(II)-dependent enzymes able to hydrolyze most β-lactam antibiotics, and no clinically useful inhibitors against them have yet been approved. Despite their large structural diversity, MBLs have a common catalytic mechanism with similar reaction species. Here, we describe a number of MBL inhibitors that mimic different species formed during the hydrolysis process: substrate, transition state, intermediate, or product. Recent advances in the development of boron-based and thiol-based inhibitors are discussed in the light of the mechanism of MBLs. We also discuss the use of chelators as a possible strategy, since Zn(II) ions are essential for substrate binding and catalysis.
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Affiliation(s)
- Antonela R. Palacios
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo and Esmeralda, S2002LRK Rosario, Argentina; (A.R.P.); (M.-A.-R.)
| | - María-Agustina Rossi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo and Esmeralda, S2002LRK Rosario, Argentina; (A.R.P.); (M.-A.-R.)
| | - Graciela S. Mahler
- Laboratorio de Química Farmacéutica, Facultad de Química, Universidad de la Republica (UdelaR), Montevideo 11800, Uruguay;
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo and Esmeralda, S2002LRK Rosario, Argentina; (A.R.P.); (M.-A.-R.)
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
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8
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Sharma S, Sharma S, Singh PP, Khan IA. Potential Inhibitors Against NDM-1 Type Metallo-β-Lactamases: An Overview. Microb Drug Resist 2020; 26:1568-1588. [PMID: 32486911 DOI: 10.1089/mdr.2019.0315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A new member of the class metallo-β-lactamase (MBL), New Delhi metallo-beta-lactamase 1 (NDM-1) has emerged recently as a leading threat to the treatment of infections that have spread in all major Gram-negative pathogens. The enzyme inactivates antibiotics of the carbapenem family, which are a mainstay for the treatment of antibiotic-resistant bacterial infections. This review provides information about NDM-1 spatial structure, potential features of the active site, and its mechanism of action. It also enlists the inhibitors/compounds/drugs against NDM-1 in various development phases. Understanding their mode of inhibition and the structure-activity relationship would be beneficial for development, synthesis, and even increasing biological efficacy of inhibitors, making them more promising drug candidates.
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Affiliation(s)
- Smriti Sharma
- Clinical Microbiology Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India.,Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India
| | - Sumit Sharma
- Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India.,Medicinal Chemistry Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India
| | - Parvinder Pal Singh
- Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India.,Medicinal Chemistry Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India
| | - Inshad Ali Khan
- Clinical Microbiology Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India.,Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu Tawi, India
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9
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Mechanistic Insights into β-Lactamase-Catalysed Carbapenem Degradation Through Product Characterisation. Sci Rep 2019; 9:13608. [PMID: 31541180 PMCID: PMC6754457 DOI: 10.1038/s41598-019-49264-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/15/2019] [Indexed: 01/20/2023] Open
Abstract
β-Lactamases are a major threat to the clinical use of carbapenems, which are often antibiotics of last resort. Despite this, the reaction outcomes and mechanisms by which β-lactamases degrade carbapenems are still not fully understood. The carbapenem bicyclic core consists of a β-lactam ring fused to a pyrroline ring. Following β-lactamase-mediated opening of the β-lactam, the pyrroline may interconvert between an enamine (2-pyrroline) form and two epimeric imine (1-pyrroline) forms; previous crystallographic and spectroscopic studies have reported all three of these forms in the contexts of hydrolysis by different β-lactamases. As we show by NMR spectroscopy, the serine β-lactamases (KPC-2, SFC-1, CMY-10, OXA-23, and OXA-48) and metallo-β-lactamases (NDM-1, VIM-1, BcII, CphA, and L1) tested all degrade carbapenems to preferentially give the Δ2 (enamine) and/or (R)-Δ1 (imine) products. Rapid non-enzymatic tautomerisation of the Δ2 product to the (R)-Δ1 product prevents assignment of the nascent enzymatic product by NMR. The observed stereoselectivity implies that carbapenemases control the form of their pyrroline ring intermediate(s)/product(s), thereby preventing pyrroline tautomerisation from inhibiting catalysis.
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10
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Tooke CL, Hinchliffe P, Bragginton EC, Colenso CK, Hirvonen VHA, Takebayashi Y, Spencer J. β-Lactamases and β-Lactamase Inhibitors in the 21st Century. J Mol Biol 2019; 431:3472-3500. [PMID: 30959050 PMCID: PMC6723624 DOI: 10.1016/j.jmb.2019.04.002] [Citation(s) in RCA: 440] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/27/2019] [Accepted: 04/01/2019] [Indexed: 12/31/2022]
Abstract
The β-lactams retain a central place in the antibacterial armamentarium. In Gram-negative bacteria, β-lactamase enzymes that hydrolyze the amide bond of the four-membered β-lactam ring are the primary resistance mechanism, with multiple enzymes disseminating on mobile genetic elements across opportunistic pathogens such as Enterobacteriaceae (e.g., Escherichia coli) and non-fermenting organisms (e.g., Pseudomonas aeruginosa). β-Lactamases divide into four classes; the active-site serine β-lactamases (classes A, C and D) and the zinc-dependent or metallo-β-lactamases (MBLs; class B). Here we review recent advances in mechanistic understanding of each class, focusing upon how growing numbers of crystal structures, in particular for β-lactam complexes, and methods such as neutron diffraction and molecular simulations, have improved understanding of the biochemistry of β-lactam breakdown. A second focus is β-lactamase interactions with carbapenems, as carbapenem-resistant bacteria are of grave clinical concern and carbapenem-hydrolyzing enzymes such as KPC (class A) NDM (class B) and OXA-48 (class D) are proliferating worldwide. An overview is provided of the changing landscape of β-lactamase inhibitors, exemplified by the introduction to the clinic of combinations of β-lactams with diazabicyclooctanone and cyclic boronate serine β-lactamase inhibitors, and of progress and strategies toward clinically useful MBL inhibitors. Despite the long history of β-lactamase research, we contend that issues including continuing unresolved questions around mechanism; opportunities afforded by new technologies such as serial femtosecond crystallography; the need for new inhibitors, particularly for MBLs; the likely impact of new β-lactam:inhibitor combinations and the continuing clinical importance of β-lactams mean that this remains a rewarding research area.
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Affiliation(s)
- Catherine L Tooke
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Philip Hinchliffe
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Eilis C Bragginton
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Charlotte K Colenso
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Viivi H A Hirvonen
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Yuiko Takebayashi
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol Biomedical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom.
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11
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Insight into the catalytic hydrolysis mechanism of New Delhi metallo-β-lactamase to aztreonam by molecular modeling. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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The Reaction Mechanism of Metallo-β-Lactamases Is Tuned by the Conformation of an Active-Site Mobile Loop. Antimicrob Agents Chemother 2018; 63:AAC.01754-18. [PMID: 30348667 DOI: 10.1128/aac.01754-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/01/2018] [Indexed: 12/31/2022] Open
Abstract
Carbapenems are "last resort" β-lactam antibiotics used to treat serious and life-threatening health care-associated infections caused by multidrug-resistant Gram-negative bacteria. Unfortunately, the worldwide spread of genes coding for carbapenemases among these bacteria is threatening these life-saving drugs. Metallo-β-lactamases (MβLs) are the largest family of carbapenemases. These are Zn(II)-dependent hydrolases that are active against almost all β-lactam antibiotics. Their catalytic mechanism and the features driving substrate specificity have been matter of intense debate. The active sites of MβLs are flanked by two loops, one of which, loop L3, was shown to adopt different conformations upon substrate or inhibitor binding, and thus are expected to play a role in substrate recognition. However, the sequence heterogeneity observed in this loop in different MβLs has limited the generalizations about its role. Here, we report the engineering of different loops within the scaffold of the clinically relevant carbapenemase NDM-1. We found that the loop sequence dictates its conformation in the unbound form of the enzyme, eliciting different degrees of active-site exposure. However, these structural changes have a minor impact on the substrate profile. Instead, we report that the loop conformation determines the protonation rate of key reaction intermediates accumulated during the hydrolysis of different β-lactams in all MβLs. This study demonstrates the existence of a direct link between the conformation of this loop and the mechanistic features of the enzyme, bringing to light an unexplored function of active-site loops on MβLs.
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13
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Raczynska JE, Shabalin IG, Minor W, Wlodawer A, Jaskolski M. A close look onto structural models and primary ligands of metallo-β-lactamases. Drug Resist Updat 2018; 40:1-12. [PMID: 30466711 PMCID: PMC6260963 DOI: 10.1016/j.drup.2018.08.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
Abstract
β-Lactamases are hydrolytic enzymes capable of opening the β-lactam ring of antibiotics such as penicillin, thus endowing the bacteria that produce them with antibiotic resistance. Of particular medical concern are metallo-β-lactamases (MBLs), with an active site built around coordinated Zn cations. MBLs are pan-reactive enzymes that can break down almost all classes of β-lactams, including such last-resort antibiotics as carbapenems. They are not only broad-spectrum-reactive but are often plasmid-borne (e.g., the New Delhi enzyme, NDM), and can spread horizontally even among unrelated bacteria. Acquired MBLs are encoded by mobile genetic elements, which often include other resistance genes, making the microbiological situation particularly alarming. There is an urgent need to develop MBL inhibitors in order to rescue our antibiotic armory. A number of such efforts have been undertaken, most notably using the 3D structures of various MBLs as drug-design targets. Structure-guided drug discovery depends on the quality of the structures that are collected in the Protein Data Bank (PDB) and on the consistency of the information in dedicated β-lactamase databases. We conducted a careful review of the crystal structures of class B β-lactamases, concluding that the quality of these structures varies widely, especially in the regions where small molecules interact with the macromolecules. In a number of examples the interpretation of the bound ligands (e.g., inhibitors, substrate/product analogs) is doubtful or even incorrect, and it appears that in some cases the modeling of ligands was not supported by electron density. For ten MBL structures, alternative interpretations of the original diffraction data could be proposed and the new models have been deposited in the PDB. In four cases, these models, prepared jointly with the authors of the original depositions, superseded the previous deposits. This review emphasizes the importance of critical assessment of structural models describing key drug design targets at the level of the raw experimental data. Since the structures reviewed here are the basis for ongoing design of new MBL inhibitors, it is important to identify and correct the problems with ambiguous crystallographic interpretations, thus enhancing reproducibility in this highly medically relevant area.
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Affiliation(s)
- Joanna E Raczynska
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Ivan G Shabalin
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA; Center for Structural Genomics of Infectious Diseases, Charlottesville, VA 22908, USA
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA; Center for Structural Genomics of Infectious Diseases, Charlottesville, VA 22908, USA
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Mariusz Jaskolski
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland; Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland.
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Das CK, Nair NN. Hydrolysis of cephalexin and meropenem by New Delhi metallo-β-lactamase: the substrate protonation mechanism is drug dependent. Phys Chem Chem Phys 2018; 19:13111-13121. [PMID: 28489087 DOI: 10.1039/c6cp08769h] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Emergence of antibiotic resistance due to New Delhi metallo-β-lactamase (NDM-1) bacterial enzymes is of great concern due to their ability to hydrolyze a wide range of antibiotics. There are ongoing efforts to obtain the atomistic details of the hydrolysis mechanism in order to develop inhibitors for NDM-1. In particular, it remains elusive how drug molecules of different families of antibiotics are hydrolyzed by NDM-1 in an efficient manner. Here we report the detailed molecular mechanism of NDM-1 catalyzed hydrolysis of cephalexin, a cephalosporin family drug, and meropenem, a carbapenem family drug. This study employs molecular dynamics (MD) simulations using hybrid quantum mechanical/molecular mechanical (QM/MM) methods at the density functional theory (DFT) level, based on which reaction pathways and the associated free energies are obtained. We find that the mechanism and the free energy barrier for the ring-opening step are the same for both the drug molecules, while the subsequent protonation step differs. In particular, we observe that the mechanism of the protonation step depends on the R2 group of the drug molecule. Our simulations show that allylic carbon protonation occurs in the case of the cephalexin drug molecule where Lys211 is the proton donor, and the proton transfer occurs via a water chain formed (only) at the ring-opened intermediate structure. Based on the free energy profiles, the overall kinetics of drug hydrolysis is discussed. Finally, we show that the proposed mechanisms and free energy profiles could explain various experimental observations.
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Affiliation(s)
- Chandan Kumar Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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15
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The mechanism of NDM-1-catalyzed carbapenem hydrolysis is distinct from that of penicillin or cephalosporin hydrolysis. Nat Commun 2017; 8:2242. [PMID: 29269938 PMCID: PMC5740130 DOI: 10.1038/s41467-017-02339-w] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 11/22/2017] [Indexed: 02/08/2023] Open
Abstract
New Delhi metallo-β-lactamases (NDMs), the recent additions to metallo-β-lactamases (MBLs), pose a serious public health threat due to its highly efficient hydrolysis of β-lactam antibiotics and rapid worldwide dissemination. The MBL-hydrolyzing mechanism for carbapenems is less studied than that of penicillins and cephalosporins. Here, we report crystal structures of NDM-1 in complex with hydrolyzed imipenem and meropenem, at resolutions of 1.80–2.32 Å, together with NMR spectra monitoring meropenem hydrolysis. Three enzyme-intermediate/product derivatives, EI1, EI2, and EP, are trapped in these crystals. Our structural data reveal double-bond tautomerization from Δ2 to Δ1, absence of a bridging water molecule and an exclusive β-diastereomeric product, all suggesting that the hydrolytic intermediates are protonated by a bulky water molecule incoming from the β-face. These results strongly suggest a distinct mechanism of NDM-1-catalyzed carbapenem hydrolysis from that of penicillin or cephalosporin hydrolysis, which may provide a novel rationale for design of mechanism-based inhibitors. New Delhi metallo-β-lactamases (NDMs) hydrolyze almost all β-lactam antibiotics and pose a major public health threat. Here, the authors study the mechanism of NDM-1 catalyzed carbapenem hydrolysis and present the crystal structures of the enzyme-intermediate and product complexes, which is important for drug design.
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Stewart AC, Bethel CR, VanPelt J, Bergstrom A, Cheng Z, Miller CG, Williams C, Poth R, Morris M, Lahey O, Nix JC, Tierney DL, Page RC, Crowder MW, Bonomo RA, Fast W. Clinical Variants of New Delhi Metallo-β-Lactamase Are Evolving To Overcome Zinc Scarcity. ACS Infect Dis 2017; 3:927-940. [PMID: 28965402 DOI: 10.1021/acsinfecdis.7b00128] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Use and misuse of antibiotics have driven the evolution of serine β-lactamases to better recognize new generations of β-lactam drugs, but the selective pressures driving evolution of metallo-β-lactamases are less clear. Here, we present evidence that New Delhi metallo-β-lactamase (NDM) is evolving to overcome the selective pressure of zinc(II) scarcity. Studies of NDM-1, NDM-4 (M154L), and NDM-12 (M154L, G222D) demonstrate that the point mutant M154L, contained in 50% of clinical NDM variants, selectively enhances resistance to the penam ampicillin at low zinc(II) concentrations relevant to infection sites. Each of the clinical variants is shown to be progressively more thermostable and to bind zinc(II) more tightly than NDM-1, but a selective enhancement of penam turnover at low zinc(II) concentrations indicates that most of the improvement derives from catalysis rather than stability. X-ray crystallography of NDM-4 and NDM-12, as well as bioinorganic spectroscopy of dizinc(II), zinc(II)/cobalt(II), and dicobalt(II) metalloforms probe the mechanism of enhanced resistance and reveal perturbations of the dinuclear metal cluster that underlie improved catalysis. These studies support the proposal that zinc(II) scarcity, rather than changes in antibiotic structure, is driving the evolution of new NDM variants in clinical settings.
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Affiliation(s)
- Alesha C. Stewart
- Division of Chemical
Biology and Medicinal Chemistry, College of Pharmacy, and the LaMontagne
Center for Infectious Disease, University of Texas, Austin, Texas 78712, United States
| | - Christopher R. Bethel
- Research Services, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Jamie VanPelt
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Alex Bergstrom
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Zishuo Cheng
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Callie G. Miller
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Cameron Williams
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert Poth
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Matthew Morris
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Olivia Lahey
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Jay C. Nix
- Molecular Biology Consortium, Beamline 4.2.2, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - David L. Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Richard C. Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Michael W. Crowder
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert A. Bonomo
- Research Services, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
- Departments
of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry,
Proteomics and Bioinformatics, and the CWRU-Cleveland VAMC Center
for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio 44106, United States
| | - Walter Fast
- Division of Chemical
Biology and Medicinal Chemistry, College of Pharmacy, and the LaMontagne
Center for Infectious Disease, University of Texas, Austin, Texas 78712, United States
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17
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A general reaction mechanism for carbapenem hydrolysis by mononuclear and binuclear metallo-β-lactamases. Nat Commun 2017; 8:538. [PMID: 28912448 PMCID: PMC5599593 DOI: 10.1038/s41467-017-00601-9] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/12/2017] [Indexed: 12/16/2022] Open
Abstract
Carbapenem-resistant Enterobacteriaceae threaten human health, since carbapenems are last resort drugs for infections by such organisms. Metallo-β-lactamases (MβLs) are the main mechanism of resistance against carbapenems. Clinically approved inhibitors of MBLs are currently unavailable as design has been limited by the incomplete knowledge of their mechanism. Here, we report a biochemical and biophysical study of carbapenem hydrolysis by the B1 enzymes NDM-1 and BcII in the bi-Zn(II) form, the mono-Zn(II) B2 Sfh-I and the mono-Zn(II) B3 GOB-18. These MβLs hydrolyse carbapenems via a similar mechanism, with accumulation of the same anionic intermediates. We characterize the Michaelis complex formed by mono-Zn(II) enzymes, and we identify all intermediate species, enabling us to propose a chemical mechanism for mono and binuclear MβLs. This common mechanism open avenues for rationally designed inhibitors of all MβLs, notwithstanding the profound differences between these enzymes’ active site structure, β-lactam specificity and metal content. Carbapenem-resistant bacteria pose a major health threat by expressing metallo-β-lactamases (MβLs), enzymes able to hydrolyse these life-saving drugs. Here the authors use biophysical and computational methods and show that different MβLs share the same reaction mechanism, suggesting new strategies for drug design.
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18
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Kim YJ, Kim HS, Kim KY, Chon JW, Kim DH, Seo KH. High Occurrence Rate and Contamination Level of Bacillus cereus in Organic Vegetables on Sale in Retail Markets. Foodborne Pathog Dis 2016; 13:656-660. [PMID: 27992273 DOI: 10.1089/fpd.2016.2163] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Organic foods have risen in popularity recently. However, the increased risk of bacterial contamination of organic foods has not been fully evaluated. In this study, 100 samples each of organic and conventional fresh vegetables (55 lettuce samples and 45 sprout samples) sold in South Korea were analyzed for aerobic bacteria, coliforms, Escherichia coli, and Bacillus cereus. Although the aerobic bacteria and coliform counts were not significantly different between the two farming types (p > 0.05), the occurrence rate of B. cereus was higher in organically cultivated vegetables compared with those grown conventionally (70% vs. 30%, respectively). The mean contamination level of B. cereus-positive organic samples was also significantly higher (1.86 log colony-forming unit [CFU]/g vs. 0.69 log CFU/g, respectively) (p < 0.05). In addition, six samples of organic vegetables were found to be contaminated with B. cereus at over 4 log CFU/g categorized as unsatisfactory according to Health Protection Agency guideline. The relatively higher occurrence rate of B. cereus in organic vegetables emphasizes the importance of implementing control measures in organic vegetable production and postharvest processing to reduce the risk of food poisoning.
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Affiliation(s)
- Young-Ji Kim
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
| | - Hong-Seok Kim
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
| | - Kwang-Yeop Kim
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
| | - Jung-Whan Chon
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
| | - Dong-Hyeon Kim
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
| | - Kun-Ho Seo
- Center for One Health, College of Veterinary Medicine, Konkuk University , Seoul, South Korea
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19
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Cahill ST, Tarhonskaya H, Rydzik AM, Flashman E, McDonough MA, Schofield CJ, Brem J. Use of ferrous iron by metallo-β-lactamases. J Inorg Biochem 2016; 163:185-193. [PMID: 27498591 PMCID: PMC5108564 DOI: 10.1016/j.jinorgbio.2016.07.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 07/12/2016] [Accepted: 07/25/2016] [Indexed: 01/01/2023]
Abstract
Metallo-β-lactamases (MBLs) catalyse the hydrolysis of almost all β-lactam antibacterials including the latest generation carbapenems and are a growing worldwide clinical problem. It is proposed that MBLs employ one or two zinc ion cofactors in vivo. Isolated MBLs are reported to use transition metal ions other than zinc, including copper, cadmium and manganese, with iron ions being a notable exception. We report kinetic and biophysical studies with the di-iron(II)-substituted metallo-β-lactamase II from Bacillus cereus (di-Fe(II) BcII) and the clinically relevant B1 subclass Verona integron-encoded metallo-β-lactamase 2 (di-Fe(II) VIM-2). The results reveal that MBLs can employ ferrous iron in catalysis, but with altered kinetic and inhibition profiles compared to the zinc enzymes. A crystal structure of di-Fe(II) BcII reveals only small overall changes in the active site compared to the di-Zn(II) enzyme including retention of the di-metal bridging water; however, the positions of the metal ions are altered in the di-Fe(II) compared to the di-Zn(II) structure. Stopped-flow analyses reveal that the mechanism of nitrocefin hydrolysis by both di-Fe(II) BcII and di-Fe(II) VIM-2 is altered compared to the di-Zn(II) enzymes. Notably, given that the MBLs are the subject of current medicinal chemistry efforts, the results raise the possibility the Fe(II)-substituted MBLs may be of clinical relevance under conditions of low zinc availability, and reveal potential variation in inhibitor activity against the differently metallated MBLs.
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Affiliation(s)
| | | | - Anna M Rydzik
- Chemistry Research Laboratory, Oxford, United Kingdom
| | | | | | | | - Jürgen Brem
- Chemistry Research Laboratory, Oxford, United Kingdom.
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20
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Cross-class metallo-β-lactamase inhibition by bisthiazolidines reveals multiple binding modes. Proc Natl Acad Sci U S A 2016; 113:E3745-54. [PMID: 27303030 DOI: 10.1073/pnas.1601368113] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metallo-β-lactamases (MBLs) hydrolyze almost all β-lactam antibiotics and are unaffected by clinically available β-lactamase inhibitors (βLIs). Active-site architecture divides MBLs into three classes (B1, B2, and B3), complicating development of βLIs effective against all enzymes. Bisthiazolidines (BTZs) are carboxylate-containing, bicyclic compounds, considered as penicillin analogs with an additional free thiol. Here, we show both l- and d-BTZ enantiomers are micromolar competitive βLIs of all MBL classes in vitro, with Kis of 6-15 µM or 36-84 µM for subclass B1 MBLs (IMP-1 and BcII, respectively), and 10-12 µM for the B3 enzyme L1. Against the B2 MBL Sfh-I, the l-BTZ enantiomers exhibit 100-fold lower Kis (0.26-0.36 µM) than d-BTZs (26-29 µM). Importantly, cell-based time-kill assays show BTZs restore β-lactam susceptibility of Escherichia coli-producing MBLs (IMP-1, Sfh-1, BcII, and GOB-18) and, significantly, an extensively drug-resistant Stenotrophomonas maltophilia clinical isolate expressing L1. BTZs therefore inhibit the full range of MBLs and potentiate β-lactam activity against producer pathogens. X-ray crystal structures reveal insights into diverse BTZ binding modes, varying with orientation of the carboxylate and thiol moieties. BTZs bind the di-zinc centers of B1 (IMP-1; BcII) and B3 (L1) MBLs via the free thiol, but orient differently depending upon stereochemistry. In contrast, the l-BTZ carboxylate dominates interactions with the monozinc B2 MBL Sfh-I, with the thiol uninvolved. d-BTZ complexes most closely resemble β-lactam binding to B1 MBLs, but feature an unprecedented disruption of the D120-zinc interaction. Cross-class MBL inhibition therefore arises from the unexpected versatility of BTZ binding.
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21
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Yamaguchi Y. [Structure-Function Analysis and Development of Inhibitors of Metallo-β-lactamases Conferring Drug Resistance in Bacteria]. YAKUGAKU ZASSHI 2016; 135:1299-305. [PMID: 26521879 DOI: 10.1248/yakushi.15-00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Metallo-β-lactamases (MBLs) are di-Zn(II) metalloenzymes that efficiently hydrolyze most β-lactam antibiotics used in clinical settings. Bacteria producing MBLs have been isolated from clinical settings and from natural environments such as rivers and soils, and are now recognized as a new potential threat to human health. No effective inhibitors are available for clinical use, making the treatment of infectious diseases caused by bacteria producing MBLs more difficult. IMP-1 is encoded on a plasmid which can be horizontally transferred between bacterial strains. Our studies on MBLs, and especially on IMP-1, focus on understanding the role of Zn(II) ion(s) in the hydrolysis of β-lactam antibiotics and on the detailed structure of the IMP-1 active site in order to develop efficient inhibitors. We investigated the role of the two Zn(II) ions in IMP-1 by kinetic, spectroscopic and thermodynamic analyses. The results revealed that the first Zn(II) ion is necessary for the hydrolysis of β-lactam antibiotics while the second Zn(II) ion enhances enzyme activity and structural stability, thus helping the enzyme achieve maximum activity. The detailed structures of the IMP-1 active site were examined by X-ray crystallography. Thiol compounds for irreversibly inhibiting IMP-1 were developed and the binding mode of these inhibitors was investigated in detail. These findings will aid the design of inhibitors that target MBLs.
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Meini MR, Llarrull LI, Vila AJ. Evolution of Metallo-β-lactamases: Trends Revealed by Natural Diversity and in vitro Evolution. Antibiotics (Basel) 2016; 3:285-316. [PMID: 25364574 PMCID: PMC4212336 DOI: 10.3390/antibiotics3030285] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The production of β-lactamase enzymes is one of the most distributed resistance mechanisms towards β-lactam antibiotics. Metallo-β-lactamases constitute a worrisome group of these kinds of enzymes, since they present a broad spectrum profile, being able to hydrolyze not only penicillins, but also the latest generation of cephalosporins and carbapenems, which constitute at present the last resource antibiotics. The VIM, IMP, and NDM enzymes comprise the main groups of clinically relevant metallo-β-lactamases. Here we present an update of the features of the natural variants that have emerged and of the ones that have been engineered in the laboratory, in an effort to find sequence and structural determinants of substrate preferences. This knowledge is of upmost importance in novel drug design efforts. We also discuss the advances in knowledge achieved by means of in vitro directed evolution experiments, and the potential of this approach to predict natural evolution of metallo-β-lactamases.
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Affiliation(s)
- María-Rocío Meini
- Authors to whom correspondence should be addressed; E-Mails: (M.-R.M.); (L.I.L.); (A.J.V.); Tel.: +54-341-423-7070 (ext. 611 M.-R.M.; 637 L.I.L.; 632 A.J.V.); Fax: 54-341-423-7070 (ext. 607)
| | - Leticia I. Llarrull
- Authors to whom correspondence should be addressed; E-Mails: (M.-R.M.); (L.I.L.); (A.J.V.); Tel.: +54-341-423-7070 (ext. 611 M.-R.M.; 637 L.I.L.; 632 A.J.V.); Fax: 54-341-423-7070 (ext. 607)
| | - Alejandro J. Vila
- Authors to whom correspondence should be addressed; E-Mails: (M.-R.M.); (L.I.L.); (A.J.V.); Tel.: +54-341-423-7070 (ext. 611 M.-R.M.; 637 L.I.L.; 632 A.J.V.); Fax: 54-341-423-7070 (ext. 607)
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23
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Baum RR, Myers WK, Greer SM, Breece RM, Tierney DL. The Original CoII Heteroscorpionates Revisited: On the EPR of Pseudotetrahedral CoII. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert R. Baum
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - William K. Myers
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Samuel M. Greer
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Robert M. Breece
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - David L. Tierney
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
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Aitha M, Al-Adbul-Wahid S, Tierney DL, Crowder MW. Probing substrate binding to the metal binding sites in metallo-β-lactamase L1 during catalysis. MEDCHEMCOMM 2016; 7:194-201. [PMID: 27087914 DOI: 10.1039/c5md00358j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal ions in metallo-β-lactamases (MBLs) play a major role in catalysis. In this study we investigated the role of the metal ions in the Zn1 and Zn2 sites of MBL L1 during catalysis. A ZnCo (with Zn(II) in the invariant Zn1 site and Co(II) in the Zn2 site) analog of MBL L1 was prepared by using a biological incorporation method. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopic studies were used to confirm that the ZnCo analog was prepared. To study the roles of the Zn(II) and Co(II) ions during catalysis, rapid freeze quench (RFQ)-EXAFS studies were used to probe the reaction of the ZnCo-L1 analog with chromacef when quenched at 10 ms, 50 ms, and 100 ms. The L1-product complex was also analyzed with EXAFS spectroscopy. The data show that the Zn-Co distance is 3.49 Å in the resting enzyme and that this distance increases by 0.3 Å in the sample that was quenched at 10 ms. The average Zn-Co distance decreases at the other time points until reaching a distance of 3.58 Å in the L1-product complex. The data also show that a Co-S interaction is present in the 100 ms quenched sample and in the L1-product complex, which suggests that there is a significant rearrangement of product in the active site.
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Affiliation(s)
- Mahesh Aitha
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Sameer Al-Adbul-Wahid
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Michael W Crowder
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
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González MM, Vila AJ. An Elusive Task: A Clinically Useful Inhibitor of Metallo-β-Lactamases. TOPICS IN MEDICINAL CHEMISTRY 2016. [DOI: 10.1007/7355_2016_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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26
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González MM, Kosmopoulou M, Mojica MF, Castillo V, Hinchliffe P, Pettinati I, Brem J, Schofield CJ, Mahler G, Bonomo RA, Llarrull LI, Spencer J, Vila AJ. Bisthiazolidines: A Substrate-Mimicking Scaffold as an Inhibitor of the NDM-1 Carbapenemase. ACS Infect Dis 2015; 1:544-54. [PMID: 27623409 DOI: 10.1021/acsinfecdis.5b00046] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Pathogenic Gram-negative bacteria resistant to almost all β-lactam antibiotics are a major public health threat. Zn(II)-dependent or metallo-β-lactamases (MBLs) produced by these bacteria inactivate most β-lactam antibiotics, including the carbapenems, which are "last line therapies" for life-threatening Gram-negative infections. NDM-1 is a carbapenemase belonging to the MBL family that is rapidly spreading worldwide. Regrettably, inhibitors of MBLs are not yet developed. Here we present the bisthiazolidine (BTZ) scaffold as a structure with some features of β-lactam substrates, which can be modified with metal-binding groups to target the MBL active site. Inspired by known interactions of MBLs with β-lactams, we designed four BTZs that behave as in vitro NDM-1 inhibitors with Ki values in the low micromolar range (from 7 ± 1 to 19 ± 3 μM). NMR spectroscopy demonstrated that they inhibit hydrolysis of imipenem in NDM-1-producing Escherichia coli. In vitro time kill cell-based assays against a variety of bacterial strains harboring blaNDM-1 including Acinetobacter baumannii show that the compounds restore the antibacterial activity of imipenem. A crystal structure of the most potent heterocycle (L-CS319) in complex with NDM-1 at 1.9 Å resolution identified both structural determinants for inhibitor binding and opportunities for further improvements in potency.
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Affiliation(s)
- Mariano M. González
- Instituto de Biologı́a Molecular y Celular
de Rosario (IBR-CONICET), Facultad de Ciencias Bioquı́micas
y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo
y Esmeralda, 2000 Rosario, Argentina
| | - Magda Kosmopoulou
- School of Cellular
and Molecular Medicine, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Maria F. Mojica
- Research
Service, Louis Stokes Cleveland Department of Veterans Affairs Medical
Center, and Departments of Pharmacology, Biochemistry, Microbiology,
and Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Valerie Castillo
- Laboratorio de Quı́mica Farmacéutica,
Facultad de Quı́mica, Universidad de la República (UdelaR), Montevideo 11800, Uruguay
| | - Philip Hinchliffe
- School of Cellular
and Molecular Medicine, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Ilaria Pettinati
- 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
| | - Graciela Mahler
- Laboratorio de Quı́mica Farmacéutica,
Facultad de Quı́mica, Universidad de la República (UdelaR), Montevideo 11800, Uruguay
| | - Robert A. Bonomo
- Research
Service, Louis Stokes Cleveland Department of Veterans Affairs Medical
Center, and Departments of Pharmacology, Biochemistry, Microbiology,
and Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Leticia I. Llarrull
- Instituto de Biologı́a Molecular y Celular
de Rosario (IBR-CONICET), Facultad de Ciencias Bioquı́micas
y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo
y Esmeralda, 2000 Rosario, Argentina
| | - James Spencer
- School of Cellular
and Molecular Medicine, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Alejandro J. Vila
- Instituto de Biologı́a Molecular y Celular
de Rosario (IBR-CONICET), Facultad de Ciencias Bioquı́micas
y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo
y Esmeralda, 2000 Rosario, Argentina
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27
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Meini MR, Llarrull LI, Vila AJ. Overcoming differences: The catalytic mechanism of metallo-β-lactamases. FEBS Lett 2015; 589:3419-32. [PMID: 26297824 DOI: 10.1016/j.febslet.2015.08.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/27/2015] [Accepted: 08/05/2015] [Indexed: 10/23/2022]
Abstract
Metallo-β-lactamases are the latest resistance mechanism of pathogenic and opportunistic bacteria against carbapenems, considered as last resort drugs. The worldwide spread of genes coding for these enzymes, together with the lack of a clinically useful inhibitor, have raised a sign of alarm. Inhibitor design has been mostly impeded by the structural diversity of these enzymes. Here we provide a critical review of mechanistic studies of the three known subclasses of metallo-β-lactamases, analyzed at the light of structural and mutagenesis investigations. We propose that these enzymes present a modular structure in their active sites that can be dissected into two halves: one providing the attacking nucleophile, and the second one stabilizing a negatively charged reaction intermediate. These are common mechanistic elements in all metallo-β-lactamases. Nucleophile activation does not necessarily requires a Zn(II) ion, but a Zn(II) center is essential for stabilization of the anionic intermediate. Design of a common inhibitor could be therefore approached based in these convergent mechanistic features despite the structural differences.
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Affiliation(s)
- María-Rocío Meini
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, 200 Rosario, Argentina
| | - Leticia I Llarrull
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, 200 Rosario, Argentina; Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 2000 Rosario, Argentina.
| | - Alejandro J Vila
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, 200 Rosario, Argentina; Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 2000 Rosario, Argentina.
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Meropenem and chromacef intermediates observed in IMP-25 metallo-β-lactamase-catalyzed hydrolysis. Antimicrob Agents Chemother 2015; 59:4326-30. [PMID: 25918145 DOI: 10.1128/aac.04409-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 04/12/2015] [Indexed: 01/09/2023] Open
Abstract
Metallo-β-lactamases inactivate most β-lactam antibacterials, and much attention has been paid to their catalytic mechanism. One issue of controversy has been whether β-lactam hydrolysis generally proceeds through an anionic intermediate bound to the active-site Zn(II) ions or not. The formation of an intermediate has not been shown conclusively in imipenemase (IMP) enzymes to date. Here, we provide evidence that intermediates are formed during the hydrolysis of meropenem and chromacef catalyzed by the variant IMP-25 and, to a lesser degree, IMP-1.
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Affiliation(s)
- Ravi Tripathi
- Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Nisanth N. Nair
- Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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30
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Targeting metallo-carbapenemases via modulation of electronic properties of cephalosporins. Biochem J 2015; 464:271-9. [PMID: 25220027 DOI: 10.1042/bj20140364] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The global proliferation of metallo-carbapenemase-producing Enterobacteriaceae has created an unmet need for inhibitors of these enzymes. The rational design of metallo-carbapenemase inhibitors requires detailed knowledge of their catalytic mechanisms. Nine cephalosporins, structurally identical except for the systematic substitution of electron-donating and withdrawing groups in the para position of the styrylbenzene ring, were synthesized and utilized to probe the catalytic mechanism of New Delhi metallo-β-lactamase (NDM-1). Under steady-state conditions, K(m) values were all in the micromolar range (1.5-8.1 μM), whereas k(cat) values varied widely (17-220 s(-1)). There were large solvent deuterium isotope effects for all substrates under saturating conditions, suggesting a proton transfer is involved in the rate-limiting step. Pre-steady-state UV-visible scans demonstrated the formation of short-lived intermediates for all compounds. Hammett plots yielded reaction constants (ρ) of -0.34 ± 0.02 and -1.15 ± 0.08 for intermediate formation and breakdown, respectively. Temperature-dependence experiments yielded ΔG(‡) values that were consistent with the Hammett results. These results establish the commonality of the formation of an azanide intermediate in the NDM-1-catalysed hydrolysis of a range cephalosporins with differing electronic properties. This intermediate is a promising target for judiciously designed β-lactam antibiotics that are poor NDM-1 substrates and inhibitors with enhanced active-site residence times.
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Meini MR, Tomatis PE, Weinreich DM, Vila AJ. Quantitative Description of a Protein Fitness Landscape Based on Molecular Features. Mol Biol Evol 2015; 32:1774-87. [PMID: 25767204 DOI: 10.1093/molbev/msv059] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Understanding the driving forces behind protein evolution requires the ability to correlate the molecular impact of mutations with organismal fitness. To address this issue, we employ here metallo-β-lactamases as a model system, which are Zn(II) dependent enzymes that mediate antibiotic resistance. We present a study of all the possible evolutionary pathways leading to a metallo-β-lactamase variant optimized by directed evolution. By studying the activity, stability and Zn(II) binding capabilities of all mutants in the preferred evolutionary pathways, we show that this local fitness landscape is strongly conditioned by epistatic interactions arising from the pleiotropic effect of mutations in the different molecular features of the enzyme. Activity and stability assays in purified enzymes do not provide explanatory power. Instead, measurement of these molecular features in an environment resembling the native one provides an accurate description of the observed antibiotic resistance profile. We report that optimization of Zn(II) binding abilities of metallo-β-lactamases during evolution is more critical than stabilization of the protein to enhance fitness. A global analysis of these parameters allows us to connect genotype with fitness based on quantitative biochemical and biophysical parameters.
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Affiliation(s)
- María-Rocío Meini
- Laboratory of Metalloproteins, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) and Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Pablo E Tomatis
- Laboratory of Metalloproteins, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) and Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Daniel M Weinreich
- Department of Ecology and Evolutionary Biology, and Center for Computational Molecular Biology, Brown University
| | - Alejandro J Vila
- Laboratory of Metalloproteins, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) and Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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32
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Brem J, Struwe WB, Rydzik AM, Tarhonskaya H, Pfeffer I, Flashman E, van Berkel SS, Spencer J, Claridge TDW, McDonough MA, Benesch JLP, Schofield CJ. Studying the active-site loop movement of the São Paolo metallo-β-lactamase-1†Electronic supplementary information (ESI) available: Procedures for protein expression and purification, 19F-labelling, crystallisation, data collection, and structure determination, table of crystallographic data, table of crystallographic parameters and refinement statistics, figures showing binding mode and distances, procedures for mass spectrometry measurements, differential scanning fluorimetry measurements, stopped-flow measurements and other kinetics measurements. See DOI: 10.1039/c4sc01752hClick here for additional data file. Chem Sci 2015; 6:956-963. [PMID: 25717359 PMCID: PMC4333608 DOI: 10.1039/c4sc01752h] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/24/2014] [Indexed: 11/21/2022] Open
Abstract
Metallo-β-lactamases (MBLs) catalyse the hydrolysis of almost all β-lactam antibiotics. We report biophysical and kinetic studies on the São Paulo MBL (SPM-1), which reveal its Zn(ii) ion usage and mechanism as characteristic of the clinically important di-Zn(ii) dependent B1 MBL subfamily. Biophysical analyses employing crystallography, dynamic 19F NMR and ion mobility mass spectrometry, however, reveal that SPM-1 possesses loop and mobile element regions characteristic of the B2 MBLs. These include a mobile α3 region which is important in catalysis and determining inhibitor selectivity. SPM-1 thus appears to be a hybrid B1/B2 MBL. The results have implications for MBL evolution and inhibitor design.
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Affiliation(s)
- Jürgen Brem
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Weston B Struwe
- Department of Chemistry , Physical and Theoretical Chemistry Laboratory , University of Oxford , South Parks Road , Oxford , OX1 3QZ , UK .
| | - Anna M Rydzik
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Hanna Tarhonskaya
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Inga Pfeffer
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Emily Flashman
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Sander S van Berkel
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - James Spencer
- School of Cellular and Molecular Medicine , University of Bristol , Medical Sciences Building , Bristol , BS8 1TD , UK
| | - Timothy D W Claridge
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Michael A McDonough
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
| | - Justin L P Benesch
- Department of Chemistry , Physical and Theoretical Chemistry Laboratory , University of Oxford , South Parks Road , Oxford , OX1 3QZ , UK .
| | - Christopher J Schofield
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK .
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33
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Theoretical studies of the hydrolysis of antibiotics catalyzed by a metallo-β-lactamase. Arch Biochem Biophys 2015; 582:116-26. [PMID: 25622886 DOI: 10.1016/j.abb.2015.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 12/27/2022]
Abstract
In this paper, hybrid QM/MM molecular dynamics (MD) simulations have been performed to explore the mechanisms of hydrolysis of two antibiotics, Imipenen (IMI), an antibiotic belonging to the subgroup of carbapenems, and the Cefotaxime (CEF), a third-generation cephalosporin antibiotic, in the active site of a mono-nuclear β-lactamase, CphA from Aeromonas hydrophila. Significant different transition state structures are obtained for the hydrolysis of both antibiotics: while the TS of the CEF is an ionic species with negative charge on nitrogen, the IMI TS presents a tetrahedral-like character with negative charge on oxygen atom of the carbonyl group of the lactam ring. Thus, dramatic conformational changes can take place in the cavity of CphA to accommodate different substrates, which would be the origin of its substrate promiscuity. Since CphA shows only activity against carbapenem antibiotic, this study sheds some light into the origin of the selectivity of the different MbL and, as a consequence, into the discovery of specific and potent MβL inhibitors against a broad spectrum of bacterial pathogens. We have finally probed that a re-parametrization of semiempirical methods should be done to properly describe the behavior the metal cation in active site, Zn(2+), when used in QM/MM calculations.
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34
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Daumann LJ, Schenk G, Gahan LR. Metallo-β-lactamases and Their Biomimetic Complexes. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Yang H, Aitha M, Marts AR, Hetrick A, Bennett B, Crowder MW, Tierney DL. Spectroscopic and mechanistic studies of heterodimetallic forms of metallo-β-lactamase NDM-1. J Am Chem Soc 2014; 136:7273-85. [PMID: 24754678 PMCID: PMC4046764 DOI: 10.1021/ja410376s] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Indexed: 11/29/2022]
Abstract
In an effort to characterize the roles of each metal ion in metallo-β-lactamase NDM-1, heterodimetallic analogues (CoCo-, ZnCo-, and CoCd-) of the enzyme were generated and characterized. UV-vis, (1)H NMR, EPR, and EXAFS spectroscopies were used to confirm the fidelity of the metal substitutions, including the presence of a homogeneous, heterodimetallic cluster, with a single-atom bridge. This marks the first preparation of a metallo-β-lactamase selectively substituted with a paramagnetic metal ion, Co(II), either in the Zn1 (CoCd-NDM-1) or in the Zn2 site (ZnCo-NDM-1), as well as both (CoCo-NDM-1). We then used these metal-substituted forms of the enzyme to probe the reaction mechanism, using steady-state and stopped-flow kinetics, stopped-flow fluorescence, and rapid-freeze-quench EPR. Both metal sites show significant effects on the kinetic constants, and both paramagnetic variants (CoCd- and ZnCo-NDM-1) showed significant structural changes on reaction with substrate. These changes are discussed in terms of a minimal kinetic mechanism that incorporates all of the data.
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Affiliation(s)
- Hao Yang
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Mahesh Aitha
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Amy R. Marts
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Alyssa Hetrick
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Brian Bennett
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Michael W. Crowder
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - David L. Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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36
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37
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Meini MR, González LJ, Vila AJ. Antibiotic resistance in Zn(II)-deficient environments: metallo-β-lactamase activation in the periplasm. Future Microbiol 2014; 8:947-79. [PMID: 23902139 DOI: 10.2217/fmb.13.34] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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38
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Motara H, Mistry D, Brown DR, Cryan RA, Nigen M, Page MI. pH and basicity of ligands control the binding of metal-ions to B. cereus B1 β-lactamase. Chem Sci 2014. [DOI: 10.1039/c4sc00601a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metallo-β-lactamases (MBLs) are a group of enzymes responsible for a significant proportion of bacterial resistance to β-lactam antibiotics by catalysing the hydrolysis of the β-lactam.
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Affiliation(s)
- Hasina Motara
- IPOS
- The Page Laboratories
- Department of Chemical and Biological Sciences
- The University of Huddersfield
- Huddersfield, UK
| | - Dharmit Mistry
- IPOS
- The Page Laboratories
- Department of Chemical and Biological Sciences
- The University of Huddersfield
- Huddersfield, UK
| | - David R. Brown
- IPOS
- The Page Laboratories
- Department of Chemical and Biological Sciences
- The University of Huddersfield
- Huddersfield, UK
| | - Robert A. Cryan
- IPOS
- The Page Laboratories
- Department of Chemical and Biological Sciences
- The University of Huddersfield
- Huddersfield, UK
| | - Michaël Nigen
- Centre d'Ingénierie des Protéines
- Institut de Chimie B6
- Université de Liège
- B-4000 Liège, Belgium
| | - Michael I. Page
- IPOS
- The Page Laboratories
- Department of Chemical and Biological Sciences
- The University of Huddersfield
- Huddersfield, UK
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Identification and characterization of an unusual metallo-β-lactamase from Serratia proteamaculans. J Biol Inorg Chem 2013; 18:855-63. [DOI: 10.1007/s00775-013-1035-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/14/2013] [Indexed: 11/25/2022]
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40
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Daumann LJ, Larrabee JA, Comba P, Schenk G, Gahan LR. Dinuclear Cobalt(II) Complexes as Metallo-β-lactamase Mimics. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201300280] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Abstract
MβL (metallo-β-lactamase) enzymes are usually produced by multi-resistant Gram-negative bacterial strains and have spread worldwide. An approach on the basis of phage display was used to select single-domain antibody fragments (VHHs, also called nanobodies) that would inhibit the clinically relevant VIM (Verona integron-encoded MβL)-4 MβL. Out of more than 50 selected nanobodies, only the NbVIM_38 nanobody inhibited VIM-4. The paratope, inhibition mechanism and epitope of the NbVIM_38 nanobody were then characterized. An alanine scan of the NbVIM_38 paratope showed that its binding was driven by hydrophobic amino acids. The inhibitory concentration was in the micromolar range for all β-lactams tested. In addition, the inhibition was found to follow a mixed hyperbolic profile with a predominantly uncompetitive component. Moreover, substrate inhibition was recorded only after nanobody binding. These kinetic data are indicative of a binding site that is distant from the active site. This finding was confirmed by epitope mapping analysis that was performed using peptides, and which identified two stretches of amino acids in the L6 loop and at the end of the α2 helix. Because this binding site is distant from the active site and alters both the substrate binding and catalytic properties of VIM-4, this nanobody can be considered as an allosteric inhibitor.
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Biapenem inactivation by B2 metallo β-lactamases: energy landscape of the hydrolysis reaction. PLoS One 2013; 8:e55136. [PMID: 23372827 PMCID: PMC3556986 DOI: 10.1371/journal.pone.0055136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 12/18/2012] [Indexed: 11/26/2022] Open
Abstract
Background A general mechanism has been proposed for metallo β-lactamases (MβLs), in which deprotonation of a water molecule near the Zn ion(s) results in the formation of a hydroxide ion that attacks the carbonyl oxygen of the β-lactam ring. However, because of the absence of X-ray structures that show the exact position of the antibiotic in the reactant state (RS) it has been difficult to obtain a definitive validation of this mechanism. Methodology/Principal Findings We have employed a strategy to identify the RS, which does not rely on substrate docking and/or molecular dynamics. Starting from the X-ray structure of the enzyme:product complex (the product state, PS), a QM/MM scan was used to drive the reaction uphill from product back to reactant. Since in this process also the enzyme changes from PS to RS, we actually generate the enzyme:substrate complex from product and avoid the uncertainties associated with models of the reactant state. We used this strategy to study the reaction of biapenem hydrolysis by B2 MβL CphA. QM/MM simulations were carried out under 14 different ionization states of the active site, in order to generate potential energy surfaces (PESs) corresponding to a variety of possible reaction paths. Conclusions/Significance The calculations support a model for biapenem hydrolysis by CphA, in which the nucleophile that attacks the β-lactam ring is not the water molecule located in proximity of the active site Zn, but a second water molecule, hydrogen bonded to the first one, which is used up in the reaction, and thus is not visible in the X-ray structure of the enzyme:product complex.
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Abstract
β-Lactam antibiotics are the most commonly used antibacterial agents and growing resistance to these drugs is a concern. Metallo-β-lactamases are a diverse set of enzymes that catalyze the hydrolysis of a broad range of β-lactam drugs including carbapenems. This diversity is reflected in the observation that the enzyme mechanisms differ based on whether one or two zincs are bound in the active site that, in turn, is dependent on the subclass of β-lactamase. The dissemination of the genes encoding these enzymes among Gram-negative bacteria has made them an important cause of resistance. In addition, there are currently no clinically available inhibitors to block metallo-β-lactamase action. This review summarizes the numerous studies that have yielded insights into the structure, function, and mechanism of action of these enzymes.
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Affiliation(s)
- Timothy Palzkill
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030, USA.
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Lisa MN, Morán-Barrio J, Guindón MF, Vila AJ. Probing the role of Met221 in the unusual metallo-β-lactamase GOB-18. Inorg Chem 2012; 51:12419-25. [PMID: 23113650 DOI: 10.1021/ic301801h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metallo-β-lactamases (MβLs) are the main mechanism of bacterial resistance against last generation β-lactam antibiotics such as carbapenems. Most MβLs display unusual structural features in their active sites, such as binuclear zinc centers without carboxylate bridging ligands and/or a Cys ligand in a catalytic zinc site. Cys221 is an essential residue for catalysis conserved in B1 and B2 lactamases, while most B3 enzymes present a Ser in this position. GOB lactamases stand as an exception within this picture, with a Met residue in position 221. Then, we obtained a series of GOB-18 point mutants in order to analyze the role of this unusual Met221 residue. We found that Met221 is essential for the protein stability, most likely due to its involvement in a hydrophobic core. In contrast to other known MβLs, residue 221 is not involved in metal binding or in catalysis in GOB enzymes, according to spectroscopic and kinetic studies. Our findings show that the essential catalytic features are maintained despite the structural heterogeneity among MβLs and suggest that a strategy to design general inhibitors should be undertaken on the basis of mechanistic rather than structural information.
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Affiliation(s)
- María-Natalia Lisa
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR) and Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, Predio CONICET Rosario, 2000 Rosario, Argentina
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A potential substrate binding conformation of β-lactams and insight into the broad spectrum of NDM-1 activity. Antimicrob Agents Chemother 2012; 56:5157-63. [PMID: 22825119 DOI: 10.1128/aac.05896-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New Delhi metallo-β-lactamase 1 (NDM-1) is a key enzyme that the pathogen Klebsiella pneumonia uses to hydrolyze almost all β-lactam antibiotics. It is currently unclear why NDM-1 has a broad spectrum of activity. Docking of the representatives of the β-lactam families into the active site of NDM-1 is reported here. All the β-lactams naturally fit the NDM-1 pocket, implying that NDM-1 can accommodate the substrates without dramatic conformation changes. The docking reveals two major binding modes of the β-lactams, which we tentatively name the S (substrate) and I (inhibitor) conformers. In the S conformers of all the β-lactams, the amide oxygen and the carboxylic group conservatively interact with two zinc ions, while the substitutions on the fused rings show dramatic differences in their conformations and positions. Since the bridging hydroxide ion/water in the S conformer is at the position for the nucleophilic attack, the S conformation may simulate the true binding of a substrate to NDM-1. The I conformer either blocks or displaces the bridging hydroxide ion/water, such as in the case of aztreonam, and is thus inhibitory. The docking also suggests that substitutions on the β-lactam ring are required for β-lactams to bind in the S conformation, and therefore, small β-lactams such as clavulanic acid would be inhibitors of NDM-1. Finally, our docking shows that moxalactam uses its tyrosyl-carboxylic group to compete with the S conformer and would thus be a poor substrate of NDM-1.
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Metallo-β-lactamases withstand low Zn(II) conditions by tuning metal-ligand interactions. Nat Chem Biol 2012; 8:698-700. [PMID: 22729148 PMCID: PMC3470787 DOI: 10.1038/nchembio.1005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 05/14/2012] [Indexed: 11/25/2022]
Abstract
A number of multiresistant bacterial pathogens inactivate antibiotics by producing ZnII-dependent β-lactamases. We show that metal uptake leading to an active dinuclear enzyme in the periplasmic space of Gram-negative bacteria is ensured by a cysteine residue, an unusual metal ligand in oxidizing environments. Kinetic, structural and affinity data show that such ZnII-Cys interaction is an adaptive trait tuning the metal binding affinity, thus enabling antibiotic resistance at restrictive ZnII concentrations.
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Crystal structure of the mobile metallo-β-lactamase AIM-1 from Pseudomonas aeruginosa: insights into antibiotic binding and the role of Gln157. Antimicrob Agents Chemother 2012; 56:4341-53. [PMID: 22664968 DOI: 10.1128/aac.00448-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Metallo-β-lactamase (MBL) genes confer resistance to virtually all β-lactam antibiotics and are rapidly disseminated by mobile genetic elements in Gram-negative bacteria. MBLs belong to three different subgroups, B1, B2, and B3, with the mobile MBLs largely confined to subgroup B1. The B3 MBLs are a divergent subgroup of predominantly chromosomally encoded enzymes. AIM-1 (Adelaide IMipenmase 1) from Pseudomonas aeruginosa was the first B3 MBL to be identified on a readily mobile genetic element. Here we present the crystal structure of AIM-1 and use in silico docking and quantum mechanics and molecular mechanics (QM/MM) calculations, together with site-directed mutagenesis, to investigate its interaction with β-lactams. AIM-1 adopts the characteristic αβ/βα sandwich fold of MBLs but differs from other B3 enzymes in the conformation of an active site loop (residues 156 to 162) which is involved both in disulfide bond formation and, we suggest, interaction with substrates. The structure, together with docking and QM/MM calculations, indicates that the AIM-1 substrate binding site is narrower and more restricted than those of other B3 MBLs, possibly explaining its higher catalytic efficiency. The location of Gln157 adjacent to the AIM-1 zinc center suggests a role in drug binding that is supported by our in silico studies. However, replacement of this residue by either Asn or Ala resulted in only modest reductions in AIM-1 activity against the majority of β-lactam substrates, indicating that this function is nonessential. Our study reveals AIM-1 to be a subclass B3 MBL with novel structural and mechanistic features.
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Yang H, Aitha M, Hetrick AM, Richmond TK, Tierney DL, Crowder MW. Mechanistic and spectroscopic studies of metallo-β-lactamase NDM-1. Biochemistry 2012; 51:3839-47. [PMID: 22482529 DOI: 10.1021/bi300056y] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an effort to biochemically characterize metallo-β-lactamase NDM-1, we cloned, overexpressed, purified, and characterized several maltose binding protein (MBP)-NDM-1 fusion proteins with different N-termini (full-length, Δ6, Δ21, and Δ36). All MBP-NDM-1 fusion proteins were soluble; however, only one, MBP-NDM-1Δ36, exhibited high activity and bound 2 equiv of Zn(II). Thrombin cleavage of this fusion protein resulted in the truncated NDM-1Δ36 variant, which exhibited a k(cat) of 16 s(-1) and a K(m) of 1.1 μM when using nitrocefin as a substrate, bound 2 equiv of Zn(II), and was monomeric in solution. Extended X-ray absorption fine structure studies of the NDM-1Δ36 variant indicate the average metal binding site for Zn(II) in this variant consists of four N/O donors (two of which are histidines) and 0.5 sulfur donor per zinc, with a Zn-Zn distance of 3.38 Å. This metal binding site is very similar to those of other metallo-β-lactamases that belong to the B1 subclass. Pre-steady-state kinetic studies using nitrocefin and chromacef and the NDM-1Δ36 variant indicate that the enzyme utilizes a kinetic mechanism similar to that used by metallo-β-lactamases L1 and CcrA, in which a reactive nitrogen anion is stabilized and its protonation is rate-limiting. While they are very different in terms of amino acid sequence, these studies demonstrate that NDM-1 is structurally and mechanistically very similar to metallo-β-lactamase CcrA.
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Affiliation(s)
- Hao Yang
- Department of Chemistry and Biochemistry, 160 Hughes Hall, Miami University, Oxford, Ohio 45056, USA
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Sgrignani J, Magistrato A, Dal Peraro M, Vila AJ, Carloni P, Pierattelli R. On the active site of mononuclear B1 metallo β-lactamases: a computational study. J Comput Aided Mol Des 2012; 26:425-35. [PMID: 22532071 DOI: 10.1007/s10822-012-9571-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 04/09/2012] [Indexed: 11/28/2022]
Abstract
Metallo-β-lactamases (MβLs) are Zn(II)-based bacterial enzymes that hydrolyze β-lactam antibiotics, hampering their beneficial effects. In the most relevant subclass (B1), X-ray crystallography studies on the enzyme from Bacillus Cereus point to either two zinc ions in two metal sites (the so-called '3H' and 'DCH' sites) or a single Zn(II) ion in the 3H site, where the ion is coordinated by Asp120, Cys221 and His263 residues. However, spectroscopic studies on the B1 enzyme from B. Cereus in the mono-zinc form suggested the presence of the Zn(II) ion also in the DCH site, where it is bound to an aspartate, a cysteine, a histidine and a water molecule. A structural model of this enzyme in its DCH mononuclear form, so far lacking, is therefore required for inhibitor design and mechanistic studies. By using force field based and mixed quantum-classical (QM/MM) molecular dynamics (MD) simulations of the protein in aqueous solution we constructed such structural model. The geometry and the H-bond network at the catalytic site of this model, in the free form and in complex with two common β-lactam drugs, is compared with experimental and theoretical findings of CphA and the recently solved crystal structure of new B2 MβL from Serratia fonticola (Sfh-I). These are MβLs from the B2 subclass, which features an experimentally well established mono-zinc form, in which the Zn(II) is located in the DCH site. From our simulations the εεδ and δεδ protomers emerge as possible DCH mono-zinc reactive species, giving a novel contribution to the discussion on the MβL reactivity and to the drug design process.
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Affiliation(s)
- Jacopo Sgrignani
- CERM and Department of Chemistry Ugo Schiff, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
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Breece RM, Llarrull LI, Tioni MF, Vila AJ, Tierney DL. X-ray absorption spectroscopy of metal site speciation in the metallo-β-lactamase BcII from Bacillus cereus. J Inorg Biochem 2012; 111:182-6. [PMID: 22381913 DOI: 10.1016/j.jinorgbio.2011.12.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 01/25/2023]
Abstract
Cobalt and zinc binding by the subclass B1 metallo-β-lactamase BcII from Bacillus cereus is examined by X-ray absorption spectroscopy, at various levels of metal loading. The data show that a significant amount of the dinuclear enzyme is formed, even at substoichiometric levels of metal loading, whether the added metal is Zn(II) or Co(II). Increasing metal addition, from 0.5 to 1.0 to 2.0eq/mol of enzyme, are shown to result in a more ordered active site. While Zn(II) appears to show no preference for the Zn(1) (3H) or Zn(2) (DCH) sites, the extended X-ray absorption fine structure (EXAFS) suggests that Co(II) shows a slight preference for the DCH site at low levels of added Co(II). The results are discussed in the context of similar metal-binding studies of other B1 metallo-β-lactamases.
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Affiliation(s)
- Robert M Breece
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, United States
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