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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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2
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Vogiatzis KD, Polynski MV, Kirkland JK, Townsend J, Hashemi A, Liu C, Pidko EA. Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities. Chem Rev 2019; 119:2453-2523. [PMID: 30376310 PMCID: PMC6396130 DOI: 10.1021/acs.chemrev.8b00361] [Citation(s) in RCA: 214] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Indexed: 12/28/2022]
Abstract
Computational chemistry provides a versatile toolbox for studying mechanistic details of catalytic reactions and holds promise to deliver practical strategies to enable the rational in silico catalyst design. The versatile reactivity and nontrivial electronic structure effects, common for systems based on 3d transition metals, introduce additional complexity that may represent a particular challenge to the standard computational strategies. In this review, we discuss the challenges and capabilities of modern electronic structure methods for studying the reaction mechanisms promoted by 3d transition metal molecular catalysts. Particular focus will be placed on the ways of addressing the multiconfigurational problem in electronic structure calculations and the role of expert bias in the practical utilization of the available methods. The development of density functionals designed to address transition metals is also discussed. Special emphasis is placed on the methods that account for solvation effects and the multicomponent nature of practical catalytic systems. This is followed by an overview of recent computational studies addressing the mechanistic complexity of catalytic processes by molecular catalysts based on 3d metals. Cases that involve noninnocent ligands, multicomponent reaction systems, metal-ligand and metal-metal cooperativity, as well as modeling complex catalytic systems such as metal-organic frameworks are presented. Conventionally, computational studies on catalytic mechanisms are heavily dependent on the chemical intuition and expert input of the researcher. Recent developments in advanced automated methods for reaction path analysis hold promise for eliminating such human-bias from computational catalysis studies. A brief overview of these approaches is presented in the final section of the review. The paper is closed with general concluding remarks.
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Affiliation(s)
| | | | - Justin K. Kirkland
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jacob Townsend
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ali Hashemi
- Inorganic
Systems Engineering group, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Chong Liu
- Inorganic
Systems Engineering group, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Evgeny A. Pidko
- TheoMAT
group, ITMO University, Lomonosova 9, St. Petersburg 191002, Russia
- Inorganic
Systems Engineering group, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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3
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Yue X, Qi X, Bai R, Lei A, Lan Y. Mononuclear or Dinuclear? Mechanistic Study of the Zinc-Catalyzed Oxidative Coupling of Aldehydes and Acetylenes. Chemistry 2017; 23:6419-6425. [DOI: 10.1002/chem.201700733] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Xiaoyu Yue
- School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 400030 P. R. China
| | - Xiaotian Qi
- School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 400030 P. R. China
- College of Chemistry and Molecular Sciences; Wuhan University, Wuhan; 430072 Hubei P. R. China
| | - Ruopeng Bai
- School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 400030 P. R. China
| | - Aiwen Lei
- College of Chemistry and Molecular Sciences; Wuhan University, Wuhan; 430072 Hubei P. R. China
| | - Yu Lan
- School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 400030 P. R. China
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Blumberger J, Lamoureux G, Klein ML. Peptide Hydrolysis in Thermolysin: Ab Initio QM/MM Investigation of the Glu143-Assisted Water Addition Mechanism. J Chem Theory Comput 2015; 3:1837-50. [PMID: 26627626 DOI: 10.1021/ct7000792] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Thermolysin (TLN) is one of the best-studied zinc metalloproteases. Yet the mechanism of action is still under debate. In order to investigate the energetic feasibility of the currently most favored mechanism, we have docked a tripeptide to the active site of TLN and computed the free energy profile at the quantum mechanics/molecular mechanics level of theory. The mechanism consists of three distinct steps: (i) a Zn-bound water molecule is deprotonated by Glu143 and attacks the carbonyl bond of the substrate; (ii) Glu143 transfers the proton to the amide nitrogen atom; (iii) the nitrogen atom is protonated and the peptide bond is irreversibly broken. The free energy barriers for steps i and iii have almost equal heights, 14.8 and 14.7 kcal/mol, respectively, and are in good agreement with the effective experimental activation barrier obtained for similar substrates, 12.1-13.6 kcal/mol. Transition state stabilization for nucleophilic attack is achieved by formation of a weak coordination bond between the substrate carbonyl oxygen atom and the Zn ion and of three strong hydrogen bonds between the substrate and protonated His231 and two solvent molecules. The transition state for the nucleophilic attack (step i) is more tightly bonded than the enzyme-substrate complex, implying that TLN complies with Pauling's hypothesis regarding transition-state stabilization. Glu143, at first unfavorably oriented for protonation of the amide nitrogen atom, displayed large structural fluctuations that facilitated reorganization of the local hydrogen-bond network and transport of the proton to the leaving group on the nanosecond time scale. The present simulations give further evidence that Glu143 is a highly effective proton shuttle which should be assigned a key role in any reaction mechanism proposed for TLN.
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Affiliation(s)
- Jochen Blumberger
- Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104-6323
| | - Guillaume Lamoureux
- Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104-6323
| | - Michael L Klein
- Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104-6323
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Recognition of multiepitope dendrimeric antigens by human immunoglobulin E. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2015; 11:579-88. [DOI: 10.1016/j.nano.2015.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/22/2014] [Accepted: 01/14/2015] [Indexed: 12/14/2022]
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6
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Vidossich P, Magistrato A. QM/MM molecular dynamics studies of metal binding proteins. Biomolecules 2014; 4:616-45. [PMID: 25006697 PMCID: PMC4192665 DOI: 10.3390/biom4030616] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 11/16/2022] Open
Abstract
Mixed quantum-classical (quantum mechanical/molecular mechanical (QM/MM)) simulations have strongly contributed to providing insights into the understanding of several structural and mechanistic aspects of biological molecules. They played a particularly important role in metal binding proteins, where the electronic effects of transition metals have to be explicitly taken into account for the correct representation of the underlying biochemical process. In this review, after a brief description of the basic concepts of the QM/MM method, we provide an overview of its capabilities using selected examples taken from our work. Specifically, we will focus on heme peroxidases, metallo-β-lactamases, α-synuclein and ligase ribozymes to show how this approach is capable of describing the catalytic and/or structural role played by transition (Fe, Zn or Cu) and main group (Mg) metals. Applications will reveal how metal ions influence the formation and reduction of high redox intermediates in catalytic cycles and enhance drug metabolism, amyloidogenic aggregate formation and nucleic acid synthesis. In turn, it will become manifest that the protein frame directs and modulates the properties and reactivity of the metal ions.
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Affiliation(s)
- Pietro Vidossich
- Department of Chemistry, Autonomous University of Barcelona, 08193 Cerdanyola del Vallés, Spain.
| | - Alessandra Magistrato
- CNR-IOM-Democritos National Simulation Center c/o, International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34165 Trieste, Italy.
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7
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Grigorenko BL, Khrenova MG, Nilov DK, Nemukhin AV, Švedas VK. Catalytic Cycle of Penicillin Acylase from Escherichia coli: QM/MM Modeling of Chemical Transformations in the Enzyme Active Site upon Penicillin G Hydrolysis. ACS Catal 2014. [DOI: 10.1021/cs5002898] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Bella L. Grigorenko
- Chemistry
Department, Lomonosov Moscow State University, 1-3 Leninskiye Gory, Moscow 119991, Russia
- Emanuel
Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119991, Russia
| | - Maria G. Khrenova
- Chemistry
Department, Lomonosov Moscow State University, 1-3 Leninskiye Gory, Moscow 119991, Russia
| | - Dmitry K. Nilov
- Belozersky
Institute of Physicochemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Alexander V. Nemukhin
- Chemistry
Department, Lomonosov Moscow State University, 1-3 Leninskiye Gory, Moscow 119991, Russia
- Emanuel
Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119991, Russia
| | - Vytas K. Švedas
- Belozersky
Institute of Physicochemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
- Faculty
of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 1-73 Leninskie Gory, Moscow 119991, Russia
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8
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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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10
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Chen J, Chen H, Zhu T, Zhou D, Zhang F, Lao X, Zheng H. Asp120Asn mutation impairs the catalytic activity of NDM-1 metallo-β-lactamase: experimental and computational study. Phys Chem Chem Phys 2014; 16:6709-16. [PMID: 24584846 DOI: 10.1039/c3cp55069a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New Delhi metallo-β-lactamase-1 (NDM-1) has attracted extensive attention in recent years for its high activity for hydrolyzing almost all β-lactam antibiotics. Like other metallo-β-lactamases (MβLs), NDM-1 features an invariant Asp120 that ligates the zinc ion (ZN2) in the active site. Previous studies showed that substitutions of Asp120 with residues such as Ala, Ser, Asn and Glu dramatically impaired the MβL (BcII, IMP-1, L1) activity, but no consensus about the exact role of Asp120 has reached. Here we constructed D120N mutant of NDM-1 by site-directed mutagenesis. The replacement of Asp120 with Asn, which has much weaker metal ligating capabilities than Asp, severely impaired the lactamase activity without abolishing the ZN2 site. Molecular dynamics simulations suggested that the ZN1-ZN2 distance increased because of mutation, leading to a rearrangement of the active site, including the bridging OH(-). Thereby, the Mulliken charges of ZN1 and ZN2 redistributed, especially for ZN2, which might be the major cause of the impaired activity. Reducing the point charges of Asp120 carboxyl oxygens weakened the ionic interactions between Asp120 and ZN2, and the positions of the zinc ions were also changed as a result. It is proposed that Asp120 acts as a strong ZN2 ligand, positioning ZN2 for catalytically important interactions with the substrate, stabilizing the negatively charged amide nitrogen of the hydrolyzed intermediate, and more importantly, orienting the ZN-bound OH(-) for nucleophilic attacks and protonation. These functions are of general importance for catalyzing β-lactam antibiotics by NDM-1 as well as other MβLs.
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Affiliation(s)
- Jiao Chen
- School of Life Science and Technology, China Pharmaceutical University, China.
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11
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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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12
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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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13
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GU WEI, ZHU JIANG, LIU HAIYAN. DIFFERENT PROTONATION STATES OF THE BACILLUS CEREUS BINUCLEAR ZINC METALLO-β-LACTAMASE ACTIVE SITE STUDIED BY COMBINED QUANTUM MECHANICAL AND MOLECULAR MECHANICAL SIMULATIONS. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2012. [DOI: 10.1142/s0219633602000038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Three different protonation states of the active site of the Bacillus cereus zinc-β-lactamase in its binuclear form are studied using combined quantum mechanics/molecular mechanics molecular dynamics simulations. The reliability of the quantum mechanical model, the self-consistent-charge density-functional-based tight binding method, in describing the zinc centers are tested through comparisons with ab initio quantum mechanical results. We found that this model gave relatively accurate results for structures and performed much better than the MNDO type semi-empirical method for the particular systems. The enzyme simulations suggested that when the overall charge of the active site is +1, i.e., both Asp90 and Wat1 (a water molecule coordinated with the first zinc ion) deprotonated, the second zinc ion is coordinated with Asp90 and Wat1, and a second water molecule cannot coordinate with the second zinc ion. When the overall charge is +2, i.e., either Asp90 or Wat1 protonated, Asp90 and Wat1 form a stable hydrogen bond. Depending on the proton being on Asp90 or on Wat1, the active site structure produced by the simulations is either similar to molecule A or to molecule B, both contained in the same crystal structure that has two enzyme molecules in a single asymmetric unit. The simulations of the +2 charge states also reproduced the experimentally observed "loose" coordination around the second zinc for the Bacillus Cereus enzyme. Based on the simulations and a gas phase potential energy surface scanning using ab initio model, we argue that the penta-coordination around the second zinc ion is not a stable arrangement. Mechanistic implications of these results are discussed.
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Affiliation(s)
- WEI GU
- School of Life Science, University of Science and Technology of China (USTC), Laboratory of Structural Biology, Chinese Academy of Science (CAS), USTC, Hefei, Anhui, 230026, China
| | - JIANG ZHU
- School of Life Science, University of Science and Technology of China (USTC), Laboratory of Structural Biology, Chinese Academy of Science (CAS), USTC, Hefei, Anhui, 230026, China
| | - HAIYAN LIU
- School of Life Science, University of Science and Technology of China (USTC), Laboratory of Structural Biology, Chinese Academy of Science (CAS), USTC, Hefei, Anhui, 230026, China
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14
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Lee JS, White E, Kim SG, Kim SK. Virtual Screening of Penicillin-derived Inhibitors for the Metallo-β-lactamase from Bacillus cereus. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.12.3644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Peters MB, Yang Y, Wang B, Füsti-Molnár L, Weaver MN, Merz KM. Structural Survey of Zinc Containing Proteins and the Development of the Zinc AMBER Force Field (ZAFF). J Chem Theory Comput 2010; 6:2935-2947. [PMID: 20856692 PMCID: PMC2941202 DOI: 10.1021/ct1002626] [Citation(s) in RCA: 338] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Currently the Protein Data Bank (PDB) contains over 18,000 structures that contain a metal ion including Na, Mg, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd, Ag, Cd, Ir, Pt, Au, and Hg. In general, carrying out classical molecular dynamics (MD) simulations of metalloproteins is a convoluted and time consuming process. Herein, we describe MCPB (Metal Center Parameter Builder), which allows one, to conveniently and rapidly incorporate metal ions using the bonded plus electrostatics model (Hoops et al., J. Am. Chem. Soc. 1991, 113, 8262-8270) into the AMBER Force Field (FF). MCPB was used to develop a Zinc FF, ZAFF, which is compatible with the existing AMBER FFs. The PDB was mined for all Zn containing structures with most being tetrahedrally bound. The most abundant primary shell ligand combinations were extracted and FFs were created. These include Zn bound to CCCC, CCCH, CCHH, CHHH, HHHH, HHHO, HHOO, HOOO, HHHD, and HHDD (O = water and the remaining are 1 letter amino acid codes). Bond and angle force constants and RESP charges were obtained from B3LYP/6-31G* calculations of model structures from the various primary shell combinations. MCPB and ZAFF can be used to create FFs for MD simulations of metalloproteins to study enzyme catalysis, drug design and metalloprotein crystal refinement.
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Affiliation(s)
- Martin B. Peters
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
| | - Yue Yang
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
| | - Bing Wang
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
| | - László Füsti-Molnár
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
| | - Michael N. Weaver
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
| | - Kenneth M. Merz
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, PO Box 118435, University of Florida, Gainesville, Florida 32611-8435
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Oelschlaeger P, Ai N, Duprez KT, Welsh WJ, Toney JH. Evolving carbapenemases: can medicinal chemists advance one step ahead of the coming storm? J Med Chem 2010; 53:3013-27. [PMID: 20121112 DOI: 10.1021/jm9012938] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Oelschlaeger
- Chemistry Department and Center for Macromolecular Modeling and Materials Design, California State Polytechnic University, Pomona, California, USA.
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17
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Lundberg M, Sasakura Y, Zheng G, Morokuma K. Case Studies of ONIOM(DFT:DFTB) and ONIOM(DFT:DFTB:MM) for Enzymes and Enzyme Mimics. J Chem Theory Comput 2010. [DOI: 10.1021/ct100029p] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marcus Lundberg
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan, and Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322
| | - Yoko Sasakura
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan, and Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322
| | - Guishan Zheng
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan, and Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan, and Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322
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18
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Lisa MN, Hemmingsen L, Vila AJ. Catalytic role of the metal ion in the metallo-beta-lactamase GOB. J Biol Chem 2009; 285:4570-7. [PMID: 20007696 DOI: 10.1074/jbc.m109.063743] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metallo-beta-lactamases (MbetaLs) stand as one of the main mechanisms of bacterial resistance toward carbapenems. The rational design of an inhibitor for MbetaLs has been limited by an incomplete knowledge of their catalytic mechanism and by the structural diversity of their active sites. Here we show that the MbetaL GOB from Elizabethkingia meningoseptica is active as a monometallic enzyme by using different divalent transition metal ions as surrogates of the native Zn(II) ion. Of the metal derivatives in which Zn(II) is replaced, Co(II) and Cd(II) give rise to the most active enzymes and are shown to occupy the same binding site as the native ion. However, Zn(II) is the only metal ion capable of stabilizing an anionic intermediate that accumulates during nitrocefin hydrolysis, in which the C-N bond has already been cleaved. This finding demonstrates that the catalytic role of the metal ion in GOB is to stabilize the formation of this intermediate prior to nitrogen protonation. This role may be general to all MbetaLs, whereas nucleophile activation by a Zn(II) ion is not a conserved mechanistic feature.
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Affiliation(s)
- María-Natalia Lisa
- Departamento de Química Biológica and Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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19
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Suárez D, Suárez E, Díaz N. Molecular dynamics and quantum mechanical calculations on the mononuclear zinc-β-lactamase from Bacillus cereus: Protonation state of the active site and imipenem binding. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2008.12.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Simona F, Magistrato A, Dal Peraro M, Cavalli A, Vila AJ, Carloni P. Common mechanistic features among metallo-beta-lactamases: a computational study of Aeromonas hydrophila CphA enzyme. J Biol Chem 2009; 284:28164-28171. [PMID: 19671702 DOI: 10.1074/jbc.m109.049502] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metallo-beta-lactamases (MbetaLs) constitute an increasingly serious clinical threat by giving rise to beta-lactam antibiotic resistance. They accommodate in their catalytic pocket one or two zinc ions, which are responsible for the hydrolysis of beta-lactams. Recent x-ray studies on a member of the mono-zinc B2 MbetaLs, CphA from Aeromonas hydrophila, have paved the way to mechanistic studies of this important subclass, which is selective for carbapenems. Here we have used hybrid quantum mechanical/molecular mechanical methods to investigate the enzymatic hydrolysis by CphA of the antibiotic biapenem. Our calculations describe the entire reaction and point to a new mechanistic description, which is in agreement with the available experimental evidence. Within our proposal, the zinc ion properly orients the antibiotic while directly activating a second catalytic water molecule for the completion of the hydrolytic cycle. This mechanism provides an explanation for a variety of mutagenesis experiments and points to common functional facets across B2 and B1 MbetaLs.
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Affiliation(s)
- Fabio Simona
- Laboratory of Computational Chemistry and Biochemistry, Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Alessandra Magistrato
- CNR-INFM-Democritos National Simulation Center, via Beirut 4, 34014 Grignano, Trieste, Italy; SISSA, Via Beirut 2-4, 34014 Grignano, Trieste, Italy
| | - Matteo Dal Peraro
- Laboratory for Biomolecular Modeling, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, EPFL, CH-1015 Lausanne, Switzerland
| | - Andrea Cavalli
- Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, I-40126 Bologna, Italy; Department of Drug Discovery and Development, Italian Institute of Technology, Via Morego 30, I-16163 Genova, Italy
| | - Alejandro J Vila
- Instituto de BiologiaMolecular y Celular de Rosario, Facultad de Bioquímicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Paolo Carloni
- SISSA, Via Beirut 2-4, 34014 Grignano, Trieste, Italy.
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21
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Oelschlaeger P. Outsmarting metallo-β-lactamases by mimicking their natural evolution. J Inorg Biochem 2008; 102:2043-51. [DOI: 10.1016/j.jinorgbio.2008.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2008] [Revised: 05/20/2008] [Accepted: 05/21/2008] [Indexed: 11/25/2022]
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22
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Hong R, Magistrato A, Carloni P. Anthrax Lethal Factor Investigated by Molecular Simulations. J Chem Theory Comput 2008; 4:1745-56. [DOI: 10.1021/ct8001877] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Rolando Hong
- International School for Advanced Studies (SISSA/ISAS), CNR-INFM-Democritos National Simulation Center, and Italian Institute of Technology (IIT), Trieste, Italy
| | - Alessandra Magistrato
- International School for Advanced Studies (SISSA/ISAS), CNR-INFM-Democritos National Simulation Center, and Italian Institute of Technology (IIT), Trieste, Italy
| | - Paolo Carloni
- International School for Advanced Studies (SISSA/ISAS), CNR-INFM-Democritos National Simulation Center, and Italian Institute of Technology (IIT), Trieste, Italy
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23
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Zinc and antibiotic resistance: metallo-β-lactamases and their synthetic analogues. J Biol Inorg Chem 2008; 13:1039-53. [DOI: 10.1007/s00775-008-0407-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 07/02/2008] [Indexed: 10/21/2022]
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24
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Frison G, Ohanessian G. A comparative study of semiempirical, ab initio, and DFT methods in evaluating metal-ligand bond strength, proton affinity, and interactions between first and second shell ligands in Zn-biomimetic complexes. J Comput Chem 2008; 29:416-33. [PMID: 17631650 DOI: 10.1002/jcc.20800] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Although theoretical methods are now available which give very accurate results, often comparable to the experimental ones, modeling chemical or biological interesting systems often requires less demanding and less accurate theoretical methods, mainly due to computer limitations. Therefore, it is crucial to know the precision of such less reliable methods for relevant models and data. This has been done in this work for small zinc-active site models including O- (H(2)O and OH(-)) and N-donor (NH(3) and imidazole) ligands. Calculations using a number of quantum mechanical methods were carried out to determine their precision for geometries, coordination number relative stability, metal-ligand bond strengths, proton affinities, and interaction energies between first and second shell ligands. We have found that obtaining chemical accuracy can be as straightforward as HF geometry optimization with a double-zeta plus polarization basis followed by a B3LYP energy calculation with a triple-zeta quality basis set including diffuse and polarization functions. The use of levels as low as PM3 geometry optimization followed by a B3LYP single-point energy calculation with a double-zeta quality basis including polarization functions already yields useful trends in bond length, proton affinities or bond dissociation energies, provided that appropriate caution is taken with the optimized structures. The reliability of these levels of calculation has been successfully demonstrated for real biomimetic cases.
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Affiliation(s)
- Gilles Frison
- Laboratoire des Mécanismes Réactionnels, Département de Chimie, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France.
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25
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Simona F, Magistrato A, Vera DMA, Garau G, Vila AJ, Carloni P. Protonation state and substrate binding to B2 metallo-beta-lactamase CphA from Aeromonas hydrofila. Proteins 2007; 69:595-605. [PMID: 17623844 DOI: 10.1002/prot.21476] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The zinc enzymes metallo beta-lactamases counteract the beneficial action of beta-lactam antibiotics against bacterial infections, by hydrolyzing their beta-lactam rings. To understand structure/function relationships on a representative member of this class, the B2 M beta L CphA, we have investigated the H-bond pattern at the Zn enzymatic active site and substrate binding mode by molecular simulation methods. Extensive QM calculations at the DFT-BLYP level on eleven models of the protein active site, along with MD simulations of the protein in aqueous solution, allow us to propose two plausible protonation states for the unbound enzyme, which are probably in equilibrium. Docking procedures along with MD simulations and QM calculations suggest that in the complex between the enzyme and its substrate (biapenem), the latter is stable in only one of the two protonation states, in addition it exhibits two different binding modes, of which only one agrees with previous proposals. In both cases, the substrate is polarized as in aqueous solution. We conclude that addressing mechanistic issues on this class of enzymes requires a careful procedure to assign protonation states and substrate docking modes.
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Affiliation(s)
- F Simona
- SISSA, Via Beirut 2-4, 34014 Grignano, Trieste, Italy
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26
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Estiu G, Suárez D, Merz KM. Quantum mechanical and molecular dynamics simulations of ureases and Zn beta-lactamases. J Comput Chem 2007; 27:1240-62. [PMID: 16773613 DOI: 10.1002/jcc.20411] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Herein we briefly review theoretical contributions that have increased our understanding of the structure and function of metallo-beta-lactamases and ureases. Both are bimetallic metalloenzymes, with the former containing two zinc ions and the latter containing two nickel ions. We describe the use of several different methodologies, including quantum chemical calculations, molecular dynamic simulations, as well as mixed QM/MM approaches and how they have impacted our understanding of the structure and function of metallo-beta-lactamases and ureases.
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Affiliation(s)
- Guillermina Estiu
- Department of Chemistry, Quantum Theory Project, University of Florida, 2328 New Physics Building, P.O. Box 118435, Gainesville, Florida 32611-8435, USA
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27
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Wang C, Guo H. Inhibitor Binding by Metallo-β-lactamase IMP-1 from Pseudomonas aeruginosa: Quantum Mechanical/Molecular Mechanical Simulations. J Phys Chem B 2007; 111:9986-92. [PMID: 17663582 DOI: 10.1021/jp073864g] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dynamics of the IMP-1 enzyme complexed with three prototypical inhibitors are investigated using a quantum mechanical/molecular mechanical (QM/MM) method based on the self-consistent-charge density-functional tight-binding model. The binding patterns of the inhibitors observed in X-ray diffraction experiments are well reproduced in 600 ps molecular dynamics simulations at room temperature. These inhibitors anchor themselves in the enzyme active site by direct coordination with the two zinc ions, displacing the hydroxide nucleophile that bridges the two zinc ions. In addition, they also interact with several active-site residues and those in two mobile loops. The excellent agreement with experimental structural data validates the QM/MM treatment used in our simulations.
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Affiliation(s)
- Canhui Wang
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, USA
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28
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Tamilselvi A, Nethaji M, Mugesh G. Antibiotic resistance: mono- and dinuclear zinc complexes as metallo-beta-lactamase mimics. Chemistry 2007; 12:7797-806. [PMID: 16906495 DOI: 10.1002/chem.200600629] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Biomimetic systems containing one or two zinc(II) ions supported by phenolate ligands were developed as functional mimics of metallo-beta-lactamase. These complexes were shown to catalytically hydrolyze beta-lactam substrates, such as oxacillin and penicillin G. The dinuclear zinc complex 1, which has a coordinated water molecule, exhibits high beta-lactamase activity, whereas the dinuclear zinc complex 2, which has no water molecules, but labile chloride ligands, shows a much lower activity. The high beta-lactamase activity of complex 1 can be ascribed to the presence of a zinc-bound water molecule that is activated by being hydrogen bonded to acetate substituents. The kinetics of the hydrolysis of oxacillin by complex 1 and the effect of pH on the reaction rates are reported in detail. In addition, the kinetic parameters obtained for the synthetic analogues are compared with those of the natural metallo-beta-lactamase from Bacillus cereus (BcII). To understand the role of the second metal ion in hydrolysis, the syntheses and catalytic activities of two mononuclear complexes (3 and 4) that include coordinated water molecules are described. Interestingly, the mononuclear zinc complexes 3 and 4 also exhibit high activity, supporting the assumption that the second zinc ion is not crucial for the beta-lactamase activity.
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Affiliation(s)
- A Tamilselvi
- Department of Inorganic and Physical Chemistry Indian Institute of Science, Bangalore 560 012, India
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29
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Dal Peraro M, Vila AJ, Carloni P, Klein ML. Role of zinc content on the catalytic efficiency of B1 metallo beta-lactamases. J Am Chem Soc 2007; 129:2808-16. [PMID: 17305336 PMCID: PMC2597527 DOI: 10.1021/ja0657556] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metallo beta-lactamases (MbetaL) are enzymes naturally evolved by bacterial strains under the evolutionary pressure of beta-lactam antibiotic clinical use. They have a broad substrate spectrum and are resistant to all the clinically useful inhibitors, representing a potential risk of infection if massively disseminated. The MbetaL scaffold is designed to accommodate one or two zinc ions able to activate a nucleophilic hydroxide for the hydrolysis of the beta-lactam ring. The role of zinc content on the binding and reactive mechanism of action has been the subject of debate and still remains an open issue despite the large amount of data acquired. We report herein a study of the reaction pathway for binuclear CcrA from Bacteroides fragilis using density functional theory based quantum mechanics-molecular mechanics dynamical modeling. CcrA is the prototypical binuclear enzyme belonging to the B1 MbetaL family, which includes several harmful chromosomally encoded and transferable enzymes. The involvement of a second zinc ion in the catalytic mechanism lowers the energetic barrier for beta-lactam hydrolysis, preserving the essential binding features found in mononuclear B1 enzymes (BcII from Bacillus cereus) while providing a more efficient single-step mechanism. Overall, this study suggests that uptake of a second equivalent zinc ion is evolutionary favored.
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Affiliation(s)
- Matteo Dal Peraro
- Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
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30
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Cavalli A, Carloni P, Recanatini M. Target-Related Applications of First Principles Quantum Chemical Methods in Drug Design. Chem Rev 2006; 106:3497-519. [PMID: 16967914 DOI: 10.1021/cr050579p] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrea Cavalli
- Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, I-40126 Bologna, Italy
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31
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Cui G, Wang B, Merz KM. Computational studies of the farnesyltransferase ternary complex part I: substrate binding. Biochemistry 2006; 44:16513-23. [PMID: 16342942 PMCID: PMC2566548 DOI: 10.1021/bi051020m] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Farnesyltransferase (FTase) catalyzes the transfer of farnesyl from farnesyl diphosphate (FPP) to cysteine residues at or near the C-terminus of protein acceptors with a CaaX motif (a, aliphatic; X, Met). Farnesylation is a critical modification to many switch proteins involved in the extracellular signal transduction pathway, which facilitates their fixation on the cell membrane where the extracellular signal is processed. The malfunction caused by mutations in these proteins often causes uncontrolled cell reproduction and leads to tumor formation. FTase inhibitors have been extensively studied as potential anticancer agents in recent years, several of which have advanced to different phases of clinical trials. However, the mechanism of this biologically important enzyme has not been firmly established. Understanding how FTase recruits the FPP substrate is the first and foremost step toward further mechanistic investigations and the design of effective FTase inhibitors. Molecular dynamic simulations were carried out on the ternary structure of FTase complexed with the FPP substrate and an acetyl-capped tetrapeptide (acetyl-CVIM), which revealed that the FPP substrate maintains an inactive conformation and the binding of the diphosphate group can be largely attributed to residues R291beta, K164alpha, K294beta, and H248beta. The FPP substrate assumes an extended conformation in the binding site with restricted rotation of the backbone dihedral angles; however, it does not have a well-defined conformation when unbound in solution. This is evident from multinanosecond MD simulations of the FPP substrate in a vacuum and solution. Our conclusion is further supported by theoretical J coupling calculations. Our results on the FPP binding are in good agreement with previous experimental kinetic studies on FTase mutants. The hypothetical conformational activation of the FPP substrate is currently under investigation.
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Affiliation(s)
- Guanglei Cui
- Department of Chemistry, 104 Chemistry Building, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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32
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Costello A, Periyannan G, Yang KW, Crowder MW, Tierney DL. Site-selective binding of Zn(II) to metallo-beta-lactamase L1 from Stenotrophomonas maltophilia. J Biol Inorg Chem 2006; 11:351-8. [PMID: 16489411 DOI: 10.1007/s00775-006-0083-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 01/20/2006] [Indexed: 11/27/2022]
Abstract
Extended X-ray absorption fine structure studies of the metallo-beta-lactamase L1 from Stenotrophomonas maltophilia containing 1 and 2 equiv of Zn(II) and containing 2 equiv of Zn(II) plus hydrolyzed nitrocefin are presented. The data indicate that the first, catalytically dominant metal ion is bound by L1 at the consensus Zn1 site. The data further suggest that binding of the first metal helps preorganize the ligands for binding of the second metal ion. The di-Zn enzyme displays a well-defined metal-metal interaction at 3.42 A. Reaction with the beta-lactam antibiotic nitrocefin results in a product-bound species, in which the ring-opened lactam rotates in the active site to present the S1 sulfur atom of nitrocefin to one of the metal ions for coordination. The product bridges the two metal ions, with a concomitant lengthening of the Zn-Zn interaction to 3.62 A.
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Affiliation(s)
- Alison Costello
- Department of Chemistry, University of New Mexico, 87131, Albuquerque, NM, USA
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33
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Weston J. Mode of action of bi- and trinuclear zinc hydrolases and their synthetic analogues. Chem Rev 2005; 105:2151-74. [PMID: 15941211 DOI: 10.1021/cr020057z] [Citation(s) in RCA: 272] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennie Weston
- Institut für Organische und Makromolekulare Chemie, Friedrich-Schiller-Universität, Jena, Germany.
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34
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Antony J, Piquemal JP, Gresh N. Complexes of thiomandelate and captopril mercaptocarboxylate inhibitors to metallo-β-lactamase by polarizable molecular mechanics. Validation on model binding sites by quantum chemistry. J Comput Chem 2005; 26:1131-47. [PMID: 15937993 DOI: 10.1002/jcc.20245] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Using the polarizable molecular mechanics method SIBFA, we have performed a search for the most stable binding modes of D- and L-thiomandelate to a 104-residue model of the metallo-beta-lactamase from B. fragilis, an enzyme involved in the acquired resistance of bacteria to antibiotics. Energy balances taking into account solvation effects computed with a continuum reaction field procedure indicated the D-isomer to be more stably bound than the L-one, conform to the experimental result. The most stably bound complex has the S(-) ligand bridging monodentately the two Zn(II) cations and one carboxylate O(-) H-bonded to the Asn193 side chain. We have validated the SIBFA energy results by performing additional SIBFA as well as quantum chemical (QC) calculations on small (88 atoms) model complexes extracted from the 104-residue complexes, which include the residues involved in inhibitor binding. Computations were done in parallel using uncorrelated (HF) as well as correlated (DFT, LMP2, MP2) computations, and the comparisons extended to corresponding captopril complexes (Antony et al., J Comput Chem 2002, 23, 1281). The magnitudes of the SIBFA intermolecular interaction energies were found to correctly reproduce their QC counterparts and their trends for a total of twenty complexes.
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Affiliation(s)
- Jens Antony
- Freie Universität Berlin, FB Mathematik und Informatik, Institut für Mathematik II, AG Biocomputing, Arnimallee 2-6, D-14195 Berlin, Germany
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35
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Gross F, Vahrenkamp H. Reactions of Pyrazolylborate−Zinc−Hydroxide Complexes Related to β-Lactamase Activity. Inorg Chem 2005; 44:4433-40. [PMID: 15934776 DOI: 10.1021/ic050220j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Simple beta-lactams and their hydrolysis products, the beta-amino acids, react with TpZn-OH under deprotonation. The latter become semibidentate carboxylate ligands with a NH...O hydrogen bond, and the former become N-bound beta-lactamide ligands. Likewise the antibiotic derivatives 6-aminopenicillanic acid and 7-aminocephalosporanic acid are incorporated as carboxylate ligands. beta-Lactams bearing nitrophenyl or acyl substituents at the nitrogen atoms are opened hydrolytically by TpZn-OH, and the resulting N-substituted beta-amino acids are attached to zinc by their carboxylate functions. Only with trifluoroacetyl as the N-substituent does the hydrolytic cleavage occur at the external amide bond, yielding the free beta-lactam and TpZn-trifluoroacetate. The kinetic investigation of the opening reactions has shown them to be of second order like all other TpZn-OH-induced hydrolytic cleavages, thereby supporting the four-center mechanism for the monozinc beta-lactamases.
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Affiliation(s)
- Florian Gross
- Institut für Anorganische und Analytische Chemie der Universität Freiburg, Albertstrasse 21, D-79104 Freiburg, Germany
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36
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Fisher JF, Meroueh SO, Mobashery S. Bacterial resistance to beta-lactam antibiotics: compelling opportunism, compelling opportunity. Chem Rev 2005; 105:395-424. [PMID: 15700950 DOI: 10.1021/cr030102i] [Citation(s) in RCA: 684] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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37
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Olsen L, Rasmussen T, Hemmingsen L, Ryde U. Binding of Benzylpenicillin to Metallo-β-lactamase: A QM/MM Study. J Phys Chem B 2004. [DOI: 10.1021/jp0482215] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lars Olsen
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark, Department of Theoretical Chemistry, University of Lund, Chemical Center, P.O.B. 124 S-221 00 Lund, Sweden, and Department of Physics, The Quantum Protein Centre, The Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - T. Rasmussen
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark, Department of Theoretical Chemistry, University of Lund, Chemical Center, P.O.B. 124 S-221 00 Lund, Sweden, and Department of Physics, The Quantum Protein Centre, The Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - L. Hemmingsen
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark, Department of Theoretical Chemistry, University of Lund, Chemical Center, P.O.B. 124 S-221 00 Lund, Sweden, and Department of Physics, The Quantum Protein Centre, The Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - U. Ryde
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark, Department of Theoretical Chemistry, University of Lund, Chemical Center, P.O.B. 124 S-221 00 Lund, Sweden, and Department of Physics, The Quantum Protein Centre, The Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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38
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Rasia RM, Vila AJ. Structural determinants of substrate binding to Bacillus cereus metallo-beta-lactamase. J Biol Chem 2004; 279:26046-51. [PMID: 15140877 DOI: 10.1074/jbc.m311373200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Binding and hydrolysis of the beta-lactams cefotaxime, cephapirin, imipenem, and benzylpenicillin by the metallo-beta-lactamase from Bacillus cereus were studied by presteady state kinetic measurements. In all cases, the substrate was unmodified in the most populated reaction intermediate, and no chemically modified substrate species accumulated to a detectable amount. The cephalosporins tested showed similar formation rate constants for this intermediate, and they differed mostly in their decay rates. Formation of a non-productive enzyme.substrate complex was detected for imipenem. The substrate binding differences can be accounted for by considering the structural features of each substrate. The apoenzyme could not bind any of the substrates, but binding was restored when the apoenzyme was reconstituted with Zn(II), revealing that the metal ions are the main determinants of substrate binding. This evidence is in line with the lack of an optimized substrate recognition patch in B1 and B3 metallo-beta-lactamases that provides a broad substrate spectrum.
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Affiliation(s)
- Rodolfo M Rasia
- Area Biofisica and Instituto de Biologia Molecular y Celular de Rosario, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
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Díaz N, Sordo TL, Suárez D, Méndez R, Martín-Villacorta J. Zn2+catalysed hydrolysis of β-lactams: experimental and theoretical studies on the influence of the β-lactam structure. NEW J CHEM 2004. [DOI: 10.1039/b306799h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Dal Peraro M, Vila AJ, Carloni P. Substrate binding to mononuclear metallo-β-lactamase from Bacillus cereus. Proteins 2003; 54:412-23. [PMID: 14747990 DOI: 10.1002/prot.10554] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Structure and dynamics of substrate binding (cefotaxime) to the catalytic pocket of the mononuclear zinc-beta-lactamase from Bacillus cereus are investigated by molecular dynamics simulations. The calculations, which are based on the hydrogen-bond pattern recently proposed by Dal Peraro et al. (J Biol Inorg Chem 2002; 7:704-712), are carried out for both the free and the complexed enzyme. In the resting state, active site pattern and temperature B-factors are in agreement with crystallographic data. In the complexed form, cefotaxime is accommodated into a stable orientation in the catalytic pocket within the nanosecond timescale, interacting with the enzyme zinc-bound hydroxide and the surrounding loops. The beta-lactam ring remains stable and very close to the hydroxide nucleophile agent, giving a stable representation of the productive enzyme-substrate complex.
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Affiliation(s)
- Matteo Dal Peraro
- International School for Advanced Studies, SISSA and INFM-DEMOCRITOS, Trieste, Italy
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41
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Weltman JK, Loriot GB. Molecular modeling of penicilloate anions: an RHF-SCF analysis. J Mol Model 2003; 9:225-9. [PMID: 12764687 DOI: 10.1007/s00894-003-0131-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2002] [Accepted: 03/19/2003] [Indexed: 10/26/2022]
Abstract
An ab initio restricted Hartree-Fock self-consistent field (RHF-SCF) analysis of penicilloate anions was performed at the TZV level with GAMESS. Geometry optimization was initialized by the semi-empirical AM1 method followed by optimization at the 6-31++G** level. The total energy obtained was -1116.0997 a.u. for the penicilloate amine, -1115.3164 a.u. for the imine, -1115.2969 a.u. for the enamine and -1115.2017 a.u. for the amine that was deprotonated at the thiazolidine nitrogen. Formation of the free thiolate in the imine and enamine anions by deprotonation of the penicilloate amine is associated with: (1) an increase in total energy (2) an increase in the energy of the highest occupied molecular orbital (HOMO) to that of anti-bonding (3) a decrease in chemical hardness (4) an increase in the chemical potential (5) a more negative Mulliken net charge on the sulfur atom and (6) an increase in the Mulliken atomic population on the former thiazolidine sulfur atom in the HOMO. The RHF-SCF analysis presented here suggests a potential role for the thiolate sulfur of penicilloate anions, especially of the imine, as a chemically reactive soft nucleophile.
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Affiliation(s)
- Joel K Weltman
- Department of Medicine, Brown University School of Medicine, Providence, RI 02912, USA.
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42
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García-Saez I, Hopkins J, Papamicael C, Franceschini N, Amicosante G, Rossolini GM, Galleni M, Frère JM, Dideberg O. The 1.5-A structure of Chryseobacterium meningosepticum zinc beta-lactamase in complex with the inhibitor, D-captopril. J Biol Chem 2003; 278:23868-73. [PMID: 12684522 DOI: 10.1074/jbc.m301062200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structure of the class-B beta-lactamase, BlaB, from the pathogenic bacterium, Chryseobacterium meningosepticum, in complex with the inhibitor, d-captopril, has been solved at 1.5-A resolution. The enzyme has the typical alphabeta/betaalpha metallo-beta-lactamase fold and the characteristic two metal binding sites of members of the subclass B1, in which two Zn2+ ions were identified. d-Captopril, a diastereoisomer of the commercial drug, captopril, acts as an inhibitor by displacing the catalytic hydroxyl ion required for antibiotic hydrolysis and intercalating its sulfhydryl group between the two Zn2+ ions. Interestingly, d-captopril is located on one side of the active site cleft. The x-ray structure of the complex of the closely related enzyme, IMP-1, with a mercaptocarboxylate inhibitor, which also contains a sulfhydryl group bound to the two Zn2+ ions, shows the ligand to be located on the opposite side of the active site cleft. A molecule generated by fusion of these two inhibitors would cover the entire cleft, suggesting an interesting approach to the design of highly specific inhibitors.
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Affiliation(s)
- Isabel García-Saez
- Laboratoire de Cristallographie Macromoléculaire, Institut de Biologie Structurale Jean-Pierre Ebel (CNRS-Commissariat à l'Energie Atomique, Saclay, France
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43
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Smyth TP, Wall JG, Nitanai Y. A substrate variant as a high-affinity, reversible inhibitor: insight from the X-ray structure of cilastatin bound to membrane dipeptidase. Bioorg Med Chem 2003; 11:991-8. [PMID: 12614884 DOI: 10.1016/s0968-0896(02)00519-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An analysis of the X-ray structure of cilastatin bound to membrane dipeptidase, together with docking studies, is presented here to reveal how a simple amide may act as a high-affinity, reversible, amidase inhibitor. Cilastatin binds as a normal substrate and is orientated in a perfect near-attack conformer for formation of a tetrahedral intermediate with the zinc-bound water/hydroxide. This intermediate is fated, however, only to revert to its starting components as scission of the amide bond is prevented by the precise fit of cilastatin within the active site. The cilastatin alkyl end groups that are tightly buttressed against amino acid residues on opposite sides of the active site, are aligned along the C-N reaction coordinate axis thereby preventing collapse of the intermediate via rupture of the C-N bond. Such a feature could have more general applicability in the explicit design of substrate variants as selective, tight-binding, and reversible inhibitors.
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Affiliation(s)
- Timothy P Smyth
- Department of Chemical and Environmental Sciences, Univeristy of Limerick, National Technological Park, County Limerick, Ireland.
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44
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Suárez D, Díaz N, Merz KM. Molecular dynamics simulations of the dinuclear zinc-beta-lactamase from Bacteroides fragilis complexed with imipenem. J Comput Chem 2002; 23:1587-600. [PMID: 12395427 DOI: 10.1002/jcc.10157] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Herein, we present results from MD simulations of the Michaelis complex formed between the dizinc beta-lactamase from B. fragilis and imipenem. We considered two catalytically important configurations, which differ in the presence or absence of a hydroxide bridge connecting the two zinc ions in the active site. The structural and dynamical effects induced by substrate binding, the specific roles of the conserved residues and the zinc-bound water molecules, the near attack conformers of the Michaelis complex, and so forth, are discussed in detail. The relative stability of the two configurations was estimated from QM linear scaling calculations on the enzyme-substrate complex combined with Poisson-Boltzmann electrostatic calculations and normal mode calculations. Importantly, we find that the two configurations have similar energies, indicating that these two structures could readily be interchanged, thereby facilitating catalysis. The configuration with the hydroxide bound to the two zinc ions is predicted to be the resting form of the enzyme, while the configuration without the bridge is the reactive form that was found to place the hydroxide in position to attack the carbonyl of the beta-lactam ring. Thus, we propose that the enzyme initiates catalysis by converting from the hydroxide bridge form into the configuration that lacks the hydroxide bridge. This interconversion increases the nucleophilicity of the hydroxide ion and exposes it to the beta-lactam carbonyl, which ultimately facilitates nucleophilic attack. The implications of the observed modes of binding, the possible influence of mutating the Lys184 and Asn193 residues on substrate binding, and the reaction mechanism are also discussed in detail.
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Affiliation(s)
- Dimas Suárez
- Departamento de Química Física y Analítica, Universidad de Oviedo, Julián Clavería 8, 33006 Oviedo, Asturias, Spain
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45
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Banci L, Bertini I, Ciofi-Baffoni S, Finney LA, Outten CE, O'Halloran TV. A new zinc-protein coordination site in intracellular metal trafficking: solution structure of the Apo and Zn(II) forms of ZntA(46-118). J Mol Biol 2002; 323:883-97. [PMID: 12417201 DOI: 10.1016/s0022-2836(02)01007-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Zinc, a metal ion that functions in a wide variety of catalytic and structural sites in metalloproteins, is shown here to adopt a novel coordination environment in the Escherichia coli transport protein ZntA. The ZntA protein is a P-type ATPase that pumps zinc out of the cytoplasm and into the periplasm. It is physiologically selective for Zn(II) and functions with metalloregulatory proteins in the cell to keep the zinc quota within strict limits. Yet, the N-terminal cytoplasmic domain contains a region that is highly homologous to the yeast Cu(I) metallochaperone Atx1. To investigate how the structure of this region may influence its function, this fragment, containing residues 46-118, has been cloned out of the gene and overexpressed. We report here the solution structure of this fragment as determined by NMR. Both the apo and Zn(II)-ZntA(46-118) structures have been determined. It contains a previously unknown protein coordination site for zinc that includes two cysteine residues, Cys59 and Cys62, and a carboxylate residue, Asp58. The solvent accessibility of this site is also remarkably high, a feature that increasingly appears to be a characteristic of domains of heavy metal ion transport proteins. The participation of Asp58 in this ZntA metal ion binding site may play an important role in modulating the relative affinities and metal exchange rates for Zn(II)/Pb(II)/Cd(II) as compared with other P-type ATPases, which are selective for Cu(I) or Ag(I).
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
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46
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Antony J, Gresh N, Olsen L, Hemmingsen L, Schofield CJ, Bauer R. Binding of D- and L-captopril inhibitors to metallo-beta-lactamase studied by polarizable molecular mechanics and quantum mechanics. J Comput Chem 2002; 23:1281-96. [PMID: 12210153 DOI: 10.1002/jcc.10111] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The bacterial Zn2+ metallo-beta-lactamase from B. fragilis is a zinc-enzyme with two potential metal ion binding sites. It cleaves the lactam ring of antibiotics, thus contributing to the acquired resistance of bacteria against antibiotics. The present study bears on the binuclear form of the enzyme. We compare several possible binding modes of captopril, a mercaptocarboxamide inhibitor of several zinc-metalloenzymes. Two diastereoisomers of captopril were considered, with either a D- or an L-proline residue. We have used the polarizable molecular mechanics procedure SIBFA (Sum of Interactions Between Fragments ab initio computed). Two beta-lactamase models were considered, encompassing 104 and 188 residues, respectively. The energy balances included the inter and intramolecular interaction energies as well as the contribution from solvation computed using a continuum reaction field procedure. The thiolate ion of the inhibitor is binding to both metal ions, expelling the bridging solvent molecule from the uncomplexed enzyme. Different competing binding modes of captopril were considered, either where the inhibitor binds in a monodentate mode to the zinc cations only with its thiolate ion, or in bidentate modes involving additional zinc binding by its carboxylate or ketone carbonyl groups. The additional coordination by the inhibitor's carboxylate or carbonyl group always occurs at the zinc ion, which is bound by a histidine, a cysteine, and an aspartate side chain. For both diastereomers, the energy balances favor monodentate binding of captopril via S-. The preference over bidentate binding is small. The interaction energies were recomputed in model sites restricted to captopril, the Zn2+ cations, and their coordinating end side chains from beta-lactamase (98 atoms). The interaction energies and their ranking among competing arrangements were consistent with those computed by ab initio HF and DFT procedures.
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Affiliation(s)
- Jens Antony
- Department of Mathematics and Physics, The Royal Veterinary and Agricultural University, DK-1871 Frederiksberg C, Denmark
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47
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Siemann S, Brewer D, Clarke AJ, Dmitrienko GI, Lajoie G, Viswanatha T. IMP-1 metallo-beta-lactamase: effect of chelators and assessment of metal requirement by electrospray mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1571:190-200. [PMID: 12090933 DOI: 10.1016/s0304-4165(02)00258-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Metallo-beta-lactamases have attracted considerable attention due to their role in microbial resistance to beta-lactam antibiotics. IMP-1, the binuclear Zn-dependent beta-lactamase produced by Pseudomonas aeruginosa and other microorganisms, is of particular interest in view of its increasing prevalence. An examination of the susceptibility of IMP-1 to inactivation by six different divalent metal ion chelators has revealed that all except Zincon cause inhibition by forming a complex with the holoenzyme. Exposure of the enzyme to dipicolinic acid (DPA), the most potent inhibitor, results in the production of the mononuclear Zn form of the protein as determined by electrospray ionization mass spectrometry (ESI-MS) under nondenaturing conditions. This mononuclear Zn species was found to be catalytically competent. Studies with the chromophoric chelator 4-(2-pyridylazo)resorcinol (PAR) show that the two zinc centers in IMP-1 differ in their accessibility, a feature that could be overcome in the presence of guanidine hydrochloride (GdnHCl, 1.5 M).
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Affiliation(s)
- Stefan Siemann
- Department of Chemistry, University of Waterloo, 200 University Ave. W, Waterloo, ON, Canada N2L 3G1
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