1
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Salleh MZ, Banga Singh KK, Deris ZZ. Structural Insights into Substrate Binding and Antibiotic Inhibition of Enterobacterial Penicillin-Binding Protein 6. LIFE (BASEL, SWITZERLAND) 2022; 12:life12071022. [PMID: 35888109 PMCID: PMC9320039 DOI: 10.3390/life12071022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/03/2022] [Accepted: 07/07/2022] [Indexed: 11/16/2022]
Abstract
Shigella sonnei remains the second most common cause of shigellosis in young children and is now increasingly dominant across developing countries. The global emergence of drug resistance has become a main burden in the treatment of S. sonnei infections and β-lactam antibiotics, such as pivmecillinam and ceftriaxone, are recommended to be used as second-line treatment. They work by inhibiting the biosynthesis of the peptidoglycan layer of bacterial cell walls, in which the final transpeptidation step is facilitated by penicillin-binding proteins (PBPs). In this study, using protein homology modelling, we modelled the structure of PBP6 from S. sonnei and comprehensively examined the molecular interactions between PBP6 and its pentapeptide substrate and two antibiotic inhibitors. The docked complex of S. sonnei PBP6 with pentapeptides showed that the substrate bound to the active site groove of the DD-carboxypeptidase domain, via hydrogen bonding interactions with the residues S79, V80, Q101, G144, D146 and R240, in close proximity to the catalytic nucleophile S36 for the nucleophilic attack. Two residues, R240 and T208, were found to be important in ligand recognition and binding, where they formed strong hydrogen bonds with the substrate and β-lactams, respectively. Our results provide valuable information on the molecular interactions essential for ligand recognition and catalysis by PBP6. Understanding these interactions will be helpful in the development of effective drugs to treat S. sonnei infections.
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2
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Dalal V, Golemi-Kotra D, Kumar P. Quantum Mechanics/Molecular Mechanics Studies on the Catalytic Mechanism of a Novel Esterase (FmtA) of Staphylococcus aureus. J Chem Inf Model 2022; 62:2409-2420. [PMID: 35475370 DOI: 10.1021/acs.jcim.2c00057] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
FmtA is a novel esterase that shares the penicillin-binding protein (PBP) core structural folding but found to hydrolyze the removal of d-Ala from teichoic acids. Molecular docking, dynamics, and MM-GBSA of FmtA and its variants S127A, K130A, Y211A, D213A, and K130AY211A, in the presence or absence of wall teichoic acid (WTA), suggest that active site residues S127, K130, Y211, D213, N343, and G344 play a role in substrate binding. Quantum mechanics (QM)/molecular mechanics (MM) calculations reveal that during WTA catalysis, K130 deprotonates S127, and the nucleophilic S127 attacks the carbonyl carbon of d-Ala bound to WTA. The tetrahedral intermediate (TI) complex is stabilized by hydrogen bonding to the oxyanion holes. The TI complex displays a high energy gap and collapses to an energetically favorable acyl-enzyme complex.
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Affiliation(s)
- Vikram Dalal
- Department of Biosciences and Bioengineering, IIT Roorkee, Roorkee, Uttrakhand 247667, India
| | - Dasantila Golemi-Kotra
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Pravindra Kumar
- Department of Biosciences and Bioengineering, IIT Roorkee, Roorkee, Uttrakhand 247667, India
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3
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Ntombela T, Seupersad A, Maseko S, Ibeji CU, Tolufashe G, Maphumulo SI, Naicker T, Baijnath S, Maguire GEM, Govender T, Lamichhane G, Honarparvar B, Kruger HG. Mechanistic insight on the inhibition of D, D-carboxypeptidase from Mycobacterium tuberculosis by β-lactam antibiotics: an ONIOM acylation study. J Biomol Struct Dyn 2021; 40:7645-7655. [PMID: 33719919 DOI: 10.1080/07391102.2021.1899052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Mycobacterium tuberculosis cell wall is intricate and impermeable to many agents. A D, D-carboxypeptidase (DacB1) is one of the enzymes involved in the biosynthesis of cell wall peptidoglycan and catalyzes the terminal D-alanine cleavage from pentapeptide precursors. Catalytic activity and mechanism by which DacB1 functions is poorly understood. Herein, we investigated the acylation mechanism of DacB1 by β-lactams using a 6-membered ring transition state model that involves a catalytic water molecule in the reaction pathway. The full transition states (TS) optimization plus frequency were achieved using the ONIOM (B3LYP/6-31 + G(d): AMBER) method. Subsequently, the activation free energies were computed via single-point calculations on fully optimized structures using B3LYP/6-311++(d,p): AMBER and M06-2X/6-311++(d,p): AMBER with an electronic embedding scheme. The 6-membered ring transition state is an effective model to examine the inactivation of DacB1 via acylation by β-lactams antibiotics (imipenem, meropenem, and faropenem) in the presence of the catalytic water. The ΔG# values obtained suggest that the nucleophilic attack on the carbonyl carbon is the rate-limiting step with 13.62, 19.60 and 30.29 kcal mol-1 for Imi-DacB1, Mero-DacB1 and Faro-DacB1, respectively. The electrostatic potential (ESP) and natural bond orbital (NBO) analysis provided significant electronic details of the electron-rich region and charge delocalization, respectively, based on the concerted 6-membered ring transition state. The stabilization energies of charge transfer within the catalytic reaction pathway concurred with the obtained activation free energies. The outcomes of this study provide important molecular insight into the inactivation of D, D-carboxypeptidase by β-lactams.
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Affiliation(s)
- Thandokuhle Ntombela
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Anya Seupersad
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sibusiso Maseko
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Collins U Ibeji
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Gideon Tolufashe
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Siyabonga Innocent Maphumulo
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Tricia Naicker
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sooraj Baijnath
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Glenn E M Maguire
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.,School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Thavendran Govender
- Faculty of Science and Agriculture, Department of Chemistry, University of Zululand, Richards Bay, South Africa
| | - Gyanu Lamichhane
- Center for Tuberculosis Research, Division of Infectious Diseases, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Bahareh Honarparvar
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Hendrik G Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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4
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Catherwood AC, Lloyd AJ, Tod JA, Chauhan S, Slade SE, Walkowiak GP, Galley NF, Punekar AS, Smart K, Rea D, Evans ND, Chappell MJ, Roper DI, Dowson CG. Substrate and Stereochemical Control of Peptidoglycan Cross-Linking by Transpeptidation by Escherichia coli PBP1B. J Am Chem Soc 2020; 142:5034-5048. [DOI: 10.1021/jacs.9b08822] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Glover SA. Comment on "Penicillin's catalytic mechanism revealed by inelastic neutrons and quantum chemical theory" by Z. Mucsi, G. A. Chass, P. Ábrányi-Balogh, B. Jójárt, D.-C. Fang, A. J. Ramirez-Cuesta, B. Viskolczc and I. G. Csizmadia, Phys. Chem. Chem. Phys., 2013, 15, 20447. Phys Chem Chem Phys 2019; 21:18012-18025. [PMID: 31363727 DOI: 10.1039/c8cp02413h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nature of amide resonance in the β-lactam ring of β-propiolactams and penicillin type structures has been evaluated by the Mucsi hydrogenation method on the one hand, and isodesmic trans-amidation (TA) and the carbonyl substitution nitrogen atom replacement (COSNAR) methods on the other hand. The discrepancy between the two approaches points to two errors, one arithmetic and the other conceptual, in the manner in which the hydrogenation method is applied to β-lactams and which leads to much lower resonance stabilisation and amidicities than found by the TA and COSNAR methodologies. Correction of these errors yields amidicities in line with the TA and COSNAR results demonstrating that amide bonds in simple β-propiolactams are not weakened by strain relative to normal amides such as N,N-dimethylacetamide. Mucsi's results for penicillin are similarly in error, critically so in light of their use of the drastically reduced resonance in rationalising their proposed mechanism of reaction of the antibiotic with transpeptidase. Correction of the errors in application to penicillin-models points to other difficulties in applying the methodology to complex molecules. A detailed analysis of penicillin-type structures has been carried out using the reliable TA and COSNAR methods, which both point to relatively modest reductions in amidicity or resonance stabilisation in accordance with the known stability of the penam-type structures. At the very least, penicillin retains about 60% the resonance of N,N-dimethylacetamide in stark contrast to the erroneous -36% reported from the hydrogenation method.
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Affiliation(s)
- Stephen A Glover
- Department of Chemistry, School of Science and Technology, University of New England, Armidale, New South Wales 2350, Australia.
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6
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Dik DA, Fisher JF, Mobashery S. Cell-Wall Recycling of the Gram-Negative Bacteria and the Nexus to Antibiotic Resistance. Chem Rev 2018; 118:5952-5984. [PMID: 29847102 PMCID: PMC6855303 DOI: 10.1021/acs.chemrev.8b00277] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The importance of the cell wall to the viability of the bacterium is underscored by the breadth of antibiotic structures that act by blocking key enzymes that are tasked with cell-wall creation, preservation, and regulation. The interplay between cell-wall integrity, and the summoning forth of resistance mechanisms to deactivate cell-wall-targeting antibiotics, involves exquisite orchestration among cell-wall synthesis and remodeling and the detection of and response to the antibiotics through modulation of gene regulation by specific effectors. Given the profound importance of antibiotics to the practice of medicine, the assertion that understanding this interplay is among the most fundamentally important questions in bacterial physiology is credible. The enigmatic regulation of the expression of the AmpC β-lactamase, a clinically significant and highly regulated resistance response of certain Gram-negative bacteria to the β-lactam antibiotics, is the exemplar of this challenge. This review gives a current perspective to this compelling, and still not fully solved, 35-year enigma.
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Affiliation(s)
- David A. Dik
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
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7
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Kar D, Pandey SD, Mallick S, Dutta M, Ghosh AS. Substitution of Alanine at Position 184 with Glutamic Acid in Escherichia coli PBP5 Ω-Like Loop Introduces a Moderate Cephalosporinase Activity. Protein J 2018; 37:122-131. [DOI: 10.1007/s10930-018-9765-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Lewandowski EM, Lethbridge KG, Sanishvili R, Skiba J, Kowalski K, Chen Y. Mechanisms of proton relay and product release by Class A β-lactamase at ultrahigh resolution. FEBS J 2017; 285:87-100. [PMID: 29095570 DOI: 10.1111/febs.14315] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/15/2017] [Accepted: 10/28/2017] [Indexed: 01/25/2023]
Abstract
The β-lactam antibiotics inhibit penicillin-binding proteins (PBPs) by forming a stable, covalent, acyl-enzyme complex. During the evolution from PBPs to Class A β-lactamases, the β-lactamases acquired Glu166 to activate a catalytic water and cleave the acyl-enzyme bond. Here we present three product complex crystal structures of CTX-M-14 Class A β-lactamase with a ruthenocene-conjugated penicillin-a 0.85 Å resolution structure of E166A mutant complexed with the penilloate product, a 1.30 Å resolution complex structure of the same mutant with the penicilloate product, and a 1.18 Å resolution complex structure of S70G mutant with a penicilloate product epimer-shedding light on the catalytic mechanisms and product inhibition of PBPs and Class A β-lactamases. The E166A-penilloate complex captured the hydrogen bonding network following the protonation of the leaving group and, for the first time, unambiguously show that the ring nitrogen donates a proton to Ser130, which in turn donates a proton to Lys73. These observations indicate that in the absence of Glu166, the equivalent lysine would be neutral in PBPs and therefore capable of serving as the general base to activate the catalytic serine. Together with previous results, this structure suggests a common proton relay network shared by Class A β-lactamases and PBPs, from the catalytic serine to the lysine, and ultimately to the ring nitrogen. Additionally, the E166A-penicilloate complex reveals previously unseen conformational changes of key catalytic residues during the release of the product, and is the first structure to capture the hydrolyzed product in the presence of an unmutated catalytic serine. DATABASE Structural data are available in the PDB database under the accession numbers 5TOP, 5TOY, and 5VLE.
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Affiliation(s)
- Eric M Lewandowski
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Kathryn G Lethbridge
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Ruslan Sanishvili
- GMCA@APS, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, IL, USA
| | - Joanna Skiba
- Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, Poland
| | - Konrad Kowalski
- Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, Poland
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
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9
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Biochemical and Structural Analysis of a Novel Esterase from Caulobacter crescentus related to Penicillin-Binding Protein (PBP). Sci Rep 2016; 6:37978. [PMID: 27905486 PMCID: PMC5131357 DOI: 10.1038/srep37978] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/03/2016] [Indexed: 01/16/2023] Open
Abstract
Considering that the prevalence of antibiotic-resistant pathogenic bacteria is largely increasing, a thorough understanding of penicillin-binding proteins (PBPs) is of great importance and crucial significance because this enzyme family is a main target of β-lactam-based antibiotics. In this work, combining biochemical and structural analysis, we present new findings that provide novel insights into PBPs. Here, a novel PBP homologue (CcEstA) from Caulobacter crescentus CB15 was characterized using native-PAGE, mass spectrometry, gel filtration, CD spectroscopy, fluorescence, reaction kinetics, and enzyme assays toward various substrates including nitrocefin. Furthermore, the crystal structure of CcEstA was determined at a 1.9 Å resolution. Structural analyses showed that CcEstA has two domains: a large α/β domain and a small α-helix domain. A nucleophilic serine (Ser68) residue is located in a hydrophobic groove between the two domains along with other catalytic residues (Lys71 and Try157). Two large flexible loops (UL and LL) of CcEstA are proposed to be involved in the binding of incoming substrates. In conclusion, CcEstA could be described as a paralog of the group that contains PBPs and β-lactamases. Therefore, this study could provide new structural and functional insights into the understanding this protein family.
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10
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Bhattacharjee N, Field MJ, Simorre JP, Arthur M, Bougault CM. Hybrid Potential Simulation of the Acylation of Enterococcus faecium l,d-Transpeptidase by Carbapenems. J Phys Chem B 2016; 120:4767-81. [DOI: 10.1021/acs.jpcb.6b02836] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholus Bhattacharjee
- DYNAMO/DYNAMOP,
UMR 5075, Université Grenoble 1, CNRS, CEA, Institut de Biologie
Structurale, 71 Avenue des Martyrs,
CS 10090, 38044 Grenoble Cedex 9, France
| | - Martin J. Field
- DYNAMO/DYNAMOP,
UMR 5075, Université Grenoble 1, CNRS, CEA, Institut de Biologie
Structurale, 71 Avenue des Martyrs,
CS 10090, 38044 Grenoble Cedex 9, France
| | - Jean-Pierre Simorre
- RMN, UMR 5075,
Université Grenoble 1, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
| | - Michel Arthur
- Centre de Recherche
des Cordeliers, Equipe 12, UMR S 872, Université Pierre et
Marie Curie-Paris 6, INSERM, Université Paris Descartes, Sorbonne
Paris Cité, 15 rue de l’Ecole
de Médecine, 75006 Paris, France
| | - Catherine M. Bougault
- RMN, UMR 5075,
Université Grenoble 1, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
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11
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Choi H, Paton RS, Park H, Schofield CJ. Investigations on recyclisation and hydrolysis in avibactam mediated serine β-lactamase inhibition. Org Biomol Chem 2016; 14:4116-28. [PMID: 27072755 PMCID: PMC4847122 DOI: 10.1039/c6ob00353b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/04/2016] [Indexed: 01/13/2023]
Abstract
β-Lactams inhibit penicillin-binding proteins (PBPs) and serine β-lactamases by acylation of a nucleophilic active site serine. Avibactam is approved for clinical use in combination with ceftazidime, and is a breakthrough non β-lactam β-lactamase inhibitor also reacting via serine acylation. Molecular dynamics (MD) and quantum chemical calculations on avibactam-mediated inhibition of a clinically relevant cephalosporinase reveal that recyclisation of the avibactam derived carbamoyl complex is favoured over hydrolysis. In contrast, we show that analogous recyclisation in β-lactam mediated inhibition is disfavoured. Avibactam recyclisation is promoted by a proton shuttle, a 'structural' water protonating the nucleophilic serine, and stabilization of the negative charge developed on aminocarbonyl oxygen. The results imply the potential of calculations for distinguishing between bifurcating pathways during inhibition and in generating hypotheses for predicting resistance. The inability of β-lactams to undergo recyclisation may be an Achilles heel, but one that can be addressed by suitably functionalized reversibly binding inhibitors.
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Affiliation(s)
- Hwanho Choi
- Department of Bioscience and Biotechnology, Sejong University, 209 Neungdong-ro, Kwangjin-gu, Seoul 143-747, Korea. and Chemical Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Robert S Paton
- Chemical Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Hwangseo Park
- Department of Bioscience and Biotechnology, Sejong University, 209 Neungdong-ro, Kwangjin-gu, Seoul 143-747, Korea.
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12
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Structural and computational analysis of peptide recognition mechanism of class-C type penicillin binding protein, alkaline D-peptidase from Bacillus cereus DF4-B. Sci Rep 2015; 5:13836. [PMID: 26370172 PMCID: PMC4570186 DOI: 10.1038/srep13836] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/07/2015] [Indexed: 01/07/2023] Open
Abstract
Alkaline D-peptidase from Bacillus cereus DF4-B, called ADP, is a D-stereospecific endopeptidase reacting with oligopeptides containing D-phenylalanine (D-Phe) at N-terminal penultimate residue. ADP has attracted increasing attention because it is useful as a catalyst for synthesis of D-Phe oligopeptides or, with the help of substrate mimetics, L-amino acid peptides and proteins. Structure and functional analysis of ADP is expected to elucidate molecular mechanism of ADP. In this study, the crystal structure of ADP (apo) form was determined at 2.1 Å resolution. The fold of ADP is similar to that of the class C penicillin-binding proteins of type-AmpH. Docking simulations and fragment molecular orbital analyses of two peptides, (D-Phe)4 and (D-Phe)2-(L-Phe)2, with the putative substrate binding sites of ADP indicated that the P1 residue of the peptide interacts with hydrophobic residues at the S1 site of ADP. Furthermore, molecular dynamics simulation of ADP for 50 nsec suggested that the ADP forms large cavity at the active site. Formation of the cavity suggested that the ADP has open state in the solution. For the ADP, having the open state is convenient to bind the peptides having bulky side chain, such as (D-Phe)4. Taken together, we predicted peptide recognition mechanism of ADP.
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13
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Chung LW, Sameera WMC, Ramozzi R, Page AJ, Hatanaka M, Petrova GP, Harris TV, Li X, Ke Z, Liu F, Li HB, Ding L, Morokuma K. The ONIOM Method and Its Applications. Chem Rev 2015; 115:5678-796. [PMID: 25853797 DOI: 10.1021/cr5004419] [Citation(s) in RCA: 734] [Impact Index Per Article: 81.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lung Wa Chung
- †Department of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China
| | - W M C Sameera
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Romain Ramozzi
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Alister J Page
- §Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
| | - Miho Hatanaka
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Galina P Petrova
- ∥Faculty of Chemistry and Pharmacy, University of Sofia, Bulgaria Boulevard James Bourchier 1, 1164 Sofia, Bulgaria
| | - Travis V Harris
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan.,⊥Department of Chemistry, State University of New York at Oswego, Oswego, New York 13126, United States
| | - Xin Li
- #State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zhuofeng Ke
- ∇School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Fengyi Liu
- ○Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Hai-Bei Li
- ■School of Ocean, Shandong University, Weihai 264209, China
| | - Lina Ding
- ▲School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Keiji Morokuma
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
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14
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Hargis JC, White JK, Chen Y, Woodcock HL. Can molecular dynamics and QM/MM solve the penicillin binding protein protonation puzzle? J Chem Inf Model 2014; 54:1412-24. [PMID: 24697903 PMCID: PMC4036751 DOI: 10.1021/ci5000517] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
![]()
Benzylpenicillin, a member of the
β-lactam antibiotic class, has been widely used to combat bacterial
infections since 1947. The general mechanism is well-known: a serine
protease enzyme (i.e., DD-peptidase) forms a long lasting intermediate
with the lactam ring of the antibiotic known as acylation, effectively
preventing biosynthesis of the bacterial cell wall. Despite this overall
mechanistic understanding, many details of binding and catalysis are
unclear. Specifically, there is ongoing debate about active site protonation
states and the role of general acids/bases in the reaction. Herein,
a unique combination of MD simulations, QM/MM minimizations, and QM/MM
orbital analyses is combined with systematic variation of active site
residue protonation states. Critical interactions that maximize the
stability of the bound inhibitor are examined and used as metrics.
This approach was validated by examining cefoxitin interactions in
the CTX-M β-lactamase from E. coli and compared to an ultra high-resolution (0.88 Å) crystal structure.
Upon confirming the approach used, an investigation of the preacylated Streptomyces R61 active site with bound benzylpenicillin
was performed, varying the protonation states of His298 and Lys65.
We concluded that protonated His298 and deprotonated Lys65 are most
likely to exist in the R61 active site.
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Affiliation(s)
- Jacqueline C Hargis
- Department of Chemistry, University of South Florida , Tampa, Florida 33620, United States
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15
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Kamiya K, Baba T, Boero M, Matsui T, Negoro S, Shigeta Y. Nylon-Oligomer Hydrolase Promoting Cleavage Reactions in Unnatural Amide Compounds. J Phys Chem Lett 2014; 5:1210-1216. [PMID: 26274473 DOI: 10.1021/jz500323y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The active site of 6-aminohexanoate-dimer hydrolase, a nylon-6 byproduct-degrading enzyme with a β-lactamase fold, possesses a Ser112/Lys115/Tyr215 catalytic triad similar to the one of penicillin-recognizing family of serine-reactive hydrolases but includes a unique Tyr170 residue. By using a reactive quantum mechanics/molecular mechanics (QM/MM) approach, we work out its catalytic mechanism and related functional/structural specificities. At variance with other peptidases, we show that the involvement of Tyr170 in the enzyme-substrate interactions is responsible for a structural variation in the substrate-binding state. The acylation via a tetrahedral intermediate is the rate-limiting step, with a free-energy barrier of ∼21 kcal/mol, driven by the catalytic triad Ser112, Lys115, and Tyr215, acting as a nucleophile, general base, and general acid, respectively. The functional interaction of Tyr170 with this triad leads to an efficient disruption of the tetrahedral intermediate, promoting a conformational change of the substrate favorable for proton donation from the general acid.
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Affiliation(s)
- Katsumasa Kamiya
- †Center for Basic Education and Integrated Learning, Kanagawa Institute of Technology, 1030 Shimo-Ogino, Atsugi, Kanagawa 243-0292, Japan
| | - Takeshi Baba
- ‡Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Mauro Boero
- §Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS and University of Strasbourg, 23 rue du Loess, 67034 Strasbourg, France
| | - Toru Matsui
- ∥RIKEN, Advanced Institute for Computational Science, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Seiji Negoro
- ⊥Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280, Japan
| | - Yasuteru Shigeta
- ‡Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- #CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 Japan
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16
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Kumarasiri M, Zhang W, Shi Q, Fisher JF, Mobashery S. Protonation states of active-site lysines of penicillin-binding protein 6 from Escherichia coli and the mechanistic implications. Proteins 2014; 82:1348-58. [PMID: 24375650 DOI: 10.1002/prot.24501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 11/15/2013] [Accepted: 12/09/2013] [Indexed: 02/02/2023]
Abstract
The protonation states of the two active-site lysines (Lys69 and Lys235) of PBP 6 of Escherichia coli were explored to understand the active site chemistry of this enzyme. Each lysine was individually mutated to cysteine, and the resultant two mutant proteins were purified to homogeneity. Each protein was denatured, and its cysteine was chemically modified to produce an S-aminoethylated cysteine (γ-thialysine) residue. Following renaturation, the evaluation of the kinetics of the dd-carboxypeptidase activity of PBP 6 as a function of pH was found consistent with one lysine in its free-base (Lys69) and the other in the protonated state (Lys235) for optimal catalysis. The experimental estimates for their pKa values were compared with the pKa values calculated computationally, using molecular-dynamics simulations and a thermodynamic cycle. Study of the γ-thialysine69 showed that lysine at position 69 influenced the basic limb of catalysis, consistent with the fact that the two lysine side chains are in proximity to each other in the active site. Based on these observations, a reaction sequence for PBP 6 is proposed, wherein protonated Lys235 serves as the electrostatic substrate anchor and Lys69 as the conduit for protons in the course of the acylation and deacylation half-reactions.
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Affiliation(s)
- Malika Kumarasiri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556
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17
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Lupoli TJ, Lebar MD, Markovski M, Bernhardt T, Kahne D, Walker S. Lipoprotein activators stimulate Escherichia coli penicillin-binding proteins by different mechanisms. J Am Chem Soc 2013; 136:52-5. [PMID: 24341982 DOI: 10.1021/ja410813j] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In Escherichia coli , the bifunctional penicillin-binding proteins (PBPs), PBP1A and PBP1B, play critical roles in the final stage of peptidoglycan (PG) biosynthesis. These synthetic enzymes each possess a PG glycosyltransferase (PGT) domain and a transpeptidase (TP) domain. Recent genetic experiments have shown that PBP1A and PBP1B each require an outer membrane lipoprotein, LpoA and LpoB, respectively, to function properly in vivo. Here, we use complementary assays to show that LpoA and LpoB each increase the PGT and TP activities of their cognate PBPs, albeit by different mechanisms. LpoA directly increases the rate of the PBP1A TP reaction, which also results in enhanced PGT activity; in contrast, LpoB directly affects PGT domain activity, resulting in enhanced TP activity. These studies demonstrate bidirectional coupling of PGT and TP domain function. Additionally, the transpeptidation assay described here can be applied to study other activators or inhibitors of the TP domain of PBPs, which are validated drug targets.
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Affiliation(s)
- Tania J Lupoli
- Department of Microbiology and Immunobiology, Harvard Medical School , Boston, Massachusetts 02115, United States
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18
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Structural analysis of the role of Pseudomonas aeruginosa penicillin-binding protein 5 in β-lactam resistance. Antimicrob Agents Chemother 2013; 57:3137-46. [PMID: 23629710 DOI: 10.1128/aac.00505-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Penicillin-binding protein 5 (PBP5) is one of the most abundant PBPs in Pseudomonas aeruginosa. Although its main function is that of a cell wall dd-carboxypeptidase, it possesses sufficient β-lactamase activity to contribute to the ability of P. aeruginosa to resist the antibiotic activity of the β-lactams. The study of these dual activities is important for understanding the mechanisms of antibiotic resistance by P. aeruginosa, an important human pathogen, and to the understanding of the evolution of β-lactamase activity from the PBP enzymes. We purified a soluble version of P. aeruginosa PBP5 (designated Pa sPBP5) by deletion of its C-terminal membrane anchor. Under in vitro conditions, Pa sPBP5 demonstrates both dd-carboxypeptidase and expanded-spectrum β-lactamase activities. Its crystal structure at a 2.05-Å resolution shows features closely resembling those of the class A β-lactamases, including a shortened loop spanning residues 74 to 78 near the active site and with respect to the conformations adopted by two active-site residues, Ser101 and Lys203. These features are absent in the related PBP5 of Escherichia coli. A comparison of the two Pa sPBP5 monomers in the asymmetric unit, together with molecular dynamics simulations, revealed an active-site flexibility that may explain its carbapenemase activity, a function that is absent in the E. coli PBP5 enzyme. Our functional and structural characterizations underscore the versatility of this PBP5 in contributing to the β-lactam resistance of P. aeruginosa while highlighting how broader β-lactamase activity may be encoded in the structural folds shared by the PBP and serine β-lactamase classes.
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19
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Zhang W, Lee M, Hesek D, Lastochkin E, Boggess B, Mobashery S. Reactions of the three AmpD enzymes of Pseudomonas aeruginosa. J Am Chem Soc 2013; 135:4950-3. [PMID: 23510438 DOI: 10.1021/ja400970n] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A group of Gram-negative bacteria, including the problematic pathogen Pseudomonas aeruginosa, has linked the steps in cell-wall recycling with the ability to manifest resistance to β-lactam antibiotics. A key step at the crossroads of the two events is performed by the protease AmpD, which hydrolyzes the peptide in the metabolite that influences these events. In contrast to other organisms that harbor this elaborate system, the genomic sequences of P. aeruginosa reveal it to have three paralogous genes for this protease, designated as ampD, ampDh2, and ampDh3. The recombinant gene products were purified to homogeneity, and their functions were assessed by the use of synthetic samples of three bacterial metabolites in cell-wall recycling and of three surrogates of cell-wall peptidoglycan. The results unequivocally identify AmpD as the bona fide recycling enzyme and AmpDh2 and AmpDh3 as enzymes involved in turnover of the bacterial cell wall itself. These findings define for the first time the events mediated by these three enzymes that lead to turnover of a key cell-wall recycling metabolite as well as the cell wall itself in its maturation.
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Affiliation(s)
- Weilie Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
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20
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Mucsi Z, Chass GA, Ábrányi-Balogh P, Jójárt B, Fang DC, Ramirez-Cuesta AJ, Viskolcz B, Csizmadia IG. Penicillin's catalytic mechanism revealed by inelastic neutrons and quantum chemical theory. Phys Chem Chem Phys 2013; 15:20447-20455. [DOI: 10.1039/c3cp50868d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Penicillin's dynamic structure–activity relationship resolved by inelastic neutrons kinetics, NMR and QM/MM-theory. Self-activating geometric changes catalyse bacterial enzyme inactivation.
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Affiliation(s)
- Zoltán Mucsi
- Department of Chemistry
- University of Toronto
- Toronto
- Canada
| | - Gregory A. Chass
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
| | | | - Balázs Jójárt
- Department of Chemical Informatics University of Szeged
- Szeged
- Hungary
| | - De-Cai Fang
- College of Chemistry
- Beijing Normal University
- Beijing
- China
| | | | - Béla Viskolcz
- Department of Chemical Informatics University of Szeged
- Szeged
- Hungary
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21
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Abstract
Many Gram-negative and Gram-positive bacteria recycle a significant proportion of the peptidoglycan components of their cell walls during their growth and septation. In many--and quite possibly all--bacteria, the peptidoglycan fragments are recovered and recycled. Although cell-wall recycling is beneficial for the recovery of resources, it also serves as a mechanism to detect cell-wall-targeting antibiotics and to regulate resistance mechanisms. In several Gram-negative pathogens, anhydro-MurNAc-peptide cell-wall fragments regulate AmpC β-lactamase induction. In some Gram-positive organisms, short peptides derived from the cell wall regulate the induction of both β-lactamase and β-lactam-resistant penicillin-binding proteins. The involvement of peptidoglycan recycling with resistance regulation suggests that inhibitors of the enzymes involved in the recycling might synergize with cell-wall-targeted antibiotics. Indeed, such inhibitors improve the potency of β-lactams in vitro against inducible AmpC β-lactamase-producing bacteria. We describe the key steps of cell-wall remodeling and recycling, the regulation of resistance mechanisms by cell-wall recycling, and recent advances toward the discovery of cell-wall-recycling inhibitors.
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Affiliation(s)
- Jarrod W Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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22
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Iqbal A, Clifton IJ, Chowdhury R, Ivison D, Domene C, Schofield CJ. Structural and biochemical analyses reveal how ornithine acetyl transferase binds acidic and basic amino acid substrates. Org Biomol Chem 2011; 9:6219-25. [PMID: 21796301 DOI: 10.1039/c1ob05554b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural and biochemical analyses reveal how ornithine acetyl-transferases catalyse the reversible transfer of an acetyl-group from a basic (ornithine) to an acidic (glutamate) amino acid by employing a common mechanism involving an acetyl-enzyme intermediate but using different side chain binding modes.
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Affiliation(s)
- Aman Iqbal
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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23
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Shi Q, Meroueh SO, Fisher JF, Mobashery S. A computational evaluation of the mechanism of penicillin-binding protein-catalyzed cross-linking of the bacterial cell wall. J Am Chem Soc 2011; 133:5274-83. [PMID: 21417389 DOI: 10.1021/ja1074739] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Penicillin-binding protein 1b (PBP 1b) of the gram-positive bacterium Streptococcus pneumoniae catalyzes the cross-linking of adjacent peptidoglycan strands, as a critical event in the biosynthesis of its cell wall. This enzyme is representative of the biosynthetic PBP structures of the β-lactam-recognizing enzyme superfamily and is the target of the β-lactam antibiotics. In the cross-linking reaction, the amide between the -D-Ala-D-Ala dipeptide at the terminus of a peptide stem acts as an acyl donor toward the ε-amino group of a lysine found on an adjacent stem. The mechanism of this transpeptidation was evaluated using explicit-solvent molecular dynamics simulations and ONIOM quantum mechanics/molecular mechanics calculations. Sequential acyl transfer occurs to, and then from, the active site serine. The resulting cross-link is predicted to have a cis-amide configuration. The ensuing and energetically favorable cis- to trans-amide isomerization, within the active site, may represent the key event driving product release to complete enzymatic turnover.
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Affiliation(s)
- Qicun Shi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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24
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Chowdhury C, Ghosh AS. Differences in active-site microarchitecture explain the dissimilar behaviors of PBP5 and 6 in Escherichia coli. J Mol Graph Model 2011; 29:650-6. [DOI: 10.1016/j.jmgm.2010.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 11/10/2010] [Accepted: 11/15/2010] [Indexed: 11/29/2022]
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25
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Kawai F, Clarke TB, Roper DI, Han GJ, Hwang KY, Unzai S, Obayashi E, Park SY, Tame JR. Crystal Structures of Penicillin-Binding Proteins 4 and 5 from Haemophilus influenzae. J Mol Biol 2010; 396:634-45. [DOI: 10.1016/j.jmb.2009.11.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 11/20/2009] [Accepted: 11/22/2009] [Indexed: 10/20/2022]
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26
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Fisher JF, Mobashery S. Three decades of the class A beta-lactamase acyl-enzyme. Curr Protein Pept Sci 2010; 10:401-7. [PMID: 19538154 DOI: 10.2174/138920309789351967] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 11/10/2008] [Indexed: 11/22/2022]
Abstract
The discovery that the mechanism of beta-lactam hydrolysis catalyzed by the class A (active site serine-dependent) beta-lactamases proceeds via an acyl-enzyme intermediate was made thirty years ago. Since this discovery, the active site circumstance that enables acylation of the active site serine and further enables hydrolytic deacylation of the acyl-serine intermediate, has received extraordinary scrutiny. The justification for this scrutiny is the direct relevance of the beta-lactamases to the manifestation of bacterial resistance to the beta-lactam antibiotics, and the subsequent (to the discovery of the beta-lactamase acyl-enzyme) recognition of the direct evolutionary relationship between the serine beta-lactamase acyl-enzyme, and the penicillin binding protein acyl-enzyme that is key to beta-lactam antibiotic activity. This short review describes the early events leading to the recognition that serine beta-lactamase catalysis proceeds via an acyl-enzyme intermediate, and summarizes several of the key mechanistic studies--including infrared spectroscopy, cryoenzymology, beta-lactam design, and x-ray crystallography--that have been exploited to understand this pivotal catalytic intermediate.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame IN 46556-5670, USA
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27
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Lu Y, Wang Y, Xu Z, Yan X, Luo X, Jiang H, Zhu W. C-X...H contacts in biomolecular systems: how they contribute to protein-ligand binding affinity. J Phys Chem B 2009; 113:12615-21. [PMID: 19708644 DOI: 10.1021/jp906352e] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hydrogen bond acceptor capability of halogens has long been underappreciated in the field of biology. In this work, we have surveyed structures of protein complexes with halogenated ligands to characterize geometrical preferences of C-X...H contacts and contributions of such interactions to protein-ligand binding affinity. Notably, F...H interactions in biomolecules exhibit a remarkably different behavior as compared to three other kinds of X...H (X = Cl, Br, I) interactions, which has been rationalized by means of ab initio calculations using simple model systems. The C-X...H contacts in biological systems are characterized as weak hydrogen bonding interactions. Furthermore, the electrophile "head on" and nucleophile "side on" interactions of halogens have been extensively investigated through the examination of interactions in protein structures and a two-layer ONIOM-based QM/MM method. In biomolecular systems, C-X...H contacts are recognized as secondary interaction contributions to C-X...O halogen bonds that play important roles in conferring specificity and affinity for halogenated ligands. The results presented here are within the context of their potential applications in drug design, including relevance to the development of accurate force fields for halogens.
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Affiliation(s)
- Yunxiang Lu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
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28
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Chen Y, Zhang W, Shi Q, Hesek D, Lee M, Mobashery S, Shoichet BK. Crystal structures of penicillin-binding protein 6 from Escherichia coli. J Am Chem Soc 2009; 131:14345-54. [PMID: 19807181 PMCID: PMC3697005 DOI: 10.1021/ja903773f] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Penicillin-binding protein 6 (PBP6) is one of the two main DD-carboxypeptidases in Escherichia coli, which are implicated in maturation of bacterial cell wall and formation of cell shape. Here, we report the first X-ray crystal structures of PBP6, capturing its apo state (2.1 A), an acyl-enzyme intermediate with the antibiotic ampicillin (1.8 A), and for the first time for a PBP, a preacylation complex (a "Michaelis complex", determined at 1.8 A) with a peptidoglycan substrate fragment containing the full pentapeptide, NAM-(L-Ala-D-isoGlu-L-Lys-D-Ala-D-Ala). These structures illuminate the molecular interactions essential for ligand recognition and catalysis by DD-carboxypeptidases, and suggest a coupling of conformational flexibility of active site loops to the reaction coordinate. The substrate fragment complex structure, in particular, provides templates for models of cell wall recognition by PBPs, as well as substantiating evidence for the molecular mimicry by beta-lactam antibiotics of the peptidoglycan acyl-D-Ala-D-Ala moiety.
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Affiliation(s)
- Yu Chen
- Department of Pharmaceutical Chemistry, University of California San Francisco, Byers Hall, Room 508D, 1700 Fourth Street, San Francisco, California 94158-2550
| | - Weilie Zhang
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, UniVersity of Notre Dame, Notre Dame, Indiana 46556
| | - Qicun Shi
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, UniVersity of Notre Dame, Notre Dame, Indiana 46556
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, UniVersity of Notre Dame, Notre Dame, Indiana 46556
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, UniVersity of Notre Dame, Notre Dame, Indiana 46556
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, UniVersity of Notre Dame, Notre Dame, Indiana 46556
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California San Francisco, Byers Hall, Room 508D, 1700 Fourth Street, San Francisco, California 94158-2550
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29
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Chen Y, McReynolds A, Shoichet BK. Re-examining the role of Lys67 in class C beta-lactamase catalysis. Protein Sci 2009; 18:662-9. [PMID: 19241376 DOI: 10.1002/pro.60] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lys67 is essential for the hydrolysis reaction mediated by class C beta-lactamases. Its exact catalytic role lies at the center of several different proposed reaction mechanisms, particularly for the deacylation step, and has been intensely debated. Whereas a conjugate base hypothesis postulates that a neutral Lys67 and Tyr150 act together to deprotonate the deacylating water, previous experiments on the K67R mutants of class C beta-lactamases suggested that the role of Lys67 in deacylation is mainly electrostatic, with only a 2- to 3-fold decrease in the rate of the mutant vs the wild type enzyme. Using the Class C beta-lactamase AmpC, we have reinvestigated the activity of this K67R mutant enzyme, using biochemical and structural studies. Both the rates of acylation and deacylation were affected in the AmpC K67R mutant, with a 61-fold decrease in k(cat), the deacylation rate. We have determined the structure of the K67R mutant by X-ray crystallography both in apo and transition state-analog complexed forms, and observed only minimal conformational changes in the catalytic residues relative to the wild type. These results suggest that the arginine side chain is unable to play the same catalytic role as Lys67 in either the acylation or deacylation reactions catalyzed by AmpC. Therefore, the activity of this mutant can not be used to discredit the conjugate base hypothesis as previously concluded, although the reaction catalyzed by the K67R mutant itself likely proceeds by an alternative mechanism. Indeed, a manifold of mechanisms may contribute to hydrolysis in class C beta-lactamases, depending on the enzyme (wt or mutant) and the substrate, explaining why different mutants and substrates seem to support different pathways. For the WT enzyme itself, the conjugate base mechanism may be well favored.
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Affiliation(s)
- Yu Chen
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158-2550, USA
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30
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Lu Y, Shi T, Wang Y, Yang H, Yan X, Luo X, Jiang H, Zhu W. Halogen Bonding—A Novel Interaction for Rational Drug Design? J Med Chem 2009; 52:2854-62. [PMID: 19358610 DOI: 10.1021/jm9000133] [Citation(s) in RCA: 449] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Yunxiang Lu
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Ting Shi
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Yong Wang
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Huaiyu Yang
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Xiuhua Yan
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Xiaoming Luo
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Hualiang Jiang
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
| | - Weiliang Zhu
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, and School of Science, East China University of Science and Technology, Shanghai, 200237, China
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