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Agarwal V, Yadav TC, Tiwari A, Varadwaj P. Detailed investigation of catalytically important residues of class A β-lactamase. J Biomol Struct Dyn 2023; 41:2046-2073. [PMID: 34986744 DOI: 10.1080/07391102.2021.2023645] [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: 02/02/2023]
Abstract
An increasing global health challenge is antimicrobial resistance. Bacterial infections are often treated by using β-lactam antibiotics. But several resistance mechanisms have evolved in clinically mutated bacteria, which results in resistance against such antibiotics. Among which production of novel β-lactamase is the major one. This results in bacterial resistance against penicillin, cephalosporin, and carbapenems, which are considered to be the last resort of antibacterial treatment. Hence, β-lactamase enzymes produced by such bacteria are called extended-spectrum β-lactamase and carbapenemase enzymes. Further, these bacteria have developed resistance against many β-lactamase inhibitors as well. So, investigation of important residues that play an important role in altering and expanding the spectrum activity of these β-lactamase enzymes becomes necessary. This review aims to gather knowledge about the role of residues and their mutations in class A β-lactamase, which could be responsible for β-lactamase mediated resistance. Class A β-lactamase enzymes contain most of the clinically significant and expanded spectrum of β-lactamase enzymes. Ser70, Lys73, Ser130, Glu166, and Asn170 residues are mostly conserved and have a role in the enzyme's catalytic activity. In-depth investigation of 69, 130, 131, 132, 164, 165, 166, 170, 171, 173, 176, 178, 179, 182, 237, 244, 275 and 276 residues were done along with its kinetic analysis for knowing its significance. Further, detailed information from many previous studies was gathered to know the effect of mutations on the kinetic activity of class A β-lactamase enzymes with β-lactam antibiotics.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Vidhu Agarwal
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, Jhalwa, Uttar Pradesh, India
| | - Tara Chand Yadav
- Department of Biotechnology, Indian Institute of Technology, Roorkee, Uttarakhand, India
| | - Akhilesh Tiwari
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, Jhalwa, Uttar Pradesh, India
| | - Pritish Varadwaj
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, Jhalwa, Uttar Pradesh, India
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2
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Bellini R, Guedes IA, Ciapina LP, de Vasconcelos ATR, Dardenne LE, Nicolás MF. Analysis of a novel class A β-lactamase OKP-B-6 of Klebsiella quasipneumoniae: structural characterisation and interaction with commercially available drugs. Mem Inst Oswaldo Cruz 2022; 117:e220102. [PMID: 36169569 PMCID: PMC9506704 DOI: 10.1590/0074-02760220102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 08/22/2022] [Indexed: 08/30/2023] Open
Abstract
BACKGROUND Gram-negative and Gram-positive bacteria produce beta-lactamase as factors to overcome beta-lactam antibiotics, causing their hydrolysis and impaired antimicrobial action. Class A beta-lactamase contains the chromosomal sulfhydryl reagent variable (SHV, point mutation variants of SHV-1), LEN (Klebsiella pneumoniae strain LEN-1), and other K. pneumoniae beta-lactamase (OKP) found mostly in Klebsiella’s phylogroups. The SHV known as extended-spectrum β-lactamase can inactivate most beta-lactam antibiotics. Class A also includes the worrisome plasmid-encoded Klebsiella pneumoniae carbapenemase (KPC-2), a carbapenemase that can inactivate most beta-lactam antibiotics, carbapenems, and some beta-lactamase inhibitors. OBJECTIVES So far, there is no 3D crystal structure for OKP-B, so our goal was to perform structural characterisation and molecular docking studies of this new enzyme. METHODS We applied a homology modelling method to build the OKP-B-6 structure, which was compared with SHV-1 and KPC-2 according to their electrostatic potentials at the active site. Using the DockThor-VS, we performed molecular docking of the SHV-1 inhibitors commercially available as sulbactam, tazobactam, and avibactam against the constructed model of OKP-B-6. FINDINGS From the point of view of enzyme inhibition, our results indicate that OKP-B-6 should be an extended-spectrum beta-lactamase (ESBL) susceptible to the same drugs as SHV-1. MAIN CONCLUSIONS This conclusion advantageously impacts the clinical control of the bacterial pathogens encoding OKP-B in their genome by using any effective, broad-spectrum, and multitarget inhibitor against SHV-containing bacteria.
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Affiliation(s)
- Reinaldo Bellini
- Laboratório Nacional de Computação Científica, Petrópolis, RJ, Brasil
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3
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Grigorenko VG, Petrova TE, Carolan C, Rubtsova MY, Uporov IV, Pereira J, Chojnowski G, Samygina VR, Lamzin VS, Egorov AM. Crystal structures of the molecular class A β-lactamase TEM-171 and its complexes with tazobactam. Acta Crystallogr D Struct Biol 2022; 78:825-834. [DOI: 10.1107/s2059798322004879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/06/2022] [Indexed: 11/10/2022] Open
Abstract
The resistance of bacteria to β-lactam antibiotics is primarily caused by the production of β-lactamases. Here, novel crystal structures of the native β-lactamase TEM-171 and two complexes with the widely used inhibitor tazobactam are presented, alongside complementary data from UV spectroscopy and fluorescence quenching. The six chemically identical β-lactamase molecules in the crystallographic asymmetric unit displayed different degrees of disorder. The tazobactam intermediate was covalently bound to the catalytic Ser70 in the trans-enamine configuration. While the conformation of tazobactam in the first complex resembled that in published β-lactamase–tazobactam structures, in the second complex, which was obtained after longer soaking of the native crystals in the inhibitor solution, a new and previously unreported tazobactam conformation was observed. It is proposed that the two complexes correspond to different stages along the deacylation path of the acyl-enzyme intermediate. The results provide a novel structural basis for the rational design of new β-lactamase inhibitors.
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Lang PA, Raj R, Tumber A, Lohans CT, Rabe P, Robinson CV, Brem J, Schofield CJ. Studies on enmetazobactam clarify mechanisms of widely used β-lactamase inhibitors. Proc Natl Acad Sci U S A 2022; 119:e2117310119. [PMID: 35486701 PMCID: PMC9170034 DOI: 10.1073/pnas.2117310119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 03/14/2022] [Indexed: 11/18/2022] Open
Abstract
β-Lactams are the most important class of antibacterials, but their use is increasingly compromised by resistance, most importantly via serine β-lactamase (SBL)-catalyzed hydrolysis. The scope of β-lactam antibacterial activity can be substantially extended by coadministration with a penicillin-derived SBL inhibitor (SBLi), i.e., the penam sulfones tazobactam and sulbactam, which are mechanism-based inhibitors working by acylation of the nucleophilic serine. The new SBLi enmetazobactam, an N-methylated tazobactam derivative, has recently completed clinical trials. Biophysical studies on the mechanism of SBL inhibition by enmetazobactam reveal that it inhibits representatives of all SBL classes without undergoing substantial scaffold fragmentation, a finding that contrasts with previous reports on SBL inhibition by tazobactam and sulbactam. We therefore reinvestigated the mechanisms of tazobactam and sulbactam using mass spectrometry under denaturing and nondenaturing conditions, X-ray crystallography, and NMR spectroscopy. The results imply that the reported extensive fragmentation of penam sulfone–derived acyl–enzyme complexes does not substantially contribute to SBL inhibition. In addition to observation of previously identified inhibitor-induced SBL modifications, the results reveal that prolonged reaction of penam sulfones with SBLs can induce dehydration of the nucleophilic serine to give a dehydroalanine residue that undergoes reaction to give a previously unobserved lysinoalanine cross-link. The results clarify the mechanisms of action of widely clinically used SBLi, reveal limitations on the interpretation of mass spectrometry studies concerning mechanisms of SBLi, and will inform the development of new SBLi working by reaction to form hydrolytically stable acyl–enzyme complexes.
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Affiliation(s)
- Pauline A. Lang
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Ritu Raj
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Anthony Tumber
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Christopher T. Lohans
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Patrick Rabe
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Carol V. Robinson
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jürgen Brem
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
- Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford OX1 3TA, United Kingdom
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5
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Cao TP, Yi H, Dhanasingh I, Ghosh S, Choi JM, Lee KH, Ryu S, Kim HS, Lee SH. Non-catalytic-Region Mutations Conferring Transition of Class A β-Lactamases Into ESBLs. Front Mol Biosci 2020; 7:598998. [PMID: 33335913 PMCID: PMC7737660 DOI: 10.3389/fmolb.2020.598998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/28/2020] [Indexed: 12/03/2022] Open
Abstract
Despite class A ESBLs carrying substitutions outside catalytic regions, such as Cys69Tyr or Asn136Asp, have emerged as new clinical threats, the molecular mechanisms underlying their acquired antibiotics-hydrolytic activity remains unclear. We discovered that this non-catalytic-region (NCR) mutations induce significant dislocation of β3-β4 strands, conformational changes in critical residues associated with ligand binding to the lid domain, dynamic fluctuation of Ω-loop and β3-β4 elements. Such structural changes increase catalytic regions’ flexibility, enlarge active site, and thereby accommodate third-generation cephalosporin antibiotics, ceftazidime (CAZ). Notably, the electrostatic property around the oxyanion hole of Cys69Tyr ESBL is significantly changed, resulting in possible additional stabilization of the acyl-enzyme intermediate. Interestingly, the NCR mutations are as effective for antibiotic resistance by altering the structure and dynamics in regions mediating substrate recognition and binding as single amino-acid substitutions in the catalytic region of the canonical ESBLs. We believe that our findings are crucial in developing successful therapeutic strategies against diverse class A ESBLs, including the new NCR-ESBLs.
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Affiliation(s)
- Thinh-Phat Cao
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju, South Korea.,Department of Biomedical Sciences, Gwangju Alzheimer's Disease and Related Dementia Cohort Research Center, College of Natural Sciences and Public Health and Safety, Chosun University, Gwangju, South Korea
| | - Hyojeong Yi
- Division of Biosystems & Biomedical Sciences, College of Health Sciences, Korea University, Seoul, South Korea
| | - Immanuel Dhanasingh
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju, South Korea
| | - Suparna Ghosh
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju, South Korea
| | - Jin Myung Choi
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju, South Korea
| | - Kun Ho Lee
- Department of Biomedical Sciences, Gwangju Alzheimer's Disease and Related Dementia Cohort Research Center, College of Natural Sciences and Public Health and Safety, Chosun University, Gwangju, South Korea.,Aging Neuroscience Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Seol Ryu
- Department of Chemistry, Chosun University, Gwangju, South Korea
| | - Heenam Stanley Kim
- Division of Biosystems & Biomedical Sciences, College of Health Sciences, Korea University, Seoul, South Korea
| | - Sung Haeng Lee
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju, South Korea.,Department of Biomedical Sciences, Gwangju Alzheimer's Disease and Related Dementia Cohort Research Center, College of Natural Sciences and Public Health and Safety, Chosun University, Gwangju, South Korea
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6
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Microwave-assisted one-pot quick synthesis of 1-monosubstituted 1,2,3-triazoles from arylboronic acids, sodium azide and 3-butyn-2-ols. J CHEM SCI 2020. [DOI: 10.1007/s12039-020-01856-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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7
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Cheng Q, Xu C, Chai J, Zhang R, Wai chi Chan E, Chen S. Structural Insight into the Mechanism of Inhibitor Resistance in CTX-M-199, a CTX-M-64 Variant Carrying the S 130T Substitution. ACS Infect Dis 2020; 6:577-587. [PMID: 31709791 DOI: 10.1021/acsinfecdis.9b00345] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The smart design of β-lactamase inhibitors allowed us to combat extended-spectrum β-lactamase (ESBL)-producing organisms for many years without developing resistance to these inhibitors. However, novel resistant variants have emerged recently, and notable examples are the CTX-M-190 and CTX-M-199 variants, which carried a S130T amino acid substitution and exhibited resistance to inhibitors such as sulbactam and tazobactam. Using mass spectrometric and crystallographic approaches, this study depicted the mechanisms of inhibitor resistance. Our data showed that CTX-M-64 (S130T) did not cause any conformational change or exert any effect on its ability to hydrolyze β-lactam substrates. However, binding of sulbactam, but not clavulanic acid, to the active site of CTX-M-64 (S130T) led to the conformational changes in such active site, which comprised the key residues involved in substrate catalysis, namely, Thr130, Lys73, Lys234, Asn104, and Asn132. This conformational change weakened the binding of the sulbactam trans-enamine intermediate (TSL) to the active site and rendered the formation of the inhibitor-enzyme complex, which features a covalent acrylic acid (AKR)-T130 bond, inefficient, thereby resulting in inhibitor resistance in CTX-M-64 (S130T). Understanding the mechanisms of inhibitor resistance provided structural insight for the future development of new inhibitors against inhibitor-resistant β-lactamases.
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Affiliation(s)
- Qipeng Cheng
- State Key Lab of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chen Xu
- State Key Lab of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Jiachang Chai
- Department of Clinical Medicine, Second Affiliated Hospital of Zhejiang University, Hangzhou 310009, China
| | - Rong Zhang
- Department of Clinical Medicine, Second Affiliated Hospital of Zhejiang University, Hangzhou 310009, China
| | - Edward Wai chi Chan
- State Key Lab of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Sheng Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
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8
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Daraie M, Heravi MM, Sarmasti N. Synthesis of polymer-supported Zn(II) as a novel and green nanocatalyst for promoting click reactions and using design of experiment for optimization of reaction conditions. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2020. [DOI: 10.1080/10601325.2020.1725389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Mansoureh Daraie
- Department of Chemistry, School of Science, Alzahra University, Vanak, Tehran, Iran
| | - Majid M. Heravi
- Department of Chemistry, School of Science, Alzahra University, Vanak, Tehran, Iran
| | - Negin Sarmasti
- Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
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9
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Cifuentes-Castro V, Rodríguez-Almazán C, Silva-Sánchez J, Rudiño-Piñera E. The crystal structure of ESBL TLA-1 in complex with clavulanic acid reveals a second acylation site. Biochem Biophys Res Commun 2020; 522:545-551. [PMID: 31780261 DOI: 10.1016/j.bbrc.2019.11.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 11/20/2019] [Indexed: 11/28/2022]
Abstract
β-lactamases are the main molecules responsible for giving bacterial resistance against β-lactam antibiotics. The study of β-lactamases has allowed the development of antibiotics capable of inhibiting these enzymes. In this context, extended spectrum β-lactamase (ESBL) TLA-1 has spread in Escherichia coli and Enterobacter cloacae clinical isolates during the last 30 years in Mexico. In this research, the 3D structures of ESBL TLA-1 and TLA-1 S70G mutant, both ligand-free and in complex with clavulanic acid were determined by X-ray crystallography. Four clavulanic acid molecules were found in the structure of TLA-1, two of those were intermediaries of the acylation process and were localized covalently bound to two different amino acid residues, Ser70 and Ser237. The coordinates of TLA-1 in complex with clavulanic acid shows the existence of a second acylation site, additional to Ser70, which might be extendable to several members of the subclass A β-lactamases family. This is the first time that two serines involved in binding clavulanic acid has been reported and described to an atomic level.
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Affiliation(s)
- Víctor Cifuentes-Castro
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, C.P. 62210, Cuernavaca, Morelos, Mexico
| | - Claudia Rodríguez-Almazán
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, C.P. 62210, Cuernavaca, Morelos, Mexico
| | - Jesús Silva-Sánchez
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Enrique Rudiño-Piñera
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, C.P. 62210, Cuernavaca, Morelos, Mexico.
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10
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Shurina BA, Page RC. Influence of substrates and inhibitors on the structure of Klebsiella pneumoniae carbapenemase-2. Exp Biol Med (Maywood) 2019; 244:1596-1604. [PMID: 31161945 DOI: 10.1177/1535370219854322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The hydrolysis of last resort carbapenem antibiotics by Klebsiella pneumoniae carbapenemase-2 (KPC-2) presents a significant danger to global health. Combined with horizontal gene transfer, the emergence KPC-2 threatens to quickly expand carbapenemase activity to ever increasing numbers of pathogens. Our understanding of KPC-2 has greatly increased over the past decade thanks, in great part, to 20 crystal structures solved by groups around the world. These include apo KPC-2 structures, along with structures featuring a library of 10 different inhibitors representing diverse structural and functional classes. Herein we focus on cataloging the available KPC-2 structures and presenting a discussion of key aspects of each structure and important relationships between structures. Although the available structures do not provide information on dynamic motions with KPC-2, and the family of structures indicates small conformational changes across a wide array of bound inhibitors, substrates, and products, the structures provide a strong foundation for additional studies in the coming years to discover new KPC-2 inhibitors. Impact statement The work herein is important to the field as it provides a clear and succinct accounting of available KPC-2 structures. The work advances the field by collecting and analyzing differences and similarities across the available structures. This work features new analyses and interpretations of the existing structures which will impact the field in a positive way by making structural insights more widely available among the beta-lactamase community.
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Affiliation(s)
- Ben A Shurina
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
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11
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Regioselective Synthesis, Molecular Descriptors of (1,5‐Disubstituted 1,2,3‐Triazolyl)Coumarin/Quinolone Derivatives and Their Docking Studies against Cancer Targets. ChemistrySelect 2019. [DOI: 10.1002/slct.201900114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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12
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Tassoni R, Blok A, Pannu NS, Ubbink M. New Conformations of Acylation Adducts of Inhibitors of β-Lactamase from Mycobacterium tuberculosis. Biochemistry 2019; 58:997-1009. [PMID: 30632739 PMCID: PMC6383187 DOI: 10.1021/acs.biochem.8b01085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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Mycobacterium tuberculosis (Mtb), the main causative
agent of tuberculosis (TB), is naturally resistant to β-lactam
antibiotics due to the production of the extended spectrum β-lactamase
BlaC. β-Lactam/β-lactamase inhibitor combination therapies
can circumvent the BlaC-mediated resistance of Mtb and are promising
treatment options against TB. However, still little is known of the
exact mechanism of BlaC inhibition by the β-lactamase inhibitors
currently approved for clinical use, clavulanic acid, sulbactam, tazobactam,
and avibactam. Here, we present the X-ray diffraction crystal structures
of the acyl-enzyme adducts of wild-type BlaC with the four inhibitors.
The +70 Da adduct derived from clavulanate and the trans-enamine acylation adducts of sulbactam and tazobactam are reported.
BlaC in complex with avibactam revealed two inhibitor conformations.
Preacylation binding could not be observed because inhibitor binding
was not detected in BlaC variants carrying a substitution of the active
site serine 70 to either alanine or cysteine, by crystallography,
ITC or NMR. These results suggest that the catalytic serine 70 is
necessary not only for enzyme acylation but also for increasing BlaC
affinity for inhibitors in the preacylation state. The structure of
BlaC with the serine to cysteine mutation showed a covalent linkage
of the cysteine 70 Sγ atom to the nearby amino group of lysine
73. The differences of adduct conformations between BlaC and other
β-lactamases are discussed.
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Affiliation(s)
- Raffaella Tassoni
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , Leiden 2333CC , The Netherlands
| | - Anneloes Blok
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , Leiden 2333CC , The Netherlands
| | - Navraj S Pannu
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , Leiden 2333CC , The Netherlands
| | - Marcellus Ubbink
- Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , Leiden 2333CC , The Netherlands
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13
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Pereira R, Rabelo VWH, Sibajev A, Abreu PA, Castro HC. Class A β-lactamases and inhibitors: In silico analysis of the binding mode and the relationship with resistance. J Biotechnol 2018; 279:37-46. [PMID: 29753682 DOI: 10.1016/j.jbiotec.2018.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/22/2018] [Accepted: 05/03/2018] [Indexed: 02/01/2023]
Abstract
β-lactams are one of the most common antimicrobials used to treat bacterial infections. However, bacterial resistance has compromised their efficacy, mainly due to the β-lactamase enzyme production. To overcome this resistance, β-lactamase inhibitors can be used in association with these antimicrobials. Herein, we analyzed the structural characteristics of β-lactamases and their interactions with classical inhibitors, such as clavulanic acid (CA), sulbactam (SB) and tazobactam (TZ) to gain insights into resistance. The homology models of five class A β-lactamases, namely CARB-3, IMI-1, SFO-1, SHV-5 and TEM-10, were constructed and validated and revealed an overall 3D structural conservation, but with significant differences in the electrostatic potential maps, especially at important regions in the catalytic site. Molecular dockings of CA, SB and TZ with these enzymes revealed a covalent bond with the S70 in all complexes, except Carb-3 which is in agreement with experimental data reported so far. This is likely related to the less voluminous active site of Carb-3 model. Although few specific contacts were observed in the β-lactamase-inhibitor complexes, all compounds interacted with the residues in positions 73, 130, 132, 236 and 237. Therefore, this study provides new perspectives for the design of innovative compounds with broad-spectrum inhibitory profiles against β-lactamases.
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Affiliation(s)
- Rebeca Pereira
- Programa de Pós-graduação em Ciências e Biotecnologia - Instituto de Biologia, Universidade Federal Fluminense, Campus do Valonguinho, Niterói, RJ, CEP 24210-130, Brazil
| | - Vitor Won-Held Rabelo
- Programa de Pós-graduação em Ciências e Biotecnologia - Instituto de Biologia, Universidade Federal Fluminense, Campus do Valonguinho, Niterói, RJ, CEP 24210-130, Brazil; Laboratório de Modelagem Molecular e Pesquisa em Ciências Farmacêuticas, Universidade Federal do Rio de Janeiro, Campus Macaé, RJ, CEP 27965-045, Brazil
| | - Alexander Sibajev
- Centro de Ciências da Saúde - Curso de Medicina, Universidade Federal de Roraima, Campus do Paricarana, Boa Vista, RR, CEP 69304-000, Brazil
| | - Paula Alvarez Abreu
- Laboratório de Modelagem Molecular e Pesquisa em Ciências Farmacêuticas, Universidade Federal do Rio de Janeiro, Campus Macaé, RJ, CEP 27965-045, Brazil.
| | - Helena Carla Castro
- Programa de Pós-graduação em Ciências e Biotecnologia - Instituto de Biologia, Universidade Federal Fluminense, Campus do Valonguinho, Niterói, RJ, CEP 24210-130, Brazil.
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14
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Fritz RA, Alzate-Morales JH, Spencer J, Mulholland AJ, van der Kamp MW. Multiscale Simulations of Clavulanate Inhibition Identify the Reactive Complex in Class A β-Lactamases and Predict the Efficiency of Inhibition. Biochemistry 2018; 57:3560-3563. [PMID: 29812917 DOI: 10.1021/acs.biochem.8b00480] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Clavulanate is used as an effective drug in combination with β-lactam antibiotics to treat infections of some antibiotic resistant bacteria. Here, we perform combined quantum mechanics/molecular mechanics simulations of several covalent complexes of clavulanate with class A β-lactamases KPC-2 and TEM-1. Simulations of the deacylation reactions identify the decarboxylated trans-enamine complex as being responsible for inhibition. Further, the obtained free energy barriers discriminate clinically relevant inhibition (TEM-1) from less effective inhibition (KPC-2).
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Affiliation(s)
- Rubén A Fritz
- Center for Bioinformatics and Molecular Simulations, Faculty of Engineering , University of Talca , Talca , Chile
| | - Jans H Alzate-Morales
- Center for Bioinformatics and Molecular Simulations, Faculty of Engineering , University of Talca , Talca , Chile
| | - James Spencer
- School of Cellular and Molecular Medicine , University of Bristol , University Walk , Bristol BS8 1TD , U.K
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
| | - Marc W van der Kamp
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
- School of Biochemistry , University of Bristol , University Walk , Bristol BS8 1TD , U.K
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15
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van den Akker F, Bonomo RA. Exploring Additional Dimensions of Complexity in Inhibitor Design for Serine β-Lactamases: Mechanistic and Intra- and Inter-molecular Chemistry Approaches. Front Microbiol 2018; 9:622. [PMID: 29675000 PMCID: PMC5895744 DOI: 10.3389/fmicb.2018.00622] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/19/2018] [Indexed: 01/14/2023] Open
Abstract
As a bacterial resistance strategy, serine β-lactamases have evolved from cell wall synthesizing enzymes known as penicillin-binding proteins (PBP), by not only covalently binding β-lactam antibiotics but, also acquiring mechanisms of deacylating these antibiotics. This critical deacylation step leads to release of hydrolyzed and inactivated β-lactams, thereby providing resistance for the bacteria against these antibiotics targeting the cell wall. To combat β-lactamase-mediated antibiotic resistance, numerous β-lactamase inhibitors were developed that utilize various strategies to inactivate the β-lactamase. Most of these compounds are “mechanism-based” inhibitors that in some manner mimic the β-lactam substrate, having a carbonyl moiety and a negatively charged carboxyl or sulfate group. These compounds form a covalent adduct with the catalytic serine via an initial acylation step. To increase the life-time of the inhibitory covalent adduct intermediates, a remarkable array of different strategies was employed to improve inhibition potency. Such approaches include post-acylation intra- and intermolecular chemical rearrangements as well as affecting the deacylation water. These approaches transform the inhibitor design process from a 3-dimensional problem (i.e., XYZ coordinates) to one with additional dimensions of complexity as the reaction coordinate and time spent at each chemical state need to be taken into consideration. This review highlights the mechanistic intricacies of the design efforts of the β-lactamase inhibitors which so far have resulted in the development of “two generations” and 5 clinically available inhibitors.
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Affiliation(s)
- Focco van den Akker
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Robert A Bonomo
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States.,Medicine, Pharmacology, Molecular Biology and Microbiology, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, United States.,Medical Service and Geriatric Research, Education, and Clinical Centers (GRECC), Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States.,Case Western Reserve University-VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, United States
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16
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Latallo MJ, Cortina GA, Faham S, Nakamoto RK, Kasson PM. Predicting allosteric mutants that increase activity of a major antibiotic resistance enzyme. Chem Sci 2017; 8:6484-6492. [PMID: 28989673 PMCID: PMC5628580 DOI: 10.1039/c7sc02676e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Allosteric mutations increasing kcat in a beta lactamase act by changing conformational ensembles of active-site residues identified by machine learning.
The CTX-M family of beta lactamases mediate broad-spectrum antibiotic resistance and are present in the majority of drug-resistant Gram-negative bacterial infections worldwide. Allosteric mutations that increase catalytic rates of these drug resistance enzymes have been identified in clinical isolates but are challenging to predict prospectively. We have used molecular dynamics simulations to predict allosteric mutants increasing CTX-M9 drug resistance, experimentally testing top mutants using multiple antibiotics. Purified enzymes show an increase in catalytic rate and efficiency, while mutant crystal structures show no detectable changes from wild-type CTX-M9. We hypothesize that increased drug resistance results from changes in the conformational ensemble of an acyl intermediate in hydrolysis. Machine-learning analyses on the three top mutants identify changes to the binding-pocket conformational ensemble by which these allosteric mutations transmit their effect. These findings show how molecular simulation can predict how allosteric mutations alter active-site conformational equilibria to increase catalytic rates and thus resistance against common clinically used antibiotics.
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Affiliation(s)
- M J Latallo
- Department of Molecular Physiology , University of Virginia , Box 800886 , Charlottesville , VA 22908 , USA .
| | - G A Cortina
- Department of Molecular Physiology , University of Virginia , Box 800886 , Charlottesville , VA 22908 , USA . .,Department of Biomedical Engineering , University of Virginia , USA
| | - S Faham
- Department of Molecular Physiology , University of Virginia , Box 800886 , Charlottesville , VA 22908 , USA .
| | - R K Nakamoto
- Department of Molecular Physiology , University of Virginia , Box 800886 , Charlottesville , VA 22908 , USA .
| | - P M Kasson
- Department of Molecular Physiology , University of Virginia , Box 800886 , Charlottesville , VA 22908 , USA . .,Department of Biomedical Engineering , University of Virginia , USA.,Science for Life Laboratory , Department of Cell and Molecular Biology , Uppsala University , Sweden
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17
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Chellat MF, Raguž L, Riedl R. Targeting Antibiotic Resistance. Angew Chem Int Ed Engl 2016; 55:6600-26. [PMID: 27000559 PMCID: PMC5071768 DOI: 10.1002/anie.201506818] [Citation(s) in RCA: 280] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 10/10/2015] [Indexed: 12/11/2022]
Abstract
Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human-pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even last-resort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled "Combat drug resistance: no action today means no cure tomorrow" triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens.
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Affiliation(s)
- Mathieu F Chellat
- Institute of Chemistry and Biotechnology, Center for Organic and Medicinal Chemistry, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820, Wädenswil, Switzerland
| | - Luka Raguž
- Institute of Chemistry and Biotechnology, Center for Organic and Medicinal Chemistry, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820, Wädenswil, Switzerland
| | - Rainer Riedl
- Institute of Chemistry and Biotechnology, Center for Organic and Medicinal Chemistry, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820, Wädenswil, Switzerland.
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18
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Affiliation(s)
- Mathieu F. Chellat
- Institut für Chemie und Biotechnologie, FS Organische Chemie und Medizinalchemie; Zürcher Hochschule für Angewandte Wissenschaften (ZHAW); Einsiedlerstrasse 31 CH-8820 Wädenswil Schweiz
| | - Luka Raguž
- Institut für Chemie und Biotechnologie, FS Organische Chemie und Medizinalchemie; Zürcher Hochschule für Angewandte Wissenschaften (ZHAW); Einsiedlerstrasse 31 CH-8820 Wädenswil Schweiz
| | - Rainer Riedl
- Institut für Chemie und Biotechnologie, FS Organische Chemie und Medizinalchemie; Zürcher Hochschule für Angewandte Wissenschaften (ZHAW); Einsiedlerstrasse 31 CH-8820 Wädenswil Schweiz
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19
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Crystal Structures of KPC-2 and SHV-1 β-Lactamases in Complex with the Boronic Acid Transition State Analog S02030. Antimicrob Agents Chemother 2016; 60:1760-6. [PMID: 26729491 DOI: 10.1128/aac.02643-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 12/27/2015] [Indexed: 01/29/2023] Open
Abstract
Resistance to expanded-spectrum cephalosporins and carbapenems has rendered certain strains of Klebsiella pneumoniae the most problematic pathogens infecting patients in the hospital and community. This broad-spectrum resistance to β-lactamases emerges in part via the expression of KPC-2 and SHV-1 β-lactamases and variants thereof. KPC-2 carbapenemase is particularly worrisome, as the genetic determinant encoding this β-lactamase is rapidly spread via plasmids. Moreover, KPC-2, a class A enzyme, is difficult to inhibit with mechanism-based inactivators (e.g., clavulanate). In order to develop new β-lactamase inhibitors (BLIs) to add to the limited available armamentarium that can inhibit KPC-2, we have structurally probed the boronic acid transition state analog S02030 for its inhibition of KPC-2 and SHV-1. S02030 contains a boronic acid, a thiophene, and a carboxyl triazole moiety. We present here the 1.54- and 1.87-Å resolution crystal structures of S02030 bound to SHV-1 and KPC-2 β-lactamases, respectively, as well as a comparative analysis of the S02030 binding modes, including a previously determined S02030 class C ADC-7 β-lactamase complex. S02030 is able to inhibit vastly different serine β-lactamases by interacting with the conserved features of these active sites, which includes (i) forming the bond with catalytic serine via the boron atom, (ii) positioning one of the boronic acid oxygens in the oxyanion hole, and (iii) utilizing its amide moiety to make conserved interactions across the width of the active site. In addition, S02030 is able to overcome more distantly located structural differences between the β-lactamases. This unique feature is achieved by repositioning the more polar carboxyl-triazole moiety, generated by click chemistry, to create polar interactions as well as reorient the more hydrophobic thiophene moiety. The former is aided by the unusual polar nature of the triazole ring, allowing it to potentially form a unique C-H…O 2.9-Å hydrogen bond with S130 in KPC-2.
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20
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21
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Exposing a β-Lactamase "Twist": the Mechanistic Basis for the High Level of Ceftazidime Resistance in the C69F Variant of the Burkholderia pseudomallei PenI β-Lactamase. Antimicrob Agents Chemother 2015; 60:777-88. [PMID: 26596949 DOI: 10.1128/aac.02073-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/08/2015] [Indexed: 12/31/2022] Open
Abstract
Around the world, Burkholderia spp. are emerging as pathogens highly resistant to β-lactam antibiotics, especially ceftazidime. Clinical variants of Burkholderia pseudomallei possessing the class A β-lactamase PenI with substitutions at positions C69 and P167 are known to demonstrate ceftazidime resistance. However, the biochemical basis for ceftazidime resistance in class A β-lactamases in B. pseudomallei is largely undefined. Here, we performed site saturation mutagenesis of the C69 position and investigated the kinetic properties of the C69F variant of PenI from B. pseudomallei that results in a high level of ceftazidime resistance (2 to 64 mg/liter) when expressed in Escherichia coli. Surprisingly, quantitative immunoblotting showed that the steady-state protein levels of the C69F variant β-lactamase were ∼4-fold lower than those of wild-type PenI (0.76 fg of protein/cell versus 4.1 fg of protein/cell, respectively). However, growth in the presence of ceftazidime increases the relative amount of the C69F variant to greater than wild-type PenI levels. The C69F variant exhibits a branched kinetic mechanism for ceftazidime hydrolysis, suggesting there are two different conformations of the enzyme. When incubated with an anti-PenI antibody, one conformation of the C69F variant rapidly hydrolyzes ceftazidime and most likely contributes to the higher levels of ceftazidime resistance observed in cell-based assays. Molecular dynamics simulations suggest that the electrostatic characteristics of the oxyanion hole are altered in the C69F variant. When ceftazidime was positioned in the active site, the C69F variant is predicted to form a greater number of hydrogen-bonding interactions than PenI with ceftazidime. In conclusion, we propose "a new twist" for enhanced ceftazidime resistance mediated by the C69F variant of the PenI β-lactamase based on conformational changes in the C69F variant. Our findings explain the biochemical basis of ceftazidime resistance in B. pseudomallei, a pathogen of considerable importance, and suggest that the full repertoire of conformational states of a β-lactamase profoundly affects β-lactam resistance.
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22
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Carey PR, Heidari-Torkabadi H. New techniques in antibiotic discovery and resistance: Raman spectroscopy. Ann N Y Acad Sci 2015; 1354:67-81. [PMID: 26275225 DOI: 10.1111/nyas.12847] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 11/29/2022]
Abstract
Raman spectroscopy can play a role in both antibiotic discovery and understanding the molecular basis of resistance. A major challenge in drug development is to measure the population of the drug molecules inside a cell line and to follow the chemistry of their reactions with intracellular targets. Recently, a protocol based on Raman microscopy has been developed that achieves these goals. Drug candidates are soaked into live bacterial cells and subsequently the cells are frozen and freeze-dried. The samples yield exemplary (nonresonance) Raman data that provide a measure of the number of drug molecules within each cell, as well as details of drug-target interactions. Results are discussed for two classes of compounds inhibiting either β-lactamase or dihydrofolate reductase enzymes in a number of Gram-positive or Gram-negative cell lines. The advantages of the present protocol are that it does not use labels and it can measure the kinetics of cell-compound uptake on the time scale of minutes. Spectroscopic interpretation is supported by in vitro Raman experiments. Studying drug-target interactions in aqueous solution and in single crystals can provide molecular level insights into drug-target interactions, which, in turn, provide the underpinnings of our understanding of data from bacterial cells. Thus, the applicability of X-ray crystallographic-derived data to in-cell chemistry can be tested.
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Affiliation(s)
- Paul R Carey
- Department of Biochemistry.,Department of Chemistry, Case Western Reserve University, Cleveland, Ohio
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23
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Avibactam and inhibitor-resistant SHV β-lactamases. Antimicrob Agents Chemother 2015; 59:3700-9. [PMID: 25691639 DOI: 10.1128/aac.04405-14] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/18/2015] [Indexed: 11/20/2022] Open
Abstract
β-Lactamase enzymes (EC 3.5.2.6) are a significant threat to the continued use of β-lactam antibiotics to treat infections. A novel non-β-lactam β-lactamase inhibitor with activity against many class A and C and some class D β-lactamase variants, avibactam, is now available in the clinic in partnership with ceftazidime. Here, we explored the activity of avibactam against a variety of characterized isogenic laboratory constructs of β-lactamase inhibitor-resistant variants of the class A enzyme SHV (M69I/L/V, S130G, K234R, R244S, and N276D). We discovered that the S130G variant of SHV-1 shows the most significant resistance to inhibition by avibactam, based on both microbiological and biochemical characterizations. Using a constant concentration of 4 mg/liter of avibactam as a β-lactamase inhibitor in combination with ampicillin, the MIC increased from 1 mg/liter for blaSHV-1 to 256 mg/liter for blaSHV S130G expressed in Escherichia coli DH10B. At steady state, the k2/K value of the S130G variant when inactivated by avibactam was 1.3 M(-1) s(-1), versus 60,300 M(-1) s(-1) for the SHV-1 β-lactamase. Under timed inactivation conditions, we found that an approximately 1,700-fold-higher avibactam concentration was required to inhibit SHV S130G than the concentration that inhibited SHV-1. Molecular modeling suggested that the positioning of amino acids in the active site of SHV may result in an alternative pathway of inactivation when complexed with avibactam, compared to the structure of CTX-M-15-avibactam, and that S130 plays a role in the acylation of avibactam as a general acid/base. In addition, S130 may play a role in recyclization. As a result, we advance that the lack of a hydroxyl group at position 130 in the S130G variant of SHV-1 substantially slows carbamylation of the β-lactamase by avibactam by (i) removing an important proton acceptor and donator in catalysis and (ii) decreasing the number of H bonds. In addition, recyclization is most likely also slow due to the lack of a general base to initiate the process. Considering other inhibitor-resistant mechanisms among class A β-lactamases, S130 may be the most important amino acid for the inhibition of class A β-lactamases, perhaps even for the novel diazabicyclooctane class of β-lactamase inhibitors.
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24
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Crystal structure of the extended-spectrum β-lactamase PER-2 and insights into the role of specific residues in the interaction with β-lactams and β-lactamase inhibitors. Antimicrob Agents Chemother 2014; 58:5994-6002. [PMID: 25070104 DOI: 10.1128/aac.00089-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PER-2 belongs to a small (7 members to date) group of extended-spectrum β-lactamases. It has 88% amino acid identity with PER-1 and both display high catalytic efficiencies toward most β-lactams. In this study, we determined the X-ray structure of PER-2 at 2.20 Å and evaluated the possible role of several residues in the structure and activity toward β-lactams and mechanism-based inhibitors. PER-2 is defined by the presence of a singular trans bond between residues 166 to 167, which generates an inverted Ω loop, an expanded fold of this domain that results in a wide active site cavity that allows for efficient hydrolysis of antibiotics like the oxyimino-cephalosporins, and a series of exclusive interactions between residues not frequently involved in the stabilization of the active site in other class A β-lactamases. PER β-lactamases might be included within a cluster of evolutionarily related enzymes harboring the conserved residues Asp136 and Asn179. Other signature residues that define these enzymes seem to be Gln69, Arg220, Thr237, and probably Arg/Lys240A ("A" indicates an insertion according to Ambler's scheme for residue numbering in PER β-lactamases), with structurally important roles in the stabilization of the active site and proper orientation of catalytic water molecules, among others. We propose, supported by simulated models of PER-2 in combination with different β-lactams, the presence of a hydrogen-bond network connecting Ser70-Gln69-water-Thr237-Arg220 that might be important for the proper activity and inhibition of the enzyme. Therefore, we expect that mutations occurring in these positions will have impacts on the overall hydrolytic behavior.
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25
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Rodkey EA, McLeod DC, Bethel CR, Smith KM, Xu Y, Chai W, Che T, Carey PR, Bonomo RA, van den Akker F, Buynak JD. β-Lactamase inhibition by 7-alkylidenecephalosporin sulfones: allylic transposition and formation of an unprecedented stabilized acyl-enzyme. J Am Chem Soc 2013; 135:18358-69. [PMID: 24219313 PMCID: PMC4042847 DOI: 10.1021/ja403598g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The inhibition of the class A SHV-1 β-lactamase by 7-(tert-butoxycarbonyl)methylidenecephalosporin sulfone was examined kinetically, spectroscopically, and crystallographically. An 1.14 Å X-ray crystal structure shows that the stable acyl-enzyme, which incorporates an eight-membered ring, is a covalent derivative of Ser70 linked to the 7-carboxy group of 2-H-5,8-dihydro-1,1-dioxo-1,5-thiazocine-4,7-dicarboxylic acid. A cephalosporin-derived enzyme complex of this type is unprecedented, and the rearrangement leading to its formation may offer new possibilities for inhibitor design. The observed acyl-enzyme derives its stability from the resonance stabilization conveyed by the β-aminoacrylate (i.e., vinylogous urethane) functionality as there is relatively little interaction of the eight-membered ring with active site residues. Two mechanistic schemes are proposed, differing in whether, subsequent to acylation of the active site serine and opening of the β-lactam, the resultant dihydrothiazine fragments on its own or is assisted by an adjacent nucleophilic atom, in the form of the carbonyl oxygen of the C7 tert-butyloxycarbonyl group. This compound was also found to be a submicromolar inhibitor of the class C ADC-7 and PDC-3 β-lactamases.
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Affiliation(s)
- Elizabeth A. Rodkey
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106, United States
| | - David C. McLeod
- Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275, United States
| | - Christopher R. Bethel
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106, United States
| | - Kerri M. Smith
- Department of Chemistry, Cleveland State University, 2121 Euclid Ave., Cleveland, Ohio 44115, United States
| | - Yan Xu
- Department of Chemistry, Cleveland State University, 2121 Euclid Ave., Cleveland, Ohio 44115, United States
| | - Weirui Chai
- Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275, United States
| | - Tao Che
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106, United States
| | - Paul R. Carey
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106, United States
| | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106, United States
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106, United States
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275, United States
- Center for Drug Discovery, Design, and Development, Southern Methodist University, Dallas, Texas 75275, United States
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26
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N152G, -S, and -T substitutions in CMY-2 β-lactamase increase catalytic efficiency for cefoxitin and inactivation rates for tazobactam. Antimicrob Agents Chemother 2013; 57:1596-602. [PMID: 23318801 DOI: 10.1128/aac.01334-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Class C cephalosporinases are a growing threat, and clinical inhibitors of these enzymes are currently unavailable. Previous studies have explored the role of Asn152 in the Escherichia coli AmpC and P99 enzymes and have suggested that interactions between C-6' or C-7' substituents on penicillins or cephalosporins and Asn152 are important in determining substrate specificity and enzymatic stability. We sought to characterize the role of Asn152 in the clinically important CMY-2 cephalosporinase with substrates and inhibitors. Mutagenesis of CMY-2 at position 152 yields functional mutants (N152G, -S, and -T) that exhibit improved penicillinase activity and retain cephamycinase activity. We also tested whether the position 152 substitutions would affect the inactivation kinetics of tazobactam, a class A β-lactamase inhibitor with in vitro activity against CMY-2. Using standard assays, we showed that the N152G, -S, and -T variants possessed increased catalytic activity against cefoxitin compared to the wild type. The 50% inhibitory concentration (IC50) for tazobactam improved dramatically, with an 18-fold reduction for the N152S mutant due to higher rates of enzyme inactivation. Modeling studies have shown active-site expansion due to interactions between Y150 and S152 in the apoenzyme and the Michaelis-Menten complex with tazobactam. Substitutions at N152 might become clinically important as new class C β-lactamase inhibitors are developed.
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27
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Rodkey EA, Drawz SM, Sampson JM, Bethel CR, Bonomo RA, van den Akker F. Crystal structure of a preacylation complex of the β-lactamase inhibitor sulbactam bound to a sulfenamide bond-containing thiol-β-lactamase. J Am Chem Soc 2012; 134:16798-804. [PMID: 22974281 DOI: 10.1021/ja3073676] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The rise of inhibitor-resistant and other β-lactamase variants is generating an interest in developing new β-lactamase inhibitors to complement currently available antibiotics. To gain insight into the chemistry of inhibitor recognition, we determined the crystal structure of the inhibitor preacylation complex of sulbactam, a clinical β-lactamase inhibitor, bound in the active site of the S70C variant of SHV-1 β-lactamase, a resistance enzyme that is normally present in Klebsiella pneumoniae. The S70C mutation was designed to affect the reactivity of that catalytic residue to allow for capture of the preacylation complex. Unexpectedly, the 1.45 Å resolution inhibitor complex structure revealed that residue C70 is involved in a sulfenamide bond with K73. Such a covalent bond is not present in the wild-type SHV-1 or in an apo S70C structure also determined in this study. This bond likely contributed significantly to obtaining the preacylation complex with sulbactam due to further decreased reactivity toward substrates. The intact sulbactam is positioned in the active site such that its carboxyl moiety interacts with R244, S130, and T235 and its carbonyl moiety is situated in the oxyanion hole. To our knowledge, in addition to being the first preacylation inhibitor β-lactamase complex, this is also the first observation of a sulfenamide bond between a cysteine and lysine in an active site. Not only could our results aid, therefore, structure-based inhibitor design efforts in class A β-lactamases, but the sulfenamide-bond forming approach to yield preacylation complexes could also be applied to other classes of β-lactamases and penicillin-binding proteins with the SXXK motif.
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Affiliation(s)
- Elizabeth A Rodkey
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
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Structure of an engineered β-lactamase maltose binding protein fusion protein: insights into heterotropic allosteric regulation. PLoS One 2012; 7:e39168. [PMID: 22720063 PMCID: PMC3375305 DOI: 10.1371/journal.pone.0039168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/16/2012] [Indexed: 11/21/2022] Open
Abstract
Engineering novel allostery into existing proteins is a challenging endeavor to obtain novel sensors, therapeutic proteins, or modulate metabolic and cellular processes. The RG13 protein achieves such allostery by inserting a circularly permuted TEM-1 β-lactamase gene into the maltose binding protein (MBP). RG13 is positively regulated by maltose yet is, serendipitously, inhibited by Zn2+ at low µM concentration. To probe the structure and allostery of RG13, we crystallized RG13 in the presence of mM Zn2+ concentration and determined its structure. The structure reveals that the MBP and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn2+ acts to “twist tie” the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical β3 and β4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn2+ site only slightly affected Zn2+ inhibition 2- to 4-fold. Combined with previous mutagenesis results we therefore hypothesize the presence of two or more inter-domain mutually exclusive inhibitory Zn2+ sites. Mutagenesis and molecular modeling of an intact TEM-1 domain near MBP within the RG13 framework indicated a close surface proximity of the two domains with maltose switching being critically dependent on MBP linker anchoring residues and linker length. Structural analysis indicated that the linker attachment sites on MBP are at a site that, upon maltose binding, harbors both the largest local Cα distance changes and displays surface curvature changes, from concave to relatively flat becoming thus less sterically intrusive. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 β3 linker region via steric and/or linker juxtapositioning mechanisms.
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Ke W, Rodkey EA, Sampson JM, Skalweit MJ, Sheri A, Pagadala SRR, Nottingham MD, Buynak JD, Bonomo RA, van den Akker F. The importance of the trans-enamine intermediate as a β-lactamase inhibition strategy probed in inhibitor-resistant SHV β-lactamase variants. ChemMedChem 2012; 7:1002-8. [PMID: 22438274 DOI: 10.1002/cmdc.201200006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Indexed: 11/07/2022]
Abstract
The ability of bacteria to express inhibitor-resistant (IR) β-lactamases is stimulating the development of novel inhibitors of these enzymes. The 2'β-glutaroxypenicillinate sulfone, SA2-13, was previously designed to enhance the stabilization of the deacylation-refractory, trans-enamine inhibitory intermediate. To test whether this mode of inhibition can overcome different IR mutations, we determined the binding mode of SA2-13 through X-ray crystallography, obtaining co-crystals of the inhibitor-protein complex by soaking crystals of the IR sulfhydryl variable (SHV) β-lactamase variants S130G and M69V with the inhibitor. The 1.45 Å crystal structure of the S130G SHV:SA2-13 complex reveals that SA2-13 is still able to form the stable trans-enamine intermediate similar to the wild-type complex structure, yet with its carboxyl linker shifted deeper into the active site in the space vacated by the S130G mutation. In contrast, data from crystals of the M69V SHV:SA2-13 complex at 1.3 Å did not reveal clear inhibitor density indicating that this IR variant disfavors the trans-enamine conformation, likely due to a subtle shift in A237.
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Affiliation(s)
- Wei Ke
- Department of Biochemistry, RT500, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Frase H, Smith CA, Toth M, Champion MM, Mobashery S, Vakulenko SB. Identification of products of inhibition of GES-2 beta-lactamase by tazobactam by x-ray crystallography and spectrometry. J Biol Chem 2011; 286:14396-409. [PMID: 21345789 PMCID: PMC3077639 DOI: 10.1074/jbc.m110.208744] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/19/2011] [Indexed: 01/28/2023] Open
Abstract
The GES-2 β-lactamase is a class A carbapenemase, the emergence of which in clinically important bacterial pathogens is a disconcerting development as the enzyme confers resistance to carbapenem antibiotics. Tazobactam is a clinically used inhibitor of class A β-lactamases, which inhibits the GES-2 enzyme effectively, restoring susceptibility to β-lactam antibiotics. We have investigated the details of the mechanism of inhibition of the GES-2 enzyme by tazobactam. By the use of UV spectrometry, mass spectroscopy, and x-ray crystallography, we have documented and identified the involvement of a total of seven distinct GES-2·tazobactam complexes and one product of the hydrolysis of tazobactam that contribute to the inhibition profile. The x-ray structures for the GES-2 enzyme are for both the native (1.45 Å) and the inhibited complex with tazobactam (1.65 Å). This is the first such structure of a carbapenemase in complex with a clinically important β-lactam inhibitor, shedding light on the structural implications for the inhibition process.
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Affiliation(s)
- Hilary Frase
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 and
| | - Clyde A. Smith
- the Stanford Synchrotron Radiation Laboratory, Stanford University, Menlo Park, California 94025
| | - Marta Toth
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 and
| | - Matthew M. Champion
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 and
| | - Shahriar Mobashery
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 and
| | - Sergei B. Vakulenko
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 and
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Carey PR, Chen Y, Gong B, Kalp M. Kinetic crystallography by Raman microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:742-9. [PMID: 20797452 DOI: 10.1016/j.bbapap.2010.08.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/12/2010] [Accepted: 08/16/2010] [Indexed: 11/16/2022]
Abstract
Raman spectra, obtained using a Raman microscope, offer a unique and incisive approach to follow interactions and reactions inside a single crystal under soak-in or soak-out conditions. The utility of this approach derives from the finding that the Raman spectra from single macromolecular crystals, under normal (non-resonance) conditions, are extremely stable, with a low "light background," and provide ideal platforms for Raman difference spectroscopy. In turn, this allows the interrogation of sub-molecular changes in very large and complex macromolecular environments. There is often great synergy with X-ray crystallography, with the Raman spectroscopist providing crystallography colleagues with the best soak-in conditions to generate a targeted intermediate for flash freezing and X-ray analysis. On the other hand, X-ray structures at points along a reaction pathway provide invaluable benchmarks for interpreting the Raman data from populations seen by Raman to be changing in real-time. These principles will be illustrated by two reactions: the first involves a complex, branching reaction pathway underlying the inhibition of β-lactamases by clinically important pharmaceutical compounds, where different combinations of drug and enzyme function in different regions of the pathway. The second shows how temporal data can be derived for several events in the initiation step of RNA synthesis-more specifically, when one GTP molecule is joined to one ATP molecule to form a G∙A dimer in the active site of a 115,000 Dalton crystalline RNA polymerase. Finally, we will summarize the extension of Raman microscopy to nucleic acid crystals and the information that has been obtained for RNA-based enzymes. This article is part of a Special Issue entitled: Protein Structure and Function in the Crystalline State.
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Affiliation(s)
- Paul R Carey
- Case Western Reserve University, Department of Biochemistry, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Abstract
Since the introduction of penicillin, beta-lactam antibiotics have been the antimicrobial agents of choice. Unfortunately, the efficacy of these life-saving antibiotics is significantly threatened by bacterial beta-lactamases. beta-Lactamases are now responsible for resistance to penicillins, extended-spectrum cephalosporins, monobactams, and carbapenems. In order to overcome beta-lactamase-mediated resistance, beta-lactamase inhibitors (clavulanate, sulbactam, and tazobactam) were introduced into clinical practice. These inhibitors greatly enhance the efficacy of their partner beta-lactams (amoxicillin, ampicillin, piperacillin, and ticarcillin) in the treatment of serious Enterobacteriaceae and penicillin-resistant staphylococcal infections. However, selective pressure from excess antibiotic use accelerated the emergence of resistance to beta-lactam-beta-lactamase inhibitor combinations. Furthermore, the prevalence of clinically relevant beta-lactamases from other classes that are resistant to inhibition is rapidly increasing. There is an urgent need for effective inhibitors that can restore the activity of beta-lactams. Here, we review the catalytic mechanisms of each beta-lactamase class. We then discuss approaches for circumventing beta-lactamase-mediated resistance, including properties and characteristics of mechanism-based inactivators. We next highlight the mechanisms of action and salient clinical and microbiological features of beta-lactamase inhibitors. We also emphasize their therapeutic applications. We close by focusing on novel compounds and the chemical features of these agents that may contribute to a "second generation" of inhibitors. The goal for the next 3 decades will be to design inhibitors that will be effective for more than a single class of beta-lactamases.
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Affiliation(s)
- Sarah M. Drawz
- Departments of Pathology, Medicine, Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | - Robert A. Bonomo
- Departments of Pathology, Medicine, Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
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Kalp M, Bethel CR, Bonomo RA, Carey PR. Why the extended-spectrum beta-lactamases SHV-2 and SHV-5 are "hypersusceptible" to mechanism-based inhibitors. Biochemistry 2009; 48:9912-20. [PMID: 19736945 DOI: 10.1021/bi9012098] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Extended-spectrum beta-lactamases (ESBLs) are derivatives of enzymes such as SHV-1 and TEM-1 that have undergone site-specific mutations that enable them to hydrolyze, and thus inactivate, oxyimino-cephalosporins, such as cefotaxime and ceftazidime. X-ray crystallographic data provide an explanation for this in that the mutations bring about an expansion of the binding pocket by moving a beta-strand that forms part of the active site wall. Another characteristic of ESBLs that has remained enigmatic is the fact that they are "hypersusceptible" to inhibition by the mechanism-based inactivators tazobactam, sulbactam, and clavulanic acid. Here, we provide a rationale for this "hypersusceptibility" based on a comparative analysis of the intermediates formed by these compounds with wild-type (WT) SHV-1 beta-lactamase and its ESBL variants SHV-2 and SHV-5, which carry the G238S and G238S/E240K substitutions, respectively. A Raman spectroscopic analysis of the reactions in single crystals shows that, compared to WT, the SHV-2 and SHV-5 variants have relatively higher populations of the stable trans-enamine intermediate over the less stable and more easily hydrolyzable cis-enamine and imine co-intermediates. In solution, SHV-2 and SHV-5 also form larger populations of an enamine species compared to SHV-1 as detected by stopped-flow kinetic experiments under single-turnover conditions. Moreover, a simple Raman band shape analysis predicts that the trans-enamine intermediates themselves in SHV-2 and SHV-5 are held in more stable, rigid conformations compared to their trans-enamine analogues in WT SHV-1. As a result of this stabilization, more of the trans-enamine intermediate is formed, which subsequently lowers the K(I) values of the mechanism-based inhibitors up to 50-fold in SHV-2 and SHV-5.
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Affiliation(s)
- Matthew Kalp
- Department of Biochemistry, Molecular Biology and Microbiology, and Medicine,Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
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Drawz SM, Bethel CR, Hujer KM, Hurless KN, Distler AM, Caselli E, Prati F, Bonomo RA. The role of a second-shell residue in modifying substrate and inhibitor interactions in the SHV beta-lactamase: a study of ambler position Asn276. Biochemistry 2009; 48:4557-66. [PMID: 19351161 DOI: 10.1021/bi9003292] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Inhibitor-resistant class A beta-lactamases of the TEM and SHV families that arise by single amino acid substitutions are a significant threat to the efficacy of beta-lactam/beta-lactamase inhibitor combinations. To better understand the basis of the inhibitor-resistant phenotype in SHV, we performed mutagenesis to examine the role of a second-shell residue, Asn276. Of the 19 variants expressed in Escherichia coli, only the Asn276Asp enzyme demonstrated reduced susceptibility to ampicillin/clavulanate (MIC increased from 50/2 --> 50/8 microg/mL) while maintaining high-level resistance to ampicillin (MIC = 8192 microg/mL). Steady-state kinetic analyses of Asn276Asp revealed slightly diminished k(cat)/K(m) for all substrates tested. In contrast, we observed a 5-fold increase in K(i) for clavulanate (7.4 +/- 0.9 microM for Asn276Asp vs 1.4 +/- 0.2 microM for SHV-1) and a 40% reduction in k(inact)/K(I) (0.013 +/- 0.002 microM(-1 )s(-1) for Asn276Asp vs 0.021 +/- 0.004 microM(-1) s(-1) for SHV-1). Timed electrospray ionization mass spectrometry of clavulanate-inhibited SHV-1 and SHV Asn276Asp showed nearly identical mass adducts, arguing for a similar pathway of inactivation. Molecular modeling shows that novel electrostatic interactions are formed between Arg244Neta2 and both 276AspOdelta1 and Odelta2; these new forces restrict the spatial position of Arg244, a residue important in the recognition of the C(3)/C(4) carboxylate of beta-lactam substrates and inhibitors. Testing the functional consequences of this interaction, we noted considerable free energy costs (+DeltaDeltaG) for substrates and inhibitors. A rigid carbapenem (meropenem) was most affected by the Asn276Asp substitution (46-fold increase in K(i) vs SHV-1). We conclude that residue 276 is an important second-shell residue in class A beta-lactamase-mediated resistance to substrates and inhibitors, and only Asn is able to precisely modulate the conformational flexibility of Arg244 required for successful evolution in nature.
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Affiliation(s)
- Sarah M Drawz
- Department of Pathology, CaseWestern Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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Kalp M, Totir MA, Buynak JD, Carey PR. Different intermediate populations formed by tazobactam, sulbactam, and clavulanate reacting with SHV-1 beta-lactamases: Raman crystallographic evidence. J Am Chem Soc 2009; 131:2338-47. [PMID: 19161282 DOI: 10.1021/ja808311s] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tazobactam, sulbactam, and clavulanic acid are the only beta-lactamase inhibitors in clinical use. Comparative inhibitory activities of clavulanic acid, sulbactam, and tazobactam against clinically important beta-lactamases conclude that tazobactam is superior to both clavulanic acid and sulbactam. Thus far, the majority of explanations for this phenomenon have relied on kinetic studies, which report differences in the ligands' apparent dissociation constants and number of turnovers before inactivation. Due their innate limitations, these investigations do not examine the identity of intermediates on the reaction pathway and relate them to the efficacy of the inhibitors. In the present study, the reactions between the three inhibitors and SHV-1 beta-lactamase have been examined in single crystals using a Raman microscope. The results show that tazobactam forms a predominant population of trans-enamine, a chemically inert species, with SHV-1, while clavulanate and sulbactam form a mixture of trans-enamine and two labile species, the cis-enamine and imine. The same reactions are then reexamined using a deacylation-deficient variant, SHV E166A, that has been used to trap acyl-enzyme intermediates for X-ray crystallographic analysis. Our Raman data show that significant differences exist between the wild-type and SHV E166A acyl-enzyme populations. Namely, compared to SHV-1, sulbactam shows significantly smaller populations of cis-enamine and imine in the E166A variant, while clavulanate exists almost exclusively as trans-enamine in the E166A active site. Using clavulanate as an example, we also show that Raman crystallography can provide novel information on the presence of multiple conformers or tautomers for intermediates within a complex reaction pathway. These insights caution against the interpretation of experimental data obtained with deacylation-deficient beta-lactamases to make mechanistic conclusions about inhibitors within the enzyme.
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Affiliation(s)
- Matthew Kalp
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
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36
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Li R, Feng D, Feng S. Computational study on decarboxylation mechanism of β-lactamases inhibitors: Clavulanate vs. sulbactam. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Bourgeois D, Weik M. Kinetic protein crystallography: a tool to watch proteins in action. CRYSTALLOGR REV 2009. [DOI: 10.1080/08893110802604868] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kalp M, Carey PR. Carbapenems and SHV-1 beta-lactamase form different acyl-enzyme populations in crystals and solution. Biochemistry 2008; 47:11830-7. [PMID: 18922024 DOI: 10.1021/bi800833u] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions between single crystals of the SHV-1 beta-lactamase enzyme and the carbapenems, meropenem, imipenem, and ertapenem, have been studied by Raman microscopy. Aided by quantum mechanical calculations, major populations of two acyl-enzyme species, a labile Delta (2)-pyrroline and a more tightly bound Delta (1)-pyrroline, have been identified for all three compounds. These isomers differ only in the position of the double bond about the carbapenem nucleus. This discovery is consonant with X-ray crystallographic findings that also identified two populations for meropenem bound in SHV-1: one with the acyl CO group in the oxyanion hole and the second with the acyl group rotated 180 degrees compared to its expected position [Nukaga, M., Bethel, C. R., Thomson, J. M., Hujer, A. M., Distler, A. M., Anderson, V. E., Knox, J. R., and Bonomo, R. A. (2008) J. Am. Chem. Soc. (in press)]. When crystals of the Delta (1)- and Delta (2)-containing acyl-enzymes were exposed to solutions with no carbapenem, rapid deacylation of the Delta (2) species was observed by kinetic Raman experiments. However, no change in the Delta (1) population was observed over 1 h, the effective lifetime of the crystal. These observations lead to the hypothesis that the stable Delta (1) species is due to the form seen by X-ray with the acyl carbonyl outside the oxyanion hole, while the Delta (2) species corresponds to the form with the carbonyl inside the oxyanion hole. Soak-in and soak-out Raman experiments also demonstrated that tautomeric exchange between the Delta (1) and Delta (2) forms does not occur on the crystalline enzyme. When meropenem or ertapenem was reacted with SHV-1 in solution, the Raman difference spectra demonstrated that only a major population corresponding to the Delta (1) acyl-enzyme could be detected. The 1003 cm (-1) mode of the phenyl ring positioned on the C3 side chain of ertapenem acts as an effective internal Raman intensity standard, and the ratio of its intensity to that of the 1600 cm (-1) feature of Delta (1) provides an estimate of the relative populations of Delta (1). In solution, I 1600/ I 1003 equals 2, and in the crystal, I 1600 /I 1003 equals 1. This is strong evidence that the Delta (1) and Delta (2) acyl-enzymes in the crystal are present in approximately equal amounts, in agreement with the X-ray data. However, in solution there are twice as many Delta (1) species per Phe group, and this represents approximately 100% of the active sites, which is consistent with the observed inhibition of the enzyme's activity.
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Affiliation(s)
- Matthew Kalp
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
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Abstract
The partnering of a beta-lactam with a beta-lactamase inhibitor is a highly effective strategy that can be used to combat bacterial resistance to beta-lactam antibiotics mediated by serine beta-lactamases (EC 3.2.5.6). To this end, we tested two novel penem inhibitors against OXA-1, a class D beta-lactamase that is resistant to inactivation by tazobactam. The K(i) of each penem inhibitor for OXA-1 was in the nM range (K(i) of penem 1, 45 +/- 8 nM; K(i) of penem 2, 12 +/- 2 nM). The first-order rate constant for enzyme and inhibitor complex inactivation of penems 1 and 2 for OXA-1 beta-lactamase were 0.13 +/- 0.01 s(-1) and 0.11 +/- 0.01 s(-1), respectively. By using an inhibitor-to-enzyme ratio of 1:1, 100% inactivation was achieved in <or=900 s and the recovery of OXA-1 beta-lactamase activity was not detected at 24 h. Covalent adducts of penems 1 and 2 (changes in molecular masses, +306 +/- 3 and +321 +/- 3 Da, respectively) were identified by electrospray ionization mass spectrometry (ESI-MS). After tryptic digestion of OXA-1 inactivated by penems 1 and 2, ESI-MS and matrix-assisted laser desorption ionization-time-of-flight MS identified the adducts of 306 +/- 3 and 321 +/- 3 Da attached to the peptide containing the active-site Ser67. The base hydrolysis of penem 2, monitored by serial (1)H nuclear magnetic resonance analysis, suggested that penem 2 formed a linear imine species that underwent 7-endo-trig cyclization to ultimately form a cyclic enamine, the 1,4-thiazepine derivative. Susceptibility testing demonstrated that the penem inhibitors at 4 mg/liter effectively restored susceptibility to piperacillin. Penem beta-lactamase inhibitors which demonstrate high affinities and which form long-lived acyl intermediates may prove to be extremely useful against the broad range of inhibitor-resistant serine beta-lactamases present in gram-negative bacteria.
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Totir MA, Cha J, Ishiwata A, Wang B, Sheri A, Anderson VE, Buynak J, Mobashery S, Carey PR. Why clinically used tazobactam and sulbactam are poor inhibitors of OXA-10 beta-lactamase: Raman crystallographic evidence. Biochemistry 2008; 47:4094-101. [PMID: 18324783 DOI: 10.1021/bi702348w] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The clinically used inhibitors tazobactam and sulbactam are effective in the inhibition of activity of class A beta-lactamases, but not for class D beta-lactamases. The two inhibitors exhibit a complex multistep profile for their chemistry of inhibition with class A beta-lactamases. To compare the inhibition profiles for class A and D enzymes, the reactions were investigated within OXA-10 beta-lactamase (a class D enzyme) crystals using a Raman microscope. The favored reaction pathway appears to be distinctly different from that for class A beta-lactamases. In contrast to the case of class A enzymes that favor the formation of a key enamine species, the OXA-10 enzyme forms an alpha,beta-unsaturated acrylate (acid or ester). Quantum mechanical calculations support the likely product as the adduct of Ser115 to the acrylate. Few enamine-like species are formed by sulbactam or tazobactam with this enzyme. Taken together, our results show that the facile conversion of the initial imine, formed upon acylation of the active site Ser67, to the cis- and/or trans-enamine is disfavored. Instead, there is a significant population of the imine that could either experience cross-linking to a second nucleophile (e.g., Ser115) or give rise to the alpha,beta-unsaturated product and permanent inhibition. Alternatively, the imine can undergo hydrolysis to regenerate the catalytically active OXA-10 enzyme. This last process is the dominant one for class D beta-lactamases since the enzyme is not effectively inhibited. In contrast to sulbactam and tazobactam, the reactions between oxacillin or 6alpha-hydroxyisopropylpenicillinate (both substrates) and OXA-10 beta-lactamase appear much less complex. These compounds lead to a single acyl-enzyme species, the presence of which was confirmed by Raman and MALDI-TOF experiments.
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Affiliation(s)
- Monica A Totir
- Departments of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
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De la Mora-Rey T, Wilmot CM. Synergy within structural biology of single crystal optical spectroscopy and X-ray crystallography. Curr Opin Struct Biol 2007; 17:580-6. [PMID: 17959373 DOI: 10.1016/j.sbi.2007.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 09/11/2007] [Indexed: 11/30/2022]
Abstract
Advances in the adaptation of optical spectroscopy to monitor photo-induced or enzyme-catalyzed reactions in the crystalline state have enabled X-ray crystal structures to be accurately linked with spectroscopically defined intermediates. This, in turn, has led to a deeper understanding of the role protein structural changes play in function. The integration of optical spectroscopy with X-ray crystallography is growing and now extends beyond linking crystal structure to reaction intermediate. Recent examples of this synergy include applications in protein crystallization, X-ray data acquisition, radiation damage, and acquisition of phase information important for structure determination.
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Affiliation(s)
- Teresa De la Mora-Rey
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis 55455, USA
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Totir MA, Helfand MS, Carey MP, Sheri A, Buynak JD, Bonomo RA, Carey PR. Sulbactam forms only minimal amounts of irreversible acrylate-enzyme with SHV-1 beta-lactamase. Biochemistry 2007; 46:8980-7. [PMID: 17630699 PMCID: PMC2596720 DOI: 10.1021/bi7006146] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulbactam is a mechanism-based inhibitor of beta-lactamase enzymes used in clinical practice. It undergoes a complex series of chemical reactions in the active site that have been studied extensively in the past three decades. However, the actual species that gives rise to inhibition in a clinical setting has not been established. Recent studies by our group, using Raman microscopy and X-ray crystallography, have found that large quantities of enamine-based acyl-enzyme species are present within minutes in single crystals of SHV-1 beta-lactamases which can lead to significant inhibition. The enamines are formed by breakdown of the cyclic beta-lactam structures with further transformations leading to imine formation and subsequent isomerization to cis and/or trans enamines. Another favored form of inhibition arises from attack on the imine by a second nucleophilic amino acid side chain, e.g., from serine 130, to form a cross-linked species in the active site that can degrade to an acrylate-like species irreversibly bound to the enzyme. Thus, the imine is at a branch point on the reaction pathway. Using sulbactam and 6,6-dideuterated sulbactam we follow these alternate paths in WT and E166A SHV-1 beta-lactamase by means of Raman microscopic studies on single enzyme crystals. For the unlabeled sulbactam, the Raman data show the presence of an acrylate-like species, probably 3-serine acrylate, several hours after the reaction is started in the crystal. However, for the 6,6-dideutero analogue the acrylate signature appears on the time scale of minutes. The Raman signatures, principally an intense feature near 1530 cm-1, are assigned based on quantum mechanical calculations on model compounds that mimic acrylate species in the active site. The different time scales observed for acrylate-like product formation are ascribed to different rates of reaction involving the imine intermediate. It is proposed that for the unsubstituted sulbactam the conversion from imine to enamine, which involves breaking a C-H bond, is aided by quantum mechanical tunneling. For the 6,6-dideutero-sulbactam the same step involves breaking a C-D bond, which has little or no assistance from tunneling. Consequently the conversion to enamines is slower, and a higher population of imine results, presenting the opportunity for the competing reaction with the second nucleophile, serine 130 being the prime candidate. The hydrolysis of the resulting cross-linked intermediate leads to the observed rapid buildup of the acrylate product in the Raman spectra from the dideutero analogue. The protocol used here, essentially running the reactions with the two forms of sulbactam in parallel, provides an element of control and enables us to conclude that, for the unsubstituted sulbactam, the formation of the cross-linked intermediate and the final irreversible acrylate product is not a significant route to inhibition of SHV-1.
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Affiliation(s)
- Monica A. Totir
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Marion S. Helfand
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
- Research Division, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106
| | - Marianne P. Carey
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Anjaneyulu Sheri
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75205
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75205
| | - Robert A. Bonomo
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
- Research Division, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106
| | - Paul R. Carey
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106
- * To whom correspondence should be addressed: . Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue Cleveland, Ohio 44106 Tel. (216) 368 0031 Fax (216) 368 3419
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Kalp M, Sheri A, Buynak JD, Bethel CR, Bonomo RA, Carey PR. Efficient inhibition of class A and class D beta-lactamases by Michaelis complexes. J Biol Chem 2007; 282:21588-91. [PMID: 17561511 DOI: 10.1074/jbc.c700080200] [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: 11/06/2022] Open
Abstract
A 6-alkylidiene penam sulfone, SA-1-204, is an efficient inhibitor of both SHV-1 and OXA-1 beta-lactamases with K(I) = 42 +/- 4 nm and 1.0 +/- 0.1 microm, respectively. To gain insight into the reaction chemistry of SA-1-204, the reactions between this inhibitor and SHV-1 and OXA-1 were studied by Raman spectroscopy in single crystals and in solution. Raman signatures characteristic of the unreacted beta-lactam ring show that in both phases the inhibitor binds as a noncovalent Michaelis-like complex. This complex is present as the major population for periods of up to an hour. On longer time scales, the Raman data show that beta-lactam ring opening eventually leads to a complex mixture of reaction products. However, the data clearly demonstrate that the key species for inhibition on the time scale of bacterial half-lives is the noncovalent complex preceding acylation.
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Affiliation(s)
- Matthew Kalp
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
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