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Shurina BA, Page RC. Structural Comparisons of Cefotaximase (CTX-M-ase) Sub Family 1. Front Microbiol 2021; 12:688509. [PMID: 34504475 PMCID: PMC8421805 DOI: 10.3389/fmicb.2021.688509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/22/2021] [Indexed: 12/17/2022] Open
Abstract
The cefotaximase or CTX-M, family of serine-β-lactamases represents a significant clinical concern due to the ability for these enzymes to confer resistance to a broad array of β-lactam antibiotics an inhibitors. This behavior lends CTX-M-ases to be classified as extended spectrum β-lactamases (ESBL). Across the family of CTX-M-ases most closely related to CTX-M-1, the structures of CTX-M-15 with a library of different ligands have been solved and serve as the basis of comparison within this review. Herein we focus on the structural changes apparent in structures of CTX-M-15 in complex with diazabicyclooctane (DABCO) and boronic acid transition state analog inhibitors. Interactions between a positive surface patch near the active site and complementary functional groups of the bound inhibitor play key roles in the dictating the conformations of active site residues. The insights provided by analyzing structures of CTX-M-15 in complex with DABCO and boronic acid transition state analog inhibitors and analyzing existing structures of CTX-M-64 offer opportunities to move closer to making predictions as to how CTX-M-ases may interact with potential drug candidates, setting the stage for the further development of new antibiotics and β-lactamase inhibitors.
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Affiliation(s)
- Ben A Shurina
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, United States
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, United States.,Cell, Molecular, and Structural Biology Program, Miami University, Oxford, OH, United States
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2
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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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3
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Dite TA, Langendorf CG, Hoque A, Galic S, Rebello RJ, Ovens AJ, Lindqvist LM, Ngoei KRW, Ling NXY, Furic L, Kemp BE, Scott JW, Oakhill JS. AMP-activated protein kinase selectively inhibited by the type II inhibitor SBI-0206965. J Biol Chem 2018; 293:8874-8885. [PMID: 29695504 DOI: 10.1074/jbc.ra118.003547] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Indexed: 12/30/2022] Open
Abstract
Inhibition of the metabolic regulator AMP-activated protein kinase (AMPK) is increasingly being investigated for its therapeutic potential in diseases where AMPK hyperactivity results in poor prognoses, as in established cancers and neurodegeneration. However, AMPK-inhibitory tool compounds are largely limited to compound C, which has a poor selectivity profile. Here we identify the pyrimidine derivative SBI-0206965 as a direct AMPK inhibitor. SBI-0206965 inhibits AMPK with 40-fold greater potency and markedly lower kinase promiscuity than compound C and inhibits cellular AMPK signaling. Biochemical characterization reveals that SBI-0206965 is a mixed-type inhibitor. A co-crystal structure of the AMPK kinase domain/SBI-0206965 complex shows that the drug occupies a pocket that partially overlaps the ATP active site in a type IIb inhibitor manner. SBI-0206965 has utility as a tool compound for investigating physiological roles for AMPK and provides fresh impetus to small-molecule AMPK inhibitor therapeutic development.
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Affiliation(s)
- Toby A Dite
- From the Metabolic Signalling Laboratory and
| | - Christopher G Langendorf
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | | | - Sandra Galic
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | - Richard J Rebello
- the Prostate Cancer Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.,the Cancer Program, Biomedicine Discovery Institute, and Department of Anatomy and Developmental Biology, Monash University, Clayton 3800, Victoria, Australia
| | | | - Lisa M Lindqvist
- the Cell Signalling and Cell Death Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Kevin R W Ngoei
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | | | - Luc Furic
- the Prostate Cancer Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.,the Cancer Program, Biomedicine Discovery Institute, and Department of Anatomy and Developmental Biology, Monash University, Clayton 3800, Victoria, Australia.,the Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Bruce E Kemp
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia.,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
| | - John W Scott
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia.,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
| | - Jonathan S Oakhill
- From the Metabolic Signalling Laboratory and .,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
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4
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Wang DY, Abboud MI, Markoulides MS, Brem J, Schofield CJ. The road to avibactam: the first clinically useful non-β-lactam working somewhat like a β-lactam. Future Med Chem 2016; 8:1063-84. [PMID: 27327972 DOI: 10.4155/fmc-2016-0078] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Avibactam, which is the first non-β-lactam β-lactamase inhibitor to be introduced for clinical use, is a broad-spectrum serine β-lactamase inhibitor with activity against class A, class C, and, some, class D β-lactamases. We provide an overview of efforts, which extend to the period soon after the discovery of the penicillins, to develop clinically useful non-β-lactam compounds as antibacterials, and, subsequently, penicillin-binding protein and β-lactamase inhibitors. Like the β-lactam inhibitors, avibactam works via a mechanism involving covalent modification of a catalytically important nucleophilic serine residue. However, unlike the β-lactam inhibitors, avibactam reacts reversibly with its β-lactamase targets. We discuss chemical factors that may account for the apparently special nature of β-lactams and related compounds as antibacterials and β-lactamase inhibitors, including with respect to resistance. Avenues for future research including non-β-lactam antibacterials acting similarly to β-lactams are discussed.
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Affiliation(s)
| | | | | | - Jürgen Brem
- Department of Chemistry, University of Oxford, UK
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5
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Boronic Acid Transition State Inhibitors Active against KPC and Other Class A β-Lactamases: Structure-Activity Relationships as a Guide to Inhibitor Design. Antimicrob Agents Chemother 2016; 60:1751-9. [PMID: 26729496 DOI: 10.1128/aac.02641-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/27/2015] [Indexed: 11/20/2022] Open
Abstract
Boronic acid transition state inhibitors (BATSIs) are competitive, reversible β-lactamase inhibitors (BLIs). In this study, a series of BATSIs with selectively modified regions (R1, R2, and amide group) were strategically designed and tested against representative class A β-lactamases of Klebsiella pneumoniae, KPC-2 and SHV-1. Firstly, the R1 group of compounds 1a to 1c and 2a to 2e mimicked the side chain of cephalothin, whereas for compounds 3a to 3c, 4a, and 4b, the thiophene ring was replaced by a phenyl, typical of benzylpenicillin. Secondly, variations in the R2 groups which included substituted aryl side chains (compounds 1a, 1b, 1c, 3a, 3b, and 3c) and triazole groups (compounds 2a to 2e) were chosen to mimic the thiazolidine and dihydrothiazine ring of penicillins and cephalosporins, respectively. Thirdly, the amide backbone of the BATSI, which corresponds to the amide at C-6 or C-7 of β-lactams, was also changed to the following bioisosteric groups: urea (compound 3b), thiourea (compound 3c), and sulfonamide (compounds 4a and 4b). Among the compounds that inhibited KPC-2 and SHV-1 β-lactamases, nine possessed 50% inhibitory concentrations (IC50s) of ≤ 600 nM. The most active compounds contained the thiopheneacetyl group at R1 and for the chiral BATSIs, a carboxy- or hydroxy-substituted aryl group at R2. The most active sulfonamido derivative, compound 4b, lacked an R2 group. Compound 2b (S02030) was the most active, with acylation rates (k2/K) of 1.2 ± 0.2 × 10(4) M(-1) s(-1) for KPC-2 and 4.7 ± 0.6 × 10(3) M(-1) s(-1) for SHV-1, and demonstrated antimicrobial activity against Escherichia coli DH10B carrying blaSHV variants and blaKPC-2 or blaKPC-3 and against clinical strains of Klebsiella pneumoniae and E. coli producing different class A β-lactamase genes. At most, MICs decreased from 16 to 0.5 mg/liter.
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6
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Kurz SG, Hazra S, Bethel CR, Romagnoli C, Caselli E, Prati F, Blanchard JS, Bonomo RA. Inhibiting the β-Lactamase of Mycobacterium tuberculosis (Mtb) with Novel Boronic Acid Transition-State Inhibitors (BATSIs). ACS Infect Dis 2015; 1:234-42. [PMID: 27622739 DOI: 10.1021/acsinfecdis.5b00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BlaC, the single chromosomally encoded β-lactamase of Mycobacterium tuberculosis, has been identified as a promising target for novel therapies that rely upon β-lactamase inhibition. Boronic acid transition-state inhibitors (BATSIs) are a class of β-lactamase inhibitors which permit rational inhibitor design by combinations of various R1 and R2 side chains. To explore the structural determinants of effective inhibition, we screened a panel of 25 BATSIs to explore key structure-function relationships. We identified a cefoperazone analogue, EC19, which displayed slow, time-dependent inhibition against BlaC with a potency similar to that of clavulanate (Ki* of 0.65 ± 0.05 μM). To further characterize the molecular basis of inhibition, we solved the crystallographic structure of the EC19-BlaC(N172A) complex and expanded our analysis to variant enzymes. The results of this structure-function analysis encourage the design of a novel class of β-lactamase inhibitors, BATSIs, to be used against Mycobacterium tuberculosis.
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Affiliation(s)
- Sebastian G. Kurz
- Department of Medicine, Tufts Medical Center, 600 Washington Street, No. 257, Boston, Massachusetts 02111, United States
| | - Saugata Hazra
- Department of Biotechnology, Indian Institute of Technology Roorkee (IITR), Roorkee, Uttarakhand 247667, India
| | - Christopher R. Bethel
- Research Service, Louis
Stokes Cleveland Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106, United States
| | - Chiara Romagnoli
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Emilia Caselli
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Fabio Prati
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - John S. Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Robert A. Bonomo
- Research Service, Louis
Stokes Cleveland Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106, United States
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7
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Winkler ML, Rodkey EA, Taracila MA, Drawz SM, Bethel CR, Papp-Wallace KM, Smith KM, Xu Y, Dwulit-Smith JR, Romagnoli C, Caselli E, Prati F, van den Akker F, Bonomo RA. Design and exploration of novel boronic acid inhibitors reveals important interactions with a clavulanic acid-resistant sulfhydryl-variable (SHV) β-lactamase. J Med Chem 2013; 56:1084-97. [PMID: 23252553 PMCID: PMC3943433 DOI: 10.1021/jm301490d] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Inhibitor resistant (IR) class A β-lactamases pose a significant threat to many current antibiotic combinations. The K234R substitution in the SHV β-lactamase, from Klebsiella pneumoniae , results in resistance to ampicillin/clavulanate. After site-saturation mutagenesis of Lys-234 in SHV, microbiological and biochemical characterization of the resulting β-lactamases revealed that only -Arg conferred resistance to ampicillin/clavulanate. X-ray crystallography revealed two conformations of Arg-234 and Ser-130 in SHV K234R. The movement of Ser-130 is the principal cause of the observed clavulanate resistance. A panel of boronic acid inhibitors was designed and tested against SHV-1 and SHV K234R. A chiral ampicillin analogue was discovered to have a 2.4 ± 0.2 nM K(i) for SHV K234R; the chiral ampicillin analogue formed a more complex hydrogen-bonding network in SHV K234R vs SHV-1. Consideration of the spatial position of Ser-130 and Lys-234 and this hydrogen-bonding network will be important in the design of novel antibiotics targeting IR β-lactamases.
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Affiliation(s)
- Marisa L. Winkler
- Department of Microbiology and Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Elizabeth A. Rodkey
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Magdalena A. Taracila
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Sarah M. Drawz
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Christopher R. Bethel
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Krisztina M. Papp-Wallace
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States,Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Kerri M. Smith
- Department of Chemistry, Cleveland State University, Cleveland Ohio 44115, United States
| | - Yan Xu
- Department of Chemistry, Cleveland State University, Cleveland Ohio 44115, United States
| | - Jeffrey R. Dwulit-Smith
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Chiara Romagnoli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Emilia Caselli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Fabio Prati
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States,Corresponding Author. For F.v.d.A.: . For R.A.B.: phone, (216) 791-3800 ext 4399; ; address, Robert A. Bonomo, MD, 10701 East Boulevard, Cleveland, Ohio, 44106
| | - Robert A. Bonomo
- Department of Microbiology and Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, United States,Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States,Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, United States,Corresponding Author. For F.v.d.A.: . For R.A.B.: phone, (216) 791-3800 ext 4399; ; address, Robert A. Bonomo, MD, 10701 East Boulevard, Cleveland, Ohio, 44106
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8
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Touchet S, Carreaux F, Carboni B, Bouillon A, Boucher JL. Aminoboronic acids and esters: from synthetic challenges to the discovery of unique classes of enzyme inhibitors. Chem Soc Rev 2011; 40:3895-914. [DOI: 10.1039/c0cs00154f] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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9
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Natural and synthetic small boron-containing molecules as potential inhibitors of bacterial and fungal quorum sensing. Chem Rev 2010; 111:209-37. [PMID: 21171664 DOI: 10.1021/cr100093b] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Novel insights into the mode of inhibition of class A SHV-1 beta-lactamases revealed by boronic acid transition state inhibitors. Antimicrob Agents Chemother 2010; 55:174-83. [PMID: 21041505 DOI: 10.1128/aac.00930-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Boronic acid transition state inhibitors (BATSIs) are potent class A and C β-lactamase inactivators and are of particular interest due to their reversible nature mimicking the transition state. Here, we present structural and kinetic data describing the inhibition of the SHV-1 β-lactamase, a clinically important enzyme found in Klebsiella pneumoniae, by BATSI compounds possessing the R1 side chains of ceftazidime and cefoperazone and designed variants of the latter, compounds 1 and 2. The ceftazidime and cefoperazone BATSI compounds inhibit the SHV-1 β-lactamase with micromolar affinity that is considerably weaker than their inhibition of other β-lactamases. The solved crystal structures of these two BATSIs in complex with SHV-1 reveal a possible reason for SHV-1's relative resistance to inhibition, as the BATSIs adopt a deacylation transition state conformation compared to the usual acylation transition state conformation when complexed to other β-lactamases. Active-site comparison suggests that these conformational differences might be attributed to a subtle shift of residue A237 in SHV-1. The ceftazidime BATSI structure revealed that the carboxyl-dimethyl moiety is positioned in SHV-1's carboxyl binding pocket. In contrast, the cefoperazone BATSI has its R1 group pointing away from the active site such that its phenol moiety moves residue Y105 from the active site via end-on stacking interactions. To work toward improving the affinity of the cefoperazone BATSI, we synthesized two variants in which either one or two extra carbons were added to the phenol linker. Both variants yielded improved affinity against SHV-1, possibly as a consequence of releasing the strain of its interaction with the unusual Y105 conformation.
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Tondi D, Calò S, Shoichet BK, Costi MP. Structural study of phenyl boronic acid derivatives as AmpC beta-lactamase inhibitors. Bioorg Med Chem Lett 2010; 20:3416-9. [PMID: 20452208 DOI: 10.1016/j.bmcl.2010.04.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 03/29/2010] [Accepted: 04/05/2010] [Indexed: 11/28/2022]
Abstract
A small set of boronic acids acting as low nanomolar inhibitors of AmpC beta-lactamase were designed and synthesized in the effort to improve affinity, pharmacokinetic properties, and to provide a valid lead compound. X-ray crystallography revealed the binary complex of the best inhibitor bound to the enzyme, highlighting possibilities for its further rational derivatization and chemical optimization.
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Affiliation(s)
- Donatella Tondi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41126 Modena, Italy.
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12
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Trippier PC, McGuigan C. Boronic acids in medicinal chemistry: anticancer, antibacterial and antiviral applications. MEDCHEMCOMM 2010. [DOI: 10.1039/c0md00119h] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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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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14
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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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