1
|
Kumar R, Bhadoria D, Kant R, Kumar A. Regio- and Stereoselective Intermolecular 1,2-Difunctionalization of Terminal Alkynes: An Approach to Access ( Z)-β-Amidovinylsulfones. J Org Chem 2024; 89:2873-2884. [PMID: 38354303 DOI: 10.1021/acs.joc.3c02155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
We have developed the first I2/base-catalyzed regio- and stereoselective intermolecular β-amidosulfonylation of terminal alkynes using sodium sulfinates and quinoxalinone derivatives. The present methodology is compatible with a broad spectrum of various heterocyclic amides, terminal alkynes, and sodium sulfinates. It provides rapid access to valuable (Z)-β-amidovinyl sulfones at mild conditions. Moreover, the synthetic application of this methodology was demonstrated by the late-stage functionalization of numerous bioactive molecules.
Collapse
Affiliation(s)
- Rajesh Kumar
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, P.O. Box 173, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Deepak Bhadoria
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, P.O. Box 173, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ruchir Kant
- Molecular and Structural Biology, CSIR-Central Drug Research Institute, P.O. Box 173, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Atul Kumar
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, P.O. Box 173, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
2
|
Filby BW, Weldrick PJ, Paunov VN. Overcoming Beta-Lactamase-Based Antimicrobial Resistance by Nanocarrier-Loaded Clavulanic Acid and Antibiotic Cotreatments. ACS APPLIED BIO MATERIALS 2022; 5:3826-3840. [PMID: 35819369 DOI: 10.1021/acsabm.2c00369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Antimicrobial resistance (AMR) is one of the major threats to modern healthcare. Many types of bacteria have developed resistance to multiple antibiotic treatments, while additional antibiotics have not been recently brought to market. One approach to counter AMR based on the beta-lactamase enzyme has been to use cotreatments of an antibiotic and an inhibitor, to enhance the antibiotic action. Here, we aimed to enhance this technique by developing nanocarriers of two cationic beta-lactam class antibiotics, amoxicillin, and ticarcillin, combined with a beta-lactamase inhibitor, clavulanic acid, which can potentially overcome this type of AMR. We demonstrate for the first time that beta-lactamase inhibitor-loaded nanocarriers in cotreatments with either free or nanocarrier-loaded beta-lactam antibiotics can enhance their effectiveness further than when used alone. We use surface-functionalized shellac-/Poloxamer 407-stabilized antibiotic nanocarriers on Pseudomonas aeruginosa, which is susceptible to ticarcillin but is resistant to amoxicillin. We show an amplification of the antibiotic effect of amoxicillin and ticarcillin loaded in shellac nanoparticles, both alone and as a cotreatment with free or nanocarrier-loaded clavulanic acid. We also report a significant increase in the antimicrobial effects of clavulanic acid loaded in such nanocarriers as a cotreatment. We explain the increased antimicrobial activity of the cationically functionalized antibiotic-loaded nanoparticles with electrostatic attraction to the bacterial cell wall, which delivers higher local antibiotic and inhibitor concentrations. The effect is due to the accumulation of the clavulanic acid-loaded nanocarriers on the bacterial cell walls that allows a higher proportion of the inhibitor to engage with the produced intracellular beta-lactamases. These nanocarriers were also found to have a very low cytotoxic effect against human keratinocytes, which shows great potential for overcoming enzyme-based AMR.
Collapse
Affiliation(s)
- Benjamin W Filby
- Department of Chemistry and Biochemistry, University of Hull, Hull HU6 7RX, United Kingdom
| | - Paul J Weldrick
- Department of Chemistry and Biochemistry, University of Hull, Hull HU6 7RX, United Kingdom
| | - Vesselin N Paunov
- Department of Chemistry, School of Sciences and Humanities, Nazarbayev University, Kabanbay Batyr Ave 53, Nur-Sultan 020000, Kazakhstan
| |
Collapse
|
3
|
Structural Characterization of the D179N and D179Y Variants of KPC-2 β-Lactamase: Ω-Loop Destabilization as a Mechanism of Resistance to Ceftazidime-Avibactam. Antimicrob Agents Chemother 2022; 66:e0241421. [PMID: 35341315 DOI: 10.1128/aac.02414-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Klebsiella pneumoniae carbapenemases (KPC-2 and KPC-3) present a global clinical threat, as these β-lactamases confer resistance to carbapenems and oxyimino-cephalosporins. Recent clinically identified KPC variants with substitutions at Ambler position D179, located in the Ω loop, are resistant to the β-lactam/β-lactamase inhibitor combination ceftazidime-avibactam, but susceptible to meropenem-vaborbactam. To gain insights into ceftazidime-avibactam resistance conferred by D179N/Y variants of KPC-2, crystal structures of these variants were determined. The D179N KPC-2 structure revealed that the change of the carboxyl to an amide moiety at position 179 disrupted the salt bridge with R164 present in wild-type KPC-2. Additional interactions were disrupted in the Ω loop, causing a decrease in the melting temperature. Shifts originating from N179 were also transmitted toward the active site, including ∼1-Å shifts of the deacylation water and interacting residue N170. The structure of the D179Y KPC-2 β-lactamase revealed more drastic changes, as this variant exhibited disorder of the Ω loop, with other flanking regions also being disordered. We postulate that the KPC-2 variants can accommodate ceftazidime because the Ω loop is displaced in D179Y or can be more readily displaced in D179N KPC-2. To understand why the β-lactamase inhibitor vaborbactam is less affected by the D179 variants than avibactam, we determined the crystal structure of D179N KPC-2 in complex with vaborbactam, which revealed wild-type KPC-2-like vaborbactam-active site interactions. Overall, the structural results regarding KPC-2 D179 variants revealed various degrees of destabilization of the Ω loop that contribute to ceftazidime-avibactam resistance, possible substrate-assisted catalysis of ceftazidime, and meropenem and meropenem-vaborbactam susceptibility.
Collapse
|
4
|
Wang YC, Huang SW, Chiang MH, Lee IM, Kuo SC, Yang YS, Chiu CH, Su YS, Chen TL, Wang FD, Lee YT. In vitro and in vivo activities of imipenem combined with BLI-489 against class D β-lactamase-producing Acinetobacter baumannii. J Antimicrob Chemother 2021; 76:451-459. [PMID: 33057603 DOI: 10.1093/jac/dkaa421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/11/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND According to our preliminary study, BLI-489 has the potential to inhibit the hydrolysing activity of OXA-51-like β-lactamase produced by carbapenem-resistant Acinetobacter baumannii (CRAb). OBJECTIVES In the present study, the in vitro and in vivo activities of imipenem combined with BLI-489 against CRAb producing carbapenem-hydrolysing class D β-lactamases (CHDLs), namely OXA-23, OXA-24, OXA-51 and OXA-58, were determined. METHODS A chequerboard analysis of imipenem and BLI-489 was performed using 57 and 7 clinical CRAb isolates producing different CHDLs and MBLs, respectively. Four representative strains harbouring different CHDL genes were subjected to a time-kill assay to evaluate the synergistic effects. An in silico docking analysis was conducted to simulate the interactions between BLI-489 and the different families of CHDLs. The in vivo activities of this combination were assessed using a Caenorhabditis elegans survival assay and a mouse pneumonia model. RESULTS Chequerboard analysis showed that imipenem and BLI-489 had a synergistic effect on 14.3, 92.9, 100, 16.7 and 100% of MBL-, OXA-23-, OXA-24-like-, OXA-51-like- and OXA-58-producing CRAb isolates, respectively. In the time-kill assay, imipenem and BLI-489 showed synergy against OXA-24-like-, OXA-51-like- and OXA-58-, but not OXA-23-producing CRAb isolates after 24 h. The in silico docking analysis showed that BLI-489 could bind to the active sites of OXA-24 and OXA-58 to confer strong inhibition activity. The combination of imipenem and BLI-489 exhibited synergistic effects for the rescue of CRAb-infected C. elegans and mice. CONCLUSIONS Imipenem combined with BLI-489 has synergistic effects against CHDL-producing CRAb isolates.
Collapse
Affiliation(s)
- Yung-Chih Wang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shu-Wei Huang
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Ming-Hsien Chiang
- Department and Graduate Institute of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - I-Ming Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Shu-Chen Kuo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Ya-Sung Yang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chun-Hsiang Chiu
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Ying-Shih Su
- Institute of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan
| | - Te-Li Chen
- Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Fu-Der Wang
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Tzu Lee
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| |
Collapse
|
5
|
Zhou Y, Wu C, Ma H, Chen J, Sun T. Precise Preparation of a High-Purity Key Intermediate of Tazobactam. Org Process Res Dev 2020. [DOI: 10.1021/acs.oprd.0c00407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yanan Zhou
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, Shenyang 110016, P. R. China
| | - Chengjun Wu
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, Shenyang 110016, P. R. China
| | - Hongzhi Ma
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, Shenyang 110016, P. R. China
| | - Jianchao Chen
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, Shenyang 110016, P. R. China
| | - Tiemin Sun
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, Shenyang 110016, P. R. China
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Modified Penicillin Molecule with Carbapenem-Like Stereochemistry Specifically Inhibits Class C β-Lactamases. Antimicrob Agents Chemother 2017; 61:AAC.01288-17. [PMID: 28971874 DOI: 10.1128/aac.01288-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/19/2017] [Indexed: 11/20/2022] Open
Abstract
Bacterial β-lactamases readily inactivate most penicillins and cephalosporins by hydrolyzing and "opening" their signature β-lactam ring. In contrast, carbapenems resist hydrolysis by many serine-based class A, C, and D β-lactamases due to their unique stereochemical features. To improve the resistance profile of penicillins, we synthesized a modified penicillin molecule, MPC-1, by "grafting" carbapenem-like stereochemistry onto the penicillin core. Chemical modifications include the trans conformation of hydrogen atoms at C-5 and C-6 instead of cis, and a 6-α hydroxyethyl moiety to replace the original 6-β aminoacyl group. MPC-1 selectively inhibits class C β-lactamases, such as P99, by forming a nonhydrolyzable acyl adduct, and its inhibitory potency is ∼2 to 5 times higher than that for clinically used β-lactamase inhibitors clavulanate and sulbactam. The crystal structure of MPC-1 forming the acyl adduct with P99 reveals a novel binding mode for MPC-1 that resembles carbapenem bound in the active site of class A β-lactamases. Furthermore, in this novel binding mode, the carboxyl group of MPC-1 blocks the deacylation reaction by occluding the critical catalytic water molecule and renders the acyl adduct nonhydrolyzable. Our results suggest that by incorporating carbapenem-like stereochemistry, the current collection of over 100 penicillins and cephalosporins can be modified into candidate compounds for development of novel β-lactamase inhibitors.
Collapse
|
10
|
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.
Collapse
|
11
|
González-Bello C. Designing Irreversible Inhibitors-Worth the Effort? ChemMedChem 2015; 11:22-30. [DOI: 10.1002/cmdc.201500469] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS); Universidade de Santiago de Compostela; calle Jenaro de la Fuente s/n Santiago de Compostela 15782 Spain
| |
Collapse
|
12
|
Krishnan NP, Nguyen NQ, Papp-Wallace KM, Bonomo RA, van den Akker F. Inhibition of Klebsiella β-Lactamases (SHV-1 and KPC-2) by Avibactam: A Structural Study. PLoS One 2015; 10:e0136813. [PMID: 26340563 PMCID: PMC4560403 DOI: 10.1371/journal.pone.0136813] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/07/2015] [Indexed: 11/18/2022] Open
Abstract
β-Lactamase inhibition is an important clinical strategy in overcoming β-lactamase-mediated resistance to β-lactam antibiotics in Gram negative bacteria. A new β-lactamase inhibitor, avibactam, is entering the clinical arena and promising to be a major step forward in our antibiotic armamentarium. Avibactam has remarkable broad-spectrum activity in being able to inhibit classes A, C, and some class D β-lactamases. We present here structural investigations into class A β-lactamase inhibition by avibactam as we report the crystal structures of SHV-1, the chromosomal penicillinase of Klebsiella pneumoniae, and KPC-2, an acquired carbapenemase found in the same pathogen, complexed with avibactam. The 1.80 Å KPC-2 and 1.42 Å resolution SHV-1 β-lactamase avibactam complex structures reveal avibactam covalently bonded to the catalytic S70 residue. Analysis of the interactions and chair-shaped conformation of avibactam bound to the active sites of KPC-2 and SHV-1 provides structural insights into recently laboratory-generated amino acid substitutions that result in resistance to avibactam in KPC-2 and SHV-1. Furthermore, we observed several important differences in the interactions with amino acid residues, in particular that avibactam forms hydrogen bonds to S130 in KPC-2 but not in SHV-1, that can possibly explain some of the different kinetic constants of inhibition. Our observations provide a possible reason for the ability of KPC-2 β-lactamase to slowly desulfate avibactam with a potential role for the stereochemistry around the N1 atom of avibactam and/or the presence of an active site water molecule that could aid in avibactam desulfation, an unexpected consequence of novel inhibition chemistry.
Collapse
Affiliation(s)
- Nikhil P. Krishnan
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH, 44106, United States of America
| | - Nhu Q. Nguyen
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH, 44106, United States of America
| | - Krisztina M. Papp-Wallace
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, OH, 44106, United States of America
| | - Robert A. Bonomo
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH, 44106, United States of America
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, OH, 44106, United States of America
- Department of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, United States of America
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH, 44106, United States of America
- * E-mail:
| |
Collapse
|
13
|
Winkler ML, Papp-Wallace KM, Bonomo RA. Activity of ceftazidime/avibactam against isogenic strains of Escherichia coli containing KPC and SHV β-lactamases with single amino acid substitutions in the Ω-loop. J Antimicrob Chemother 2015; 70:2279-86. [PMID: 25957381 DOI: 10.1093/jac/dkv094] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 03/20/2015] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVES The objective of this study was to explore the activity of ceftazidime and ceftazidime/avibactam against a collection of isogenic strains of Escherichia coli DH10B possessing SHV and KPC β-lactamases containing single amino acid substitutions in the Ω-loop (residues 164-179). METHODS Ceftazidime and ceftazidime/avibactam MICs were determined by the agar dilution method for a panel of isogenic E. coli strains expressing SHV-1 and KPC-2 with amino acid substitutions at positions 164, 167, 169 or 179. Two KPC-2 β-lactamase variants that possessed elevated MICs of ceftazidime/avibactam were selected for further biochemical analyses. RESULTS Avibactam restored susceptibility to ceftazidime for all Ω-loop variants of SHV-1 with MICs <8 mg/L. In contrast, several of the Arg164 and Asp179 variants of KPC-2 demonstrated MICs of ceftazidime/avibactam >8 mg/L. β-Lactamase kinetics showed that the Asp179Asn variant of KPC-2 demonstrated enhanced kinetic properties against ceftazidime. The Ki app, k2/K and koff of the Arg164Ala and Asp179Asn variant KPC-2 β-lactamases indicated that avibactam effectively inhibited these enzymes. CONCLUSIONS Several KPC-2 variants demonstrating ceftazidime resistance as a result of single amino acid substitutions in the Ω-loop were not susceptible to ceftazidime/avibactam (MICs >8 mg/L). We hypothesize that this observation is due to the stabilizing interactions (e.g. hydrogen bonds) of ceftazidime within the active site of variant β-lactamases that prevent avibactam from binding to and inhibiting the β-lactamase. As ceftazidime/avibactam is introduced into the clinic, monitoring for new KPC-2 variants that may exhibit increased ceftazidime kinetics as well as resistance to this novel antibiotic combination will be important.
Collapse
Affiliation(s)
- Marisa L Winkler
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA Research Service, Louis Stokes Veteran Affairs Medical Center, Cleveland, OH, USA
| | - Krisztina M Papp-Wallace
- Research Service, Louis Stokes Veteran Affairs Medical Center, Cleveland, OH, USA Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Robert A Bonomo
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA Research Service, Louis Stokes Veteran Affairs Medical Center, Cleveland, OH, USA Department of Medicine, Case Western Reserve University, Cleveland, OH, USA Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| |
Collapse
|
14
|
Che T, Rodkey E, Bethel CR, Shanmugam S, Ding Z, Pusztai-Carey M, Nottingham M, Chai W, Buynak JD, Bonomo RA, van den Akker F, Carey PR. Detecting a quasi-stable imine species on the reaction pathway of SHV-1 β-lactamase and 6β-(hydroxymethyl)penicillanic acid sulfone. Biochemistry 2015; 54:734-43. [PMID: 25536850 PMCID: PMC4310624 DOI: 10.1021/bi501197t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/22/2014] [Indexed: 11/30/2022]
Abstract
For the class A β-lactamase SHV-1, the kinetic and mechanistic properties of the clinically used inhibitor sulbactam are compared with the sulbactam analog substituted in its 6β position by a CH2OH group (6β-(hydroxymethyl)penicillanic acid). The 6β substitution improves both in vitro and microbiological inhibitory properties of sulbactam. Base hydrolysis of both compounds was studied by Raman and NMR spectroscopies and showed that lactam ring opening is followed by fragmentation of the dioxothiazolidine ring leading to formation of the iminium ion within 3 min. The iminium ion slowly loses a proton and converts to cis-enamine (which is a β-aminoacrylate) in 1 h for sulbactam and in 4 h for 6β-(hydroxymethyl) sulbactam. Rapid mix-rapid freeze Raman spectroscopy was used to follow the reactions between the two sulfones and SHV-1. Within 23 ms, a 10-fold excess of sulbactam was entirely hydrolyzed to give a cis-enamine product. In contrast, the 6β-(hydroxymethyl) sulbactam formed longer-lived acyl-enzyme intermediates that are a mixture of imine and enamines. Single crystal Raman studies, soaking in and washing out unreacted substrates, revealed stable populations of imine and trans-enamine acyl enzymes. The corresponding X-ray crystallographic data are consonant with the Raman data and also reveal the role played by the 6β-hydroxymethyl group in retarding hydrolysis of the acyl enzymes. The 6β-hydroxymethyl group sterically hinders approach of the water molecule as well as restraining the side chain of E166 that facilitates hydrolysis.
Collapse
Affiliation(s)
- Tao Che
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Elizabeth
A. Rodkey
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Christopher R. Bethel
- Research
Service, Louis Stokes Cleveland Veterans
Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Sivaprakash Shanmugam
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Zhe Ding
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Marianne Pusztai-Carey
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Michael Nottingham
- Department
of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Weirui Chai
- Department
of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - John D. Buynak
- Department
of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Robert A. Bonomo
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
- Research
Service, Louis Stokes Cleveland Veterans
Affairs Medical Center, Cleveland, Ohio 44106, United States
| | - Focco van den Akker
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Paul R. Carey
- Department of Biochemistry, Department of Molecular
Biology and Microbiology, Department of Pharmacology, and Department of
Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
| |
Collapse
|
15
|
Rodkey EA, Winkler ML, Bethel CR, Pagadala SRR, Buynak JD, Bonomo RA, van den Akker F. Penam sulfones and β-lactamase inhibition: SA2-13 and the importance of the C2 side chain length and composition. PLoS One 2014; 9:e85892. [PMID: 24454944 PMCID: PMC3894197 DOI: 10.1371/journal.pone.0085892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 12/03/2013] [Indexed: 02/01/2023] Open
Abstract
β-Lactamases are the major reason β-lactam resistance is seen in Gram-negative bacteria. To combat this resistance mechanism, β-lactamase inhibitors are currently being developed. Presently, there are only three that are in clinical use (clavulanate, sulbactam and tazobactam). In order to address this important medical need, we explored a new inhibition strategy that takes advantage of a long-lived inhibitory trans-enamine intermediate. SA2-13 was previously synthesized and shown to have a lower k(react) than tazobactam. We investigated here the importance of the carboxyl linker length and composition by synthesizing three analogs of SA2-13 (PSR-4-157, PSR-4-155, and PSR-3-226). All SA2-13 analogs yielded higher turnover numbers and k(react) compared to SA2-13. We next demonstrated using protein crystallography that increasing the linker length by one carbon allowed for better capture of a trans-enamine intermediate; in contrast, this trans-enamine intermediate did not occur when the C2 linker length was decreased by one carbon. If the linker was altered by both shortening it and changing the carboxyl moiety into a neutral amide moiety, the stable trans-enamine intermediate in wt SHV-1 did not form; this intermediate could only be observed when a deacylation deficient E166A variant was studied. We subsequently studied SA2-13 against a relatively recently discovered inhibitor-resistant (IR) variant of SHV-1, SHV K234R. Despite the alteration in the mechanism of resistance due to the K→R change in this variant, SA2-13 was effective at inhibiting this IR enzyme and formed a trans-enamine inhibitory intermediate similar to the intermediate seen in the wt SHV-1 structure. Taken together, our data reveals that the C2 side chain linker length and composition profoundly affect the formation of the trans-enamine intermediate of penam sulfones. We also show that the design of SA2-13 derivatives offers promise against IR SHV β-lactamases that possess the K234R substitution.
Collapse
Affiliation(s)
- Elizabeth A. Rodkey
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Marisa L. Winkler
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Division, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
| | - Christopher R. Bethel
- Research Division, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
| | | | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, Texas, United States of America
| | - Robert A. Bonomo
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Division, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail: (RAB); (FVDA)
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail: (RAB); (FVDA)
| |
Collapse
|
16
|
Skalweit Helfand M. β-lactams against emerging ‘superbugs’: progress and pitfalls. Expert Rev Clin Pharmacol 2014; 1:559-71. [DOI: 10.1586/17512433.1.4.559] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
A novel extended-spectrum β-lactamase, SGM-1, from an environmental isolate of Sphingobium sp. Antimicrob Agents Chemother 2013; 57:3783-8. [PMID: 23716045 DOI: 10.1128/aac.00808-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SGM-1 is a novel class A β-lactamase from an environmental isolate of Sphingobium sp. containing all of the distinct amino acid motifs of class A β-lactamases. It shares 77 to 80% amino acid sequence identity with putative β-lactamases that are present on the chromosome of all Sphingobium species whose genomes were sequenced and annotated. Thus, SGM-type β-lactamases are native to this genus. Antibiotic susceptibility testing classifies SGM-1 as an extended-spectrum β-lactamase, conferring the highest level of resistance to penicillins. Although SGM-1 contains the conserved cysteine residues characteristic of class A carbapenemases, it does not confer resistance to the carbapenem antibiotics imipenem, meropenem, or doripenem but does increase the MIC of ertapenem 8-fold. SGM-1 hydrolyzes penicillins and the monobactam aztreonam with similar catalytic efficiencies, ranging from 10(5) to 10(6) M(-1) s(-1). The catalytic efficiencies of SGM-1 for cefoxitin and ceftazidime were the lowest (10(2) to 10(3) M(-1) s(-1)) among the cephalosporins tested, while the catalytic efficiencies against all other cephalosporins varied from about 10(5) to 10(6) M(-1) s(-1). SGM-1 exhibited measurable but not significant activity toward the carbapenems tested. SGM-1 also showed high affinity for clavulanic acid, tazobactam, and sulbactam (Ki < 1 μM); however, only clavulanic acid significantly reduced the MICs of β-lactams.
Collapse
|
19
|
Heidari Torkabadi H, Che T, Shou J, Shanmugam S, Crowder MW, Bonomo RA, Pusztai-Carey M, Carey PR. Raman spectra of interchanging β-lactamase inhibitor intermediates on the millisecond time scale. J Am Chem Soc 2013; 135:2895-8. [PMID: 23406484 DOI: 10.1021/ja311440p] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rapid mix-rapid freeze is a powerful method to study the mechanisms of enzyme-substrate reactions in solution. Here we report a protocol that combines this method with normal (non-resonance) Raman microscopy to enable us to define molecular details of intermediates at early time points. With this combined method, SHV-1, a class A β-lactamase, and tazobactam, a commercially available β-lactamase inhibitor, were rapidly mixed on the millisecond time scale and then were flash-frozen by injection into an isopentane solution surrounded by liquid nitrogen. The "ice" was finally freeze-dried and characterized by Raman microscopy. We found that the reaction is almost complete in solution at 25 ms, giving rise to a major population composed of the trans-enamine intermediate. Between 25 and 500 ms, minor populations of protonated imine are detected that have previously been postulated to precede enamine intermediates. However, within 1 s, the imines are converted entirely to enamines. Interestingly, with this method, we can measure directly the turnover number of SHV-1 and tazobactam. The enzyme is completely inhibited at 1:4 ratio (enzyme:inhibitor) or greater, a number that agrees with the turnover number derived from steady-state kinetic methods. This application, employing non-intensity-enhanced Raman spectroscopy, provides a general and effective route to study the early events in enzyme-substrate reactions.
Collapse
|
20
|
Ke W, Pattanaik P, Bethel CR, Sheri A, Buynak JD, Bonomo RA, van den Akker F. Structures of SHV-1 β-lactamase with penem and penam sulfone inhibitors that form cyclic intermediates stabilized by carbonyl conjugation. PLoS One 2012; 7:e49035. [PMID: 23145056 PMCID: PMC3493512 DOI: 10.1371/journal.pone.0049035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/03/2012] [Indexed: 11/22/2022] Open
Abstract
Bacterial β-lactamase enzymes are in large part responsible for the decreased ability of β-lactam antibiotics to combat infections. The inability to overcome β-lactamase mediated resistance spurred the development of inhibitors with penems and penam sulfones being amongst the most potent and broad spectrum mechanism-based inactivators. These inhibitors form covalent, “suicide-type” inhibitory intermediates that are attached to the catalytic S70 residue. To further probe the details of the mechanism of β-lactamase inhibition by these novel compounds, we determined the crystal structures of SHV-1 bound with penem 1, and penam sulfones SA1-204 and SA3-53. Comparison with each other and with previously determined crystal structures of members of these classes of inhibitors suggests that the final conformation of the covalent adduct can vary greatly amongst the complex structures. In contrast, a common theme of carbonyl conjugation as a mechanism to avoid deacylation emerges despite that the penem and penam sulfone inhibitors form different types of intermediates. The detailed insights gained from this study could be used to further improve new mechanism-based inhibitors of these common class A serine β-lactamases.
Collapse
Affiliation(s)
- Wei Ke
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Priyaranjan Pattanaik
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Christopher R. Bethel
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
| | - Anjaneyulu Sheri
- Department of Chemistry, Southern Methodist University, Dallas, Texas, United States of America
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, Texas, United States of America
| | - Robert A. Bonomo
- Department of Medicine, Pharmacology, and Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| |
Collapse
|
21
|
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.
Collapse
Affiliation(s)
- Elizabeth A Rodkey
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
| | | | | | | | | | | |
Collapse
|
22
|
van der Westhuyzen R, Hammons JC, Meier JL, Dahesh S, Moolman WJA, Pelly SC, Nizet V, Burkart MD, Strauss E. The antibiotic CJ-15,801 is an antimetabolite that hijacks and then inhibits CoA biosynthesis. ACTA ACUST UNITED AC 2012; 19:559-71. [PMID: 22633408 DOI: 10.1016/j.chembiol.2012.03.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 03/13/2012] [Accepted: 03/27/2012] [Indexed: 01/21/2023]
Abstract
The natural product CJ-15,801 is an inhibitor of Staphylococcus aureus, but not other bacteria. Its close structural resemblance to pantothenic acid, the vitamin precursor of coenzyme A (CoA), and its Michael acceptor moiety suggest that it irreversibly inhibits an enzyme involved in CoA biosynthesis or utilization. However, its mode of action and the basis for its specificity have not been elucidated to date. We demonstrate that CJ-15,801 is transformed by the uniquely selective S. aureus pantothenate kinase, the first CoA biosynthetic enzyme, into a substrate for the next enzyme, phosphopantothenoylcysteine synthetase, which is inhibited through formation of a tight-binding structural mimic of its native reaction intermediate. These findings reveal CJ-15,801 as a vitamin biosynthetic pathway antimetabolite with a mechanism similar to that of the sulfonamide antibiotics and highlight CoA biosynthesis as a viable antimicrobial drug target.
Collapse
|
23
|
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.
Collapse
Affiliation(s)
- Wei Ke
- Department of Biochemistry, RT500, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Crystal structures of KPC-2 β-lactamase in complex with 3-nitrophenyl boronic acid and the penam sulfone PSR-3-226. Antimicrob Agents Chemother 2012; 56:2713-8. [PMID: 22330909 DOI: 10.1128/aac.06099-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Class A carbapenemases are a major threat to the potency of carbapenem antibiotics. A widespread carbapenemase, KPC-2, is not easily inhibited by β-lactamase inhibitors (i.e., clavulanic acid, sulbactam, and tazobactam). To explore different mechanisms of inhibition of KPC-2, we determined the crystal structures of KPC-2 with two β-lactamase inhibitors that follow different inactivation pathways and kinetics. The first complex is that of a small boronic acid compound, 3-nitrophenyl boronic acid (3-NPBA), bound to KPC-2 with 1.62-Å resolution. 3-NPBA demonstrated a K(m) value of 1.0 ± 0.1 μM (mean ± standard error) for KPC-2 and blocks the active site by making a reversible covalent interaction with the catalytic S70 residue. The two boron hydroxyl atoms of 3-NPBA are positioned in the oxyanion hole and the deacylation water pocket, respectively. In addition, the aromatic ring of 3-NPBA provides an edge-to-face interaction with W105 in the active site. The structure of KPC-2 with the penam sulfone PSR-3-226 was determined at 1.26-Å resolution. PSR-3-226 displayed a K(m) value of 3.8 ± 0.4 μM for KPC-2, and the inactivation rate constant (k(inact)) was 0.034 ± 0.003 s(-1). When covalently bound to S70, PSR-3-226 forms a trans-enamine intermediate in the KPC-2 active site. The predominant active site interactions are generated via the carbonyl oxygen, which resides in the oxyanion hole, and the carboxyl moiety of PSR-3-226, which interacts with N132, N170, and E166. 3-NPBA and PSR-3-226 are the first β-lactamase inhibitors to be trapped as an acyl-enzyme complex with KPC-2. The structural and inhibitory insights gained here could aid in the design of potent KPC-2 inhibitors.
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Ligand-dependent disorder of the Omega loop observed in extended-spectrum SHV-type beta-lactamase. Antimicrob Agents Chemother 2011; 55:2303-9. [PMID: 21357298 DOI: 10.1128/aac.01360-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among Gram-negative bacteria, resistance to β-lactams is mediated primarily by β-lactamases (EC 3.2.6.5), periplasmic enzymes that inactivate β-lactam antibiotics. Substitutions at critical amino acid positions in the class A β-lactamase families result in enzymes that can hydrolyze extended-spectrum cephalosporins, thus demonstrating an "extended-spectrum" β-lactamase (ESBL) phenotype. Using SHV ESBLs with substitutions in the Ω loop (R164H and R164S) as target enzymes to understand this enhanced biochemical capability and to serve as a basis for novel β-lactamase inhibitor development, we determined the spectra of activity and crystal structures of these variants. We also studied the inactivation of the R164H and R164S mutants with tazobactam and SA2-13, a unique β-lactamase inhibitor that undergoes a distinctive reaction chemistry in the active site. We noted that the reduced Ki values for the R164H and R164S mutants with SA2-13 are comparable to those with tazobactam (submicromolar). The apo enzyme crystal structures of the R164H and R164S SHV variants revealed an ordered Ω loop architecture that became disordered when SA2-13 was bound. Important structural alterations that result from the binding of SA2-13 explain the enhanced susceptibility of these ESBL enzymes to this inhibitor and highlight ligand-dependent Ω loop flexibility as a mechanism for accommodating and hydrolyzing β-lactam substrates.
Collapse
|
27
|
Importance of position 170 in the inhibition of GES-type β-lactamases by clavulanic acid. Antimicrob Agents Chemother 2011; 55:1556-62. [PMID: 21220532 DOI: 10.1128/aac.01292-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Bacterial resistance to β-lactam antibiotics (penicillins, cephalosporins, carbapenems, etc.) is commonly the result of the production of β-lactamases. The emergence of β-lactamases capable of turning over carbapenem antibiotics is of great concern, since these are often considered the last resort antibiotics in the treatment of life-threatening infections. β-Lactamases of the GES family are extended-spectrum enzymes that include members that have acquired carbapenemase activity through a single amino acid substitution at position 170. We investigated inhibition of the GES-1, -2, and -5 β-lactamases by the clinically important β-lactamase inhibitor clavulanic acid. While GES-1 and -5 are susceptible to inhibition by clavulanic acid, GES-2 shows the greatest susceptibility. This is the only variant to possess the canonical asparagine at position 170. The enzyme with asparagine, as opposed to glycine (GES-1) or serine (GES-5), then leads to a higher affinity for clavulanic acid (K(i) = 5 μM), a higher rate constant for inhibition, and a lower partition ratio (r ≈ 20). Asparagine at position 170 also results in the formation of stable complexes, such as a cross-linked species and a hydrated aldehyde. In contrast, serine at position 170 leads to formation of a long-lived trans-enamine species. These studies provide new insight into the importance of the residue at position 170 in determining the susceptibility of GES enzymes to clavulanic acid.
Collapse
|
28
|
Bebrone C, Lassaux P, Vercheval L, Sohier JS, Jehaes A, Sauvage E, Galleni M. Current challenges in antimicrobial chemotherapy: focus on ß-lactamase inhibition. Drugs 2010; 70:651-79. [PMID: 20394454 DOI: 10.2165/11318430-000000000-00000] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The use of the three classical beta-lactamase inhibitors (clavulanic acid, tazobactam and sulbactam) in combination with beta-lactam antibacterials is currently the most successful strategy to combat beta-lactamase-mediated resistance. However, these inhibitors are efficient in inactivating only class A beta-lactamases and the efficiency of the inhibitor/antibacterial combination can be compromised by several mechanisms, such as the production of naturally resistant class B or class D enzymes, the hyperproduction of AmpC or even the production of evolved inhibitor-resistant class A enzymes. Thus, there is an urgent need for the development of novel inhibitors. For serine active enzymes (classes A, C and D), derivatives of the beta-lactam ring such as 6-beta-halogenopenicillanates, beta-lactam sulfones, penems and oxapenems, monobactams or trinems seem to be potential starting points to design efficient molecules (such as AM-112 and LK-157). Moreover, a promising non-beta-lactam molecule, NXL-104, is now under clinical development. In contrast, an ideal inhibitor of metallo-beta-lactamases (class B) remains to be found, despite the huge number of potential molecules already described (biphenyl tetrazoles, cysteinyl peptides, mercaptocarboxylates, succinic acid derivatives, etc.). The search for such an inhibitor is complicated by the absence of a covalent intermediate in their catalytic mechanisms and the fact that beta-lactam derivatives often behave as substrates rather than as inhibitors. Currently, the most promising broad-spectrum inhibitors of class B enzymes are molecules presenting chelating groups (thiols, carboxylates, etc.) combined with an aromatic group. This review describes all the types of molecules already tested as potential beta-lactamase inhibitors and thus constitutes an update of the current status in beta-lactamase inhibitor discovery.
Collapse
Affiliation(s)
- Carine Bebrone
- Biological Macromolecules, Centre for Protein Engineering, University of Liège, Liège, Belgium.
| | | | | | | | | | | | | |
Collapse
|
29
|
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.
Collapse
|
30
|
Kim P, Kang S, Boshoff HI, Jiricek J, Collins M, Singh R, Manjunatha UH, Niyomrattanakit P, Zhang L, Goodwin M, Dick T, Keller TH, Dowd CS, Barry CE. Structure-activity relationships of antitubercular nitroimidazoles. 2. Determinants of aerobic activity and quantitative structure-activity relationships. J Med Chem 2010; 52:1329-44. [PMID: 19209893 DOI: 10.1021/jm801374t] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The (S)-2-nitro-6-substituted 6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazines have been extensively explored for their potential use as new antituberculars based on their excellent bactericidal properties on aerobic whole cells of Mycobacterium tuberculosis. An oxygen atom at the 2-position of the imidazole ring is required for aerobic activity. Here, we show that substitution of this oxygen by either nitrogen or sulfur yielded equipotent analogues. Acylating the amino series, oxidizing the thioether, or replacing the ether oxygen with carbon significantly reduced the potency of the compounds. Replacement of the benzylic oxygen at the 6-position by nitrogen slightly improved potency and facilitated exploration of the SAR in the more soluble 6-amino series. Significant improvements in potency were realized by extending the linker region between the 6-(S) position and the terminal hydrophobic aromatic substituent. A simple four-feature QSAR model was derived to rationalize MIC results in this series of bicyclic nitroimidazoles.
Collapse
Affiliation(s)
- Pilho Kim
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
OXA beta-lactamases are largely responsible for beta-lactam resistance in Acinetobacter spp. and Pseudomonas aeruginosa, two of the most difficult-to-treat nosocomial pathogens. In general, the beta-lactamase inhibitors used in clinical practice (clavulanic acid, sulbactam, and tazobactam) demonstrate poor activity against class D beta-lactamases. To overcome this challenge, we explored the abilities of beta-lactamase inhibitors of the C-2- and C-3-substituted penicillin and cephalosporin sulfone families against OXA-1, extended-spectrum (OXA-10, OXA-14, and OXA-17), and carbapenemase-type (OXA-24/40) class D beta-lactamases. Three C-2-substituted penicillin sulfone compounds (JDB/LN-1-255, JDB/LN-III-26, and JDB/ASR-II-292) showed low K(i) values for the OXA-1 beta-lactamase (0.70 +/- 0.14 --> 1.60 +/- 0.30 microM) and demonstrated significant K(i) improvements compared to the C-3-substituted cephalosporin sulfone (JDB/DVR-II-214), tazobactam, and clavulanic acid. The C-2-substituted penicillin sulfones JDB/ASR-II-292 and JDB/LN-1-255 also demonstrated low K(i)s for the OXA-10, -14, -17, and -24/40 beta-lactamases (0.20 +/- 0.04 --> 17 +/- 4 microM). Furthermore, JDB/LN-1-255 displayed stoichiometric inactivation of OXA-1 (the turnover number, i.e., the partitioning of the initial enzyme inhibitor complex between hydrolysis and enzyme inactivation [t(n)] = 0) and t(n)s ranging from 5 to 8 for the other OXA enzymes. Using mass spectroscopy to study the intermediates in the inactivation pathway, we determined that JDB/LN-1-255 inhibited OXA beta-lactamases by forming covalent adducts that do not fragment. On the basis of the substrate and inhibitor kinetics of OXA-1, we constructed a model showing that the C-3 carboxylate of JDB/LN-1-255 interacts with Ser115 and Thr213, the R-2 group at C-2 fits between the space created by the long B9 and B10 beta strands, and stabilizing hydrophobic interactions are formed between the pyridyl ring of JDB/LN-1-255 and Val116 and Leu161. By exploiting conserved structural and mechanistic features, JDB/LN-1-255 is a promising lead compound in the quest for effective inhibitors of OXA-type beta-lactamases.
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
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.
Collapse
Affiliation(s)
- Matthew Kalp
- Department of Biochemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
| | | | | | | |
Collapse
|
34
|
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]
|
35
|
Pattanaik P, Bethel CR, Hujer AM, Hujer KM, Distler AM, Taracila M, Anderson VE, Fritsche TR, Jones RN, Pagadala SRR, van den Akker F, Buynak JD, Bonomo RA. Strategic design of an effective beta-lactamase inhibitor: LN-1-255, a 6-alkylidene-2'-substituted penicillin sulfone. J Biol Chem 2008; 284:945-53. [PMID: 18955486 DOI: 10.1074/jbc.m806833200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In an effort to devise strategies for overcoming bacterial beta-lactamases, we studied LN-1-255, a 6-alkylidene-2'-substituted penicillin sulfone inhibitor. By possessing a catecholic functionality that resembles a natural bacterial siderophore, LN-1-255 is unique among beta-lactamase inhibitors. LN-1-255 combined with piperacillin was more potent against Escherichia coli DH10B strains bearing bla(SHV) extended-spectrum and inhibitor-resistant beta-lactamases than an equivalent amount of tazobactam and piperacillin. In addition, LN-1-255 significantly enhanced the activity of ceftazidime and cefpirome against extended-spectrum cephalosporin and Sme-1 containing carbapenem-resistant clinical strains. LN-1-255 inhibited SHV-1 and SHV-2 beta-lactamases with nm affinity (K(I) = 110 +/- 10 and 100 +/- 10 nm, respectively). When LN-1-255 inactivated SHV beta-lactamases, a single intermediate was detected by mass spectrometry. The crystal structure of LN-1-255 in complex with SHV-1 was determined at 1.55A resolution. Interestingly, this novel inhibitor forms a bicyclic aromatic intermediate with its carbonyl oxygen pointing out of the oxyanion hole and forming hydrogen bonds with Lys-234 and Ser-130 in the active site. Electron density for the "tail" of LN-1-255 is less ordered and modeled in two conformations. Both conformations have the LN-1-255 carboxyl group interacting with Arg-244, yet the remaining tails of the two conformations diverge. The observed presence of the bicyclic aromatic intermediate with its carbonyl oxygen positioned outside of the oxyanion hole provides a rationale for the stability of this inhibitory intermediate. The 2'-substituted penicillin sulfone, LN-1-255, is proving to be an important lead compound for novel beta-lactamase inhibitor design.
Collapse
Affiliation(s)
- Priyaranjan Pattanaik
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
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.
Collapse
|
37
|
Mansour TS, Bradford PA, Venkatesan AM. Recent Developments in β-Lactamases and Inhibitors. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2008. [DOI: 10.1016/s0065-7743(08)00015-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
|
38
|
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.
Collapse
Affiliation(s)
- Teresa De la Mora-Rey
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis 55455, USA
| | | |
Collapse
|
39
|
Chen PC, Wharton RE, Patel PA, Oyelere AK. Direct diazo-transfer reaction on beta-lactam: synthesis and preliminary biological activities of 6-triazolylpenicillanic acids. Bioorg Med Chem 2007; 15:7288-300. [PMID: 17855098 PMCID: PMC2755539 DOI: 10.1016/j.bmc.2007.08.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 08/14/2007] [Accepted: 08/20/2007] [Indexed: 11/30/2022]
Abstract
In this study we report the first example of a direct diazo-transfer reaction on readily available 6-aminopenicillanates to give 6-azidopenicillanates in high yield. Subsequent Cu(I)-catalyzed Huisgen cycloaddition between these 6-azidopenicillanates and assorted terminal alkynes facilely furnished 6-triazolylpenicillanic acids. Preliminary biological screening indicates that these triazolylpenicillanic acids possess low to moderate antibacterial activities.
Collapse
Affiliation(s)
- Po C Chen
- School of Chemistry and Biochemistry, Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
| | | | | | | |
Collapse
|
40
|
Helfand MS, Taracila MA, Totir MA, Bonomo RA, Buynak JD, van den Akker F, Carey PR. Raman crystallographic studies of the intermediates formed by Ser130Gly SHV, a beta-lactamase that confers resistance to clinical inhibitors. Biochemistry 2007; 46:8689-99. [PMID: 17595114 DOI: 10.1021/bi700581q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibiotic resistance to beta-lactam compounds in Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae is often mediated by beta-lactamase enzymes like TEM and SHV. Previously, a limited number of inhibitors have shown efficacy in combating such bacterial drug resistance. However, many Gram-negative pathogens have evolved inhibitor resistant forms of these hydrolytic enzymes. A single point mutation of the active site residue Ser130 to a Gly in either TEM or SHV results in resistance to amoxicillin and clavulanic acid, an important clinical beta-lactam-beta-lactamase inhibitor combination antibiotic. Previous structural and modeling studies of the S130G mutants of TEM and SHV have shown differences in how these two distinct but closely related enzymes compensate for the loss of the Ser130 residue. In the case of S130G SHV, a structure of tazobactam in the active site has suggested that the inhibitor preferentially assumes a cis-enamine intermediate form when the Ser130 hydroxyl is absent. Raman crystallographic studies of S130G SHV inhibited with tazobactam, sulbactam, clavulanic acid, and 2'-glutaroxy penem sulfone (SA2-13) were performed with the aim of identifying the type and amount of intermediate formed with each drug to understand the role of the S130G mutation in formation of the important enamine intermediates. It is demonstrated that with the exception of sulbactam, each compound forms observable trans-enamine intermediates. For S130G reacted with tazobactam, identical steady state levels of enamine are achieved when compared to those of wild-type (WT) or even deacylation deficient forms of the enzyme. With clavulanic acid, slightly smaller amounts of enamine are observed within the first 30 min of the reaction but are not significantly different than those for tazobactam. Thus, the resistance mutation does not substantially affect the amount of trans-enamine formed with clavulanic acid during the critical early time period of inhibition. This finding has important implications in the design of beta-lactamase inhibitors for drug resistant variants like S130G SHV.
Collapse
Affiliation(s)
- Marion S Helfand
- Research Service and Infectious Diseases Section, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
| | | | | | | | | | | | | |
Collapse
|
41
|
Ke W, Bethel CR, Thomson JM, Bonomo RA, van den Akker F. Crystal structure of KPC-2: insights into carbapenemase activity in class A beta-lactamases. Biochemistry 2007; 46:5732-40. [PMID: 17441734 PMCID: PMC2596071 DOI: 10.1021/bi700300u] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Beta-lactamases inactivate beta-lactam antibiotics and are a major cause of antibiotic resistance. The recent outbreaks of Klebsiella pneumoniae carbapenem resistant (KPC) infections mediated by KPC type beta-lactamases are creating a serious threat to our "last resort" antibiotics, the carbapenems. KPC beta-lactamases are serine carbapenemases and are a subclass of class A beta-lactamases that have evolved to efficiently hydrolyze carbapenems and cephamycins which contain substitutions at the alpha-position proximal to the carbonyl group that normally render these beta-lactams resistant to hydrolysis. To investigate the molecular basis of this carbapenemase activity, we have determined the structure of KPC-2 at 1.85 A resolution. The active site of KPC-2 reveals the presence of a bicine buffer molecule which interacts via its carboxyl group with conserved active site residues S130, K234, T235, and T237; these likely resemble the interactions the beta-lactam carboxyl moiety makes in the Michaelis-Menten complex. Comparison of the KPC-2 structure with non-carbapenemases and previously determined NMC-A and SME-1 carbapenemase structures shows several active site alterations that are unique among carbapenemases. An outward shift of the catalytic S70 residue renders the active sites of the carbapenemases more shallow, likely allowing easier access of the bulkier substrates. Further space for the alpha-substituents is potentially provided by shifts in N132 and N170 in addition to concerted movements in the postulated carboxyl binding pocket that might allow the substrates to bind at a slightly different angle to accommodate these alpha-substituents. The structure of KPC-2 provides key insights into the carbapenemase activity of emerging class A beta-lactamases.
Collapse
Affiliation(s)
- Wei Ke
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106-4935, USA
| | | | | | | | | |
Collapse
|
42
|
Mulchande J, Martins L, Moreira R, Archer M, Oliveira TF, Iley J. The efficiency of C-4 substituents in activating the β-lactam scaffold towards serine proteases and hydroxide ion. Org Biomol Chem 2007; 5:2617-26. [DOI: 10.1039/b706622h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|