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Stewart NK, Toth M, Quan P, Buynak JD, Smith CA, Vakulenko SB. Restricted Rotational Flexibility of the C5α-Methyl-Substituted Carbapenem NA-1-157 Leads to Potent Inhibition of the GES-5 Carbapenemase. ACS Infect Dis 2024; 10:1232-1249. [PMID: 38511828 PMCID: PMC11160566 DOI: 10.1021/acsinfecdis.3c00683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Carbapenem antibiotics are used as a last-resort treatment for infections caused by multidrug-resistant bacteria. The wide spread of carbapenemases in Gram-negative bacteria has severely compromised the utility of these drugs and represents a serious public health threat. To combat carbapenemase-mediated resistance, new antimicrobials and inhibitors of these enzymes are urgently needed. Here, we describe the interaction of the atypically C5α-methyl-substituted carbapenem, NA-1-157, with the GES-5 carbapenemase. MICs of this compound against Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii producing the enzyme were reduced 4-16-fold when compared to MICs of the commercial carbapenems, reaching clinically sensitive breakpoints. When NA-1-157 was combined with meropenem, a strong synergistic effect was observed. Kinetic and ESI-LC/MS studies demonstrated that NA-1-157 is a potent inhibitor of GES-5, with a high inactivation efficiency of (2.9 ± 0.9) × 105 M-1 s-1. Acylation of GES-5 by NA-1-157 was biphasic, with the fast phase completing within seconds, and the slow phase taking several hours and likely proceeding through a reversible tetrahedral intermediate. Deacylation was extremely slow (k3 = (2.4 ± 0.3) × 10-7 s-1), resulting in a residence time of 48 ± 6 days. MD simulation of the GES-5-meropenem and GES-5-NA-1-157 acyl-enzyme complexes revealed that the C5α-methyl group in NA-1-157 sterically restricts rotation of the 6α-hydroxyethyl group preventing ingress of the deacylating water into the vicinity of the scissile bond of the acyl-enzyme intermediate. These data demonstrate that NA-1-157 is a potent irreversible inhibitor of the GES-5 carbapenemase.
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Affiliation(s)
- Nichole K. Stewart
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Marta Toth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Pojun Quan
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275, USA
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275, USA
| | - Clyde A. Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, CA 94025, USA
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Sergei B. Vakulenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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Jacobs LMC, Consol P, Chen Y. Drug Discovery in the Field of β-Lactams: An Academic Perspective. Antibiotics (Basel) 2024; 13:59. [PMID: 38247618 PMCID: PMC10812508 DOI: 10.3390/antibiotics13010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 01/23/2024] Open
Abstract
β-Lactams are the most widely prescribed class of antibiotics that inhibit penicillin-binding proteins (PBPs), particularly transpeptidases that function in peptidoglycan synthesis. A major mechanism of antibiotic resistance is the production of β-lactamase enzymes, which are capable of hydrolyzing β-lactam antibiotics. There have been many efforts to counter increasing bacterial resistance against β-lactams. These studies have mainly focused on three areas: discovering novel inhibitors against β-lactamases, developing new β-lactams less susceptible to existing resistance mechanisms, and identifying non-β-lactam inhibitors against cell wall transpeptidases. Drug discovery in the β-lactam field has afforded a range of research opportunities for academia. In this review, we summarize the recent new findings on both β-lactamases and cell wall transpeptidases because these two groups of enzymes are evolutionarily and functionally connected. Many efforts to develop new β-lactams have aimed to inhibit both transpeptidases and β-lactamases, while several promising novel β-lactamase inhibitors have shown the potential to be further developed into transpeptidase inhibitors. In addition, the drug discovery progress against each group of enzymes is presented in three aspects: understanding the targets, screening methodology, and new inhibitor chemotypes. This is to offer insights into not only the advancement in this field but also the challenges, opportunities, and resources for future research. In particular, cyclic boronate compounds are now capable of inhibiting all classes of β-lactamases, while the diazabicyclooctane (DBO) series of small molecules has led to not only new β-lactamase inhibitors but potentially a new class of antibiotics by directly targeting PBPs. With the cautiously optimistic successes of a number of new β-lactamase inhibitor chemotypes and many questions remaining to be answered about the structure and function of cell wall transpeptidases, non-β-lactam transpeptidase inhibitors may usher in the next exciting phase of drug discovery in this field.
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Affiliation(s)
| | | | - Yu Chen
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (L.M.C.J.); (P.C.)
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Arrigoni R, Ballini A, Santacroce L, Palese LL. The Dynamics of OXA-23 β-Lactamase from Acinetobacter baumannii. Int J Mol Sci 2023; 24:17527. [PMID: 38139363 PMCID: PMC10743560 DOI: 10.3390/ijms242417527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Antibiotic resistance is a pressing topic, which also affects β-lactam antibiotic molecules. Until a few years ago, it was considered no more than an interesting species from an academic point of view, Acinetobacter baumanii is today one of the most serious threats to public health, so much so that it has been declared one of the species for which the search for new antibiotics, or new ways to avoid its resistance, is an absolute priority according to WHO. Although there are several molecular mechanisms that are responsible for the extreme resistance of A. baumanii to antibiotics, a class D β-lactamase is the main cause for the clinical concern of this bacterial species. In this work, we analyzed the A. baumanii OXA-23 protein via molecular dynamics. The results obtained show that this protein is able to assume different conformations, especially in some regions around the active site. Part of the OXA-23 protein has considerable conformational motility, while the rest is less mobile. The importance of these observations for understanding the functioning mechanism of the enzyme as well as for designing new effective molecules for the treatment of A. baumanii is discussed.
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Affiliation(s)
- Roberto Arrigoni
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy;
| | - Andrea Ballini
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Luigi Santacroce
- Interdisciplinary Department of Medicine (DIM), University of Bari ‘Aldo Moro’, 70124 Bari, Italy;
| | - Luigi Leonardo Palese
- Department of Translational Biomedicine and Neurosciences—(DiBraiN), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
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Jain D, Verma J, Ajith T, Bhattacharjee A, Ghosh AS. Two non-active site residues W165 and L166 prominently influence the beta-lactam hydrolytic ability of OXA-23 beta-lactamase. J Antibiot (Tokyo) 2023; 76:489-498. [PMID: 37095236 DOI: 10.1038/s41429-023-00624-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/28/2023] [Accepted: 04/02/2023] [Indexed: 04/26/2023]
Abstract
Dissemination of class D OXA-type carbapenemases is one of the significant causes of beta-lactam resistance in Gram-negative bacteria. The amino acid residues present near the active site are involved in hydrolytic mechanism of class D carbapenemases, though it is not identified in OXA-23. Here, with the help of site-directed mutagenesis, we aimed to explicate the importance of the residues W165, L166 and V167 of the possible omega loop and residue D222 in the short β5-β6 loop on the activity of OXA-23. All the residues were substituted with alanine. The resultant proteins were assayed for the changes in activity in E. coli cells and purified for in vitro activity, and stability assessment. E. coli cells harboring OXA-23_W165A and OXA-23_L166A, individually, exhibited a significant decrease in resistance towards beta-lactam antibiotics as compared to OXA-23. Further, purified OXA-23_W165A and OXA-23_L166A imparted about >4-fold decrease in catalytic efficiency and displayed reduced thermal stability as compared to OXA-23. Bocillin-FL binding assay revealed that W165A substitution results in improper N-carboxylation of K82, leading to deacylation deficient OXA-23. Therefore, we infer that the residue W165 maintains the integrity of N-carboxylated lysine (K82) of OXA-23 and the residue L166 might be responsible for properly orientating the antibiotic molecules.
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Affiliation(s)
- Diamond Jain
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
| | - Jyoti Verma
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
| | - Tejavath Ajith
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
| | | | - Anindya Sundar Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India.
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Smith CA, Stewart NK, Toth M, Quan P, Buynak JD, Vakulenko SB. The C5α-Methyl-Substituted Carbapenem NA-1-157 Exhibits Potent Activity against Klebsiella spp. Isolates Producing OXA-48-Type Carbapenemases. ACS Infect Dis 2023; 9:1123-1136. [PMID: 37130087 PMCID: PMC10722881 DOI: 10.1021/acsinfecdis.3c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The wide spread of carbapenem-hydrolyzing β-lactamases in Gram-negative bacteria has diminished the utility of the last-resort carbapenem antibiotics, significantly narrowing the available therapeutic options. In the Enterobacteriaceae family, which includes many important clinical pathogens such as Klebsiella pneumoniae and Escherichia coli, production of class D β-lactamases from the OXA-48-type family constitutes the major mechanism of resistance to carbapenems. To address the public health threat posed by these enzymes, novel, effective therapeutics are urgently needed. Here, we report evaluation of a novel, C5α-methyl-substituted carbapenem, NA-1-157, and show that its MICs against bacteria producing OXA-48-type enzymes were reduced by 4- to 32-fold when compared to meropenem. When combined with commercial carbapenems, the potency of NA-1-157 was further enhanced, resulting in target potentiation concentrations ranging from 0.125 to 2 μg/mL. Kinetic studies demonstrated that the compound is poorly hydrolyzed by OXA-48, with a catalytic efficiency 30- to 50-fold lower than those of imipenem and meropenem. Acylation of OXA-48 by NA-1-157 was severely impaired, with a rate 10,000- to 36,000-fold slower when compared to the commercial carbapenems. Docking, molecular dynamics, and structural studies demonstrated that the presence of the C5α-methyl group in NA-1-157 creates steric clashes within the active site, leading to differences in the position and the hydrogen-bonding pattern of the compound, which are incompatible with efficient acylation. This study demonstrates that NA-1-157 is a promising novel carbapenem for treatment of infections caused by OXA-48-producing bacterial pathogens.
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Affiliation(s)
- Clyde A Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California 94025, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Nichole K Stewart
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Marta Toth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Pojun Quan
- 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
| | - Sergei B Vakulenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Avci FG, Tastekil I, Jaisi A, Ozbek Sarica P, Sariyar Akbulut B. A review on the mechanistic details of OXA enzymes of ESKAPE pathogens. Pathog Glob Health 2022; 117:219-234. [PMID: 35758005 PMCID: PMC10081068 DOI: 10.1080/20477724.2022.2088496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The production of β-lactamases is a prevalent mechanism that poses serious pressure on the control of bacterial resistance. Furthermore, the unavoidable and alarming increase in the transmission of bacteria producing extended-spectrum β-lactamases complicates treatment alternatives with existing drugs and/or approaches. Class D β-lactamases, designated as OXA enzymes, are characterized by their activity specifically towards oxacillins. They are widely distributed among the ESKAPE bugs that are associated with antibiotic resistance and life-threatening hospital infections. The inadequacy of current β-lactamase inhibitors for conventional treatments of 'OXA' mediated infections confirms the necessity of new approaches. Here, the focus is on the mechanistic details of OXA-10, OXA-23, and OXA-48, commonly found in highly virulent and antibiotic-resistant pathogens Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter spp. to describe their similarities and differences. Furthermore, this review contains a specific emphasis on structural and computational perspectives, which will be valuable to guide efforts in the design/discovery of a common single-molecule drug against ESKAPE pathogens.
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Affiliation(s)
- Fatma Gizem Avci
- Bioengineering Department, Uskudar University, Uskudar, 34662, Turkey
| | - Ilgaz Tastekil
- Bioengineering Department, Marmara University, Kadikoy, 34722, Turkey
| | - Amit Jaisi
- Drug and Cosmetics Excellence Center, School of Pharmacy, Walailak University, 80160, Nakhon Si Thammarat, Thailand
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