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Ambade SS, Gupta VK, Bhole RP, Khedekar PB, Chikhale RV. A Review on Five and Six-Membered Heterocyclic Compounds Targeting the Penicillin-Binding Protein 2 (PBP2A) of Methicillin-Resistant Staphylococcus aureus (MRSA). Molecules 2023; 28:7008. [PMID: 37894491 PMCID: PMC10609489 DOI: 10.3390/molecules28207008] [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: 09/08/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Staphylococcus aureus is a common human pathogen. Methicillin-resistant Staphylococcus aureus (MRSA) infections pose significant and challenging therapeutic difficulties. MRSA often acquires the non-native gene PBP2a, which results in reduced susceptibility to β-lactam antibiotics, thus conferring resistance. PBP2a has a lower affinity for methicillin, allowing bacteria to maintain peptidoglycan biosynthesis, a core component of the bacterial cell wall. Consequently, even in the presence of methicillin or other antibiotics, bacteria can develop resistance. Due to genes responsible for resistance, S. aureus becomes MRSA. The fundamental premise of this resistance mechanism is well-understood. Given the therapeutic concerns posed by resistant microorganisms, there is a legitimate demand for novel antibiotics. This review primarily focuses on PBP2a scaffolds and the various screening approaches used to identify PBP2a inhibitors. The following classes of compounds and their biological activities are discussed: Penicillin, Cephalosporins, Pyrazole-Benzimidazole-based derivatives, Oxadiazole-containing derivatives, non-β-lactam allosteric inhibitors, 4-(3H)-Quinazolinones, Pyrrolylated chalcone, Bis-2-Oxoazetidinyl macrocycles (β-lactam antibiotics with 1,3-Bridges), Macrocycle-embedded β-lactams as novel inhibitors, Pyridine-Coupled Pyrimidinones, novel Naphthalimide corbelled aminothiazoximes, non-covalent inhibitors, Investigational-β-lactam antibiotics, Carbapenem, novel Benzoxazole derivatives, Pyrazolylpyridine analogues, and other miscellaneous classes of scaffolds for PBP2a. Additionally, we discuss the penicillin-binding protein, a crucial target in the MRSA cell wall. Various aspects of PBP2a, bacterial cell walls, peptidoglycans, different crystal structures of PBP2a, synthetic routes for PBP2a inhibitors, and future perspectives on MRSA inhibitors are also explored.
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Affiliation(s)
- Shraddha S. Ambade
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MH, India (P.B.K.)
| | - Vivek Kumar Gupta
- Department of Biochemistry, National JALMA Institute for Leprosy & Other Mycobacterial Diseases (ICMR), Agra 282004, UP, India
| | - Ritesh P. Bhole
- Dr. D. Y. Patil Institute of Pharmaceutical Sciences and Research, Pimpri, Pune 411018, MH, India
- Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune 411018, MH, India
| | - Pramod B. Khedekar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MH, India (P.B.K.)
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Newman H, Krajnc A, Bellini D, Eyermann CJ, Boyle GA, Paterson NG, McAuley KE, Lesniak R, Gangar M, von Delft F, Brem J, Chibale K, Schofield CJ, Dowson CG. High-Throughput Crystallography Reveals Boron-Containing Inhibitors of a Penicillin-Binding Protein with Di- and Tricovalent Binding Modes. J Med Chem 2021; 64:11379-11394. [PMID: 34337941 PMCID: PMC9282634 DOI: 10.1021/acs.jmedchem.1c00717] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The effectiveness of β-lactam antibiotics is increasingly compromised by β-lactamases. Boron-containing inhibitors are potent serine-β-lactamase inhibitors, but the interactions of boron-based compounds with the penicillin-binding protein (PBP) β-lactam targets have not been extensively studied. We used high-throughput X-ray crystallography to explore reactions of a boron-containing fragment set with the Pseudomonas aeruginosa PBP3 (PaPBP3). Multiple crystal structures reveal that boronic acids react with PBPs to give tricovalently linked complexes bonded to Ser294, Ser349, and Lys484 of PaPBP3; benzoxaboroles react with PaPBP3 via reaction with two nucleophilic serines (Ser294 and Ser349) to give dicovalently linked complexes; and vaborbactam reacts to give a monocovalently linked complex. Modifications of the benzoxaborole scaffold resulted in a moderately potent inhibition of PaPBP3, though no antibacterial activity was observed. Overall, the results further evidence the potential for the development of new classes of boron-based antibiotics, which are not compromised by β-lactamase-driven resistance.
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Affiliation(s)
- Hector Newman
- School
of Life Sciences, University of Warwick, Coventry CV4 7AL, U.K.
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Alen Krajnc
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Dom Bellini
- School
of Life Sciences, University of Warwick, Coventry CV4 7AL, U.K.
| | - Charles J. Eyermann
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Grant A. Boyle
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Neil G. Paterson
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Katherine E. McAuley
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Robert Lesniak
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Mukesh Gangar
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Frank von Delft
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
- Structural
Genomics Consortium (SGC), University of
Oxford, Oxford, U.K.
- Department
of Biochemistry, University of Johannesburg, Auckland Park 2006, South Africa
- Research
Complex at Harwell, Harwell
Science and Innovation Campus, Didcot OX11 0FA, U.K.
| | - Jürgen Brem
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Kelly Chibale
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, Department of Chemistry and Institute of Infectious Disease
and Molecular Medicine, University of Cape
Town, Rondebosch 7701, South Africa
| | - Christopher J. Schofield
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
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Singh A, Tomberg J, Nicholas RA, Davies C. Recognition of the β-lactam carboxylate triggers acylation of Neisseria gonorrhoeae penicillin-binding protein 2. J Biol Chem 2019; 294:14020-14032. [PMID: 31362987 PMCID: PMC6755799 DOI: 10.1074/jbc.ra119.009942] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/25/2019] [Indexed: 01/07/2023] Open
Abstract
Resistance of Neisseria gonorrhoeae to extended-spectrum cephalosporins (ESCs) has become a major threat to human health. The primary mechanism by which N. gonorrhoeae becomes resistant to ESCs is by acquiring a mosaic penA allele, encoding penicillin-binding protein 2 (PBP2) variants containing up to 62 mutations compared with WT, of which a subset contribute to resistance. To interpret molecular mechanisms underpinning cephalosporin resistance, it is necessary to know how PBP2 is acylated by ESCs. Here, we report the crystal structures of the transpeptidase domain of WT PBP2 in complex with cefixime and ceftriaxone, along with structures of PBP2 in the apo form and with a phosphate ion bound in the active site at resolutions of 1-7-1.9 Å. These structures reveal that acylation of PBP2 by ESCs is accompanied by rotation of the Thr-498 side chain in the KTG motif to contact the cephalosporin carboxylate, twisting of the β3 strand to form the oxyanion hole, and rolling of the β3-β4 loop toward the active site. Recognition of the cephalosporin carboxylate appears to be the key trigger for formation of an acylation-competent state of PBP2. The structures also begin to explain the impact of mutations implicated in ESC resistance. In particular, a G545S mutation may hinder twisting of β3 because its side chain hydroxyl forms a hydrogen bond with Thr-498. Overall, our data suggest that acylation is initiated by conformational changes elicited or trapped by binding of ESCs and that these movements are restricted by mutations associated with resistance against ESCs.
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Affiliation(s)
- Avinash Singh
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Joshua Tomberg
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Robert A. Nicholas
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Christopher Davies
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, To whom correspondence should be addressed:
Dept. of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425. Tel.:
843-876-2302; Fax:
843-792-8568; E-mail:
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Hart KM, Reck M, Bowman GR, Wencewicz TA. Tabtoxinine-β-lactam is a “stealth” β-lactam antibiotic that evades β-lactamase-mediated antibiotic resistance. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00325c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Tabtoxinine-β-lactam (TβL) is a phytotoxin produced by plant pathogenic strains of Pseudomonas syringae.
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Affiliation(s)
- Kathryn M. Hart
- Department of Biochemistry and Molecular Biophysics
- Washington University School of Medicine
- St. Louis
- USA
| | - Margaret Reck
- Department of Chemistry
- Washington University in St. Louis
- St. Louis
- USA
| | - Gregory R. Bowman
- Department of Biochemistry and Molecular Biophysics
- Washington University School of Medicine
- St. Louis
- USA
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Fishovitz J, Taghizadeh N, Fisher JF, Chang M, Mobashery S. The Tipper-Strominger Hypothesis and Triggering of Allostery in Penicillin-Binding Protein 2a of Methicillin-Resistant Staphylococcus aureus (MRSA). J Am Chem Soc 2015; 137:6500-5. [PMID: 25964995 DOI: 10.1021/jacs.5b01374] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The transpeptidases involved in the synthesis of the bacterial cell wall (also known as penicillin-binding proteins, PBPs) have evolved to bind the acyl-D-Ala-D-Ala segment of the stem peptide of the nascent peptidoglycan for the physiologically important cross-linking of the cell wall. The Tipper-Strominger hypothesis stipulates that β-lactam antibiotics mimic the acyl-D-Ala-D-Ala moiety of the stem and, thus, are recognized by the PBPs with bactericidal consequences. We document that this mimicry exists also at the allosteric site of PBP2a of methicillin-resistant Staphylococcus aureus (MRSA). Interactions of different classes of β-lactam antibiotics, as mimics of the acyl-D-Ala-D-Ala moiety at the allosteric site, lead to a conformational change, across a distance of 60 Å to the active site. We directly visualize this change using an environmentally sensitive fluorescent probe affixed to the protein loops that frame the active site. This conformational mobility, documented in real time, allows antibiotic access to the active site of PBP2a. Furthermore, we document that this allosteric trigger enables synergy between two different β-lactam antibiotics, wherein occupancy at the allosteric site by one facilitates occupancy by a second at the transpeptidase catalytic site, thus lowering the minimal-inhibitory concentration. This synergy has important implications for the mitigation of facile emergence of resistance to these antibiotics by MRSA.
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Affiliation(s)
- Jennifer Fishovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Negin Taghizadeh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Mayland Chang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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