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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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2
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Tan Y, Wu J, Song L, Zhang M, Hipolito CJ, Wu C, Wang S, Zhang Y, Yin Y. Merging the Versatile Functionalities of Boronic Acid with Peptides. Int J Mol Sci 2021; 22:ijms222312958. [PMID: 34884766 PMCID: PMC8657650 DOI: 10.3390/ijms222312958] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022] Open
Abstract
Peptides inherently feature the favorable properties of being easily synthesized, water-soluble, biocompatible, and typically non-toxic. Thus, boronic acid has been widely integrated with peptides with the goal of discovering peptide ligands with novel biological activities, and this effort has led to broad applications. Taking the integration between boronic acid and peptide as a starting point, we provide an overview of the latest research advances and highlight the versatile and robust functionalities of boronic acid. In this review, we summarize the diverse applications of peptide boronic acids in medicinal chemistry and chemical biology, including the identification of covalent reversible enzyme inhibitors, recognition, and detection of glycans on proteins or cancer cell surface, delivery of siRNAs, development of pH responsive devices, and recognition of RNA or bacterial surfaces. Additionally, we discuss boronic acid-mediated peptide cyclization and peptide modifications, as well as the facile chemical synthesis of peptide boronic acids, which paved the way for developing a growing number of peptide boronic acids.
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Affiliation(s)
- Yahong Tan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Junjie Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Lulu Song
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Mengmeng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Christopher John Hipolito
- Screening & Compound Profiling, Quantitative Biosciences, Merck & Co., Inc., Kenilworth, NJ 07033, USA;
| | - Changsheng Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Siyuan Wang
- Department of Medicinal Chemistry, College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China
- Correspondence: (S.W.); (Y.Y.)
| | - Youming Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
| | - Yizhen Yin
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China; (Y.T.); (J.W.); (L.S.); (M.Z.); (C.W.); (Y.Z.)
- Correspondence: (S.W.); (Y.Y.)
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3
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Kumar V, Viviani SL, Ismail J, Agarwal S, Bonomo RA, van den Akker F. Structural analysis of the boronic acid β-lactamase inhibitor vaborbactam binding to Pseudomonas aeruginosa penicillin-binding protein 3. PLoS One 2021; 16:e0258359. [PMID: 34653211 PMCID: PMC8519428 DOI: 10.1371/journal.pone.0258359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial resistance (AMR) mediated by β-lactamases is the major and leading cause of resistance to penicillins and cephalosporins among Gram-negative bacteria. β-Lactamases, periplasmic enzymes that are widely distributed in the bacterial world, protect penicillin-binding proteins (PBPs), the major cell wall synthesizing enzymes, from inactivation by β-lactam antibiotics. Developing novel PBP inhibitors with a non-β-lactam scaffold could potentially evade this resistance mechanism. Based on the structural similarities between the evolutionary related serine β-lactamases and PBPs, we investigated whether the potent β-lactamase inhibitor, vaborbactam, could also form an acyl-enzyme complex with Pseudomonas aeruginosa PBP3. We found that this cyclic boronate, vaborbactam, inhibited PBP3 (IC50 of 262 μM), and its binding to PBP3 increased the protein thermal stability by about 2°C. Crystallographic analysis of the PBP3:vaborbactam complex reveals that vaborbactam forms a covalent bond with the catalytic S294. The amide moiety of vaborbactam hydrogen bonds with N351 and the backbone oxygen of T487. The carboxyl group of vaborbactam hydrogen bonds with T487, S485, and S349. The thiophene ring and cyclic boronate ring of vaborbactam form hydrophobic interactions, including with V333 and Y503. The active site of the vaborbactam-bound PBP3 harbors the often observed ligand-induced formation of the aromatic wall and hydrophobic bridge, yet the residues involved in this wall and bridge display much higher temperature factors compared to PBP3 structures bound to high-affinity β-lactams. These insights could form the basis for developing more potent novel cyclic boronate-based PBP inhibitors to inhibit these targets and overcome β-lactamases-mediated resistance mechanisms.
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Affiliation(s)
- Vijay Kumar
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Samantha L. Viviani
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jeeda Ismail
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Shreya Agarwal
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert A. Bonomo
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stokes Cleveland Veteran’s Affairs Medical Center Research Service, Cleveland, Ohio, United States of America
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America
- VA Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Case Western Reserve University, 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:
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4
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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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5
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Design, synthesis and characterization of peptidyl boronate analogues as effective antimicrobial agents. RESEARCH ON CHEMICAL INTERMEDIATES 2017. [DOI: 10.1007/s11164-017-2961-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Abstract
This review describes available methods for the preparation of α-aminoboronic acids in their racemic or in their enantiopure form. Both, highly stereoselective syntheses and asymmetric procedures leading to the stereocontrolled generation of α-aminoboronic acid derivatives are included. The preparation of acyclic, carbocyclic and azacyclic α-aminoboronic acid derivatives is covered. Within each section, the different synthetic approaches have been classified according to the key bond which is formed to complete the α-aminoboronic acid skeleton.
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Affiliation(s)
- Patricia Andrés
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
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7
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Tilvawala R, Cammarata M, Adediran SA, Brodbelt JS, Pratt RF. A New Covalent Inhibitor of Class C β-Lactamases Reveals Extended Active Site Specificity. Biochemistry 2015; 54:7375-84. [DOI: 10.1021/acs.biochem.5b01149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Ronak Tilvawala
- Department
of Chemistry, Wesleyan University, Middletown, Connecticut 06459, United States
| | - Michael Cammarata
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
| | - S. A. Adediran
- Department
of Chemistry, Wesleyan University, Middletown, Connecticut 06459, United States
| | - Jennifer S. Brodbelt
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
| | - R. F. Pratt
- Department
of Chemistry, Wesleyan University, Middletown, Connecticut 06459, United States
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8
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Penicillin-binding proteins: evergreen drug targets. Curr Opin Pharmacol 2014; 18:112-9. [DOI: 10.1016/j.coph.2014.09.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023]
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9
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Advances in Inhibitors of Penicillin-Binding Proteins and β-Lactamases as Antibacterial Agents. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1016/b978-0-12-800167-7.00016-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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10
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Abstract
Advances in the field of boron chemistry have expanded the application of boron from material use to medicine. Boron-based drugs represent a new class of molecules that possess several biomedical applications including use as imaging agents for both optical and nuclear imaging as well as therapeutic agents with anticancer, antiviral, antibacterial, antifungal and other disease-specific activities. For example, bortezomib (Velcade(®)), the only drug in clinical use with boron as an active element, was approved in 2003 as a proteasome inhibitor for the treatment of multiple myeloma and non-Hodgkin's lymphoma. Several other boron-based compounds are in various phases of clinical trials, which illustrates the promise of this approach for medicinal chemists working in the area of boron chemistry. It is expected that in the near future, several boron-containing drugs should become available in the market with better efficacy and potency than existing drugs. This article discusses the current status of the development of boron-based compounds as diagnostic and therapeutic agents in humans.
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Abstract
New antimicrobial agents are always needed to counteract the resistant pathogens that continue to be selected by current therapeutic regimens. This review provides a survey of known antimicrobial agents that were currently in clinical development in the fall of 2012 and spring of 2013. Data were collected from published literature primarily from 2010 to 2012, meeting abstracts (2011 to 2012), government websites, and company websites when appropriate. Compared to what was reported in previous surveys, a surprising number of new agents are currently in company pipelines, particularly in phase 3 clinical development. Familiar antibacterial classes of the quinolones, tetracyclines, oxazolidinones, glycopeptides, and cephalosporins are represented by entities with enhanced antimicrobial or pharmacological properties. More importantly, compounds of novel chemical structures targeting bacterial pathways not previously exploited are under development. Some of the most promising compounds include novel β-lactamase inhibitor combinations that target many multidrug-resistant Gram-negative bacteria, a critical medical need. Although new antimicrobial agents will continue to be needed to address increasing antibiotic resistance, there are novel agents in development to tackle at least some of the more worrisome pathogens in the current nosocomial setting.
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Affiliation(s)
| | - Karen Bush
- Indiana University, Bloomington, Indiana, USA
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12
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Whyte GF, Vilar R, Woscholski R. Molecular recognition with boronic acids-applications in chemical biology. J Chem Biol 2013; 6:161-74. [PMID: 24432132 PMCID: PMC3787204 DOI: 10.1007/s12154-013-0099-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/19/2013] [Indexed: 01/14/2023] Open
Abstract
Small molecules have long been used for the selective recognition of a wide range of analytes. The ability of these chemical receptors to recognise and bind to specific targets mimics certain biological processes (such as protein-substrate interactions) and has therefore attracted recent interest. Due to the abundance of biological molecules possessing polyhydroxy motifs, boronic acids-which form five-membered boronate esters with diols-have become increasingly popular in the synthesis of small chemical receptors. Their targets include biological materials and natural products including phosphatidylinositol bisphosphate, saccharides and polysaccharides, nucleic acids, metal ions and the neurotransmitter dopamine. This review will focus on the many ways in which small chemical receptors based on boronic acids have been used as biochemical tools for various purposes, including sensing and detection of analytes, interference in signalling pathways, enzyme inhibition and cell delivery systems. The most recent developments in each area will be highlighted.
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Affiliation(s)
- Gillian F. Whyte
- Institute of Chemical Biology and Department of Chemistry, Imperial College London, London, UK
| | - Ramon Vilar
- Institute of Chemical Biology and Department of Chemistry, Imperial College London, London, UK
| | - Rudiger Woscholski
- Institute of Chemical Biology and Department of Chemistry, Imperial College London, London, UK
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13
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Olivares J, Bernardini A, Garcia-Leon G, Corona F, B Sanchez M, Martinez JL. The intrinsic resistome of bacterial pathogens. Front Microbiol 2013; 4:103. [PMID: 23641241 PMCID: PMC3639378 DOI: 10.3389/fmicb.2013.00103] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/11/2013] [Indexed: 11/13/2022] Open
Abstract
Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.
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Affiliation(s)
- Jorge Olivares
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
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14
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[Which alternatives are at our disposal in the anti-infectious therapeutics face to multi-drug resistant bacteria?]. ANNALES PHARMACEUTIQUES FRANÇAISES 2013; 71:150-8. [PMID: 23622693 DOI: 10.1016/j.pharma.2013.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/03/2013] [Accepted: 02/20/2013] [Indexed: 11/23/2022]
Abstract
The development of multi-drug resistance to antibiotics during the last years and the few number of new active molecules launched on the market have limited the treatment of some infectious diseases. Which alternatives are at our disposal in the anti-infectious therapeutics face to multi-drug resistant bacteria? Considering the bibliographic data, we can note different facts: (1) some alternatives already exist, but correspond more to targeted useful and usable therapeutics as phage therapy, honey therapy, or maggot therapy; (2) some "old" antibiotics can find new bacterial targets and reinforce the anti-infectious therapy towards some multi-drug resistant bacteria; (3) new formulations can allow targeted drug delivery via nanoparticles and the association of molecules can reinforce the antibiotic antimicrobial effect; (4) new treatment could be potentially usable as: antimicrobial peptides, probiotics, herbal medicines, statins, phosphonosulfonates, fecal transplants...; (5) at least, we must not forget that "it's better to prevent than cure". So, besides the principles of hygiene that must be respected, it is necessary to promote (if possible) the development of new vaccines against bacteria responsible for nosocomial infections. Facing with this potential, we can say that new orientations are open with very different levels of success and that it is urgent to find new targets ignored or forgotten until now.
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15
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Dzhekieva L, Adediran SA, Herman R, Kerff F, Duez C, Charlier P, Sauvage E, Pratt RF. Inhibition of DD-peptidases by a specific trifluoroketone: crystal structure of a complex with the Actinomadura R39 DD-peptidase. Biochemistry 2013; 52:2128-38. [PMID: 23484909 DOI: 10.1021/bi400048s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inhibitors of bacterial DD-peptidases represent potential antibiotics. In the search for alternatives to β-lactams, we have investigated a series of compounds designed to generate transition state analogue structures upon reaction with DD-peptidases. The compounds contain a combination of a peptidoglycan-mimetic specificity handle and a warhead capable of delivering a tetrahedral anion to the enzyme active site. The latter includes a boronic acid, two alcohols, an aldehyde, and a trifluoroketone. The compounds were tested against two low-molecular mass class C DD-peptidases. As expected from previous observations, the boronic acid was a potent inhibitor, but rather unexpectedly from precedent, the trifluoroketone [D-α-aminopimelyl(1,1,1-trifluoro-3-amino)butan-2-one] was also very effective. Taking into account competing hydration, we found the trifluoroketone was the strongest inhibitor of the Actinomadura R39 DD-peptidase, with a subnanomolar (free ketone) inhibition constant. A crystal structure of the complex between the trifluoroketone and the R39 enzyme showed that a tetrahedral adduct had indeed formed with the active site serine nucleophile. The trifluoroketone moiety, therefore, should be considered along with boronic acids and phosphonates as a warhead that can be incorporated into new and effective DD-peptidase inhibitors and therefore, perhaps, antibiotics.
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Affiliation(s)
- Liudmila Dzhekieva
- Department of Chemistry, Wesleyan University , Lawn Avenue, Middletown, Connecticut 06459, United States
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16
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Zervosen A, Zapun A, Frère JM. Inhibition of Streptococcus pneumoniae penicillin-binding protein 2x and Actinomadura R39 DD-peptidase activities by ceftaroline. Antimicrob Agents Chemother 2013; 57:661-3. [PMID: 23147739 PMCID: PMC3535952 DOI: 10.1128/aac.01593-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/04/2012] [Indexed: 11/20/2022] Open
Abstract
Although the rate of acylation of a penicillin-resistant form of Streptococcus pneumoniae penicillin-binding protein 2x (PBP2x) by ceftaroline is 80-fold lower than that of its penicillin-sensitive counterpart, it remains sufficiently high (k(2)/K = 12,600 M(-1) s(-1)) to explain the sensitivity of the penicillin-resistant strain to this new cephalosporin. Surprisingly, the Actinomadura R39 DD-peptidase is not very sensitive to ceftaroline.
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Affiliation(s)
- Astrid Zervosen
- Centre de Recherches du Cyclotron, Université de Liège, Sart-Tilman, Liège, Belgium.
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17
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Abstract
The synthesis of the bacterial peptidoglycan has been recognized for over 50 years as fertile ground for antibacterial discovery. Initially, empirical screening of natural products for inhibition of bacterial growth detected many chemical classes of antibiotics whose specific mechanisms of action were eventually dissected and defined. Of the nontoxic antibiotics discovered, most were found to be inhibitors of either protein synthesis or cell wall synthesis, which led to more directed screening for inhibitors of these pathways. Directed screening and design programs for cell wall inhibitors have been undertaken since the 1960s. In that time it has become clear that, while certain steps and intermediates have yielded selective inhibitors and are established targets, other potential targets have not yielded inhibitors whose antibacterial activity is proven to be solely due to that inhibition. Why has this search been so problematic? Are the established targets still worth pursuing? This review will attempt to answer these and other questions and evaluate the viability of targets related to peptidoglycan synthesis.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, LLC, Springfield, New Jersey 07081, USA.
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18
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East SP, Silver LL. Multitarget ligands in antibacterial research: progress and opportunities. Expert Opin Drug Discov 2012; 8:143-56. [PMID: 23252414 DOI: 10.1517/17460441.2013.743991] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Resistance to current antibacterial therapies is an inevitability that represents a significant global health concern. Bacteria have the capacity to render all current drug treatments ineffective, which places a demand on the drug discovery community to constantly develop new antibacterial agents. Compounds that inhibit multiple biological targets, often referred to as multitarget ligands, are an inviting prospect in antibacterial research because, although they will not solve the issue of resistance, they might help to delay the onset. AREAS COVERED This review covers some of the recent progress in identifying new ligands that deliberately interact with more than one essential biological target in bacteria. The two principal areas covered are inhibitors of DNA replication and cell wall biosynthesis. EXPERT OPINION Antibacterial programs for the design of multitarget ligands present an important opportunity for production of antibacterial agents. Their longevity, due to slow development of resistance, is comparable to that seen with other successful agents - but is much improved over single-targeted agents for which resistance can appear in vitro overnight. The preclinical development of these agents will have to overcome the standard problems of antibacterial discovery. Such problems include optimization of characteristics favoring cell entry and particularly the demonstration of selectivity of inhibition of the desired multiple targets without inhibition of other bacterial or any mammalian functions.
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Affiliation(s)
- Stephen P East
- Evotec (UK) Ltd., 114 Milton Park, Abingdon, Oxfordshire OX14 4SA, UK.
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Development of new drugs for an old target: the penicillin binding proteins. Molecules 2012; 17:12478-505. [PMID: 23095893 PMCID: PMC6268044 DOI: 10.3390/molecules171112478] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/05/2012] [Accepted: 10/17/2012] [Indexed: 11/16/2022] Open
Abstract
The widespread use of β-lactam antibiotics has led to the worldwide appearance of drug-resistant strains. Bacteria have developed resistance to β-lactams by two main mechanisms: the production of β-lactamases, sometimes accompanied by a decrease of outer membrane permeability, and the production of low-affinity, drug resistant Penicillin Binding Proteins (PBPs). PBPs remain attractive targets for developing new antibiotic agents because they catalyse the last steps of the biosynthesis of peptidoglycan, which is unique to bacteria, and lies outside the cytoplasmic membrane. Here we summarize the “current state of the art” of non-β-lactam inhibitors of PBPs, which have being developed in an attempt to counter the emergence of β-lactam resistance. These molecules are not susceptible to hydrolysis by β-lactamases and thus present a real alternative to β-lactams. We present transition state analogs such as boronic acids, which can covalently bind to the active serine residue in the catalytic site. Molecules containing ring structures different from the β-lactam-ring like lactivicin are able to acylate the active serine residue. High throughput screening methods, in combination with virtual screening methods and structure based design, have allowed the development of new molecules. Some of these novel inhibitors are active against major pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and thus open avenues new for the discovery of novel antibiotics.
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