1
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Batt SM, Abrahams KA, Besra GS. Top five unanswered questions in bacterial cell wall research. Cell Surf 2024; 11:100122. [PMID: 38425882 PMCID: PMC10902140 DOI: 10.1016/j.tcsw.2024.100122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/02/2024] Open
Affiliation(s)
| | | | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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2
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Abrahams KA, Batt SM, Gurcha SS, Veerapen N, Bashiri G, Besra GS. DprE2 is a molecular target of the anti-tubercular nitroimidazole compounds pretomanid and delamanid. Nat Commun 2023; 14:3828. [PMID: 37380634 DOI: 10.1038/s41467-023-39300-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 06/01/2023] [Indexed: 06/30/2023] Open
Abstract
Mycobacterium tuberculosis is one of the global leading causes of death due to a single infectious agent. Pretomanid and delamanid are new antitubercular agents that have progressed through the drug discovery pipeline. These compounds are bicyclic nitroimidazoles that act as pro-drugs, requiring activation by a mycobacterial enzyme; however, the precise mechanisms of action of the active metabolite(s) are unclear. Here, we identify a molecular target of activated pretomanid and delamanid: the DprE2 subunit of decaprenylphosphoribose-2'-epimerase, an enzyme required for the synthesis of cell wall arabinogalactan. We also provide evidence for an NAD-adduct as the active metabolite of pretomanid. Our results highlight DprE2 as a potential antimycobacterial target and provide a foundation for future exploration into the active metabolites and clinical development of pretomanid and delamanid.
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Affiliation(s)
- Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sarah M Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sudagar S Gurcha
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Natacha Veerapen
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Ghader Bashiri
- Laboratory of Molecular and Microbial Biochemistry, School of Biological Sciences, University of Auckland, 3A Symonds Street, Auckland, 1010, New Zealand
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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3
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Batt SM, Toth S, Rodriguez B, Abrahams KA, Veerapen N, Chiodarelli G, Cox LR, Moynihan PJ, Lelievre J, Fütterer K, Besra GS. Assay development and inhibition of the Mt-DprE2 essential reductase from Mycobacterium tuberculosis. Microbiology (Reading) 2023; 169:001288. [PMID: 36748627 PMCID: PMC9993113 DOI: 10.1099/mic.0.001288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
DprE2 is an essential enzyme in the synthesis of decaprenylphosphoryl-β-d-arabinofuranose (DPA) and subsequently arabinogalactan, and is a significant new drug target for M. tuberculosis. Two compounds from the GSK-177 box set, GSK301A and GSK032A, were identified through Mt-DprE2-target overexpression studies. The Mt-DprE1-DprE2 complex was co-purified and a new in vitro DprE2 assay developed, based on the oxidation of the reduced nicotinamide adenine dinucleotide cofactor of DprE2 (NADH/NADPH). The Mt-DprE1-DprE2 complex showed interesting kinetics in both the DprE1 resazurin-based assay, where Mt-DprE2 was found to enhance Mt-DprE1 activity and reduce substrate inhibition; and also in the DprE2 assay, which similarly exhibited substrate inhibition and a difference in kinetics of the two potential cofactors, NADH and NADPH. Although, no inhibition was observed in the DprE2 assay by the two GSK set compounds, spontaneous mutant generation indicated a possible explanation in the form of a pro-drug activation pathway, involving fgd1 and fbiC.
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Affiliation(s)
- Sarah M Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Szilvi Toth
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Beatriz Rodriguez
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Natacha Veerapen
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | | | - Liam R Cox
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, UK
| | - Patrick J Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Joel Lelievre
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Klaus Fütterer
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
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4
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Grover S, Engelhart CA, Perez‐Herran E, Tiwari D, Li W, Abrahams KA, Papavinasasundaram K, Bean JM, Sassetti CM, Mendoza‐Losana A, Besra GS, Jackson M, Aldrich C, Schnappinger D. Two‐way regulation of protein expression for identification and validation of on‐target inhibitors of
Mycobacterium tuberculosis. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l7723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shipra Grover
- Microbiology and ImmunologyWeill Cornell MedicineNew YorkNY
| | | | - Esther Perez‐Herran
- TB Research Unit, Global Health R&D, GlaxoSmithKlineGlaxoSmithKlineTres Cantos
| | - Divya Tiwari
- Centre for ImmunobiologyQueen Mary University of LondonLondon
| | - Wei Li
- Department of Microbiology, Immunology and PathologyColorado State UniversityFort CollinsCO
| | | | | | | | | | | | - Gurdyal S. Besra
- Institute of Microbiology and InfectionUniversity of BirminghamBirmingham
| | - Mary Jackson
- Department of Microbiology, Immunology and PathologyColorado State UniversityFort CollinsCO
| | - Courtney Aldrich
- Department of Medicinal ChemistryUniversity of MinnesotaMinneapolisMN
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Grover S, Engelhart CA, Pérez-Herrán E, Li W, Abrahams KA, Papavinasasundaram K, Bean JM, Sassetti CM, Mendoza-Losana A, Besra GS, Jackson M, Schnappinger D. Two-Way Regulation of MmpL3 Expression Identifies and Validates Inhibitors of MmpL3 Function in Mycobacterium tuberculosis. ACS Infect Dis 2021; 7:141-152. [PMID: 33319550 PMCID: PMC7802072 DOI: 10.1021/acsinfecdis.0c00675] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
MmpL3,
an essential mycolate transporter in the inner membrane
of Mycobacterium tuberculosis (Mtb), has been identified as a target of multiple, chemically diverse
antitubercular drugs. However, several of these molecules seem to
have secondary targets and inhibit bacterial growth by more than one
mechanism. Here, we describe a cell-based assay that utilizes two-way
regulation of MmpL3 expression to readily identify MmpL3-specific
inhibitors. We successfully used this assay to identify a novel guanidine-based
MmpL3 inhibitor from a library of 220 compounds that inhibit growth
of Mtb by largely unknown mechanisms. We furthermore
identified inhibitors of cytochrome bc1-aa3 oxidase as one class of off-target hits in whole-cell screens for
MmpL3 inhibitors and report a novel sulfanylacetamide as a potential
QcrB inhibitor.
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Affiliation(s)
- Shipra Grover
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10065, United States
| | - Curtis A. Engelhart
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10065, United States
| | - Esther Pérez-Herrán
- TB Research Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Katherine A. Abrahams
- Institute of Microbiology and Infection, School of Biological Sciences, University of Birmingham, Birmingham B15 2TT, U.K
| | - Kadamba Papavinasasundaram
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - James M. Bean
- Sloan Kettering Institute, New York, New York 10065, United States
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Alfonso Mendoza-Losana
- TB Research Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biological Sciences, University of Birmingham, Birmingham B15 2TT, U.K
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10065, United States
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Abstract
Mycobacterium tuberculosis is the causative pathogen of the pulmonary disease tuberculosis. Despite the availability of effective treatment programs, there is a global pursuit of new anti-tubercular agents to respond to the developing threat of drug resistance, in addition to reducing the extensive duration of chemotherapy and any associated toxicity. The route to mycobacterial drug discovery can be considered from two directions: target-to-drug and drug-to-target. The former approach uses conventional methods including biochemical assays along with innovative computational screens, but is yet to yield any drug candidates to the clinic, with a high attrition rate owing to lack of whole cell activity. In the latter approach, compound libraries are screened for efficacy against the bacilli or model organisms, ensuring whole cell activity, but here subsequent target identification is the rate-limiting step. Advances in a variety of scientific fields have enabled the amalgamation of aspects of both approaches in the development of novel drug discovery tools, which are now primed to accelerate the discovery of novel hits and leads with known targets and whole cell activity. This review discusses these traditional and innovative techniques, which are widely used in the quest for new anti-tubercular compounds. Innovations in mycobacterial drug discovery to accelerate the identification of new drug candidates with confirmed targets and whole cell activity.![]()
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Affiliation(s)
- Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham Edgbaston Birmingham B15 2TT UK +44 (0)121 41 45925 +44 (0)121 41 58125
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham Edgbaston Birmingham B15 2TT UK +44 (0)121 41 45925 +44 (0)121 41 58125
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7
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Abrahams KA, Hu W, Li G, Lu Y, Richardson EJ, Loman NJ, Huang H, Besra GS. Anti-tubercular derivatives of rhein require activation by the monoglyceride lipase Rv0183. ACTA ACUST UNITED AC 2020; 6:100040. [PMID: 32743152 PMCID: PMC7389528 DOI: 10.1016/j.tcsw.2020.100040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/17/2020] [Accepted: 04/17/2020] [Indexed: 02/01/2023]
Abstract
The emergence and perseverance of drug resistant strains of Mycobacterium tuberculosis (Mtb) ensures that drug discovery efforts remain at the forefront of tuberculosis research. There are numerous different approaches that can be employed to lead to the discovery of anti-tubercular agents. In this work, we endeavored to optimize the anthraquinone chemical scaffold of a known drug, rhein, converting it from a compound with negligible activity against Mtb, to a series of compounds with potent activity. Two compounds exhibited low toxicity and good liver microsome stability and were further progressed in attempts to identify the biological target. Whole genome sequencing of resistant isolates revealed inactivating mutations in a monoglyceride lipase. Over-expression trials and an enzyme assay confirmed that the designed compounds are prodrugs, activated by the monoglyceride lipase. We propose that rhein is the active moiety of the novel compounds, which requires chemical modifications to enable access to the cell through the extensive cell wall structure. This work demonstrates that re-engineering of existing antimicrobial agents is a valid method in the development of new anti-tubercular compounds.
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Affiliation(s)
- Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Wei Hu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Xian Nong Tan Street, Beijing 100050, China
| | - Gang Li
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Xian Nong Tan Street, Beijing 100050, China
| | - Yu Lu
- Beijing Key Laboratory of Drug Resistance Tuberculosis Research, Department of Pharmacology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, 97 Ma Chang Street, Beijing 101149, China
| | - Emily J Richardson
- MicrobesNG, Units 1-2 First Floor, The BioHub, Birmingham Research Park, 97 Vincent Drive, Birmingham B15 2SQ, UK
| | - Nicholas J Loman
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Haihong Huang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Xian Nong Tan Street, Beijing 100050, China
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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8
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Burke C, Abrahams KA, Richardson EJ, Loman NJ, Alemparte C, Lelievre J, Besra GS. Development of a whole-cell high-throughput phenotypic screen to identify inhibitors of mycobacterial amino acid biosynthesis. FASEB Bioadv 2019; 1:246-254. [PMID: 32123830 PMCID: PMC6996392 DOI: 10.1096/fba.2018-00048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 01/08/2023] Open
Abstract
Anti-tubercular drug discovery continues to be dominated by whole-cell high-throughput screening campaigns, enabling the rapid discovery of new inhibitory chemical scaffolds. Target-based screening is a popular approach to direct inhibitor discovery with a specified mode of action, eliminating the discovery of anti-tubercular agents against unsuitable targets. Herein, a screening method has been developed using Mycobacterium bovis BCG to identify inhibitors of amino acid biosynthesis. The methodology was initially optimized using the known branched-chain amino acid biosynthetic inhibitors metsulfuron-methyl (MSM) and sulfometuron-methyl (SMM), and subsequently, whole genome sequencing of resistant mutants and the use of over-expressor strains confirming their mode of action. The GlaxoSmithKline compound library of small molecule inhibitors with known activity against Mycobacterium tuberculosis was then used to validate the screen. In this paper, we have shown that media supplementation with amino acids can rescue M bovis BCG from known amino acid synthesis inhibitors, MSM and SMM, in a pathway specific manner. The therapeutic potential of amino acid biosynthesis inhibitors emphasizes the importance of this innovative screen, enabling the discovery of compounds targeting a multitude of related essential biochemical pathways, without limiting drug discovery toward a single target.
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Affiliation(s)
| | | | | | | | | | - Joel Lelievre
- Diseases of the Developing World, GlaxoSmithKlineMadridSpain
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9
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Abrahams KA, Cox JAG, Fütterer K, Rullas J, Ortega-Muro F, Loman NJ, Moynihan PJ, Pérez-Herrán E, Jiménez E, Esquivias J, Barros D, Ballell L, Alemparte C, Besra GS. Inhibiting mycobacterial tryptophan synthase by targeting the inter-subunit interface. Sci Rep 2017; 7:9430. [PMID: 28842600 PMCID: PMC5573416 DOI: 10.1038/s41598-017-09642-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/25/2017] [Indexed: 01/22/2023] Open
Abstract
Drug discovery efforts against the pathogen Mycobacterium tuberculosis (Mtb) have been advanced through phenotypic screens of extensive compound libraries. Such a screen revealed sulfolane 1 and indoline-5-sulfonamides 2 and 3 as potent inhibitors of mycobacterial growth. Optimization in the sulfolane series led to compound 4, which has proven activity in an in vivo murine model of Mtb infection. Here we identify the target and mode of inhibition of these compounds based on whole genome sequencing of spontaneous resistant mutants, which identified mutations locating to the essential α- and β-subunits of tryptophan synthase. Over-expression studies confirmed tryptophan synthase as the biological target. Biochemical techniques probed the mechanism of inhibition, revealing the mutant enzyme complex incurs a fitness cost but does not prevent inhibitor binding. Mapping of the resistance conferring mutations onto a low-resolution crystal structure of Mtb tryptophan synthase showed they locate to the interface between the α- and β-subunits. The discovery of anti-tubercular agents inhibiting tryptophan synthase highlights the therapeutic potential of this enzyme and draws attention to the prospect of other amino acid biosynthetic pathways as future Mtb drug targets.
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Affiliation(s)
- Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jonathan A G Cox
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Klaus Fütterer
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Joaquín Rullas
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Fátima Ortega-Muro
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Nicholas J Loman
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Patrick J Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Esther Pérez-Herrán
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Elena Jiménez
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Jorge Esquivias
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - David Barros
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Lluís Ballell
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Carlos Alemparte
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain.
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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Dow M, Marchetti F, Abrahams KA, Vaz L, Besra GS, Warriner S, Nelson A. Modular Synthesis of Diverse Natural Product-Like Macrocycles: Discovery of Hits with Antimycobacterial Activity. Chemistry 2017; 23:7207-7211. [PMID: 28374952 PMCID: PMC5488202 DOI: 10.1002/chem.201701150] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 12/24/2022]
Abstract
A modular synthetic approach was developed in which variation of the triplets of building blocks used enabled systematic variation of the macrocyclic scaffolds prepared. The approach was demonstrated in the synthesis of 17 diverse natural product-like macrocyclic scaffolds of varied (12-20-membered) ring size. The biological relevance of the chemical space explored was demonstrated through the discovery of a series of macrocycles with significant antimycobacterial activity.
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Affiliation(s)
- Mark Dow
- School of ChemistryUniversity of LeedsLeedsLS2 9JTUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTUK
| | - Francesco Marchetti
- School of ChemistryUniversity of LeedsLeedsLS2 9JTUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTUK
| | | | - Luis Vaz
- AstraZenecaCharter WayMacclesfieldSK10 2NAUK
| | - Gurdyal S. Besra
- School of BiosiencesUniversity of BirminghamEdgbaston, BirminghamB15 2TTUK
| | - Stuart Warriner
- School of ChemistryUniversity of LeedsLeedsLS2 9JTUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTUK
| | - Adam Nelson
- School of ChemistryUniversity of LeedsLeedsLS2 9JTUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTUK
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11
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Cox JAG, Mugumbate G, Del Peral LVG, Jankute M, Abrahams KA, Jervis P, Jackenkroll S, Perez A, Alemparte C, Esquivias J, Lelièvre J, Ramon F, Barros D, Ballell L, Besra GS. Novel inhibitors of Mycobacterium tuberculosis GuaB2 identified by a target based high-throughput phenotypic screen. Sci Rep 2016; 6:38986. [PMID: 27982051 PMCID: PMC5159837 DOI: 10.1038/srep38986] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/16/2016] [Indexed: 12/16/2022] Open
Abstract
High-throughput phenotypic screens have re-emerged as screening tools in antibiotic discovery. The advent of such technologies has rapidly accelerated the identification of 'hit' compounds. A pre-requisite to medicinal chemistry optimisation programmes required to improve the drug-like properties of a 'hit' molecule is identification of its mode of action. Herein, we have combined phenotypic screening with a biased target-specific screen. The inosine monophosphate dehydrogenase (IMPDH) protein GuaB2 has been identified as a drugable target in Mycobacterium tuberculosis, however previously identified compounds lack the desired characteristics necessary for further development into lead-like molecules. This study has identified 7 new chemical series from a high-throughput resistance-based phenotypic screen using Mycobacterium bovis BCG over-expressing GuaB2. Hit compounds were identified in a single shot high-throughput screen, validated by dose response and subjected to further biochemical analysis. The compounds were also assessed using molecular docking experiments, providing a platform for their further optimisation using medicinal chemistry. This work demonstrates the versatility and potential of GuaB2 as an anti-tubercular drug target.
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Affiliation(s)
- Jonathan A. G. Cox
- Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Grace Mugumbate
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom, CB10 1SD
| | - Laura Vela-Glez Del Peral
- Molecular Discovery Research, GlaxoSmithKline, Santiago Grisolia 4, 28760 Tres Cantos, Madrid, Spain
| | - Monika Jankute
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | - Peter Jervis
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Stefan Jackenkroll
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Arancha Perez
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Carlos Alemparte
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Jorge Esquivias
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Joël Lelièvre
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Fernando Ramon
- Molecular Discovery Research, GlaxoSmithKline, Santiago Grisolia 4, 28760 Tres Cantos, Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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12
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Abrahams KA, Chung CW, Ghidelli-Disse S, Rullas J, Rebollo-López MJ, Gurcha SS, Cox JAG, Mendoza A, Jiménez-Navarro E, Martínez-Martínez MS, Neu M, Shillings A, Homes P, Argyrou A, Casanueva R, Loman NJ, Moynihan PJ, Lelièvre J, Selenski C, Axtman M, Kremer L, Bantscheff M, Angulo-Barturen I, Izquierdo MC, Cammack NC, Drewes G, Ballell L, Barros D, Besra GS, Bates RH. Identification of KasA as the cellular target of an anti-tubercular scaffold. Nat Commun 2016; 7:12581. [PMID: 27581223 PMCID: PMC5025758 DOI: 10.1038/ncomms12581] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 07/14/2016] [Indexed: 12/12/2022] Open
Abstract
Phenotypic screens for bactericidal compounds are starting to yield promising hits against tuberculosis. In this regard, whole-genome sequencing of spontaneous resistant mutants generated against an indazole sulfonamide (GSK3011724A) identifies several specific single-nucleotide polymorphisms in the essential Mycobacterium tuberculosis β-ketoacyl synthase (kas) A gene. Here, this genomic-based target assignment is confirmed by biochemical assays, chemical proteomics and structural resolution of a KasA-GSK3011724A complex by X-ray crystallography. Finally, M. tuberculosis GSK3011724A-resistant mutants increase the in vitro minimum inhibitory concentration and the in vivo 99% effective dose in mice, establishing in vitro and in vivo target engagement. Surprisingly, the lack of target engagement of the related β-ketoacyl synthases (FabH and KasB) suggests a different mode of inhibition when compared with other Kas inhibitors of fatty acid biosynthesis in bacteria. These results clearly identify KasA as the biological target of GSK3011724A and validate this enzyme for further drug discovery efforts against tuberculosis. Screens for bactericidal compounds have resulted in promising anti-tubercular hits. Here, the authors analyse in detail the target of an indazole sulfonamide (GSK3011724A), and find that it has a different mode of inhibition compared to other Kas inhibitors of fatty acid biosynthesis in bacteria.
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Affiliation(s)
- Katherine A Abrahams
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Chun-Wa Chung
- GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, UK
| | | | - Joaquín Rullas
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - María José Rebollo-López
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Sudagar S Gurcha
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Jonathan A G Cox
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alfonso Mendoza
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Elena Jiménez-Navarro
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | | | - Margarete Neu
- GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, UK
| | | | - Paul Homes
- GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, UK
| | | | - Ruth Casanueva
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Nicholas J Loman
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Patrick J Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Joël Lelièvre
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Carolyn Selenski
- GlaxoSmithKline, 709 Swedeland Road, PO Box 1539, King of Prussia, Pennsylvania 19406-0939, USA
| | - Matthew Axtman
- GlaxoSmithKline, 709 Swedeland Road, PO Box 1539, King of Prussia, Pennsylvania 19406-0939, USA
| | - Laurent Kremer
- Centre National de la Recherche Scientifique FRE 3689, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France.,INSERM, CPBS, 34293 Montpellier, France
| | - Marcus Bantscheff
- Cellzome-a GSK Company, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Iñigo Angulo-Barturen
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Mónica Cacho Izquierdo
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Nicholas C Cammack
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Gerard Drewes
- Cellzome-a GSK Company, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Robert H Bates
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760 Madrid, Spain
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13
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Cox JAG, Abrahams KA, Alemparte C, Ghidelli-Disse S, Rullas J, Angulo-Barturen I, Singh A, Gurcha SS, Nataraj V, Bethell S, Remuiñán MJ, Encinas L, Jervis PJ, Cammack NC, Bhatt A, Kruse U, Bantscheff M, Fütterer K, Barros D, Ballell L, Drewes G, Besra GS. THPP target assignment reveals EchA6 as an essential fatty acid shuttle in mycobacteria. Nat Microbiol 2016; 1:15006. [DOI: 10.1038/nmicrobiol.2015.6] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/02/2015] [Indexed: 01/18/2023]
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14
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Mugumbate G, Abrahams KA, Cox JAG, Papadatos G, van Westen G, Lelièvre J, Calus ST, Loman NJ, Ballell L, Barros D, Overington JP, Besra GS. Mycobacterial dihydrofolate reductase inhibitors identified using chemogenomic methods and in vitro validation. PLoS One 2015; 10:e0121492. [PMID: 25799414 PMCID: PMC4370846 DOI: 10.1371/journal.pone.0121492] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/01/2015] [Indexed: 01/21/2023] Open
Abstract
The lack of success in target-based screening approaches to the discovery of antibacterial agents has led to reemergence of phenotypic screening as a successful approach of identifying bioactive, antibacterial compounds. A challenge though with this route is then to identify the molecular target(s) and mechanism of action of the hits. This target identification, or deorphanization step, is often essential in further optimization and validation studies. Direct experimental identification of the molecular target of a screening hit is often complex, precisely because the properties and specificity of the hit are not yet optimized against that target, and so many false positives are often obtained. An alternative is to use computational, predictive, approaches to hypothesize a mechanism of action, which can then be validated in a more directed and efficient manner. Specifically here we present experimental validation of an in silico prediction from a large-scale screen performed against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. The two potent anti-tubercular compounds studied in this case, belonging to the tetrahydro-1,3,5-triazin-2-amine (THT) family, were predicted and confirmed to be an inhibitor of dihydrofolate reductase (DHFR), a known essential Mtb gene, and already clinically validated as a drug target. Given the large number of similar screening data sets shared amongst the community, this in vitro validation of these target predictions gives weight to computational approaches to establish the mechanism of action (MoA) of novel screening hit.
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Affiliation(s)
- Grace Mugumbate
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Katherine A. Abrahams
- Institute of Microbiology and Infection (IMI), School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Jonathan A. G. Cox
- Institute of Microbiology and Infection (IMI), School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - George Papadatos
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Gerard van Westen
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Joël Lelièvre
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Szymon T. Calus
- Institute of Microbiology and Infection (IMI), School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Nicholas J. Loman
- Institute of Microbiology and Infection (IMI), School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - John P. Overington
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (JPO); (GSB)
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection (IMI), School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail: (JPO); (GSB)
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15
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Gurcha SS, Usha V, Cox JAG, Fütterer K, Abrahams KA, Bhatt A, Alderwick LJ, Reynolds RC, Loman NJ, Nataraj V, Alemparte C, Barros D, Lloyd AJ, Ballell L, Hobrath JV, Besra GS. Biochemical and structural characterization of mycobacterial aspartyl-tRNA synthetase AspS, a promising TB drug target. PLoS One 2014; 9:e113568. [PMID: 25409504 PMCID: PMC4237437 DOI: 10.1371/journal.pone.0113568] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/13/2014] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Mycobacterium tuberculosis is the causative agent of pulmonary tuberculosis (TB), a disease with high worldwide mortality rates. Current treatment programs are under significant threat from multi-drug and extensively-drug resistant strains of M. tuberculosis, and it is essential to identify new inhibitors and their targets. We generated spontaneous resistant mutants in Mycobacterium bovis BCG in the presence of 10× the minimum inhibitory concentration (MIC) of compound 1, a previously identified potent inhibitor of mycobacterial growth in culture. Whole genome sequencing of two resistant mutants revealed in one case a single nucleotide polymorphism in the gene aspS at 535GAC>535AAC (D179N), while in the second mutant a single nucleotide polymorphism was identified upstream of the aspS promoter region. We probed whole cell target engagement by overexpressing either M. bovis BCG aspS or Mycobacterium smegmatis aspS, which resulted in a ten-fold and greater than ten-fold increase, respectively, of the MIC against compound 1. To analyse the impact of inhibitor 1 on M. tuberculosis AspS (Mt-AspS) activity we over-expressed, purified and characterised the kinetics of this enzyme using a robust tRNA-independent assay adapted to a high-throughput screening format. Finally, to aid hit-to-lead optimization, the crystal structure of apo M. smegmatis AspS was determined to a resolution of 2.4 Å.
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Affiliation(s)
- Sudagar S. Gurcha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Veeraraghavan Usha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Jonathan A. G. Cox
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Klaus Fütterer
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Katherine A. Abrahams
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Apoorva Bhatt
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Luke J. Alderwick
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Robert C. Reynolds
- Department of Chemistry, University of Alabama at Birmingham, College of Arts and Sciences, 1530 3rd Avenue South, Birmingham, Alabama, 35294-1240, United States of America
| | - Nicholas J. Loman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - VijayaShankar Nataraj
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Carlos Alemparte
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Adrian J. Lloyd
- Department of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Judith V. Hobrath
- Organic Chemistry Department, Southern Research Institute, Birmingham, Alabama, 35205, United States of America
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
- * E-mail:
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16
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Zapun A, Philippe J, Abrahams KA, Signor L, Roper DI, Breukink E, Vernet T. In vitro reconstitution of peptidoglycan assembly from the Gram-positive pathogen Streptococcus pneumoniae. ACS Chem Biol 2013; 8:2688-96. [PMID: 24044435 DOI: 10.1021/cb400575t] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the molecular basis of bacterial cell wall assembly is of paramount importance in addressing the threat of increasing antibiotic resistance worldwide. Streptococcus pneumoniae presents a particularly acute problem in this respect, as it is capable of rapid evolution by homologous recombination with related species. Resistant strains selected by treatment with β-lactams express variants of the target enzymes that do not recognize the drugs but retain their activity in cell wall building, despite the antibiotics being mimics of the natural substrate. Until now, the crucial transpeptidase activity that is inhibited by β-lactams was not amenable to in vitro investigation with enzymes from Gram-positive organisms, including streptococci, staphylococci, or enterococci pathogens. We report here for the first time the in vitro assembly of peptidoglycan using recombinant penicillin-binding proteins from pneumococcus and the precursor lipid II. The two required enzymatic activities, glycosyl transferase for elongating glycan chains and transpeptidase for cross-linking stem-peptides, were observed. Most importantly, the transpeptidase activity was dependent on the chemical nature of the stem-peptide. Amidation of the second residue glutamate into iso-glutamine by the recently discovered amido-transferase MurT/GatD is required for efficient cross-linking of the peptidoglycan.
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Affiliation(s)
- André Zapun
- Université
Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble F-38027, France
- CNRS, IBS, UMR
5075, 71 av. des Martyrs, Grenoble F-38027, France
- CEA, DSV, IBS, Grenoble F-38027, France
| | - Jules Philippe
- Université
Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble F-38027, France
- CNRS, IBS, UMR
5075, 71 av. des Martyrs, Grenoble F-38027, France
- CEA, DSV, IBS, Grenoble F-38027, France
| | - Katherine A. Abrahams
- Department
of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Luca Signor
- Université
Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble F-38027, France
- CNRS, IBS, UMR
5075, 71 av. des Martyrs, Grenoble F-38027, France
- CEA, DSV, IBS, Grenoble F-38027, France
| | - David I. Roper
- Department
of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Eefjan Breukink
- Department
of Chemical Biology and Organic Chemistry, Institute of Biomembranes,
Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht 3584 CH, The Netherlands
| | - Thierry Vernet
- Université
Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble F-38027, France
- CNRS, IBS, UMR
5075, 71 av. des Martyrs, Grenoble F-38027, France
- CEA, DSV, IBS, Grenoble F-38027, France
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17
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Abrahams KA, Cox JAG, Spivey VL, Loman NJ, Pallen MJ, Constantinidou C, Fernández R, Alemparte C, Remuiñán MJ, Barros D, Ballell L, Besra GS. Identification of novel imidazo[1,2-a]pyridine inhibitors targeting M. tuberculosis QcrB. PLoS One 2012; 7:e52951. [PMID: 23300833 PMCID: PMC3534098 DOI: 10.1371/journal.pone.0052951] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/22/2012] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium tuberculosis is a major human pathogen and the causative agent for the pulmonary disease, tuberculosis (TB). Current treatment programs to combat TB are under threat due to the emergence of multi-drug and extensively-drug resistant TB. Through the use of high throughput whole cell screening of an extensive compound library a number of imidazo[1,2-a]pyridine (IP) compounds were obtained as potent lead molecules active against M. tuberculosis and Mycobacterium bovis BCG. The IP inhibitors (1-4) demonstrated minimum inhibitory concentrations (MICs) in the range of 0.03 to 5 µM against a panel of M. tuberculosis strains. M. bovis BCG spontaneous resistant mutants were generated against IP 1, 3, and 4 at 5× MIC and subsequent whole genome sequencing identified a single nucleotide polymorphism (937)ACC>(937)GCC (T313A) in qcrB, which encodes the b subunit of the electron transport ubiquinol cytochrome C reductase. This mutation also conferred cross-resistance against IP 1, 3 and 4 demonstrating a common target. Gene dosage experiments confirmed M. bovis BCG QcrB as the target where over-expression in M. bovis BCG led to an increase in MIC from 0.5 to >8 µM for IP 3. An acute murine model of TB infection established bacteriostatic activity of the IP series, which await further detailed characterization.
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Affiliation(s)
- Katherine A. Abrahams
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Jonathan A. G. Cox
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Vickey L. Spivey
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Nicholas J. Loman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Mark J. Pallen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | | | - Raquel Fernández
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | - Carlos Alemparte
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | - Modesto J. Remuiñán
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | - David Barros
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
- * E-mail: (GSB); (LB)
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail: (GSB); (LB)
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