1
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Lu F, Xia K, Su J, Yi J, Luo Z, Xu J, Gu Q, Chen B, Zhou H. Biochemical and structural characterization of chlorhexidine as an ATP-assisted inhibitor against type 1 methionyl-tRNA synthetase from Gram-positive bacteria. Eur J Med Chem 2024; 268:116303. [PMID: 38458107 DOI: 10.1016/j.ejmech.2024.116303] [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: 01/14/2024] [Revised: 02/27/2024] [Accepted: 03/02/2024] [Indexed: 03/10/2024]
Abstract
Methionyl-tRNA synthetase (MetRS) catalyzes the attachment of l-methionine (l-Met) to tRNAMet to generate methionyl-tRNAMet, an essential substrate for protein translation within ribosome. Owing to its indispensable biological function and the structural discrepancies with human counterpart, bacterial MetRS is considered an ideal target for developing antibacterials. Herein, chlorhexidine (CHX) was identified as a potent binder of Staphylococcus aureus MetRS (SaMetRS) through an ATP-aided affinity screening. The co-crystal structure showed that CHX simultaneously occupies the enlarged l-Met pocket (EMP) and the auxiliary pocket (AP) of SaMetRS with its two chlorophenyl groups, while its central hexyl linker swings upwards to interact with some conserved hydrophobic residues. ATP adopts alternative conformations in the active site cavity, and forms ionic bonds and water-mediated hydrogen bonds with CHX. Consistent with this synergistic binding mode, ATP concentration-dependently enhanced the binding affinity of CHX to SaMetRS from 10.2 μM (no ATP) to 0.45 μM (1 mM ATP). While it selectively inhibited two representative type 1 MetRSs from S. aureus and Enterococcus faecalis, CHX did not show significant interactions with three tested type 2 MetRSs, including human cytoplasmic MetRS, in the enzyme inhibition and biophysical binding assays, probably due to the conformational differences between two types of MetRSs at their EMP and AP. Our findings on CHX may inspire the design of MetRS-directed antimicrobials in future.
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Affiliation(s)
- Feihu Lu
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Kaijiang Xia
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jingtian Su
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jia Yi
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhiteng Luo
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jun Xu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Qiong Gu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Bingyi Chen
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
| | - Huihao Zhou
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China; Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
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2
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Takeuchi M, Teshima M, Okubo S, Aoki S. In silico
and
in vitro
Identification of Compounds with Dual Pharmacological Activity against Metionyl‐tRNA Synthetase and Isoleucyl‐tRNA Synthetase of
Staphylococcus aureus. ChemistrySelect 2023. [DOI: 10.1002/slct.202300460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Masamune Takeuchi
- Department of Bioscience & Bioinformatics Kyushu Institute of Technology 680-4 Kawadu Iizuka Fukuoka Japan. (Shunsuke Aoki
| | - Mio Teshima
- Department of Bioscience & Bioinformatics Kyushu Institute of Technology 680-4 Kawadu Iizuka Fukuoka Japan. (Shunsuke Aoki
| | - Saya Okubo
- Department of Bioscience & Bioinformatics Kyushu Institute of Technology 680-4 Kawadu Iizuka Fukuoka Japan. (Shunsuke Aoki
| | - Shunsuke Aoki
- Department of Bioscience & Bioinformatics Kyushu Institute of Technology 680-4 Kawadu Iizuka Fukuoka Japan. (Shunsuke Aoki
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3
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Pang L, Weeks SD, Van Aerschot A. Aminoacyl-tRNA Synthetases as Valuable Targets for Antimicrobial Drug Discovery. Int J Mol Sci 2021; 22:1750. [PMID: 33578647 PMCID: PMC7916415 DOI: 10.3390/ijms22041750] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/20/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) catalyze the esterification of tRNA with a cognate amino acid and are essential enzymes in all three kingdoms of life. Due to their important role in the translation of the genetic code, aaRSs have been recognized as suitable targets for the development of small molecule anti-infectives. In this review, following a concise discussion of aaRS catalytic and proof-reading activities, the various inhibitory mechanisms of reported natural and synthetic aaRS inhibitors are discussed. Using the expanding repository of ligand-bound X-ray crystal structures, we classified these compounds based on their binding sites, focusing on their ability to compete with the association of one, or more of the canonical aaRS substrates. In parallel, we examined the determinants of species-selectivity and discuss potential resistance mechanisms of some of the inhibitor classes. Combined, this structural perspective highlights the opportunities for further exploration of the aaRS enzyme family as antimicrobial targets.
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Affiliation(s)
- Luping Pang
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
- KU Leuven, Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Herestraat 49–box 822, 3000 Leuven, Belgium
| | | | - Arthur Van Aerschot
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
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4
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Torrie LS, Robinson DA, Thomas MG, Hobrath JV, Shepherd SM, Post JM, Ko EJ, Ferreira RA, Mackenzie CJ, Wrobel K, Edwards DP, Gilbert IH, Gray DW, Fairlamb AH, De Rycker M. Discovery of an Allosteric Binding Site in Kinetoplastid Methionyl-tRNA Synthetase. ACS Infect Dis 2020; 6:1044-1057. [PMID: 32275825 PMCID: PMC7294809 DOI: 10.1021/acsinfecdis.9b00453] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
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Methionyl-tRNA
synthetase (MetRS) is a chemically validated drug target in kinetoplastid
parasites Trypanosoma brucei and Leishmania
donovani. To date, all kinetoplastid MetRS inhibitors described
bind in a similar way to an expanded methionine pocket and an adjacent,
auxiliary pocket. In the current study, we have identified a structurally
novel class of inhibitors containing a 4,6-diamino-substituted pyrazolopyrimidine
core (the MetRS02 series). Crystallographic studies revealed that
MetRS02 compounds bind to an allosteric pocket in L. major MetRS not previously described, and enzymatic studies demonstrated
a noncompetitive mode of inhibition. Homology modeling of the Trypanosoma cruzi MetRS enzyme revealed key differences
in the allosteric pocket between the T. cruzi and Leishmania enzymes. These provide a likely explanation for
the lower MetRS02 potencies that we observed for the T. cruzi enzyme compared to the Leishmania enzyme. The identification
of a new series of MetRS inhibitors and the discovery of a new binding
site in kinetoplastid MetRS enzymes provide a novel strategy in the
search for new therapeutics for kinetoplastid diseases.
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Affiliation(s)
- Leah S. Torrie
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - David A. Robinson
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Michael G. Thomas
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Judith V. Hobrath
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Sharon M. Shepherd
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - John M. Post
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Eun-Jung Ko
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Rafael Alves Ferreira
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Claire J. Mackenzie
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Karolina Wrobel
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Darren P. Edwards
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Ian H. Gilbert
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - David W. Gray
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Alan H. Fairlamb
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Manu De Rycker
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
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5
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Buckner FS, Ranade RM, Gillespie JR, Shibata S, Hulverson MA, Zhang Z, Huang W, Choi R, Verlinde CLMJ, Hol WGJ, Ochida A, Akao Y, Choy RKM, Van Voorhis WC, Arnold SLM, Jumani RS, Huston CD, Fan E. Optimization of Methionyl tRNA-Synthetase Inhibitors for Treatment of Cryptosporidium Infection. Antimicrob Agents Chemother 2019; 63:e02061-18. [PMID: 30745384 PMCID: PMC6437504 DOI: 10.1128/aac.02061-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Cryptosporidiosis is one of the leading causes of moderate to severe diarrhea in children in low-resource settings. The therapeutic options for cryptosporidiosis are limited to one drug, nitazoxanide, which unfortunately has poor activity in the most needy populations of malnourished children and HIV-infected persons. We describe here the discovery and early optimization of a class of imidazopyridine-containing compounds with potential for treating Cryptosporidium infections. The compounds target the Cryptosporidium methionyl-tRNA synthetase (MetRS), an enzyme that is essential for protein synthesis. The most potent compounds inhibited the enzyme with Ki values in the low picomolar range. Cryptosporidium cells in culture were potently inhibited with 50% effective concentrations as low as 7 nM and >1,000-fold selectivity over mammalian cells. A parasite persistence assay indicates that the compounds act by a parasiticidal mechanism. Several compounds were demonstrated to control infection in two murine models of cryptosporidiosis without evidence of toxicity. Pharmacological and physicochemical characteristics of compounds were investigated to determine properties that were associated with higher efficacy. The results indicate that MetRS inhibitors are excellent candidates for development for anticryptosporidiosis therapy.
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Affiliation(s)
| | - Ranae M Ranade
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - J Robert Gillespie
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | | | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Wenlin Huang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Ryan Choi
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | | | - Wim G J Hol
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | | | | | - Robert K M Choy
- Drug Development Program, PATH, San Francisco, California, USA
| | | | - Sam L M Arnold
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Rajiv S Jumani
- Department of Medicine, University of Vermont, Burlington, Vermont, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
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6
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Wang W, Qin B, Wojdyla JA, Wang M, Gao X, Cui S. Structural characterization of free-state and product-state Mycobacterium tuberculosis methionyl-tRNA synthetase reveals an induced-fit ligand-recognition mechanism. IUCRJ 2018; 5:478-490. [PMID: 30002848 PMCID: PMC6038951 DOI: 10.1107/s2052252518008217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Mycobacterium tuberculosis (MTB) caused 10.4 million cases of tuberculosis and 1.7 million deaths in 2016. The incidence of multidrug-resistant and extensively drug-resistant MTB is becoming an increasing threat to public health and the development of novel anti-MTB drugs is urgently needed. Methionyl-tRNA synthetase (MetRS) is considered to be a valuable drug target. However, structural characterization of M. tuberculosis MetRS (MtMetRS) was lacking for decades, thus hampering drug design. Here, two high-resolution crystal structures of MtMetRS are reported: the free-state structure (apo form; 1.9 Å resolution) and a structure with the intermediate product methionyl-adenylate (Met-AMP) bound (2.4 Å resolution). It was found that free-state MtMetRS adopts a previously unseen conformation that has never been observed in other MetRS homologues. The pockets for methionine and AMP are not formed in free-state MtMetRS, suggesting that it is in a nonproductive conformation. Combining these findings suggests that MtMetRS employs an induced-fit mechanism in ligand binding. By comparison with the structure of human cytosolic MetRS, additional pockets specific to MtMetRS that could be used for anti-MTB drug design were located.
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Affiliation(s)
- Wei Wang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | - Bo Qin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | | | - Meitian Wang
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - Xiaopan Gao
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | - Sheng Cui
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
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7
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Lam PL, Lee KKH, Wong RSM, Cheng GYM, Bian ZX, Chui CH, Gambari R. Recent advances on topical antimicrobials for skin and soft tissue infections and their safety concerns. Crit Rev Microbiol 2018; 44:40-78. [PMID: 28423970 DOI: 10.1080/1040841x.2017.1313811] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Antimicrobial resistance of disease-related microorganisms is considered a worldwide prevalent and serious issue which increases the failure of treatment outcomes and leads to high mortality. Considering that the increased resistance to systemic antimicrobial therapy often needs of the use of more toxic agents, topical antimicrobial therapy emerges as an attractive route for the treatment of infectious diseases. The topical antimicrobial therapy is based on the absorption of high drug doses in a readily accessible skin surface, resulting in a reduction of microbial proliferation at infected skin sites. Topical antimicrobials retain the following features: (a) they are able to escape the enzymatic degradation and rapid clearance in the gastrointestinal tract or the first-pass metabolism during oral administration; (b) alleviate the physical discomfort related to intravenous injection; (c) reduce possible adverse effects and drug interactions of systemic administrations; (d) increase patient compliance and convenience; and (e) reduce the treatment costs. Novel antimicrobials for topical application have been widely exploited to control the emergence of drug-resistant microorganisms. This review provides a description of antimicrobial resistance, common microorganisms causing skin and soft tissue infections, topical delivery route of antimicrobials, safety concerns of topical antimicrobials, recent advances, challenges and future prospective in topical antimicrobial development.
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Affiliation(s)
- P L Lam
- a Department of Applied Biology and Chemical Technology, State Key Laboratory of Chirosciences , The Hong Kong Polytechnic University , Hong Kong , P.R. China
| | - K K H Lee
- b Department of Medicine and Therapeutics, School of Biomedical Sciences, MOE Key Laboratory for Regenerative Medicine , The Chinese University of Hong Kong , Hong Kong , P.R. China
| | - R S M Wong
- b Department of Medicine and Therapeutics, School of Biomedical Sciences, MOE Key Laboratory for Regenerative Medicine , The Chinese University of Hong Kong , Hong Kong , P.R. China
| | - G Y M Cheng
- c Faculty of Health Sciences , University of Macau , Macau , P.R. China
| | - Z X Bian
- d Clinical Division, School of Chinese Medicine , Hong Kong Baptist University , Hong Kong , P.R. China
| | - C H Chui
- a Department of Applied Biology and Chemical Technology, State Key Laboratory of Chirosciences , The Hong Kong Polytechnic University , Hong Kong , P.R. China
- d Clinical Division, School of Chinese Medicine , Hong Kong Baptist University , Hong Kong , P.R. China
| | - R Gambari
- e Department of Life Sciences and Biotechnology, Centre of Biotechnology , University of Ferrara , Ferrara , Italy
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8
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Development of Methionyl-tRNA Synthetase Inhibitors as Antibiotics for Gram-Positive Bacterial Infections. Antimicrob Agents Chemother 2017; 61:AAC.00999-17. [PMID: 28848016 DOI: 10.1128/aac.00999-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/22/2017] [Indexed: 01/17/2023] Open
Abstract
Antibiotic-resistant bacteria are widespread and pose a growing threat to human health. New antibiotics acting by novel mechanisms of action are needed to address this challenge. The bacterial methionyl-tRNA synthetase (MetRS) enzyme is essential for protein synthesis, and the type found in Gram-positive bacteria is substantially different from its counterpart found in the mammalian cytoplasm. Both previously published and new selective inhibitors were shown to be highly active against Gram-positive bacteria with MICs of ≤1.3 μg/ml against Staphylococcus, Enterococcus, and Streptococcus strains. Incorporation of radioactive precursors demonstrated that the mechanism of activity was due to the inhibition of protein synthesis. Little activity against Gram-negative bacteria was observed, consistent with the fact that Gram-negative bacterial species contain a different type of MetRS enzyme. The ratio of the MIC to the minimum bactericidal concentration (MBC) was consistent with a bacteriostatic mechanism. The level of protein binding of the compounds was high (>95%), and this translated to a substantial increase in MICs when the compounds were tested in the presence of serum. Despite this, the compounds were very active when they were tested in a Staphylococcus aureus murine thigh infection model. Compounds 1717 and 2144, given by oral gavage, resulted in 3- to 4-log decreases in the bacterial load compared to that in vehicle-treated mice, which was comparable to the results observed with the comparator drugs, vancomycin and linezolid. In summary, the research describes MetRS inhibitors with oral bioavailability that represent a class of compounds acting by a novel mechanism with excellent potential for clinical development.
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9
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Fang P, Guo M. Evolutionary Limitation and Opportunities for Developing tRNA Synthetase Inhibitors with 5-Binding-Mode Classification. Life (Basel) 2015; 5:1703-25. [PMID: 26670257 PMCID: PMC4695845 DOI: 10.3390/life5041703] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 12/30/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are enzymes that catalyze the transfer of amino acids to their cognate tRNAs as building blocks for translation. Each of the aaRS families plays a pivotal role in protein biosynthesis and is indispensable for cell growth and survival. In addition, aaRSs in higher species have evolved important non-translational functions. These translational and non-translational functions of aaRS are attractive for developing antibacterial, antifungal, and antiparasitic agents and for treating other human diseases. The interplay between amino acids, tRNA, ATP, EF-Tu and non-canonical binding partners, had shaped each family with distinct pattern of key sites for regulation, with characters varying among species across the path of evolution. These sporadic variations in the aaRSs offer great opportunity to target these essential enzymes for therapy. Up to this day, growing numbers of aaRS inhibitors have been discovered and developed. Here, we summarize the latest developments and structural studies of aaRS inhibitors, and classify them with distinct binding modes into five categories.
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Affiliation(s)
- Pengfei Fang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA.
| | - Min Guo
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA.
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10
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Inhibitors of methionyl-tRNA synthetase have potent activity against Giardia intestinalis trophozoites. Antimicrob Agents Chemother 2015; 59:7128-31. [PMID: 26324270 DOI: 10.1128/aac.01573-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/25/2015] [Indexed: 11/20/2022] Open
Abstract
The methionyl-tRNA synthetase (MetRS) is a novel drug target for the protozoan pathogen Giardia intestinalis. This protist contains a single MetRS that is distinct from the human cytoplasmic MetRS. A panel of MetRS inhibitors was tested against recombinant Giardia MetRS, Giardia trophozoites, and mammalian cell lines. The best compounds inhibited trophozoite growth at 500 nM (metronidazole did so at ∼5,000 nM) and had low cytotoxicity against mammalian cells, indicating excellent potential for further development as anti-Giardia drugs.
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11
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Group A streptococcus inhibitors by high-throughput virtual screening. Eur J Med Chem 2014; 82:120-6. [PMID: 24880231 DOI: 10.1016/j.ejmech.2014.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 11/21/2022]
Abstract
Group A streptococcus (GAS) is a Gram-positive bacterium, which can cause multiple types of disease from mild infections of skin and throat to invasive and life-threatening infections. Recently RNase J1 and J2 were found to be essential for the growth of GAS. In order to identify inhibitors against RNase J1/J2, homology models of both the ligand-free apo-form and the ligand-bound holo-form complexes were constructed as templates for high-throughput virtual screening (HTVS). A focused small molecule library and the commercially available Maybridge database were employed as sources for potential inhibitors. A cell-based biological assay identified two compounds with 10 μM MIC activity.
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12
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13
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Dewan V, Reader J, Forsyth KM. Role of aminoacyl-tRNA synthetases in infectious diseases and targets for therapeutic development. Top Curr Chem (Cham) 2013; 344:293-329. [PMID: 23666077 DOI: 10.1007/128_2013_425] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aminoacyl-tRNA synthetases (AARSs) play a pivotal role in protein synthesis and cell viability. These 22 "housekeeping" enzymes (1 for each standard amino acid plus pyrrolysine and o-phosphoserine) are specifically involved in recognizing and aminoacylating their cognate tRNAs in the cellular pool with the correct amino acid prior to delivery of the charged tRNA to the protein synthesis machinery. Besides serving this canonical function, higher eukaryotic AARSs, some of which are organized in the cytoplasm as a multisynthetase complex of nine enzymes plus additional cellular factors, have also been implicated in a variety of non-canonical roles. AARSs are involved in the regulation of transcription, translation, and various signaling pathways, thereby ensuring cell survival. Based in part on their versatility, AARSs have been recruited by viruses to perform essential functions. For example, host synthetases are packaged into some retroviruses and are required for their replication. Other viruses mimic tRNA-like structures in their genomes, and these motifs are aminoacylated by the host synthetase as part of the viral replication cycle. More recently, it has been shown that certain large DNA viruses infecting animals and other diverse unicellular eukaryotes encode tRNAs, AARSs, and additional components of the protein-synthesis machinery. This chapter will review our current understanding of the role of host AARSs and tRNA-like structures in viruses and discuss their potential as anti-viral drug targets. The identification and development of compounds that target bacterial AARSs, thereby serving as novel antibiotics, will also be discussed. Particular attention will be given to recent work on a number of tRNA-dependent AARS inhibitors and to advances in a new class of natural "pro-drug" antibiotics called Trojan Horse inhibitors. Finally, we will explore how bacteria that naturally produce AARS-targeting antibiotics must protect themselves against cell suicide using naturally antibiotic resistant AARSs, and how horizontal gene transfer of these AARS genes to pathogens may threaten the future use of this class of antibiotics.
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Affiliation(s)
- Varun Dewan
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, Center for RNA Biology, and Center for Retroviral Research, The Ohio State University, Columbus, OH, 43210, USA
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14
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Duckworth BP, Nelson KM, Aldrich CC. Adenylating enzymes in Mycobacterium tuberculosis as drug targets. Curr Top Med Chem 2012; 12:766-96. [PMID: 22283817 DOI: 10.2174/156802612799984571] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 11/08/2011] [Indexed: 11/22/2022]
Abstract
Adenylation or adenylate-forming enzymes (AEs) are widely found in nature and are responsible for the activation of carboxylic acids to intermediate acyladenylates, which are mixed anhydrides of AMP. In a second reaction, AEs catalyze the transfer of the acyl group of the acyladenylate onto a nucleophilic amino, alcohol, or thiol group of an acceptor molecule leading to amide, ester, and thioester products, respectively. Mycobacterium tuberculosis encodes for more than 60 adenylating enzymes, many of which represent potential drug targets due to their confirmed essentiality or requirement for virulence. Several strategies have been used to develop potent and selective AE inhibitors including highthroughput screening, fragment-based screening, and the rationale design of bisubstrate inhibitors that mimic the acyladenylate. In this review, a comprehensive analysis of the mycobacterial adenylating enzymes will be presented with a focus on the identification of small molecule inhibitors. Specifically, this review will cover the aminoacyl tRNAsynthetases (aaRSs), MenE required for menaquinone synthesis, the FadD family of enzymes including the fatty acyl- AMP ligases (FAAL) and the fatty acyl-CoA ligases (FACLs) involved in lipid metabolism, and the nonribosomal peptide synthetase adenylation enzyme MbtA that is necessary for mycobactin synthesis. Additionally, the enzymes NadE, GuaA, PanC, and MshC involved in the respective synthesis of NAD, guanine, pantothenate, and mycothiol will be discussed as well as BirA that is responsible for biotinylation of the acyl CoA-carboxylases.
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Koh CY, Kim JE, Shibata S, Ranade RM, Yu M, Liu J, Gillespie JR, Buckner FS, Verlinde CL, Fan E, Hol WG. Distinct states of methionyl-tRNA synthetase indicate inhibitor binding by conformational selection. Structure 2012; 20:1681-91. [PMID: 22902861 PMCID: PMC3472110 DOI: 10.1016/j.str.2012.07.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 02/07/2023]
Abstract
To guide development of new drugs targeting methionyl-tRNA synthetase (MetRS) for treatment of human African trypanosomiasis, crystal structure determinations of Trypanosoma brucei MetRS in complex with its substrate methionine and its intermediate product methionyl-adenylate were followed by those of the enzyme in complex with high-affinity aminoquinolone inhibitors via soaking experiments. Drastic changes in conformation of one of the two enzymes in the asymmetric unit allowed these inhibitors to occupy an enlarged methionine pocket and a new so-called auxiliary pocket. Interestingly, a small low-affinity compound caused the same conformational changes, removed the methionine without occupying the methionine pocket, and occupied the previously not existing auxiliary pocket. Analysis of these structures indicates that the binding of the inhibitors is the result of conformational selection, not induced fit.
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Affiliation(s)
- Cho Yeow Koh
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Jessica E. Kim
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Ranae M. Ranade
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Mingyan Yu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Shandong University, No. 44 Wenhuaxi Road, Jinan 250012, P.R. China
| | - Jiyun Liu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - J. Robert Gillespie
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Frederick S. Buckner
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Wim G.J. Hol
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Correspondence to:
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Larson ET, Kim JE, Zucker FH, Kelley A, Mueller N, Napuli AJ, Verlinde CL, Fan E, Buckner FS, Van Voorhis WC, Merritt EA, Hol WG. Structure of Leishmania major methionyl-tRNA synthetase in complex with intermediate products methionyladenylate and pyrophosphate. Biochimie 2011; 93:570-82. [PMID: 21144880 PMCID: PMC3039092 DOI: 10.1016/j.biochi.2010.11.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 11/29/2010] [Indexed: 01/07/2023]
Abstract
Leishmania parasites cause two million new cases of leishmaniasis each year with several hundreds of millions of people at risk. Due to the paucity and shortcomings of available drugs, we have undertaken the crystal structure determination of a key enzyme from Leishmania major in hopes of creating a platform for the rational design of new therapeutics. Crystals of the catalytic core of methionyl-tRNA synthetase from L. major (LmMetRS) were obtained with the substrates MgATP and methionine present in the crystallization medium. These crystals yielded the 2.0 Å resolution structure of LmMetRS in complex with two products, methionyladenylate and pyrophosphate, along with a Mg(2+) ion that bridges them. This is the first class I aminoacyl-tRNA synthetase (aaRS) structure with pyrophosphate bound. The residues of the class I aaRS signature sequence motifs, KISKS and HIGH, make numerous contacts with the pyrophosphate. Substantial differences between the LmMetRS structure and previously reported complexes of Escherichia coli MetRS (EcMetRS) with analogs of the methionyladenylate intermediate product are observed, even though one of these analogs only differs by one atom from the intermediate. The source of these structural differences is attributed to the presence of the product pyrophosphate in LmMetRS. Analysis of the LmMetRS structure in light of the Aquifex aeolicus MetRS-tRNA(Met) complex shows that major rearrangements of multiple structural elements of enzyme and/or tRNA are required to allow the CCA acceptor triplet to reach the methionyladenylate intermediate in the active site. Comparison with sequences of human cytosolic and mitochondrial MetRS reveals interesting differences near the ATP- and methionine-binding regions of LmMetRS, suggesting that it should be possible to obtain compounds that selectively inhibit the parasite enzyme.
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Affiliation(s)
- Eric T. Larson
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Jessica E. Kim
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Frank H. Zucker
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Angela Kelley
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Natascha Mueller
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Alberto J. Napuli
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Christophe L.M.J. Verlinde
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Frederick S. Buckner
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Wesley C. Van Voorhis
- Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA
| | - Ethan A. Merritt
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org
| | - Wim G.J. Hol
- Department of Biochemistry, University of Washington, Seattle, WA 98195-7742, USA,Medical Structural Genomics of Pathogenic Protozoa (MSGPP), www.msgpp.org,Corresponding author.
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Mupirocin: biosynthesis, special features and applications of an antibiotic from a gram-negative bacterium. Appl Microbiol Biotechnol 2011; 90:11-21. [PMID: 21336932 DOI: 10.1007/s00253-011-3128-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 01/12/2011] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
Abstract
Mupirocin is a polyketide antibiotic produced by Pseudomonas fluorescens. The biosynthetic cluster encodes 6 type I polyketide synthase multifunctional proteins and 29 single function proteins. The biosynthetic pathway belongs to the trans-AT group in which acyltransferase activity is provided by a separate polypeptide rather than in-cis as found in the original type I polyketide synthases. Special features of this group are in-cis methyltransferase domains and a trans-acting HMG-CoA synthase-cassette which insert α- and β- methyl groups respectively while enoyl reductase domains are absent from the condensing modules. In addition, for the mupirocin system, there is no obvious loading mechanism for initiation of the polyketide chain and many aspects of the pathway remain to be elucidated. Mupirocin inhibits isoleucyl-tRNA synthetase and has been used since 1985 to help prevent infection by methicillin-resistant Staphylococcus aureus, particularly within hospitals. Resistance to mupirocin was first detected in 1987 and high-level resistance in S. aureus is due to a plasmid-encoded second isoleucyl-tRNA synthetase, a more eukaryotic-like enzyme. Recent analysis of the biosynthetic pathway for thiomarinols from marine bacteria opens up possibilities to modify mupirocin so as to overcome this resistance.
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Abstract
Mupirocin, a polyketide antibiotic produced by Pseudomonas fluorescens, is used to control the carriage of methicillin-resistant Staphylococcus aureus on skin and in nasal passages as well as for various skin infections. Low-level resistance to the antibiotic arises by mutation of the mupirocin target, isoleucyl-tRNA synthetase, whereas high-level resistance is due to the presence of an isoleucyl-tRNA synthetase with many similarities to eukaryotic enzymes. Mupirocin biosynthesis is carried out by a combination of type I multifunctional polyketide synthases and tailoring enzymes encoded in a 75 kb gene cluster. Chemical synthesis has also been achieved. This knowledge should allow the synthesis of new and modified antibiotics for the future.
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Coates T, Bax R, Coates A. Nasal decolonization of Staphylococcus aureus with mupirocin: strengths, weaknesses and future prospects. J Antimicrob Chemother 2009; 64:9-15. [PMID: 19451132 PMCID: PMC2692503 DOI: 10.1093/jac/dkp159] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Staphylococcus aureus in the nose is a risk factor for endogenous staphylococcal infection. UK guidelines recommend the use of mupirocin for nasal decolonization in certain groups of patients colonized with methicillin-resistant S. aureus (MRSA). Mupirocin is effective at removing S. aureus from the nose over a few weeks, but relapses are common within several months. There are only a few prospective randomized clinical trials that have been completed with sufficient patients, but those that have been reported suggest that clearance of S. aureus from the nose is beneficial in some patient groups for the reduction in the incidence of nosocomial infections. There is no convincing evidence that mupirocin treatment reduces the incidence of surgical site infection. New antibiotics are needed to decolonize the nose because bacterial resistance to mupirocin is rising, and so it will become less effective. Furthermore, a more bactericidal antibiotic than mupirocin is needed, on the grounds that it might reduce the relapse rate, and so clear the patient of MRSA for a longer period of time than mupirocin.
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Affiliation(s)
- T Coates
- University College London, London, UK.
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