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Yi X, Liang JL, Wen P, Jia P, Feng SW, Liu SY, Zhuang YY, Guo YQ, Lu JL, Zhong SJ, Liao B, Wang Z, Shu WS, Li JT. Giant viruses as reservoirs of antibiotic resistance genes. Nat Commun 2024; 15:7536. [PMID: 39214976 PMCID: PMC11364636 DOI: 10.1038/s41467-024-51936-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 08/21/2024] [Indexed: 09/04/2024] Open
Abstract
Nucleocytoplasmic large DNA viruses (NCLDVs; also called giant viruses), constituting the phylum Nucleocytoviricota, can infect a wide range of eukaryotes and exchange genetic material with not only their hosts but also prokaryotes and phages. A few NCLDVs were reported to encode genes conferring resistance to beta‑lactam, trimethoprim, or pyrimethamine, suggesting that they are potential vehicles for the transmission of antibiotic resistance genes (ARGs) in the biome. However, the incidence of ARGs across the phylum Nucleocytoviricota, their evolutionary characteristics, their dissemination potential, and their association with virulence factors remain unexplored. Here, we systematically investigated ARGs of 1416 NCLDV genomes including those of almost all currently available cultured isolates and high-quality metagenome-assembled genomes from diverse habitats across the globe. We reveal that 39.5% of them carry ARGs, which is approximately 37 times higher than that for phage genomes. A total of 12 ARG types are encoded by NCLDVs. Phylogenies of the three most abundant NCLDV-encoded ARGs hint that NCLDVs acquire ARGs from not only eukaryotes but also prokaryotes and phages. Two NCLDV-encoded trimethoprim resistance genes are demonstrated to confer trimethoprim resistance in Escherichia coli. The presence of ARGs in NCLDV genomes is significantly correlated with mobile genetic elements and virulence factors.
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Affiliation(s)
- Xinzhu Yi
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Jie-Liang Liang
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Ping Wen
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Pu Jia
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Shi-Wei Feng
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Shen-Yan Liu
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Yuan-Yue Zhuang
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Yu-Qian Guo
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Jing-Li Lu
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Sheng-Ji Zhong
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Bin Liao
- School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China
| | - Zhang Wang
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Wen-Sheng Shu
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Jin-Tian Li
- Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, PR China.
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Zivkovic I, Gruic-Sovulj I. Exploring mechanisms of mupirocin resistance and hyper-resistance. Biochem Soc Trans 2024; 52:1109-1120. [PMID: 38884776 DOI: 10.1042/bst20230581] [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: 04/30/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/18/2024]
Abstract
Mupirocin is a broad-spectrum antibiotic that acts predominantly against Gram-positive bacteria. It is produced by Pseudomonas fluorescens NCIMB 10586 and has been clinically used to treat primary and secondary skin infections and to eradicate nasal colonisation of methicillin-resistant Staphylococcus aureus strains. Mupirocin inhibits protein synthesis by blocking the active site of isoleucyl-tRNA synthetase (IleRS), which prevents the enzyme from binding isoleucine and ATP for Ile-tRNAIle synthesis. Two types of IleRS are found in bacteria - while IleRS1 is susceptible to mupirocin inhibition, IleRS2 provides resistance to cells. These two types belong to distinct evolutionary clades which likely emerged from an early gene duplication in bacteria. Resistance in IleRS2 is based on the loss of interactions that govern mupirocin binding to IleRS1, such as hydrogen bonding to the carboxylate moiety of mupirocin. IleRS2 enzymes with Ki in the millimolar range have recently been discovered. These hyper-resistant IleRS2 variants surprisingly have a non-canonical version of the catalytic motif, which serves as a signature motif of class I aminoacyl-tRNA synthetases to which IleRS belongs. The non-canonical motif, in which the 1st and 3rd positions are swapped, is key for hyper-resistance and can be accommodated without abolishing enzyme activity in IleRS2 but not in IleRS1. Clinical use of mupirocin led to the emergence of resistance in S. aureus. Low-level resistance arises by mutations of the housekeeping IleRS1, while high-level resistance develops by the acquisition of the resistant IleRS2 on a plasmid. There is no evidence that hyper-resistant variants have been found in clinical isolates.
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Affiliation(s)
- Igor Zivkovic
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
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3
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Chen X, Guo Y, Shi J, Wang Y, Guo X, Wu G, Li S, Zhang T. Structural basis for substrate and antibiotic recognition by Helicobacter pylori isoleucyl-tRNA synthetase. FEBS Lett 2024; 598:521-536. [PMID: 38246751 DOI: 10.1002/1873-3468.14805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/12/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024]
Abstract
Helicobacter pylori infection is a global health concern, affecting over half of the world's population. Acquiring structural information on pharmacological targets is crucial to facilitate inhibitor design. Here, we have determined the crystal structures of H. pylori isoleucyl-tRNA synthetase (HpIleRS) in apo form as well as in complex with various substrates (Ile, Ile-AMP, Val, and Val-AMP) or an inhibitor (mupirocin). Our results provide valuable insights into substrate specificity, recognition, and the mechanism by which HpIleRS is inhibited by an antibiotic. Moreover, we identified Asp641 as a prospective regulatory site and conducted biochemical analyses to investigate its regulatory mechanism. The detailed structural information acquired from this research holds promise for the development of highly selective and effective inhibitors against H. pylori infection.
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Affiliation(s)
- Xiaobao Chen
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
| | - Yu Guo
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai, China
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiawen Shi
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
| | - Yilun Wang
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
| | - Xinyi Guo
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
| | - Guihua Wu
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
| | - Sheng Li
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai, China
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Tianlong Zhang
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, 500 Yonghe Road, Nantong, China
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Brkic A, Leibundgut M, Jablonska J, Zanki V, Car Z, Petrovic Perokovic V, Marsavelski A, Ban N, Gruic-Sovulj I. Antibiotic hyper-resistance in a class I aminoacyl-tRNA synthetase with altered active site signature motif. Nat Commun 2023; 14:5498. [PMID: 37679387 PMCID: PMC10485003 DOI: 10.1038/s41467-023-41244-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Antibiotics target key biological processes that include protein synthesis. Bacteria respond by developing resistance, which increases rapidly due to antibiotics overuse. Mupirocin, a clinically used natural antibiotic, inhibits isoleucyl-tRNA synthetase (IleRS), an enzyme that links isoleucine to its tRNAIle for protein synthesis. Two IleRSs, mupirocin-sensitive IleRS1 and resistant IleRS2, coexist in bacteria. The latter may also be found in resistant Staphylococcus aureus clinical isolates. Here, we describe the structural basis of mupirocin resistance and unravel a mechanism of hyper-resistance evolved by some IleRS2 proteins. We surprisingly find that an up to 103-fold increase in resistance originates from alteration of the HIGH motif, a signature motif of the class I aminoacyl-tRNA synthetases to which IleRSs belong. The structural analysis demonstrates how an altered HIGH motif could be adopted in IleRS2 but not IleRS1, providing insight into an elegant mechanism for coevolution of the key catalytic motif and associated antibiotic resistance.
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Affiliation(s)
- A Brkic
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
| | - M Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zürich, Switzerland
| | - J Jablonska
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - V Zanki
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
| | - Z Car
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
| | - V Petrovic Perokovic
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
| | - A Marsavelski
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
| | - N Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zürich, Switzerland.
| | - I Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia.
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5
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Ganapathy US, Del Rio RG, Cacho-Izquierdo M, Ortega F, Lelièvre J, Barros-Aguirre D, Lindman M, Dartois V, Gengenbacher M, Dick T. A Leucyl-tRNA Synthetase Inhibitor with Broad-Spectrum Anti-Mycobacterial Activity. Antimicrob Agents Chemother 2023; 95:AAC.02420-20. [PMID: 33558292 PMCID: PMC8092876 DOI: 10.1128/aac.02420-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 02/01/2021] [Indexed: 12/14/2022] Open
Abstract
Global infections by non-tuberculous mycobacteria (NTM) are steadily rising. New drugs are needed to treat NTM infections, but the NTM drug pipeline remains poorly populated and focused on repurposing or reformulating approved antibiotics. We sought to accelerate de novo NTM drug discovery by testing advanced compounds with established activity against Mycobacterium tuberculosis 3-aminomethyl 4-halogen benzoxaboroles, a novel class of leucyl-tRNA synthetase inhibitors, were recently discovered as active against M. tuberculosis Here, we report that the benzoxaborole EC/11770 is not only a potent anti-tubercular agent but is active against the M. abscessus and M. avium complexes. Focusing on M. abscessus, which causes the most difficult-to-cure NTM disease, we show that EC/11770 retained potency against drug-tolerant biofilms in vitro and was effective in a mouse lung infection model. Resistant mutant selection experiments showed a low frequency of resistance and confirmed leucyl-tRNA synthetase as the target. This work establishes the benzoxaborole EC/11770 as a novel preclinical candidate for the treatment of NTM lung disease and tuberculosis and validates leucyl-tRNA synthetase as an attractive target for the development of broad-spectrum anti-mycobacterials.
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Affiliation(s)
- Uday S Ganapathy
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | | | | | - Fátima Ortega
- Global Health R&D, GlaxoSmithKline, Tres Cantos, Spain
| | - Joël Lelièvre
- Global Health R&D, GlaxoSmithKline, Tres Cantos, Spain
| | | | - Marissa Lindman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
| | - Martin Gengenbacher
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
- Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA
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Istvan ES, Guerra F, Abraham M, Huang KS, Rocamora F, Zhao H, Xu L, Pasaje C, Kumpornsin K, Luth MR, Cui H, Yang T, Diaz SP, Gomez-Lorenzo MG, Qahash T, Mittal N, Ottilie S, Niles J, Lee MCS, Llinas M, Kato N, Okombo J, Fidock DA, Schimmel P, Gamo FJ, Goldberg DE, Winzeler EA. Cytoplasmic isoleucyl tRNA synthetase as an attractive multistage antimalarial drug target. Sci Transl Med 2023; 15:eadc9249. [PMID: 36888694 PMCID: PMC10286833 DOI: 10.1126/scitranslmed.adc9249] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
Development of antimalarial compounds into clinical candidates remains costly and arduous without detailed knowledge of the target. As resistance increases and treatment options at various stages of disease are limited, it is critical to identify multistage drug targets that are readily interrogated in biochemical assays. Whole-genome sequencing of 18 parasite clones evolved using thienopyrimidine compounds with submicromolar, rapid-killing, pan-life cycle antiparasitic activity showed that all had acquired mutations in the P. falciparum cytoplasmic isoleucyl tRNA synthetase (cIRS). Engineering two of the mutations into drug-naïve parasites recapitulated the resistance phenotype, and parasites with conditional knockdowns of cIRS became hypersensitive to two thienopyrimidines. Purified recombinant P. vivax cIRS inhibition, cross-resistance, and biochemical assays indicated a noncompetitive, allosteric binding site that is distinct from that of known cIRS inhibitors mupirocin and reveromycin A. Our data show that Plasmodium cIRS is an important chemically and genetically validated target for next-generation medicines for malaria.
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Affiliation(s)
- Eva S. Istvan
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Francisco Guerra
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Matthew Abraham
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Frances Rocamora
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Lan Xu
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - Charisse Pasaje
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Madeline R. Luth
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Haissi Cui
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tuo Yang
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sara Palomo Diaz
- Global Health Medicines, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Spain
| | | | - Tarrick Qahash
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Nimisha Mittal
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sabine Ottilie
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Jacquin Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Marcus C. S. Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - Manuel Llinas
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Nobutaka Kato
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - John Okombo
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Elizabeth A. Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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Bouz G, Zitko J. Inhibitors of aminoacyl-tRNA synthetases as antimycobacterial compounds: An up-to-date review. Bioorg Chem 2021; 110:104806. [PMID: 33799176 DOI: 10.1016/j.bioorg.2021.104806] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Accepted: 03/02/2021] [Indexed: 11/26/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are crucial for the correct assembly of amino acids to cognate tRNA to maintain the fidelity of proteosynthesis. AaRSs have become a hot target in antimicrobial research. Three aaRS inhibitors are already in clinical practice; antibacterial mupirocin inhibits the synthetic site of isoleucyl-tRNA synthetase, antifungal tavaborole inhibits the editing site of leucyl-tRNA synthetase, and antiprotozoal halofuginone inhibits proline-tRNA synthetase. According to the World Health Organization, tuberculosis globally remains the leading cause of death from a single infectious agent. The rising incidence of multidrug-resistant tuberculosis is alarming and urges the search for new antimycobacterial compounds, preferably with yet unexploited mechanism of action. In this literature review, we have covered the up-to-date state in the field of inhibitors of mycobacterial aaRSs. The most studied aaRS in mycobacteria is LeuRS with at least four structural types of inhibitors, followed by TyrRS and AspRS. Inhibitors of MetRS, LysRS, and PheRS were addressed in a single significant study each. In many cases, the enzyme inhibition activity translated into micromolar or submicromolar inhibition of growth of mycobacteria. The most promising aaRS inhibitor as an antimycobacterial compound is GSK656 (compound 8), the only aaRS inhibitor in clinical trials (Phase IIa) for systemic use against tuberculosis. GSK656 is orally available and shares the oxaborole tRNA-trapping mechanism of action with antifungal tavaborole.
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Affiliation(s)
- Ghada Bouz
- Department of Pharmaceutical Chemistry and Pharmaceutical Analysis, Faculty of Pharmacy, Charles University
| | - Jan Zitko
- Department of Pharmaceutical Chemistry and Pharmaceutical Analysis, Faculty of Pharmacy, Charles University.
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Burke C, Jankute M, Moynihan P, Gonzalez Del Rio R, Li X, Esquivias J, Lelièvre J, Cox JAG, Sacchettini J, Besra GS. Development of a novel secondary phenotypic screen to identify hits within the mycobacterial protein synthesis pipeline. FASEB Bioadv 2020; 2:600-612. [PMID: 33089076 PMCID: PMC7566049 DOI: 10.1096/fba.2020-00022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/17/2020] [Accepted: 07/31/2020] [Indexed: 12/03/2022] Open
Abstract
Background Whole‐cell phenotypic screening is the driving force behind modern anti‐tubercular drug discovery efforts. Focus has shifted from screening for bactericidal scaffolds to screens incorporating target deconvolution. Target‐based screening aims to direct drug discovery toward known effective targets and avoid investing resources into unproductive lines of enquiry. The protein synthesis pipeline, including RNA polymerase and the ribosome, is a clinically proven target in Mycobacterium tuberculosis. Screening for new hits of this effective target pathway is an invaluable tool in the drug discovery arsenal. Methods Using M. tuberculosis H37Rv augmented with anhydrotetracycline‐inducible expression of mCherry, a phenotypic screen was developed for the identification of protein synthesis inhibitors in a medium throughput screening format. Results The assay was validated using known inhibitors of protein synthesis to show a dose‐dependent reduction in mCherry fluorescence. This was expanded to a proprietary screen of hypothetical protein synthesis hits and modified to include quantitative viability measurement of cells using resazurin. Conclusion Following the success of the proprietary screen, a larger scale screen of the GlaxoSmithKline anti‐tubercular library containing 2799 compounds was conducted. Combined single shot and dose‐response screening yielded 18 hits, 0.64% of all screened compounds.
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Affiliation(s)
- Christopher Burke
- Institute of Microbiology and Infection School of Biosciences University of Birmingham Birmingham UK
| | - Monika Jankute
- Institute of Microbiology and Infection School of Biosciences University of Birmingham Birmingham UK
| | - Patrick Moynihan
- Institute of Microbiology and Infection School of Biosciences University of Birmingham Birmingham UK
| | | | - Xiaojun Li
- Department of Biochemistry and Biophysics Texas A&M University College Station Texas United States
| | - Jorge Esquivias
- Diseases of the Developing World GlaxoSmithKline Tres Cantos Madrid Spain
| | - Joël Lelièvre
- Diseases of the Developing World GlaxoSmithKline Tres Cantos Madrid Spain
| | | | - James Sacchettini
- Department of Biochemistry and Biophysics Texas A&M University College Station Texas United States
| | - Gurdyal S Besra
- Institute of Microbiology and Infection School of Biosciences University of Birmingham Birmingham UK
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9
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Behra PRK, Pettersson BMF, Das S, Dasgupta S, Kirsebom LA. Comparative genomics of Mycobacterium mucogenicum and Mycobacterium neoaurum clade members emphasizing tRNA and non-coding RNA. BMC Evol Biol 2019; 19:124. [PMID: 31215393 PMCID: PMC6582537 DOI: 10.1186/s12862-019-1447-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 05/27/2019] [Indexed: 02/07/2023] Open
Abstract
Background Mycobacteria occupy various ecological niches and can be isolated from soil, tap water and ground water. Several cause diseases in humans and animals. To get deeper insight into our understanding of mycobacterial evolution focusing on tRNA and non-coding (nc)RNA, we conducted a comparative genome analysis of Mycobacterium mucogenicum (Mmuc) and Mycobacterium neoaurum (Mneo) clade members. Results Genome sizes for Mmuc- and Mneo-clade members vary between 5.4 and 6.5 Mbps with the complete MmucT (type strain) genome encompassing 6.1 Mbp. The number of tRNA genes range between 46 and 79 (including one pseudo tRNA gene) with 39 tRNA genes common among the members of these clades, while additional tRNA genes were probably acquired through horizontal gene transfer. Selected tRNAs and ncRNAs (RNase P RNA, tmRNA, 4.5S RNA, Ms1 RNA and 6C RNA) are expressed, and the levels for several of these are higher in stationary phase compared to exponentially growing cells. The rare tRNAIleTAT isoacceptor and two for mycobacteria novel ncRNAs: the Lactobacillales-derived GOLLD RNA and a homolog to the antisense Salmonella typhimurium phage Sar RNA, were shown to be present and expressed in certain Mmuc-clade members. Conclusions Phages, IS elements, horizontally transferred tRNA gene clusters, and phage-derived ncRNAs appears to have influenced the evolution of the Mmuc- and Mneo-clades. While the number of predicted coding sequences correlates with genome size, the number of tRNA coding genes does not. The majority of the tRNA genes in mycobacteria are transcribed mainly from single genes and the levels of certain ncRNAs, including RNase P RNA (essential for the processing of tRNAs), are higher at stationary phase compared to exponentially growing cells. We provide supporting evidence that Ms1 RNA represents a mycobacterial 6S RNA variant. The evolutionary routes for the ncRNAs RNase P RNA, tmRNA and Ms1 RNA are different from that of the core genes. Electronic supplementary material The online version of this article (10.1186/s12862-019-1447-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Phani Rama Krishna Behra
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, SE-751 24, Uppsala, Sweden
| | - B M Fredrik Pettersson
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, SE-751 24, Uppsala, Sweden
| | - Sarbashis Das
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, SE-751 24, Uppsala, Sweden
| | - Santanu Dasgupta
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, SE-751 24, Uppsala, Sweden
| | - Leif A Kirsebom
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, SE-751 24, Uppsala, Sweden.
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10
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Kozhikkadan Davis C, Nasla K, Anjana AK, Rajanikant GK. Taxifolin as dual inhibitor of Mtb DNA gyrase and isoleucyl-tRNA synthetase: in silico molecular docking, dynamics simulation and in vitro assays. In Silico Pharmacol 2018; 6:8. [PMID: 30607321 DOI: 10.1007/s40203-018-0045-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 04/05/2018] [Indexed: 12/25/2022] Open
Abstract
DNA gyrase and aminoacyl-tRNA synthetases are two essential bacterial enzymes involved in DNA replication, transcription and translation. Flavonoids are plant secondary metabolites with variable phenolic structures. In this study, eight flavonoids structurally similar to quercetin were selected and their ADMET properties were evaluated. Molecular docking and free energy calculations were carried out to examine the binding of these flavonoids to the ATP-binding site and editing domain of DNA gyrase and Isoleucyl-tRNA synthetase, respectively. Taxifolin was found out to be the top lead molecule in both the docking studies with a good number of interactions with the active site amino acids. Further, binding of taxifolin to the proteins was extensively studied using 50 ns molecular dynamics simulation. In vitro anti-tuberculosis activity of taxifolin was evaluated and compared with the standard drugs. Minimal inhibition concentration of taxifolin was found to be ≤ 12.5 μg/ml.
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Affiliation(s)
| | - K Nasla
- Department of Pharmacognosy and Phytochemistry, Jamia Salafiya Pharmacy College, Malappuram, 673637 India
| | - A K Anjana
- Department of Pharmacognosy and Phytochemistry, Jamia Salafiya Pharmacy College, Malappuram, 673637 India
| | - G K Rajanikant
- 1School of Biotechnology, National Institute of Technology Calicut, Calicut, 673601 India
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11
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Barros-Álvarez X, Turley S, Ranade RM, Gillespie JR, Duster NA, Verlinde CLMJ, Fan E, Buckner FS, Hol WGJ. The crystal structure of the drug target Mycobacterium tuberculosis methionyl-tRNA synthetase in complex with a catalytic intermediate. Acta Crystallogr F Struct Biol Commun 2018; 74:245-254. [PMID: 29633973 PMCID: PMC5893993 DOI: 10.1107/s2053230x18003151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 02/23/2018] [Indexed: 12/24/2022] Open
Abstract
Mycobacterium tuberculosis is a pathogenic bacterial infectious agent that is responsible for approximately 1.5 million human deaths annually. Current treatment requires the long-term administration of multiple medicines with substantial side effects. Lack of compliance, together with other factors, has resulted in a worrisome increase in resistance. New treatment options are therefore urgently needed. Here, the crystal structure of methionyl-tRNA synthetase (MetRS), an enzyme critical for protein biosynthesis and therefore a drug target, in complex with its catalytic intermediate methionyl adenylate is reported. Phenylalanine 292 of the M. tuberculosis enzyme is in an `out' conformation and barely contacts the adenine ring, in contrast to other MetRS structures where ring stacking occurs between the adenine and a protein side-chain ring in the `in' conformation. A comparison with human cytosolic MetRS reveals substantial differences in the active site as well as regarding the position of the connective peptide subdomain 1 (CP1) near the active site, which bodes well for arriving at selective inhibitors. Comparison with the human mitochondrial enzyme at the amino-acid sequence level suggests that arriving at inhibitors with higher affinity for the mycobacterial enzyme than for the mitochondrial enzyme might be achievable.
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Affiliation(s)
- Ximena Barros-Álvarez
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, Mérida, Venezuela
| | - Stewart Turley
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Ranae M. Ranade
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA
| | - J. Robert Gillespie
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Nicole A. Duster
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Frederick S. Buckner
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Wim G. J. Hol
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
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12
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Mukai T, Reynolds NM, Crnković A, Söll D. Bioinformatic Analysis Reveals Archaeal tRNA Tyr and tRNA Trp Identities in Bacteria. Life (Basel) 2017; 7:life7010008. [PMID: 28230768 PMCID: PMC5370408 DOI: 10.3390/life7010008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 12/01/2022] Open
Abstract
The tRNA identity elements for some amino acids are distinct between the bacterial and archaeal domains. Searching in recent genomic and metagenomic sequence data, we found some candidate phyla radiation (CPR) bacteria with archaeal tRNA identity for Tyr-tRNA and Trp-tRNA synthesis. These bacteria possess genes for tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS) predicted to be derived from DPANN superphylum archaea, while the cognate tRNATyr and tRNATrp genes reveal bacterial or archaeal origins. We identified a trace of domain fusion and swapping in the archaeal-type TyrRS gene of a bacterial lineage, suggesting that CPR bacteria may have used this mechanism to create diverse proteins. Archaeal-type TrpRS of bacteria and a few TrpRS species of DPANN archaea represent a new phylogenetic clade (named TrpRS-A). The TrpRS-A open reading frames (ORFs) are always associated with another ORF (named ORF1) encoding an unknown protein without global sequence identity to any known protein. However, our protein structure prediction identified a putative HIGH-motif and KMSKS-motif as well as many α-helices that are characteristic of class I aminoacyl-tRNA synthetase (aaRS) homologs. These results provide another example of the diversity of molecular components that implement the genetic code and provide a clue to the early evolution of life and the genetic code.
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Affiliation(s)
- Takahito Mukai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Noah M Reynolds
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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13
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Discovery of Novel Oral Protein Synthesis Inhibitors of Mycobacterium tuberculosis That Target Leucyl-tRNA Synthetase. Antimicrob Agents Chemother 2016; 60:6271-80. [PMID: 27503647 PMCID: PMC5038265 DOI: 10.1128/aac.01339-16] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 07/31/2016] [Indexed: 11/30/2022] Open
Abstract
The recent development and spread of extensively drug-resistant and totally drug-resistant resistant (TDR) strains of Mycobacterium tuberculosis highlight the need for new antitubercular drugs. Protein synthesis inhibitors have played an important role in the treatment of tuberculosis (TB) starting with the inclusion of streptomycin in the first combination therapies. Although parenteral aminoglycosides are a key component of therapy for multidrug-resistant TB, the oxazolidinone linezolid is the only orally available protein synthesis inhibitor that is effective against TB. Here, we show that small-molecule inhibitors of aminoacyl-tRNA synthetases (AARSs), which are known to be excellent antibacterial protein synthesis targets, are orally bioavailable and effective against M. tuberculosis in TB mouse infection models. We applied the oxaborole tRNA-trapping (OBORT) mechanism, which was first developed to target fungal cytoplasmic leucyl-tRNA synthetase (LeuRS), to M. tuberculosis LeuRS. X-ray crystallography was used to guide the design of LeuRS inhibitors that have good biochemical potency and excellent whole-cell activity against M. tuberculosis. Importantly, their good oral bioavailability translates into in vivo efficacy in both the acute and chronic mouse models of TB with potency comparable to that of the frontline drug isoniazid.
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14
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Ramakrishnan G, Chandra NR, Srinivasan N. Recognizing drug targets using evolutionary information: implications for repurposing FDA-approved drugs against Mycobacterium tuberculosis H37Rv. MOLECULAR BIOSYSTEMS 2016; 11:3316-31. [PMID: 26429199 DOI: 10.1039/c5mb00476d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drug repurposing to explore target space has been gaining pace over the past decade with the upsurge in the use of systematic approaches for computational drug discovery. Such a cost and time-saving approach gains immense importance for pathogens of special interest, such as Mycobacterium tuberculosis H37Rv. We report a comprehensive approach to repurpose drugs, based on the exploration of evolutionary relationships inferred from the comparative sequence and structural analyses between targets of FDA-approved drugs and the proteins of M. tuberculosis. This approach has facilitated the identification of several polypharmacological drugs that could potentially target unexploited M. tuberculosis proteins. A total of 130 FDA-approved drugs, originally intended against other diseases, could be repurposed against 78 potential targets in M. tuberculosis. Additionally, we have also made an attempt to augment the chemical space by recognizing compounds structurally similar to FDA-approved drugs. For three of the attractive cases we have investigated the probable binding modes of the drugs in their corresponding M. tuberculosis targets by means of structural modelling. Such prospective targets and small molecules could be prioritized for experimental endeavours, and could significantly influence drug-discovery and drug-development programmes for tuberculosis.
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Affiliation(s)
- Gayatri Ramakrishnan
- Indian Institute of Science Mathematics Initiative, Indian Institute of Science, Bangalore-560012, India and Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
| | - Nagasuma R Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
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15
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Cvetesic N, Dulic M, Bilus M, Sostaric N, Lenhard B, Gruic-Sovulj I. Naturally Occurring Isoleucyl-tRNA Synthetase without tRNA-dependent Pre-transfer Editing. J Biol Chem 2016; 291:8618-31. [PMID: 26921320 PMCID: PMC4861432 DOI: 10.1074/jbc.m115.698225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Indexed: 11/23/2022] Open
Abstract
Isoleucyl-tRNA synthetase (IleRS) is unusual among aminoacyl-tRNA synthetases in having a tRNA-dependent pre-transfer editing activity. Alongside the typical bacterial IleRS (such as Escherichia coli IleRS), some bacteria also have the enzymes (eukaryote-like) that cluster with eukaryotic IleRSs and exhibit low sensitivity to the antibiotic mupirocin. Our phylogenetic analysis suggests that the ileS1 and ileS2 genes of contemporary bacteria are the descendants of genes that might have arisen by an ancient duplication event before the separation of bacteria and archaea. We present the analysis of evolutionary constraints of the synthetic and editing reactions in eukaryotic/eukaryote-like IleRSs, which share a common origin but diverged through adaptation to different cell environments. The enzyme from the yeast cytosol exhibits tRNA-dependent pre-transfer editing analogous to E. coli IleRS. This argues for the presence of this proofreading in the common ancestor of both IleRS types and an ancient origin of the synthetic site-based quality control step. Yet surprisingly, the eukaryote-like enzyme from Streptomyces griseus IleRS lacks this capacity; at the same time, its synthetic site displays the 103-fold drop in sensitivity to antibiotic mupirocin relative to the yeast enzyme. The discovery that pre-transfer editing is optional in IleRSs lends support to the notion that the conserved post-transfer editing domain is the main checkpoint in these enzymes. We substantiated this by showing that under error-prone conditions S. griseus IleRS is able to rescue the growth of an E. coli lacking functional IleRS, providing the first evidence that tRNA-dependent pre-transfer editing in IleRS is not essential for cell viability.
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Affiliation(s)
- Nevena Cvetesic
- From the Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia and
| | - Morana Dulic
- From the Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia and
| | - Mirna Bilus
- From the Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia and
| | - Nikolina Sostaric
- From the Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia and
| | - Boris Lenhard
- the Computational Regulatory Genomics Group, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Ita Gruic-Sovulj
- From the Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia and
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16
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Cochrane RVK, Norquay AK, Vederas JC. Natural products and their derivatives as tRNA synthetase inhibitors and antimicrobial agents. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00274a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tRNA synthetase enzymes are promising targets for development of therapeutic agents against infections by parasitic protozoans (e.g. malaria), fungi and yeast, as well as bacteria resistant to current antibiotics.
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Affiliation(s)
| | - A. K. Norquay
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
| | - J. C. Vederas
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
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17
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Thiaville PC, El Yacoubi B, Köhrer C, Thiaville JJ, Deutsch C, Iwata-Reuyl D, Bacusmo JM, Armengaud J, Bessho Y, Wetzel C, Cao X, Limbach PA, RajBhandary UL, de Crécy-Lagard V. Essentiality of threonylcarbamoyladenosine (t(6)A), a universal tRNA modification, in bacteria. Mol Microbiol 2015; 98:1199-221. [PMID: 26337258 DOI: 10.1111/mmi.13209] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2015] [Indexed: 02/06/2023]
Abstract
Threonylcarbamoyladenosine (t(6)A) is a modified nucleoside universally conserved in tRNAs in all three kingdoms of life. The recently discovered genes for t(6)A synthesis, including tsaC and tsaD, are essential in model prokaryotes but not essential in yeast. These genes had been identified as antibacterial targets even before their functions were known. However, the molecular basis for this prokaryotic-specific essentiality has remained a mystery. Here, we show that t(6)A is a strong positive determinant for aminoacylation of tRNA by bacterial-type but not by eukaryotic-type isoleucyl-tRNA synthetases and might also be a determinant for the essential enzyme tRNA(Ile)-lysidine synthetase. We confirm that t(6)A is essential in Escherichia coli and a survey of genome-wide essentiality studies shows that genes for t(6)A synthesis are essential in most prokaryotes. This essentiality phenotype is not universal in Bacteria as t(6)A is dispensable in Deinococcus radiodurans, Thermus thermophilus, Synechocystis PCC6803 and Streptococcus mutans. Proteomic analysis of t(6)A(-) D. radiodurans strains revealed an induction of the proteotoxic stress response and identified genes whose translation is most affected by the absence of t(6)A in tRNAs. Thus, although t(6)A is universally conserved in tRNAs, its role in translation might vary greatly between organisms.
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Affiliation(s)
- Patrick C Thiaville
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.,Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, 32610, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.,Institut de Génétique et Microbiologie, Université of Paris-Sud, Orsay, France
| | - Basma El Yacoubi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Caroline Köhrer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jennifer J Thiaville
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Chris Deutsch
- Department of Chemistry, Portland State University, Portland, OR, 97297, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, Portland State University, Portland, OR, 97297, USA
| | - Jo Marie Bacusmo
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Jean Armengaud
- CEA, DSV, IBiTec-S, SPI, Li2D, Laboratory 'Innovative technologies for Detection and Diagnostics', Bagnols-sur-Cèze, F-30200, France
| | - Yoshitaka Bessho
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan.,Institute of Physics, Academia Sinica, 128 Sec. 2, Academia Rd., Nankang, Taipei, 11529, Taiwan
| | - Collin Wetzel
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Xiaoyu Cao
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Patrick A Limbach
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Uttam L RajBhandary
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
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18
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Dulic M, Perona JJ, Gruic-Sovulj I. Determinants for tRNA-dependent pretransfer editing in the synthetic site of isoleucyl-tRNA synthetase. Biochemistry 2014; 53:6189-98. [PMID: 25207837 PMCID: PMC4188249 DOI: 10.1021/bi5007699] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
accurate expression of genetic information relies on the fidelity
of amino acid–tRNA coupling by aminoacyl-tRNA synthetases (aaRS).
When the specificity against structurally similar noncognate amino
acids in the synthetic reaction does not support a threshold fidelity
level for translation, the aaRS employ intrinsic hydrolytic editing
to correct errors in aminoacylation. Escherichia coli isoleucyl-tRNA synthetase (EcIleRS) is a class I aaRS that is notable
for its use of tRNA-dependent pretransfer editing to hydrolyze noncognate
valyl-adenylate prior to aminoacyl-tRNA formation. On the basis of
the finding that IleRS possessing an inactivated post-transfer editing
domain is still capable of robust tRNA-dependent editing, we have
recently proposed that the pretransfer editing activity resides within
the synthetic site. Here we apply an improved methodology that allows
quantitation of the AMP fraction that arises particularly from tRNA-dependent
aa-AMP hydrolysis. By this approach, we demonstrate that tRNA-dependent
pretransfer editing accounts for nearly one-third of the total proofreading
by EcIleRS and that a highly conserved tyrosine within the synthetic
site modulates both editing and aminoacylation. Therefore, synthesis
of aminoacyl-tRNA and hydrolysis of aminoacyl-adenylates employ overlapping
amino acid determinants. We suggest that this overlap hindered the
evolution of synthetic site-based pretransfer editing as the predominant
proofreading pathway, because that activity is difficult to accommodate
in the context of efficient aminoacyl-tRNA synthesis. Instead, the
acquisition of a spatially separate domain dedicated to post-transfer
editing alone allowed for the development of a powerful deacylation
machinery that effectively competes with dissociation of misacylated
tRNAs.
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Affiliation(s)
- Morana Dulic
- Department of Chemistry, Faculty of Science, University of Zagreb , Horvatovac 102a, 10000 Zagreb, Croatia
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19
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Lloyd AJ, Potter NJ, Fishwick CWG, Roper DI, Dowson CG. Adenosine tetraphosphoadenosine drives a continuous ATP-release assay for aminoacyl-tRNA synthetases and other adenylate-forming enzymes. ACS Chem Biol 2013; 8:2157-63. [PMID: 23898887 DOI: 10.1021/cb400248f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aminoacyl-tRNA synthetases are essential for the correct linkage of amino acids to cognate tRNAs to maintain the fidelity of protein synthesis. Tractable, continuous assays are valuable for characterizing the functions of synthetases and for their exploitation as drug targets. We have exploited the unexplored ability of these enzymes to consume adenosine tetraphosphoadenosine (diadenosine 5',5‴ P(1) P(4) tetraphosphate; Ap4A) and produce ATP to develop such an assay. We have used this assay to probe the stereoselectivity of isoleucyl-tRNA(Ile) and Valyl-tRNA(Val) synthetases and the impact of tRNA on editing by isoleucyl-tRNA(Ile) synthetase (IleRS) and to identify analogues of intermediates of these enzymes that might allow targeting of multiple synthetases. We further report the utility of Ap4A-based assays for identification of synthetase inhibitors with nanomolar to millimolar affinities. Finally, we demonstrate the broad application of Ap4A utilization with a continuous Ap4A-driven RNA ligase assay.
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Affiliation(s)
- Adrian J. Lloyd
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry,
West Midlands CV4 7AL, U.K
| | | | | | - David I. Roper
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry,
West Midlands CV4 7AL, U.K
| | - Christopher G. Dowson
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry,
West Midlands CV4 7AL, U.K
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20
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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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21
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Andam CP, Fournier GP, Gogarten JP. Multilevel populations and the evolution of antibiotic resistance through horizontal gene transfer. FEMS Microbiol Rev 2011; 35:756-67. [DOI: 10.1111/j.1574-6976.2011.00274.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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22
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Marri PR, Bannantine JP, Paustian ML, Golding GB. Lateral gene transfer in Mycobacterium avium subspecies paratuberculosis. Can J Microbiol 2006; 52:560-9. [PMID: 16788724 DOI: 10.1139/w06-001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lateral gene transfer is an integral part of genome evolution in most bacteria. Bacteria can readily change the contents of their genomes to increase adaptability to ever-changing surroundings and to generate evolutionary novelty. Here, we report instances of lateral gene transfer in Mycobacterium avium subsp. paratuberculosis, a pathogenic bacteria that causes Johne's disease in cattle. A set of 275 genes are identified that are likely to have been recently acquired by lateral gene transfer. The analysis indicated that 53 of the 275 genes were acquired after the divergence of M. avium subsp. paratuberculosis from M. avium subsp. avium, whereas the remaining 222 genes were possibly acquired by a common ancestor of M. avium subsp. paratuberculosis and M. avium subsp. avium after its divergence from the ancestor of M. tuberculosis complex. Many of the acquired genes were from proteobacteria or soil dwelling actinobacteria. Prominent among the predicted laterally transferred genes is the gene rsbR, a possible regulator of sigma factor, and the genes designated MAP3614 and MAP3757, which are similar to genes in eukaryotes. The results of this study suggest that like most other bacteria, lateral gene transfers seem to be a common feature in M. avium subsp. paratuberculosis and that the proteobacteria contribute most of these genetic exchanges.
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23
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Ardell DH, Andersson SGE. TFAM detects co-evolution of tRNA identity rules with lateral transfer of histidyl-tRNA synthetase. Nucleic Acids Res 2006; 34:893-904. [PMID: 16473847 PMCID: PMC1363771 DOI: 10.1093/nar/gkj449] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
We present TFAM, an automated, statistical method to classify the identity of tRNAs. TFAM, currently optimized for bacteria, classifies initiator tRNAs and predicts the charging identity of both typical and atypical tRNAs such as suppressors with high confidence. We show statistical evidence for extensive variation in tRNA identity determinants among bacterial genomes due to variation in overall tDNA base content. With TFAM we have detected the first case of eukaryotic-like tRNA identity rules in bacteria. An α-proteobacterial clade encompassing Rhizobiales, Caulobacter crescentus and Silicibacter pomeroyi, unlike a sister clade containing the Rickettsiales, Zymomonas mobilis and Gluconobacter oxydans, uses the eukaryotic identity element A73 instead of the highly conserved prokaryotic element C73. We confirm divergence of bacterial histidylation rules by demonstrating perfect covariation of α-proteobacterial tRNAHis acceptor stems and residues in the motif IIb tRNA-binding pocket of their histidyl-tRNA synthetases (HisRS). Phylogenomic analysis supports lateral transfer of a eukaryotic-like HisRS into the α-proteobacteria followed by in situ adaptation of the bacterial tDNAHis and identity rule divergence. Our results demonstrate that TFAM is an effective tool for the bioinformatics, comparative genomics and evolutionary study of tRNA identity.
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MESH Headings
- Alphaproteobacteria/classification
- Alphaproteobacteria/enzymology
- Alphaproteobacteria/genetics
- DNA, Bacterial/classification
- Databases, Nucleic Acid
- Evolution, Molecular
- Gene Transfer, Horizontal
- Genetic Variation
- Genome, Bacterial
- Genomics
- Histidine-tRNA Ligase/classification
- Histidine-tRNA Ligase/genetics
- Models, Statistical
- Phylogeny
- RNA, Transfer/classification
- RNA, Transfer/genetics
- RNA, Transfer, His/chemistry
- RNA, Transfer, His/classification
- RNA, Transfer, His/genetics
- RNA, Transfer, Met/classification
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Affiliation(s)
- David H Ardell
- Department of Molecular Evolution, Evolutionary Biology Center Norbyvägen 18C Uppsala University SE-752 36 Uppsala Sweden.
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24
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Yanagisawa T, Kawakami M. How does Pseudomonas fluorescens avoid suicide from its antibiotic pseudomonic acid?: Evidence for two evolutionarily distinct isoleucyl-tRNA synthetases conferring self-defense. J Biol Chem 2003; 278:25887-94. [PMID: 12672810 DOI: 10.1074/jbc.m302633200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two isoleucyl-tRNA synthetases (IleRSs) encoded by two distinct genes (ileS1 and ileS2) were identified in pseudomonic acid (mupirocin)-producing Pseudomonas fluorescens. The most striking difference between the two IleRSs (IleRS-R1 and IleRS-R2) is the difference in their abilities to resist pseudomonic acid. Purified IleRS-R2 showed no sensitivity to pseudomonic acid even at a concentration of 5 mm, 105 times higher than the Ki value of IleRS-R1. The amino acid sequence of IleRS-R2 exhibits eukaryotic features that are originally found in eukaryotic proteins. Escherichia coli cells transformed with the ileS2 gene exerted pseudomonic acid resistance more than did those transformed with ileS1. Cells transformed with both genes became almost as resistant as P. fluorescens. These results suggest that the presence of IleRS-R2 could be the major reason why P. fluorescens is intrinsically resistant to the antibiotic. Here we suggest that the evolutionary scenario of the eukaryotic ileS2 gene can be explained by gene acquisition and that the pseudomonic acid producer may have maintained the ileS2 gene to protect itself from pseudomonic acid.
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Affiliation(s)
- Tatsuo Yanagisawa
- Department of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan
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25
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Brown JR, Gentry D, Becker JA, Ingraham K, Holmes DJ, Stanhope MJ. Horizontal transfer of drug-resistant aminoacyl-transfer-RNA synthetases of anthrax and Gram-positive pathogens. EMBO Rep 2003; 4:692-8. [PMID: 12792655 PMCID: PMC1326320 DOI: 10.1038/sj.embor.embor881] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2003] [Revised: 04/30/2003] [Accepted: 05/13/2003] [Indexed: 11/08/2022] Open
Abstract
The screening of new antibiotics against several bacterial strains often reveals unexpected occurrences of natural drug resistance. Two examples of this involve specific inhibitors of Staphylococcus aureus isoleucyl-transfer-RNA synthetase 1 (IleRS1) and, more recently, Streptococcus pneumoniae methionyl-tRNA synthetase 1 (MetRS1). In both cases, resistance is due to the presence of a second gene that encodes another synthetase (IleRS2 or MetRS2). Here, we show that both S. pneumoniae MetRS2 and S. aureus IleRS2 have closely related homologues in the Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax. Furthermore, similar to drug-resistant pathogens, strains of B. anthracis and its closest relative, B. cereus, also have wild-type ileS1 and metS1 genes. Clostridium perfringens, the causative agent of gangrene, also has two metS genes, whereas Oceanobacillus iheyensis isolated from deep-sea sediments has a single ileS2-type gene. This study shows the importance of understanding complex evolutionary networks of ancient horizontal gene transfer for the development of novel antibiotics.
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Affiliation(s)
- James R. Brown
- Bioinformatics Division, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
- Tel: +1 610 917 6374; Fax: +1 610 917 7901;
| | - Daniel Gentry
- Microbial Genetics Department, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
| | - Julie A. Becker
- Bioinformatics Division, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
| | - Karen Ingraham
- Microbial Genetics Department, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
| | - David J. Holmes
- Microbial Genetics Department, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
| | - Michael J. Stanhope
- Bioinformatics Division, GlaxoSmithKline, 1250 South Collegeville Road, UP1345, Collegeville, Pennsylvania 19426, USA
- Tel: +1 610 917 6577; Fax: +1 610 917 7901;
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26
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Walter F, Pütz J, Giegé R, Westhof E. Binding of tobramycin leads to conformational changes in yeast tRNA(Asp) and inhibition of aminoacylation. EMBO J 2002; 21:760-8. [PMID: 11847123 PMCID: PMC125865 DOI: 10.1093/emboj/21.4.760] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Aminoglycosides inhibit translation in bacteria by binding to the A site in the ribosome. Here, it is shown that, in yeast, aminoglycosides can also interfere with other processes of translation in vitro. Steady-state aminoacylation kinetics of unmodified yeast tRNA(Asp) transcript indicate that the complex between tRNA(Asp) and tobramycin is a competitive inhibitor of the aspartylation reaction with an inhibition constant (K(I)) of 36 nM. Addition of an excess of heterologous tRNAs did not reverse the charging of tRNA(Asp), indicating a specific inhibition of the aspartylation reaction. Although magnesium ions compete with the inhibitory effect, the formation of the aspartate adenylate in the ATP-PP(i) exchange reaction by aspartyl-tRNA synthetase in the absence of the tRNA is not inhibited. Ultraviolet absorbance melting experiments indicate that tobramycin interacts with and destabilizes the native L-shaped tertiary structure of tRNA(Asp). Fluorescence anisotropy using fluorescein-labelled tobramycin reveals a stoichiometry of one molecule bound to tRNA(Asp) with a K(D) of 267 nM. The results indicate that aminoglycosides are biologically effective when their binding induces a shift in a conformational equilibrium of the RNA.
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Affiliation(s)
| | | | | | - Eric Westhof
- UPR 9002 du CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, F-67084 Strasbourg Cedex, France
Corresponding author e-mail:
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27
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Abstract
Bacterial genomes are extremely dynamic and mosaic in nature. A substantial amount of genetic information is inserted into or deleted from such genomes through the process of horizontal transfer. Through the introduction of novel physiological traits from distantly related organisms, horizontal gene transfer often causes drastic changes in the ecological and pathogenic character of bacterial species and thereby promotes microbial diversification and speciation. This review discusses how the recent influx of complete chromosomal sequences of various microorganisms has allowed for a quantitative assessment of the scope, rate and impact of horizontally transmitted information on microbial evolution.
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Affiliation(s)
- Chitra Dutta
- Human Genetics and Genomics Group, Indian Institute of Chemical Biology, 4, Raja SC Mullick Road, Kolkata 700 032, India.
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28
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Nakama T, Nureki O, Yokoyama S. Structural basis for the recognition of isoleucyl-adenylate and an antibiotic, mupirocin, by isoleucyl-tRNA synthetase. J Biol Chem 2001; 276:47387-93. [PMID: 11584022 DOI: 10.1074/jbc.m109089200] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An analogue of isoleucyl-adenylate (Ile-AMS) potently inhibits the isoleucyl-tRNA synthetases (IleRSs) from the three primary kingdoms, whereas the antibiotic mupirocin inhibits only the eubacterial and archaeal IleRSs, but not the eukaryotic enzymes, and therefore is clinically used against methicillin-resistant Staphylococcus aureus. We determined the crystal structures of the IleRS from the thermophilic eubacterium, Thermus thermophilus, in complexes with Ile-AMS and mupirocin at 3.0- and 2.5-A resolutions, respectively. A structural comparison of the IleRS.Ile-AMS complex with the adenylate complexes of other aminoacyl-tRNA synthetases revealed the common recognition mode of aminoacyl-adenylate by the class I aminoacyl-tRNA synthetases. The Ile-AMS and mupirocin, which have significantly different chemical structures, are recognized by many of the same amino acid residues of the IleRS, suggesting that the antibiotic inhibits the enzymatic activity by blocking the binding site of the high energy intermediate, Ile-AMP. In contrast, the two amino acid residues that concomitantly recognize Ile-AMS and mupirocin are different between the eubacterial/archaeal IleRSs and the eukaryotic IleRSs. Mutagenic analyses revealed that the replacement of the two residues significantly changed the sensitivity to mupirocin.
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Affiliation(s)
- T Nakama
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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29
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Klein M, Friedrich M, Roger AJ, Hugenholtz P, Fishbain S, Abicht H, Blackall LL, Stahl DA, Wagner M. Multiple lateral transfers of dissimilatory sulfite reductase genes between major lineages of sulfate-reducing prokaryotes. J Bacteriol 2001; 183:6028-35. [PMID: 11567003 PMCID: PMC99682 DOI: 10.1128/jb.183.20.6028-6035.2001] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A large fragment of the dissimilatory sulfite reductase genes (dsrAB) was PCR amplified and fully sequenced from 30 reference strains representing all recognized lineages of sulfate-reducing bacteria. In addition, the sequence of the dsrAB gene homologs of the sulfite reducer Desulfitobacterium dehalogenans was determined. In contrast to previous reports, comparative analysis of all available DsrAB sequences produced a tree topology partially inconsistent with the corresponding 16S rRNA phylogeny. For example, the DsrAB sequences of several Desulfotomaculum species (low G+C gram-positive division) and two members of the genus Thermodesulfobacterium (a separate bacterial division) were monophyletic with delta-proteobacterial DsrAB sequences. The most parsimonious interpretation of these data is that dsrAB genes from ancestors of as-yet-unrecognized sulfate reducers within the delta-Proteobacteria were laterally transferred across divisions. A number of insertions and deletions in the DsrAB alignment independently support these inferred lateral acquisitions of dsrAB genes. Evidence for a dsrAB lateral gene transfer event also was found within the delta-Proteobacteria, affecting Desulfobacula toluolica. The root of the dsr tree was inferred to be within the Thermodesulfovibrio lineage by paralogous rooting of the alpha and beta subunits. This rooting suggests that the dsrAB genes in Archaeoglobus species also are the result of an ancient lateral transfer from a bacterial donor. Although these findings complicate the use of dsrAB genes to infer phylogenetic relationships among sulfate reducers in molecular diversity studies, they establish a framework to resolve the origins and diversification of this ancient respiratory lifestyle among organisms mediating a key step in the biogeochemical cycling of sulfur.
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Affiliation(s)
- M Klein
- Lehrstuhl für Mikrobiologie, Technische Universität München, D-85350 Freising, Germany
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30
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Avarbock D, Avarbock A, Rubin H. Differential regulation of opposing RelMtb activities by the aminoacylation state of a tRNA.ribosome.mRNA.RelMtb complex. Biochemistry 2000; 39:11640-8. [PMID: 10995231 DOI: 10.1021/bi001256k] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rel(Mtb) of Mycobacterium tuberculosis is responsible for the intracellular regulation of (p)ppGpp and the consequent ability of the organism to survive long-term starvation, indicating a possible role in the pathogenesis of tuberculosis. Purified Rel(Mtb) is a dual-function enzyme carrying out ATP: GTP/GDP/ITP 3'-pyrophosphoryltransferase and (p)ppGpp 3'-pyrophosphohydrolase reactions. Here we show that in the absence of biological regulators, Rel(Mtb) simultaneously catalyzes both transferase and hydrolysis at the maximal rate for each reaction, indicating the existence of two distinct active sites. The differential regulation of the opposing activities of Rel(Mtb) is dependent on the ratio of uncharged to charged tRNA and the association of Rel(Mtb) with a complex containing tRNA, ribosomes, and mRNA. A 20-fold increase in the k(cat) and a 4-fold decrease in K(ATP) and K(GTP) from basal levels for transferase activity occur when Rel(Mtb) binds to a complex containing uncharged tRNA, ribosomes, and mRNA (Rel(Mtb) activating complex or RAC). The k(cat) for hydrolysis, however, is reduced 2-fold and K(m) for pppGpp increased 2-fold from basal levels in the presence of the Rel(Mtb) activating complex. The addition of charged tRNA to this complex has the opposite effect by inhibiting transferase activity and activating hydrolysis activity. Differential control of Rel(Mtb) gives the Mtb ribosomal complex a new regulatory role in controlling cellular metabolism in response to stringent growth conditions that may be present in the dormant Mtb lesion.
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Affiliation(s)
- D Avarbock
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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31
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Landeka I, Filipic-Rocak S, Zinic B, Weygand-Durasevic I. Characterization of yeast seryl-tRNA synthetase active site mutants with improved discrimination against substrate analogues. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1480:160-70. [PMID: 11004561 DOI: 10.1016/s0167-4838(00)00066-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The involvement of amino acids within the motif 2 loop of Saccharomyces cerevisiae seryl-tRNA synthetase (SerRS) in serine and ATP binding was demonstrated previously [B. Lenhard et al., J. Biol. Chem. 272 (1997) 1136-1141]. In our attempt to analyze the structural basis for the substrate specificity and to explore further the catalytic mechanism employed by S. cerevisiae SerRS, two new active site mutants, SerRS11 and SerRS12, were constructed. The catalytic effects of amino acid replacement at positions Lys287, Asp288 and Ala289 with purified wild-type and mutant seryl-tRNA synthetases were tested. The alteration of these semi-conserved amino acids interferes with tRNA-dependent optimization of serine recognition. Additionally, mutated enzymes SerRS11 (Lys287Thr, Asp288Tyr, Ala289Val) and SerRS12 (Lys287Arg) are less sensitive to inhibition by two competitive inhibitors: serine hydroxamate, an analogue of serine, and 5'-O-[N-(L-seryl)-sulfamoyl]adenosine, a stable analogue of aminoacyl adenylate, than the wild-type enzyme. SerRS mutants also display different activation kinetics for serine and serine hydroxamate, indicating that specificity toward the substrates is modulated by amino acid replacement in the motif 2 loop.
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Affiliation(s)
- I Landeka
- Department of Chemistry, Faculty of Science, University of Zagreb, Croatia
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32
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Abstract
Studies in microbial evolution have focused on the origin and vertical transmission of genetic variation within populations experiencing limited recombination. Genomic analyses have highlighted the importance of horizontal genetic transfer in shaping the composition of microbial genomes, providing novel metabolic capabilities, and catalyzing the diversification of bacterial lineages.
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Affiliation(s)
- J G Lawrence
- Department of Biological Sciences University of Pittsburgh Pittsburgh, PA 15260, USA
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33
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Wolf YI, Aravind L, Grishin NV, Koonin EV. Evolution of Aminoacyl-tRNA Synthetases—Analysis of Unique Domain Architectures and Phylogenetic Trees Reveals a Complex History of Horizontal Gene Transfer Events. Genome Res 1999. [DOI: 10.1101/gr.9.8.689] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Phylogenetic analysis of aminoacyl-tRNA synthetases (aaRSs) of all 20 specificities from completely sequenced bacterial, archaeal, and eukaryotic genomes reveals a complex evolutionary picture. Detailed examination of the domain architecture of aaRSs using sequence profile searches delineated a network of partially conserved domains that is even more elaborate than previously suspected. Several unexpected evolutionary connections were identified, including the apparent origin of the β-subunit of bacterial GlyRS from the HD superfamily of hydrolases, a domain shared by bacterial AspRS and the B subunit of archaeal glutamyl-tRNA amidotransferases, and another previously undetected domain that is conserved in a subset of ThrRS, guanosine polyphosphate hydrolases and synthetases, and a family of GTPases. Comparison of domain architectures and multiple alignments resulted in the delineation of synapomorphies—shared derived characters, such as extra domains or inserts—for most of the aaRSs specificities. These synapomorphies partition sets of aaRSs with the same specificity into two or more distinct and apparently monophyletic groups. In conjunction with cluster analysis and a modification of the midpoint-rooting procedure, this partitioning was used to infer the likely root position in phylogenetic trees. The topologies of the resulting rooted trees for most of the aaRSs specificities are compatible with the evolutionary “standard model” whereby the earliest radiation event separated bacteria from the common ancestor of archaea and eukaryotes as opposed to the two other possible evolutionary scenarios for the three major divisions of life. For almost all aaRSs specificities, however, this simple scheme is confounded by displacement of some of the bacterial aaRSs by their eukaryotic or, less frequently, archaeal counterparts. Displacement of ancestral eukaryotic aaRS genes by bacterial ones, presumably of mitochondrial origin, was observed for three aaRSs. In contrast, there was no convincing evidence of displacement of archaeal aaRSs by bacterial ones. Displacement of aaRS genes by eukaryotic counterparts is most common among parasitic and symbiotic bacteria, particularly the spirochaetes, in which 10 of the 19 aaRSs seem to have been displaced by the respective eukaryotic genes and two by the archaeal counterpart. Unlike the primary radiation events between the three main divisions of life, that were readily traceable through the phylogenetic analysis of aaRSs, no consistent large-scale bacterial phylogeny could be established. In part, this may be due to additional gene displacement events among bacterial lineages. Argument is presented that, although lineage-specific gene loss might have contributed to the evolution of some of the aaRSs, this is not a viable alternative to horizontal gene transfer as the principal evolutionary phenomenon in this gene class.[Complete multiple alignments of all aaRSs from complete genomes as well as the alignments of conserved regions used for phylogenetic tree construction are available at ftp://ncbi.nlm.nih.gov/pub/koonin/aaRS]
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34
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Martinis SA, Plateau P, Cavarelli J, Florentz C. Aminoacyl-tRNA synthetases: a new image for a classical family. Biochimie 1999; 81:683-700. [PMID: 10492015 DOI: 10.1016/s0300-9084(99)80126-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The aminoacyl-tRNA synthetases (aaRSs) are a family of enzymes well known for their role in protein synthesis. More recent investigations have discovered that this classic family of enzymes is actually capable of a broad repertoire of functions which not only impact protein synthesis, but extend to a number of other critical cellular activities. Specific aaRSs play roles in cellular fidelity, tRNA processing, RNA splicing, RNA trafficking, apoptosis, transcriptional and translational regulation. A recent EMBO workshop entitled 'Structure and Function of Aminoacyl-tRNA Synthetases' (Mittelwihr, France, October 10-15, 1998), highlighted the diversity of the aaRSs' role within the cell. These novel activities as well as significant advances in delineating mechanisms of substrate specificity and the aminoacylation reaction affirm the family of aaRSs as pharmaceutical targets.
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Affiliation(s)
- S A Martinis
- Department of Biology and Biochemistry, University of Houston, TX 77204-5513, USA
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35
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Abstract
Unexpected relationships among the various aminoacyl-tRNA synthetases continue to be uncovered. The question arises - is this mainly the result of promiscuous exchange, or is the confusion really a reflection of the differential loss of past duplications? Phylogenetic analysis may yet provide the answer.
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Affiliation(s)
- R F Doolittle
- Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093-0634, USA.
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36
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Affiliation(s)
- Paul Schimmel
- The Skaggs Institute for Chemical BiologyThe Scripps Research InstituteBeckman Center La Jolla California 92037 USA
| | - Jianshi Tao
- Cubist Pharmaceuticals Inc. Cambridge Massachusetts 02139 USA
| | - Jason Hill
- Cubist Pharmaceuticals Inc. Cambridge Massachusetts 02139 USA
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37
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Shiba K, Motegi H, Yoshida M, Noda T. Human asparaginyl-tRNA synthetase: molecular cloning and the inference of the evolutionary history of Asx-tRNA synthetase family. Nucleic Acids Res 1998; 26:5045-51. [PMID: 9801298 PMCID: PMC147956 DOI: 10.1093/nar/26.22.5045] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have cloned and sequenced a cDNA encoding human cytoplasmic asparaginyl-tRNA synthetase (AsnRS). The N-terminal appended domain of 112 amino acid represents the signature sequence for the eukaryotic AsnRS and is absent from archaebacterial or eubacterial enzymes. The canonical ortholog for AsnRS is absent from most archaebacterial and some eubacterial genomes, indicating that in those organisms, formation of asparaginyl-tRNA is independent of the enzyme. The high degree of sequence conservation among asparaginyl- and aspartyl-tRNA synthetases (AsxRS) made it possible to infer the evolutionary paths of the two enzymes. The data show the neighbor relationship between AsnRS and eubacterial aspartyl-tRNA synthetase, and support the occurrence of AsnRS early in the course of evolution, which is in contrast to the proposed late occurrence of glutaminyl-tRNA synthetase.
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Affiliation(s)
- K Shiba
- Department of Cell Biology, Cancer Institute, Japanese Foundation for Cancer Research, 1-37-1 Kami-Ikebukuro, Toshima, Tokyo 170-8455, Japan.
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38
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39
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Kim S, Jo YJ, Lee SH, Motegi H, Shiba K, Sassanfar M, Martinis SA. Biochemical and phylogenetic analyses of methionyl-tRNA synthetase isolated from a pathogenic microorganism, Mycobacterium tuberculosis. FEBS Lett 1998; 427:259-62. [PMID: 9607323 DOI: 10.1016/s0014-5793(98)00417-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mycobacterium tuberculosis methionyl-tRNA synthetase (MetRS) has been cloned and characterized. The protein contains class I signature sequences but lacks the Zn2+ binding motif and the C-terminal dimerization appendix that are found in MetRSs from several organisms including E. coli MetRS. Consistent with these features, the enzyme behaved as a monomer in a gel filtration chromatography and did not contain the bound Zn2+. Nonetheless, it was active to the tRNAMet of E. coli as determined by in vivo genetic complementation and in vitro reaction. Phylogenetic analysis separated the M. tuberculosis and E. coli MetRSs into prokaryote and eukaryote-archaea group, respectively. This result is consistent with the taxonomic locations of the organism but is an interesting contrast to the case of its paralogous protein, isoleucyl-tRNA synthetase, and suggests that the two enzymes evolved in separate idiosyncratic pathways.
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Affiliation(s)
- S Kim
- Sung Kyun Kwan University, Department of Biology, Suwon, Kyunggido, South Korea.
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40
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Shiba K, Motegi H, Schimmel P. Maintaining genetic code through adaptations of tRNA synthetases to taxonomic domains. Trends Biochem Sci 1997; 22:453-7. [PMID: 9433122 DOI: 10.1016/s0968-0004(97)01135-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The universal genetic code is determined by the aminoacylation of tRNAs. In spite of the universality of the code, there are barriers to aminoacylation across taxonomic domains. These barriers are thought to correlate with the co-segregation of sequences of synthetases and tRNAs into distinct taxonomic domains. By contrast, we show here examples of eukaryote-like synthetases that are found in certain prokaryotes. The associated tRNAs have retained their prokaryote-like character in each instance. Thus, co-segregation of domain-specific synthetases and tRNAs does not always occur. Instead, synthetases make adaptations of tRNA-protein contacts to cross taxonomic domains.
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Affiliation(s)
- K Shiba
- PRESTO, Department of Cell Biology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
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41
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Vasanthakrishna M, Kumar NV, Varshney U. Characterization of the initiator tRNA gene locus and identification of a strong promoter from Mycobacterium tuberculosis. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 11):3591-3598. [PMID: 9387237 DOI: 10.1099/00221287-143-11-3591] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An initiator tRNA gene, metA, and a closely linked fragment of a second initiator-tRNA-like sequence, metB, from Mycobacterium tuberculosis H37Ra have been cloned and characterized. The promoter region of metA shows the presence of conserved sequence elements, TAGCCT and TTGGCG, with resemblance to -10 and -35 promoter regions. The deduced sequence of the mature tRNA contains the three unique features of the eubacterial initiator tRNAs represented by (i) a C:U mismatch at position 1:72, (ii) three consecutive base pairs, 29-31G:C39-41 in the anticodon stem, and (iii) a purine:pyrimidine (A:U) base pair at position 11:24 in the dihydrouridine stem. A putative hairpin structure consisting of an 11 bp stem and a three-base loop found in the 3' flanking region is followed by a stretch of T residues and may serve as a transcription terminator. Analysis of the expression of metA and of its promoter using chloramphenicol acetyltransferase fusion constructs in Mycobacterium smegmatis shows that metA is a functional gene driven by a strong promoter. Furthermore, the overexpressed transcripts are fully processed and formylated in vivo. The metB clone shows the presence of sequences corresponding to those downstream of position 30 of the tRNA. However, the CCA sequence at the 3' end has been mutated to CCG. Interestingly, the 3' flanking sequences of both the genes are rich in GCT repeats. The metB locus also harbours a repeat element, IS6110. A method to prepare total RNA from mycobacteria (under acidic conditions) to analyse in vivo status of tRNAs is described.
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MESH Headings
- Acylation
- Anticodon/genetics
- Base Sequence
- Cloning, Molecular
- Conserved Sequence/genetics
- Genes, Bacterial/genetics
- Molecular Sequence Data
- Mycobacterium/genetics
- Mycobacterium tuberculosis/genetics
- Nucleic Acid Conformation
- Promoter Regions, Genetic/genetics
- RNA, Bacterial/analysis
- RNA, Messenger/analysis
- RNA, Transfer, Met/analysis
- RNA, Transfer, Met/chemistry
- RNA, Transfer, Met/genetics
- Recombinant Fusion Proteins
- Repetitive Sequences, Nucleic Acid/genetics
- Restriction Mapping
- Sequence Analysis, DNA
- Transcription, Genetic/genetics
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Affiliation(s)
- M Vasanthakrishna
- Centre for Genetic Engineering, Indian Institute of Science, Bangalore 560 012, India
| | - N Vinay Kumar
- Centre for Genetic Engineering, Indian Institute of Science, Bangalore 560 012, India
| | - U Varshney
- Centre for Genetic Engineering, Indian Institute of Science, Bangalore 560 012, India
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