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Sangsuwan W, Taweesablamlert A, Boonkerd A, Isarangkool Na Ayutthaya C, Yoo S, Javid B, Faikhruea K, Vilaivan T, Aonbangkhen C, Chuawong P. A quest for novel antimicrobial targets: Inhibition of Asp-tRNA Asn/Glu-tRNA Gln amidotransferase (GatCAB) by synthetic analogs of aminoacyl-adenosine in vitro and live bacteria. Bioorg Chem 2024; 150:107530. [PMID: 38852310 DOI: 10.1016/j.bioorg.2024.107530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/25/2024] [Accepted: 06/03/2024] [Indexed: 06/11/2024]
Abstract
The Asp-tRNAAsn/Glu-tRNAGln amidotransferase (GatCAB) has been proposed as a novel antibacterial drug target due to its indispensability in prominent human pathogens. While several inhibitors with in vitro activity have been identified, none have been demonstrated to have potent activity against live bacteria. In this work, seven non-hydrolyzable transition state mimics of GatCAB were synthesized and tested as the transamidase inhibitors against GatCAB from the human pathogen Helicobacter pylori. Notably, the methyl sulfone analog of glutamyl-adenosine significantly reduced GatCAB's transamination rate. Additionally, four lipid-conjugates of these mimics displayed antibacterial activity against Bacillus subtilis, likely due to enhanced cell permeability. Inhibitory activity against GatCAB in live bacteria was confirmed using a sensitive gain-of-function dual luciferase reporter in Mycobacterium bovis-BCG. Only the lipid-conjugated methyl sulfone analog exhibited a significant increase in mistranslation rate, highlighting its cell permeability and inhibitory potential. This study provides insights for developing urgently needed novel antibacterial agents amidst emerging antimicrobial drug resistance.
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Affiliation(s)
- Withsakorn Sangsuwan
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
| | - Amata Taweesablamlert
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
| | - Anon Boonkerd
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
| | - Chawarat Isarangkool Na Ayutthaya
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand
| | - Sion Yoo
- Division of Experimental Medicine, University of California, San Francisco, CA, USA
| | - Babak Javid
- Division of Experimental Medicine, University of California, San Francisco, CA, USA
| | - Kriangsak Faikhruea
- Organic Synthesis Research Unit (OSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tirayut Vilaivan
- Organic Synthesis Research Unit (OSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chanat Aonbangkhen
- Center of Excellence in Natural Products Chemistry (CENP), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330 Thailand; Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
| | - Pitak Chuawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Special Research Unit for Advanced Magnetic Resonance (AMR), Kasetsart University, Bangkok 10900, Thailand.
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2
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Lewis AM, Fallon T, Dittemore GA, Sheppard K. Evolution and variation in amide aminoacyl-tRNA synthesis. IUBMB Life 2024. [PMID: 38391119 DOI: 10.1002/iub.2811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/22/2024] [Indexed: 02/24/2024]
Abstract
The amide proteogenic amino acids, asparagine and glutamine, are two of the twenty amino acids used in translation by all known life. The aminoacyl-tRNA synthetases for asparagine and glutamine, asparaginyl-tRNA synthetase and glutaminyl tRNA synthetase, evolved after the split in the last universal common ancestor of modern organisms. Before that split, life used two-step indirect pathways to synthesize asparagine and glutamine on their cognate tRNAs to form the aminoacyl-tRNA used in translation. These two-step pathways were retained throughout much of the bacterial and archaeal domains of life and eukaryotic organelles. The indirect routes use non-discriminating aminoacyl-tRNA synthetases (non-discriminating aspartyl-tRNA synthetase and non-discriminating glutamyl-tRNA synthetase) to misaminoacylate the tRNA. The misaminoacylated tRNA formed is then transamidated into the amide aminoacyl-tRNA used in protein synthesis by tRNA-dependent amidotransferases (GatCAB and GatDE). The enzymes and tRNAs involved assemble into complexes known as transamidosomes to help maintain translational fidelity. These pathways have evolved to meet the varied cellular needs across a diverse set of organisms, leading to significant variation. In certain bacteria, the indirect pathways may provide a means to adapt to cellular stress by reducing the fidelity of protein synthesis. The retention of these indirect pathways versus acquisition of asparaginyl-tRNA synthetase and glutaminyl tRNA synthetase in lineages likely involves a complex interplay of the competing uses of glutamine and asparagine beyond translation, energetic costs, co-evolution between enzymes and tRNA, and involvement in stress response that await further investigation.
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Affiliation(s)
- Alexander M Lewis
- Chemistry Department, Skidmore College, Saratoga Springs, New York, USA
| | - Trevor Fallon
- Chemistry Department, Skidmore College, Saratoga Springs, New York, USA
| | | | - Kelly Sheppard
- Chemistry Department, Skidmore College, Saratoga Springs, New York, USA
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3
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Kim SY, Yoon SI. Structural analysis of the YqeY proteins from Campylobacter jejuni and Vibrio parahaemolyticus. Biochem Biophys Res Commun 2024; 695:149485. [PMID: 38211535 DOI: 10.1016/j.bbrc.2024.149485] [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: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 01/13/2024]
Abstract
YqeY is a functionally and structurally uncharacterized protein that is ubiquitously expressed in bacteria. To gain structural insights into the function of YqeY, we determined the crystal structures of the Campylobacter jejuni and Vibrio parahaemolyticus YqeY proteins (cjYqeY and vpYqeY, respectively) and analyzed the structural and functional roles of conserved residues via a mutational study. Both cjYqeY and vpYqeY were found to adopt a two-domain structure consisting of an N-terminal four-α-helix domain and a C-terminal three-α-helix domain, with a relatively flexible interdomain orientation. The YqeY structure is unique in its linkage of the two α-helix domains although the C-terminal YqeY domain is structurally homologous to the terminal appendages of glutaminyl-tRNA synthetase and tRNA-dependent amidotransferase. We identified six conserved YqeY residues (Y67, R72, E82, Y89, P91, and G119) and evaluated their roles in protein stability via alanine mutation using a thermal shift assay. Residues Y67, R72, Y89, and P91 were shown to be required to maintain the structural integrity of YqeY. In contrast, residues E82 and G119 were not found to be essential for protein stability and are highly likely to contribute to the biological function of YqeY.
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Affiliation(s)
- Seung Yeon Kim
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Sung-Il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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4
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Abstract
Most bacteria employ a two-step indirect tRNA aminoacylation pathway for the synthesis of aminoacylated tRNAGln and tRNAAsn. The heterotrimeric enzyme GatCAB performs a critical amidotransferase reaction in the second step of this pathway. We have previously demonstrated in mycobacteria that this two-step pathway is error prone and translational errors contribute to adaptive phenotypes such as antibiotic tolerance. Furthermore, we identified clinical isolates of the globally important pathogen Mycobacterium tuberculosis with partial loss-of-function mutations in gatA, and demonstrated that these mutations result in high, specific rates of translational error and increased rifampin tolerance. However, the mechanisms by which these clinically derived mutations in gatA impact GatCAB function were unknown. Here, we describe biochemical and biophysical characterization of M. tuberculosis GatCAB, containing either wild-type gatA or one of two gatA mutants from clinical strains. We show that these mutations have minimal impact on enzymatic activity of GatCAB; however, they result in destabilization of the GatCAB complex as well as that of the ternary asparaginyl-transamidosome. Stabilizing complex formation with the solute trehalose increases specific translational fidelity of not only the mutant strains but also of wild-type mycobacteria. Therefore, our data suggest that alteration of GatCAB stability may be a mechanism for modulation of translational fidelity. IMPORTANCE Most bacteria use a two-step indirect pathway to aminoacylate tRNAGln and tRNAAsn, despite the fact that the indirect pathway consumes more energy and is error prone. We have previously shown that the higher protein synthesis errors from this indirect pathway in mycobacteria allow adaptation to hostile environments such as antibiotic treatment through generation of novel alternate proteins not coded by the genome. However, the precise mechanisms of how translational fidelity is tuned were not known. Here, we biochemically and biophysically characterize the critical enzyme of the Mycobacterium tuberculosis indirect pathway, GatCAB, as well as two mutant enzymes previously identified from clinical isolates that were associated with increased mistranslation. We show that the mutants dysregulate the pathway via destabilizing the enzyme complex. Importantly, increasing stability improves translational fidelity in both wild-type and mutant bacteria, demonstrating a mechanism by which mycobacteria may tune mistranslation rates.
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5
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Cai RJ, Su HW, Li YY, Javid B. Forward Genetics Reveals a gatC-gatA Fusion Polypeptide Causes Mistranslation and Rifampicin Tolerance in Mycobacterium smegmatis. Front Microbiol 2020; 11:577756. [PMID: 33072044 PMCID: PMC7541841 DOI: 10.3389/fmicb.2020.577756] [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: 06/29/2020] [Accepted: 09/04/2020] [Indexed: 12/26/2022] Open
Abstract
Most bacteria, including mycobacteria, utilize a two-step indirect tRNA aminoacylation pathway to generate correctly aminoacylated glutaminyl and asparaginyl tRNAs. This involves an initial step in which a non-discriminatory aminoacyl tRNA synthetase misacylates the tRNA, followed by a second step in which the essential amidotransferase, GatCAB, amidates the misacylated tRNA to its correct, cognate form. It had been previously demonstrated that mutations in gatA can mediate increased error rates specifically of glutamine to glutamate or asparagine to aspartate in protein synthesis. However, the role of mutations in gatB or gatC in mediating mistranslation are unknown. Here, we applied a forward genetic screen to enrich for mistranslating mutants of Mycobacterium smegmatis. The majority (57/67) of mutants had mutations in one of the gatCAB genes. Intriguingly, the most common mutation identified was an insertion in the 3' of gatC, abolishing its stop codon, and resulting in a fused GatC-GatA polypeptide. Modeling the effect of the fusion on GatCAB structure suggested a disruption of the interaction of GatB with the CCA-tail of the misacylated tRNA, suggesting a potential mechanism by which this mutation may mediate increased translational errors. Furthermore, we confirm that the majority of mutations in gatCAB that result in increased mistranslation also cause increased tolerance to rifampicin, although there was not a perfect correlation between mistranslation rates and degree of tolerance. Overall, our study identifies that mutations in all three gatCAB genes can mediate adaptive mistranslation and that mycobacteria are extremely tolerant to perturbation in the indirect tRNA aminoacylation pathway.
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Affiliation(s)
- Rong-Jun Cai
- Centre for Global Health and Infectious Diseases, Collaborative Innovation Centre for the Diagnosis and Treatment of Infectious Diseases, Tsinghua University School of Medicine, Beijing, China
| | - Hong-Wei Su
- Centre for Global Health and Infectious Diseases, Collaborative Innovation Centre for the Diagnosis and Treatment of Infectious Diseases, Tsinghua University School of Medicine, Beijing, China
| | - Yang-Yang Li
- Centre for Global Health and Infectious Diseases, Collaborative Innovation Centre for the Diagnosis and Treatment of Infectious Diseases, Tsinghua University School of Medicine, Beijing, China
| | - Babak Javid
- Centre for Global Health and Infectious Diseases, Collaborative Innovation Centre for the Diagnosis and Treatment of Infectious Diseases, Tsinghua University School of Medicine, Beijing, China.,Beijing Advanced Innovation Center in Structural Biology, Beijing, China.,Division of Experimental Medicine, University of California, San Francisco, San Francisco, CA, United States
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6
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Li L, Adachi M, Yu J, Kato K, Shinoda A, Ostermann A, Schrader TE, Ose T, Yao M. Neutron crystallographic study of heterotrimeric glutamine amidotransferase CAB. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2019; 75:193-196. [PMID: 30839294 DOI: 10.1107/s2053230x19000220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 01/05/2019] [Indexed: 11/10/2022]
Abstract
Heterotrimeric glutamine amidotransferase CAB (GatCAB) possesses an ammonia-self-sufficient mechanism in which ammonia is produced and used in the inner complex by GatA and GatB, respectively. The X-ray structure of GatCAB revealed that the two identified active sites of GatA and GatB are markedly distant, but are connected in the complex by a channel of 30 Å in length. In order to clarify whether ammonia is transferred through this channel in GatCAB by visualizing ammonia, neutron diffraction studies are indispensable. Here, GatCAB crystals were grown to approximate dimensions of 2.8 × 0.8 × 0.8 mm (a volume of 1.8 mm3) with the aid of a polymer using microseeding and macroseeding processes. Monochromatic neutron diffraction data were collected using the neutron single-crystal diffractometer BIODIFF at the Heinz Maier-Leibnitz Zentrum, Germany. The GatCAB crystals belonged to space group P212121, with unit-cell parameters a = 74.6, b = 94.5, c = 182.5 Å and with one GatCAB complex (molecular mass 119 kDa) in the asymmetric unit. This study represented a challenge in current neutron diffraction technology.
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Affiliation(s)
- Long Li
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Motoyasu Adachi
- National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Jian Yu
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Koji Kato
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Akira Shinoda
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Andreas Ostermann
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstrasse 1, 85748 Garching, Germany
| | - Tobias E Schrader
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstrasse 1, 85748 Garching, Germany
| | - Toyoyuki Ose
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Min Yao
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
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7
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Friederich MW, Timal S, Powell CA, Dallabona C, Kurolap A, Palacios-Zambrano S, Bratkovic D, Derks TGJ, Bick D, Bouman K, Chatfield KC, Damouny-Naoum N, Dishop MK, Falik-Zaccai TC, Fares F, Fedida A, Ferrero I, Gallagher RC, Garesse R, Gilberti M, González C, Gowan K, Habib C, Halligan RK, Kalfon L, Knight K, Lefeber D, Mamblona L, Mandel H, Mory A, Ottoson J, Paperna T, Pruijn GJM, Rebelo-Guiomar PF, Saada A, Sainz B, Salvemini H, Schoots MH, Smeitink JA, Szukszto MJ, Ter Horst HJ, van den Brandt F, van Spronsen FJ, Veltman JA, Wartchow E, Wintjes LT, Zohar Y, Fernández-Moreno MA, Baris HN, Donnini C, Minczuk M, Rodenburg RJ, Van Hove JLK. Pathogenic variants in glutamyl-tRNA Gln amidotransferase subunits cause a lethal mitochondrial cardiomyopathy disorder. Nat Commun 2018; 9:4065. [PMID: 30283131 PMCID: PMC6170436 DOI: 10.1038/s41467-018-06250-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 08/23/2018] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial protein synthesis requires charging a mitochondrial tRNA with its amino acid. Here, the authors describe pathogenic variants in the GatCAB protein complex genes required for the generation of glutaminyl-mt-tRNAGln, that impairs mitochondrial translation and presents with cardiomyopathy. Mitochondrial protein synthesis requires charging mt-tRNAs with their cognate amino acids by mitochondrial aminoacyl-tRNA synthetases, with the exception of glutaminyl mt-tRNA (mt-tRNAGln). mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. Defects involving the mitochondrial protein synthesis machinery cause a broad spectrum of disorders, with often fatal outcome. Here, we describe nine patients from five families with genetic defects in a GatCAB complex subunit, including QRSL1, GATB, and GATC, each showing a lethal metabolic cardiomyopathy syndrome. Functional studies reveal combined respiratory chain enzyme deficiencies and mitochondrial dysfunction. Aminoacylation of mt-tRNAGln and mitochondrial protein translation are deficient in patients’ fibroblasts cultured in the absence of glutamine but restore in high glutamine. Lentiviral rescue experiments and modeling in S. cerevisiae homologs confirm pathogenicity. Our study completes a decade of investigations on mitochondrial aminoacylation disorders, starting with DARS2 and ending with the GatCAB complex.
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Affiliation(s)
- Marisa W Friederich
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, 80045, CO, USA
| | - Sharita Timal
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands.,Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Centre for Neuroscience, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Christopher A Powell
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 OXY, United Kingdom
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Alina Kurolap
- The Genetics Institute, Rambam Health Care Campus, Haifa, 3109601, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 3109601, Israel
| | - Sara Palacios-Zambrano
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, 28041, Spain
| | - Drago Bratkovic
- SA Pathology, Women and Children's Hospital Adelaide, Adelaide, 5006, Australia
| | - Terry G J Derks
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, 9700 RB, The Netherlands
| | - David Bick
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA
| | - Katelijne Bouman
- Department of Genetics, University Medical Center of Groningen, University of Groningen, Groningen, 9700 RB, The Netherlands
| | - Kathryn C Chatfield
- Department of Pediatrics, Section of Pediatric Cardiology, Children's Hospital Colorado, University of Colorado, Aurora, CO, 80045, USA
| | - Nadine Damouny-Naoum
- The Genetics Institute, Rambam Health Care Campus, Haifa, 3109601, Israel.,Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
| | - Megan K Dishop
- Department of Pathology, Children's Hospital Colorado, University of Colorado, Aurora, 80045, CO, USA
| | - Tzipora C Falik-Zaccai
- Institute of Human Genetics, Galilee Medical Center, Nahariya, 22100, Israel.,The Azrieli Faculty of Medicine in the Galilee, Bar Ilan University, Safed, 1311502, Israel
| | - Fuad Fares
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
| | - Ayalla Fedida
- Institute of Human Genetics, Galilee Medical Center, Nahariya, 22100, Israel.,The Azrieli Faculty of Medicine in the Galilee, Bar Ilan University, Safed, 1311502, Israel
| | - Ileana Ferrero
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Renata C Gallagher
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, 80045, CO, USA
| | - Rafael Garesse
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, 28041, Spain
| | - Micol Gilberti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Cristina González
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, 28041, Spain
| | - Katherine Gowan
- Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora, CO, 80045, USA
| | - Clair Habib
- Department of Pediatrics, Bnai Zion Medical Center, Haifa, 3339419, Israel
| | - Rebecca K Halligan
- SA Pathology, Women and Children's Hospital Adelaide, Adelaide, 5006, Australia
| | - Limor Kalfon
- Institute of Human Genetics, Galilee Medical Center, Nahariya, 22100, Israel
| | - Kaz Knight
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, 80045, CO, USA
| | - Dirk Lefeber
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Centre for Neuroscience, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Laura Mamblona
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, 28041, Spain
| | - Hanna Mandel
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 3109601, Israel.,Institute of Human Genetics, Galilee Medical Center, Nahariya, 22100, Israel.,Metabolic Unit, Rambam Health Care Campus, Haifa, 3109601, Israel
| | - Adi Mory
- The Genetics Institute, Rambam Health Care Campus, Haifa, 3109601, Israel
| | - John Ottoson
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, 80045, CO, USA
| | - Tamar Paperna
- The Genetics Institute, Rambam Health Care Campus, Haifa, 3109601, Israel
| | - Ger J M Pruijn
- Department of Biomolecular Chemistry, Institute for Molecules and Materials, Radboud University, Nijmegen, 6500 HB, The Netherlands
| | - Pedro F Rebelo-Guiomar
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 OXY, United Kingdom.,Graduate Program in Areas of Basic and Applied Biology (GABBA), University of Porto, Porto, 4200-135, Portugal
| | - Ann Saada
- Monique and Jacques Roboh Department of Genetic Research and the Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, 91120, Israel
| | - Bruno Sainz
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Enfermedades Crónicas y Cáncer Area, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, 28034, Spain
| | - Hayley Salvemini
- SA Pathology, Women and Children's Hospital Adelaide, Adelaide, 5006, Australia
| | - Mirthe H Schoots
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands
| | - Jan A Smeitink
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Maciej J Szukszto
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 OXY, United Kingdom
| | - Hendrik J Ter Horst
- Division of Neonatology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, 9700 RB, The Netherlands
| | - Frans van den Brandt
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Francjan J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, 9700 RB, The Netherlands
| | - Joris A Veltman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Centre for Neuroscience, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands.,Institute of Genetic Medicine, Newcastle University, Newcastle, NE1 3BZ, United Kingdom
| | - Eric Wartchow
- Department of Pathology, Children's Hospital Colorado, University of Colorado, Aurora, 80045, CO, USA
| | - Liesbeth T Wintjes
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Yaniv Zohar
- Institute of Pathology, Rambam Health Care Campus, 3109601, Haifa, Israel
| | - Miguel A Fernández-Moreno
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER). Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, 28029, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, 28041, Spain
| | - Hagit N Baris
- The Genetics Institute, Rambam Health Care Campus, Haifa, 3109601, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 3109601, Israel
| | - Claudia Donnini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Michal Minczuk
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 OXY, United Kingdom
| | - Richard J Rodenburg
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Johan L K Van Hove
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, 80045, CO, USA.
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8
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Pham VH, Maaroufi H, Balg C, Blais SP, Messier N, Roy PH, Otis F, Voyer N, Lapointe J, Chênevert R. Inhibition ofHelicobacter pyloriGlu-tRNAGlnamidotransferase by novel analogues of the putative transamidation intermediate. FEBS Lett 2016; 590:3335-3345. [DOI: 10.1002/1873-3468.12380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Van Hau Pham
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie; Université Laval; Québec Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec Canada
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
| | - Halim Maaroufi
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec Canada
| | - Christian Balg
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
- Département de Chimie, Faculté des Sciences et de Génie; Université Laval; Québec Canada
| | - Sébastien P. Blais
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie; Université Laval; Québec Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec Canada
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
| | - Nancy Messier
- CHU de Québec; Centre de Recherche en Infectiologie; Université Laval; Québec Canada
| | - Paul H. Roy
- CHU de Québec; Centre de Recherche en Infectiologie; Université Laval; Québec Canada
| | - François Otis
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
- Département de Chimie, Faculté des Sciences et de Génie; Université Laval; Québec Canada
| | - Normand Voyer
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
- Département de Chimie, Faculté des Sciences et de Génie; Université Laval; Québec Canada
| | - Jacques Lapointe
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie; Université Laval; Québec Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec Canada
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
| | - Robert Chênevert
- The Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO); Université Laval; Québec Canada
- Département de Chimie, Faculté des Sciences et de Génie; Université Laval; Québec Canada
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9
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Pham VH, Maaroufi H, Levesque RC, Lapointe J. Cyclic peptides identified by phage display are competitive inhibitors of the tRNA-dependent amidotransferase of Helicobacter pylori. Peptides 2016; 79:8-15. [PMID: 26976271 DOI: 10.1016/j.peptides.2016.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 02/07/2023]
Abstract
In Helicobacter pylori, the heterotrimeric tRNA-dependent amidotransferase (GatCAB) is essential for protein biosynthesis because it catalyzes the conversion of misacylated Glu-tRNA(Gln) and Asp-tRNA(Asn) into Gln-tRNA(Gln) and Asn-tRNA(Asn), respectively. In this study, we used a phage library to identify peptide inhibitors of GatCAB. A library displaying loop-constrained heptapeptides was used to screen for phages binding to the purified GatCAB. To optimize the probability of obtaining competitive inhibitors of GatCAB with respect to its substrate Glu-tRNA(Gln), we used that purified substrate in the biopanning process of the phage-display technique to elute phages bound to GatCAB at the third round of the biopanning process. Among the eluted phages, we identified several that encode cyclic peptides rich in Trp and Pro that inhibit H. pylori GatCAB in vitro. Peptides P10 and P9 were shown to be competitive inhibitors of GatCAB with respect to its substrate Glu-tRNA(Gln), with Ki values of 126 and 392μM, respectively. The docking models revealed that the Trp residues of these peptides form π-π stacking interactions with Tyr81 of the synthetase active site, as does the 3'-terminal A76 of tRNA, supporting their competitive behavior with respect to Glu-tRNA(Gln) in the transamidation reaction. These peptides can be used as scaffolds in the search for novel antibiotics against the pathogenic bacteria that require GatCAB for Gln-tRNA(Gln) and/or Asn-tRNA(Asn) formation.
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Affiliation(s)
- Van Hau Pham
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec G1V 0A6, Canada; Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada; The Quebec Network for Research on Protein Function, Structure, and Engineering (PROTEO), Québec G1V 0A6, Canada.
| | - Halim Maaroufi
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - Roger C Levesque
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada; Département de Biologie Médicale, Faculté de Médicine, Université Laval, Québec G1V 0A6, Canada
| | - Jacques Lapointe
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec G1V 0A6, Canada; Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada; The Quebec Network for Research on Protein Function, Structure, and Engineering (PROTEO), Québec G1V 0A6, Canada.
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10
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Nair N, Raff H, Islam MT, Feen M, Garofalo DM, Sheppard K. The Bacillus subtilis and Bacillus halodurans Aspartyl-tRNA Synthetases Retain Recognition of tRNA(Asn). J Mol Biol 2016; 428:618-630. [PMID: 26804570 DOI: 10.1016/j.jmb.2016.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/13/2016] [Accepted: 01/13/2016] [Indexed: 12/19/2022]
Abstract
Synthesis of asparaginyl-tRNA (Asn-tRNA(Asn)) in bacteria can be formed either by directly ligating Asn to tRNA(Asn) using an asparaginyl-tRNA synthetase (AsnRS) or by synthesizing Asn on the tRNA. In the latter two-step indirect pathway, a non-discriminating aspartyl-tRNA synthetase (ND-AspRS) attaches Asp to tRNA(Asn) and the amidotransferase GatCAB transamidates the Asp to Asn on the tRNA. GatCAB can be similarly used for Gln-tRNA(Gln) formation. Most bacteria are predicted to use only one route for Asn-tRNA(Asn) formation. Given that Bacillus halodurans and Bacillus subtilis encode AsnRS for Asn-tRNA(Asn) formation and Asn synthetases to synthesize Asn and GatCAB for Gln-tRNA(Gln) synthesis, their AspRS enzymes were thought to be specific for tRNA(Asp). However, we demonstrate that the AspRSs are non-discriminating and can be used with GatCAB to synthesize Asn. The results explain why B. subtilis with its Asn synthetase genes knocked out is still an Asn prototroph. Our phylogenetic analysis suggests that this may be common among Firmicutes and 30% of all bacteria. In addition, the phylogeny revealed that discrimination toward tRNA(Asp) by AspRS has evolved independently multiple times. The retention of the indirect pathway in B. subtilis and B. halodurans likely reflects the ancient link between Asn biosynthesis and its use in translation that enabled Asn to be added to the genetic code.
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Affiliation(s)
- Nilendra Nair
- Chemistry Department, Skidmore College, Saratoga Springs, NY 12866, USA
| | - Hannah Raff
- Chemistry Department, Skidmore College, Saratoga Springs, NY 12866, USA
| | | | - Melanie Feen
- Chemistry Department, Skidmore College, Saratoga Springs, NY 12866, USA
| | - Denise M Garofalo
- Chemistry Department, Skidmore College, Saratoga Springs, NY 12866, USA
| | - Kelly Sheppard
- Chemistry Department, Skidmore College, Saratoga Springs, NY 12866, USA.
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11
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Mailu BM, Li L, Arthur J, Nelson TM, Ramasamy G, Fritz-Wolf K, Becker K, Gardner MJ. Plasmodium Apicoplast Gln-tRNAGln Biosynthesis Utilizes a Unique GatAB Amidotransferase Essential for Erythrocytic Stage Parasites. J Biol Chem 2015; 290:29629-41. [PMID: 26318454 DOI: 10.1074/jbc.m115.655100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 01/25/2023] Open
Abstract
The malaria parasite Plasmodium falciparum apicoplast indirect aminoacylation pathway utilizes a non-discriminating glutamyl-tRNA synthetase to synthesize Glu-tRNA(Gln) and a glutaminyl-tRNA amidotransferase to convert Glu-tRNA(Gln) to Gln-tRNA(Gln). Here, we show that Plasmodium falciparum and other apicomplexans possess a unique heterodimeric glutamyl-tRNA amidotransferase consisting of GatA and GatB subunits (GatAB). We localized the P. falciparum GatA and GatB subunits to the apicoplast in blood stage parasites and demonstrated that recombinant GatAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln) in vitro. We demonstrate that the apicoplast GatAB-catalyzed reaction is essential to the parasite blood stages because we could not delete the Plasmodium berghei gene encoding GatA in blood stage parasites in vivo. A phylogenetic analysis placed the split between Plasmodium GatB, archaeal GatE, and bacterial GatB prior to the phylogenetic divide between bacteria and archaea. Moreover, Plasmodium GatA also appears to have emerged prior to the bacterial-archaeal phylogenetic divide. Thus, although GatAB is found in Plasmodium, it emerged prior to the phylogenetic separation of archaea and bacteria.
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Affiliation(s)
- Boniface M Mailu
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Ling Li
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Jen Arthur
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Todd M Nelson
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Gowthaman Ramasamy
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Karin Fritz-Wolf
- the Department of Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen 35392 Germany, and the Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Katja Becker
- the Department of Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen 35392 Germany, and
| | - Malcolm J Gardner
- From the Center for Infectious Disease Research, Seattle, Washington 98109, the Department of Global Health, University of Washington, Seattle, Washington 98195,
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12
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Dewage SW, Cisneros GA. Computational analysis of ammonia transfer along two intramolecular tunnels in Staphylococcus aureus glutamine-dependent amidotransferase (GatCAB). J Phys Chem B 2015; 119:3669-77. [PMID: 25654336 DOI: 10.1021/jp5123568] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Most bacteria and all archaea misacylate the tRNAs corresponding to Asn and Gln with Asp and Glu (Asp-tRNA(Asn) and Glu-tRNA(Gln)).The GatCAB enzyme of most bacteria converts misacylated Glu-tRNA(Gln) to Gln-tRNA(Gln) in order to enable the incorporation of glutamine during protein synthesis. The conversion process involves the intramolecular transfer of ammonia between two spatially separated active sites. This study presents a computational analysis of the two putative intramolecular tunnels that have been suggested to describe the ammonia transfer between the two active sites. Molecular dynamics simulations have been performed for wild-type GatCAB of S. aureus and its mutants: T175(A)V, K88(B)R, E125(B)D, and E125(B)Q. The two tunnels have been analyzed in terms of free energy of ammonia transfer along them. The probability of occurrence of each type of tunnel and the variation of the probability for wild-type GatCAB and its mutants is also discussed.
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Affiliation(s)
- Sajeewa Walimuni Dewage
- Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States
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13
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Structure of the Pseudomonas aeruginosa transamidosome reveals unique aspects of bacterial tRNA-dependent asparagine biosynthesis. Proc Natl Acad Sci U S A 2014; 112:382-7. [PMID: 25548166 DOI: 10.1073/pnas.1423314112] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many prokaryotes lack a tRNA synthetase to attach asparagine to its cognate tRNA(Asn), and instead synthesize asparagine from tRNA(Asn)-bound aspartate. This conversion involves two enzymes: a nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) that forms Asp-tRNA(Asn), and a heterotrimeric amidotransferase GatCAB that amidates Asp-tRNA(Asn) to form Asn-tRNA(Asn) for use in protein synthesis. ND-AspRS, GatCAB, and tRNA(Asn) may assemble in an ∼400-kDa complex, known as the Asn-transamidosome, which couples the two steps of asparagine biosynthesis in space and time to yield Asn-tRNA(Asn). We report the 3.7-Å resolution crystal structure of the Pseudomonas aeruginosa Asn-transamidosome, which represents the most common machinery for asparagine biosynthesis in bacteria. We show that, in contrast to a previously described archaeal-type transamidosome, a bacteria-specific GAD domain of ND-AspRS provokes a principally new architecture of the complex. Both tRNA(Asn) molecules in the transamidosome simultaneously serve as substrates and scaffolds for the complex assembly. This architecture rationalizes an elevated dynamic and a greater turnover of ND-AspRS within bacterial-type transamidosomes, and possibly may explain a different evolutionary pathway of GatCAB in organisms with bacterial-type vs. archaeal-type Asn-transamidosomes. Importantly, because the two-step pathway for Asn-tRNA(Asn) formation evolutionarily preceded the direct attachment of Asn to tRNA(Asn), our structure also may reflect the mechanism by which asparagine was initially added to the genetic code.
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14
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Ovchinnikov S, Kamisetty H, Baker D. Robust and accurate prediction of residue-residue interactions across protein interfaces using evolutionary information. eLife 2014; 3:e02030. [PMID: 24842992 PMCID: PMC4034769 DOI: 10.7554/elife.02030] [Citation(s) in RCA: 438] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Do the amino acid sequence identities of residues that make contact across protein interfaces covary during evolution? If so, such covariance could be used to predict contacts across interfaces and assemble models of biological complexes. We find that residue pairs identified using a pseudo-likelihood-based method to covary across protein–protein interfaces in the 50S ribosomal unit and 28 additional bacterial protein complexes with known structure are almost always in contact in the complex, provided that the number of aligned sequences is greater than the average length of the two proteins. We use this method to make subunit contact predictions for an additional 36 protein complexes with unknown structures, and present models based on these predictions for the tripartite ATP-independent periplasmic (TRAP) transporter, the tripartite efflux system, the pyruvate formate lyase-activating enzyme complex, and the methionine ABC transporter. DOI:http://dx.doi.org/10.7554/eLife.02030.001 Proteins are considered the ‘workhorse molecules’ of life and they are involved in virtually everything that cells do. Proteins are strings of amino acids that have folded into a specific three-dimensional shape. Proteins must have the correct shape to function properly, as they often work by binding to other proteins or molecules—much like a key fitting into a lock. Working out the structure of a protein can, therefore, provide major insights into how the protein does its job. Two or more proteins can bind together and form a complex to perform various tasks; and solving the structures of these complexes can be challenging, even if the structures of the protein subunits are known. Now, Ovchinnikov, Kamisetty, and Baker have developed a method for predicting which parts of the proteins make contact with each other in a two-protein complex. Different species can have copies of the same proteins; but a copy from one species might have different amino acids at certain positions when compared to a related copy from another species. As such, when pairs of interacting proteins from different species are compared, there will be many positions in the two proteins that vary. However, if the amino acid at a position in one protein (let's call it ‘X’) varies, and the amino acid at, say, position ‘Y’ in the other protein also varies such that for any given amino acid at position Y there is often a specific amino acid at position X; positions X and Y are said to ‘co-vary’. Ovchinnikov et al. noticed that when a pair of amino acids (one from each protein in a two-protein complex) co-varied, these two amino acids tended to make contact with each other at the protein–protein interface. Ovchinnikov et al. used the new method to make predictions about the protein–protein interfaces in 28 protein complexes found in bacteria, and also to make a prediction about the interface between protein subunits in the bacterial ribosome. When these predictions were checked against the actual structures, which were all known beforehand, they were found to be accurate if the number of copies of each protein being compared is greater than the average length of the two proteins. Ovchinnikov et al. went on to predict the amino acids on the protein–protein interfaces for another 36 bacterial protein complexes with unknown structures, and to present models for four larger complexes. The next challenge is to extend the method to protein complexes that are found only in eukaryotes (i.e., not in bacteria). Since the number of related copies for eukaryotic proteins tends to be smaller, there are fewer proteins to compare and it is therefore harder to detect ‘covariation’ when it occurs. DOI:http://dx.doi.org/10.7554/eLife.02030.002
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Affiliation(s)
- Sergey Ovchinnikov
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, United States Molecular and Cellular Biology Program, University of Washington, Seattle, United States
| | - Hetunandan Kamisetty
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, United States Facebook Inc., Seattle, United States
| | - David Baker
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, United States
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15
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Shanmugam R, Aklujkar M, Schäfer M, Reinhardt R, Nickel O, Reuter G, Lovley DR, Ehrenhofer-Murray A, Nellen W, Ankri S, Helm M, Jurkowski TP, Jeltsch A. The Dnmt2 RNA methyltransferase homolog of Geobacter sulfurreducens specifically methylates tRNA-Glu. Nucleic Acids Res 2014; 42:6487-96. [PMID: 24711368 PMCID: PMC4041430 DOI: 10.1093/nar/gku256] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Dnmt2 enzymes are conserved in eukaryotes, where they methylate C38 of tRNA-Asp with high activity. Here, the activity of one of the very few prokaryotic Dnmt2 homologs from Geobacter species (GsDnmt2) was investigated. GsDnmt2 was observed to methylate tRNA-Asp from flies and mice. Unexpectedly, it had only a weak activity toward its matching Geobacter tRNA-Asp, but methylated Geobacter tRNA-Glu with good activity. In agreement with this result, we show that tRNA-Glu is methylated in Geobacter while the methylation is absent in tRNA-Asp. The activities of Dnmt2 enzymes from Homo sapiens, Drosophila melanogaster, Schizosaccharomyces pombe and Dictyostelium discoideum for methylation of the Geobacter tRNA-Asp and tRNA-Glu were determined showing that all these Dnmt2s preferentially methylate tRNA-Asp. Hence, the GsDnmt2 enzyme has a swapped transfer ribonucleic acid (tRNA) specificity. By comparing the different tRNAs, a characteristic sequence pattern was identified in the variable loop of all preferred tRNA substrates. An exchange of two nucleotides in the variable loop of murine tRNA-Asp converted it to the corresponding variable loop of tRNA-Glu and led to a strong reduction of GsDnmt2 activity. Interestingly, the same loss of activity was observed with human DNMT2, indicating that the variable loop functions as a specificity determinant in tRNA recognition of Dnmt2 enzymes.
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Affiliation(s)
| | - Muktak Aklujkar
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | - Matthias Schäfer
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120 Heidelberg, Germany
| | | | - Olaf Nickel
- Institute of Biology, Developmental Genetics, Martin Luther University Halle, 06120 Halle, Germany
| | - Gunter Reuter
- Institute of Biology, Developmental Genetics, Martin Luther University Halle, 06120 Halle, Germany
| | - Derek R Lovley
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | | | - Wolfgang Nellen
- Department of Genetics, University of Kassel, 34132 Kassel, Germany
| | - Serge Ankri
- Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Tomasz P Jurkowski
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany
| | - Albert Jeltsch
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany
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16
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Araiso Y, Huot JL, Sekiguchi T, Frechin M, Fischer F, Enkler L, Senger B, Ishitani R, Becker HD, Nureki O. Crystal structure of Saccharomyces cerevisiae mitochondrial GatFAB reveals a novel subunit assembly in tRNA-dependent amidotransferases. Nucleic Acids Res 2014; 42:6052-63. [PMID: 24692665 PMCID: PMC4027206 DOI: 10.1093/nar/gku234] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Yeast mitochondrial Gln-mtRNAGln is synthesized by the transamidation of mischarged Glu-mtRNAGln by a non-canonical heterotrimeric tRNA-dependent amidotransferase (AdT). The GatA and GatB subunits of the yeast AdT (GatFAB) are well conserved among bacteria and eukaryota, but the GatF subunit is a fungi-specific ortholog of the GatC subunit found in all other known heterotrimeric AdTs (GatCAB). Here we report the crystal structure of yeast mitochondrial GatFAB at 2.0 Å resolution. The C-terminal region of GatF encircles the GatA–GatB interface in the same manner as GatC, but the N-terminal extension domain (NTD) of GatF forms several additional hydrophobic and hydrophilic interactions with GatA. NTD-deletion mutants displayed growth defects, but retained the ability to respire. Truncation of the NTD in purified mutants reduced glutaminase and transamidase activities when glutamine was used as the ammonia donor, but increased transamidase activity relative to the full-length enzyme when the donor was ammonium chloride. Our structure-based functional analyses suggest the NTD is a trans-acting scaffolding peptide for the GatA glutaminase active site. The positive surface charge and novel fold of the GatF–GatA interface, shown in this first crystal structure of an organellar AdT, stand in contrast with the more conventional, negatively charged bacterial AdTs described previously.
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Affiliation(s)
- Yuhei Araiso
- Unité Mixte de Recherche 7156 Génétique Moléculaire Génomique Microbiologie, Centre National de la Recherche Scientifique, Université de Strasbourg, F-67084 Strasbourg, France
| | - Jonathan L Huot
- Unité Mixte de Recherche 7156 Génétique Moléculaire Génomique Microbiologie, Centre National de la Recherche Scientifique, Université de Strasbourg, F-67084 Strasbourg, France
| | - Takuya Sekiguchi
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, 113-0033 Tokyo, Japan
| | - Mathieu Frechin
- Institute of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Frédéric Fischer
- Unité Propre de Recherche Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, F-67084 Strasbourg, France
| | - Ludovic Enkler
- Unité Mixte de Recherche 7156 Génétique Moléculaire Génomique Microbiologie, Centre National de la Recherche Scientifique, Université de Strasbourg, F-67084 Strasbourg, France
| | - Bruno Senger
- Unité Mixte de Recherche 7156 Génétique Moléculaire Génomique Microbiologie, Centre National de la Recherche Scientifique, Université de Strasbourg, F-67084 Strasbourg, France
| | - Ryuichiro Ishitani
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, 113-0033 Tokyo, Japan
| | - Hubert D Becker
- Unité Mixte de Recherche 7156 Génétique Moléculaire Génomique Microbiologie, Centre National de la Recherche Scientifique, Université de Strasbourg, F-67084 Strasbourg, France
| | - Osamu Nureki
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, 113-0033 Tokyo, Japan
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17
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Mladenova SR, Stein KR, Bartlett L, Sheppard K. Relaxed tRNA specificity of theStaphylococcus aureusaspartyl-tRNA synthetase enables RNA-dependent asparagine biosynthesis. FEBS Lett 2014; 588:1808-12. [DOI: 10.1016/j.febslet.2014.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 10/25/2022]
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18
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Grant TD, Luft JR, Wolfley JR, Snell ME, Tsuruta H, Corretore S, Quartley E, Phizicky EM, Grayhack EJ, Snell EH. The structure of yeast glutaminyl-tRNA synthetase and modeling of its interaction with tRNA. J Mol Biol 2013; 425:2480-93. [PMID: 23583912 DOI: 10.1016/j.jmb.2013.03.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/25/2013] [Accepted: 03/30/2013] [Indexed: 11/26/2022]
Abstract
Eukaryotic glutaminyl-tRNA synthetase (GlnRS) contains an appended N-terminal domain (NTD) whose precise function is unknown. Although GlnRS structures from two prokaryotic species are known, no eukaryotic GlnRS structure has been reported. Here we present the first crystallographic structure of yeast GlnRS, finding that the structure of the C-terminal domain is highly similar to Escherichia coli GlnRS but that 214 residues, including the NTD, are crystallographically disordered. We present a model of the full-length enzyme in solution, using the structures of the C-terminal domain, and the isolated NTD, with small-angle X-ray scattering data of the full-length molecule. We proceed to model the enzyme bound to tRNA, using the crystallographic structures of GatCAB and GlnRS-tRNA complex from bacteria. We contrast the tRNA-bound model with the tRNA-free solution state and perform molecular dynamics on the full-length GlnRS-tRNA complex, which suggests that tRNA binding involves the motion of a conserved hinge in the NTD.
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Affiliation(s)
- Thomas D Grant
- Hauptman Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
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Kang J, Kuroyanagi S, Akisada T, Hagiwara Y, Tateno M. Unidirectional Mechanistic Valved Mechanisms for Ammonia Transport in GatCAB. J Chem Theory Comput 2012; 8:649-60. [PMID: 26596613 DOI: 10.1021/ct200387u] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glutamine amidotransferase CAB (GatCAB), a crucial enzyme involved in translational fidelity, catalyzes three reactions: (i) the glutaminase reaction to yield ammonia (NH3 or NH4(+)) from glutamine, (ii) the phosphorylation of Glu-tRNA(Gln), and (iii) the transamidase reaction to convert the phosphorylated Glu-tRNA(Gln) to Gln-tRNA(Gln). In the crystal structure of GatCAB, the two catalytic centers are far apart, and the presence of a hydrophilic channel to transport the molecules produced by the reaction (i) was proposed. We investigated the transport mechanisms of GatCAB by molecular dynamics (MD) simulations and free energy (PMF) calculations. In the MD simulations (in total ∼1.1 μs), the entrance of the previously proposed channel is closed, as observed in the crystal structure. Instead, a novel hydrophobic channel has been identified in this study: Since the newly identified entrance opened and closed repeatedly in the MD simulations, it may act as a gate. The calculated free energy difference revealed the significant preference of the newly identified gate/channel for NH3 transport (∼10(4)-fold). In contrast, with respect to NH4(+), the free energy barriers are significantly increased for both channels due to tight hydrogen-bonding with hydrophilic residues, which hinders efficient transport. The opening of the newly identified gate is modulated by Phe206, which acts as a "valve". For the backward flow of NH3, our PMF calculation revealed that the opening of the gate is hindered by Ala207, which acts as a mechanistic "stopper" against the motion of the "valve" (Phe206). This is the first report to elucidate the detailed mechanisms of unidirectional mechanistic valved transport inside proteins.
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Affiliation(s)
- Jiyoung Kang
- Graduate School of Pure and Applied Sciences, University of Tsukuba , Tennodai 1-1-1, Tsukuba Science City, Ibaraki 305-8571, Japan
| | - Shigehide Kuroyanagi
- Graduate School of Pure and Applied Sciences, University of Tsukuba , Tennodai 1-1-1, Tsukuba Science City, Ibaraki 305-8571, Japan
| | - Tomohiro Akisada
- Graduate School of Life Science, University of Hyogo , 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yohsuke Hagiwara
- Graduate School of Pure and Applied Sciences, University of Tsukuba , Tennodai 1-1-1, Tsukuba Science City, Ibaraki 305-8571, Japan
| | - Masaru Tateno
- Graduate School of Life Science, University of Hyogo , 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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Grant TD, Snell EH, Luft JR, Quartley E, Corretore S, Wolfley JR, Snell ME, Hadd A, Perona JJ, Phizicky EM, Grayhack EJ. Structural conservation of an ancient tRNA sensor in eukaryotic glutaminyl-tRNA synthetase. Nucleic Acids Res 2011; 40:3723-31. [PMID: 22180531 PMCID: PMC3333875 DOI: 10.1093/nar/gkr1223] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In all organisms, aminoacyl tRNA synthetases covalently attach amino acids to their cognate tRNAs. Many eukaryotic tRNA synthetases have acquired appended domains, whose origin, structure and function are poorly understood. The N-terminal appended domain (NTD) of glutaminyl-tRNA synthetase (GlnRS) is intriguing since GlnRS is primarily a eukaryotic enzyme, whereas in other kingdoms Gln-tRNAGln is primarily synthesized by first forming Glu-tRNAGln, followed by conversion to Gln-tRNAGln by a tRNA-dependent amidotransferase. We report a functional and structural analysis of the NTD of Saccharomyces cerevisiae GlnRS, Gln4. Yeast mutants lacking the NTD exhibit growth defects, and Gln4 lacking the NTD has reduced complementarity for tRNAGln and glutamine. The 187-amino acid Gln4 NTD, crystallized and solved at 2.3 Å resolution, consists of two subdomains, each exhibiting an extraordinary structural resemblance to adjacent tRNA specificity-determining domains in the GatB subunit of the GatCAB amidotransferase, which forms Gln-tRNAGln. These subdomains are connected by an apparent hinge comprised of conserved residues. Mutation of these amino acids produces Gln4 variants with reduced affinity for tRNAGln, consistent with a hinge-closing mechanism proposed for GatB recognition of tRNA. Our results suggest a possible origin and function of the NTD that would link the phylogenetically diverse mechanisms of Gln-tRNAGln synthesis.
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Affiliation(s)
- Thomas D Grant
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
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Huot JL, Fischer F, Corbeil J, Madore E, Lorber B, Diss G, Hendrickson TL, Kern D, Lapointe J. Gln-tRNAGln synthesis in a dynamic transamidosome from Helicobacter pylori, where GluRS2 hydrolyzes excess Glu-tRNAGln. Nucleic Acids Res 2011; 39:9306-15. [PMID: 21813455 PMCID: PMC3241645 DOI: 10.1093/nar/gkr619] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In many bacteria and archaea, an ancestral pathway is used where asparagine and glutamine are formed from their acidic precursors while covalently linked to tRNAAsn and tRNAGln, respectively. Stable complexes formed by the enzymes of these indirect tRNA aminoacylation pathways are found in several thermophilic organisms, and are called transamidosomes. We describe here a transamidosome forming Gln-tRNAGln in Helicobacter pylori, an ε-proteobacterium pathogenic for humans; this transamidosome displays novel properties that may be characteristic of mesophilic organisms. This ternary complex containing the non-canonical GluRS2 specific for Glu-tRNAGln formation, the tRNA-dependent amidotransferase GatCAB and tRNAGln was characterized by dynamic light scattering. Moreover, we observed by interferometry a weak interaction between GluRS2 and GatCAB (KD = 40 ± 5 µM). The kinetics of Glu-tRNAGln and Gln-tRNAGln formation indicate that conformational shifts inside the transamidosome allow the tRNAGln acceptor stem to interact alternately with GluRS2 and GatCAB despite their common identity elements. The integrity of this dynamic transamidosome depends on a critical concentration of tRNAGln, above which it dissociates into separate GatCAB/tRNAGln and GluRS2/tRNAGln complexes. Ester bond protection assays show that both enzymes display a good affinity for tRNAGln regardless of its aminoacylation state, and support a mechanism where GluRS2 can hydrolyze excess Glu-tRNAGln, ensuring faithful decoding of Gln codons.
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Affiliation(s)
- Jonathan L Huot
- Département de Biochimie, de Microbiologie et de Bio-informatique, PROTEO et IBIS, Université Laval, 1045 av de la Médecine, Québec, Québec, Canada
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22
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Ito T, Yokoyama S. Two enzymes bound to one transfer RNA assume alternative conformations for consecutive reactions. Nature 2010; 467:612-6. [PMID: 20882017 DOI: 10.1038/nature09411] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/30/2010] [Indexed: 11/09/2022]
Abstract
In most bacteria and all archaea, glutamyl-tRNA synthetase (GluRS) glutamylates both tRNA(Glu) and tRNA(Gln), and then Glu-tRNA(Gln) is selectively converted to Gln-tRNA(Gln) by a tRNA-dependent amidotransferase. The mechanisms by which the two enzymes recognize their substrate tRNA(s), and how they cooperate with each other in Gln-tRNA(Gln) synthesis, remain to be determined. Here we report the formation of the 'glutamine transamidosome' from the bacterium Thermotoga maritima, consisting of tRNA(Gln), GluRS and the heterotrimeric amidotransferase GatCAB, and its crystal structure at 3.35 A resolution. The anticodon-binding body of GluRS recognizes the common features of tRNA(Gln) and tRNA(Glu), whereas the tail body of GatCAB recognizes the outer corner of the L-shaped tRNA(Gln) in a tRNA(Gln)-specific manner. GluRS is in the productive form, as its catalytic body binds to the amino-acid-acceptor arm of tRNA(Gln). In contrast, GatCAB is in the non-productive form: the catalytic body of GatCAB contacts that of GluRS and is located near the acceptor stem of tRNA(Gln), in an appropriate site to wait for the completion of Glu-tRNA(Gln) formation by GluRS. We identified the hinges between the catalytic and anticodon-binding bodies of GluRS and between the catalytic and tail bodies of GatCAB, which allow both GluRS and GatCAB to adopt the productive and non-productive forms. The catalytic bodies of the two enzymes compete for the acceptor arm of tRNA(Gln) and therefore cannot assume their productive forms simultaneously. The transition from the present glutamylation state, with the productive GluRS and the non-productive GatCAB, to the putative amidation state, with the non-productive GluRS and the productive GatCAB, requires an intermediate state with the two enzymes in their non-productive forms, for steric reasons. The proposed mechanism explains how the transamidosome efficiently performs the two consecutive steps of Gln-tRNA(Gln) formation, with a low risk of releasing the unstable intermediate Glu-tRNA(Gln).
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Affiliation(s)
- Takuhiro Ito
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Crystal structure of a transfer-ribonucleoprotein particle that promotes asparagine formation. EMBO J 2010; 29:3118-29. [PMID: 20717102 DOI: 10.1038/emboj.2010.192] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 07/15/2010] [Indexed: 11/08/2022] Open
Abstract
Four out of the 22 aminoacyl-tRNAs (aa-tRNAs) are systematically or alternatively synthesized by an indirect, two-step route requiring an initial mischarging of the tRNA followed by tRNA-dependent conversion of the non-cognate amino acid. During tRNA-dependent asparagine formation, tRNA(Asn) promotes assembly of a ribonucleoprotein particle called transamidosome that allows channelling of the aa-tRNA from non-discriminating aspartyl-tRNA synthetase active site to the GatCAB amidotransferase site. The crystal structure of the Thermus thermophilus transamidosome determined at 3 A resolution reveals a particle formed by two GatCABs, two dimeric ND-AspRSs and four tRNAs(Asn) molecules. In the complex, only two tRNAs are bound in a functional state, whereas the two other ones act as an RNA scaffold enabling release of the asparaginyl-tRNA(Asn) without dissociation of the complex. We propose that the crystal structure represents a transient state of the transamidation reaction. The transamidosome constitutes a transfer-ribonucleoprotein particle in which tRNAs serve the function of both substrate and structural foundation for a large molecular machine.
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Yuan J, Hohn MJ, Sherrer RL, Palioura S, Su D, Söll D. A tRNA-dependent cysteine biosynthesis enzyme recognizes the selenocysteine-specific tRNA in Escherichia coli. FEBS Lett 2010; 584:2857-61. [PMID: 20493852 DOI: 10.1016/j.febslet.2010.05.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 05/14/2010] [Accepted: 05/14/2010] [Indexed: 12/13/2022]
Abstract
The essential methanogen enzyme Sep-tRNA:Cys-tRNA synthase (SepCysS) converts O-phosphoseryl-tRNA(Cys) (Sep-tRNA(Cys)) into Cys-tRNA(Cys) in the presence of a sulfur donor. Likewise, Sep-tRNA:Sec-tRNA synthase converts O-phosphoseryl-tRNA(Sec) (Sep-tRNA(Sec)) to selenocysteinyl-tRNA(Sec) (Sec-tRNA(Sec)) using a selenium donor. While the Sep moiety of the aminoacyl-tRNA substrates is the same in both reactions, tRNA(Cys) and tRNA(Sec) differ greatly in sequence and structure. In an Escherichia coli genetic approach that tests for formate dehydrogenase activity in the absence of selenium donor we show that Sep-tRNA(Sec) is a substrate for SepCysS. Since Sec and Cys are the only active site amino acids known to sustain FDH activity, we conclude that SepCysS converts Sep-tRNA(Sec) to Cys-tRNA(Sec), and that Sep is crucial for SepCysS recognition.
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Affiliation(s)
- Jing Yuan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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Rampias T, Sheppard K, Söll D. The archaeal transamidosome for RNA-dependent glutamine biosynthesis. Nucleic Acids Res 2010; 38:5774-83. [PMID: 20457752 PMCID: PMC2943598 DOI: 10.1093/nar/gkq336] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Archaea make glutaminyl-tRNA (Gln-tRNAGln) in a two-step process; a non-discriminating glutamyl-tRNA synthetase (ND-GluRS) forms Glu-tRNAGln, while the heterodimeric amidotransferase GatDE converts this mischarged tRNA to Gln-tRNAGln. Many prokaryotes synthesize asparaginyl-tRNA (Asn-tRNAAsn) in a similar manner using a non-discriminating aspartyl-tRNA synthetase (ND-AspRS) and the heterotrimeric amidotransferase GatCAB. The transamidosome, a complex of tRNA synthetase, amidotransferase and tRNA, was first described for the latter system in Thermus thermophilus [Bailly, M., Blaise, M., Lorber, B., Becker, H.D. and Kern, D. (2007) The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis. Mol. Cell, 28, 228–239.]. Here, we show a similar complex for Gln-tRNAGln formation in Methanothermobacter thermautotrophicus that allows the mischarged Glu-tRNAGln made by the tRNA synthetase to be channeled to the amidotransferase. The association of archaeal ND-GluRS with GatDE (KD = 100 ± 22 nM) sequesters the tRNA synthetase for Gln-tRNAGln formation, with GatDE reducing the affinity of ND-GluRS for tRNAGlu by at least 13-fold. Unlike the T. thermophilus transamidosome, the archaeal complex does not require tRNA for its formation, is not stable through product (Gln-tRNAGln) formation, and has no major effect on the kinetics of tRNAGln glutamylation nor transamidation. The differences between the two transamidosomes may be a consequence of the fact that ND-GluRS is a class I aminoacyl-tRNA synthetase, while ND-AspRS belongs to the class II family.
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Affiliation(s)
- Theodoros Rampias
- Department of Molecular Biophysics and Biochemistry and Department of Chemistry, Yale University, New Haven, CT 06511, USA
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