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Troian EA, Maldonado HM, Chauhan U, Barth VC, Woychik NA. Mycobacterium abscessus VapC5 toxin potentiates evasion of antibiotic killing by ribosome overproduction and activation of multiple resistance pathways. Nat Commun 2023; 14:3705. [PMID: 37349306 PMCID: PMC10287673 DOI: 10.1038/s41467-023-38844-4] [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: 09/07/2021] [Accepted: 05/18/2023] [Indexed: 06/24/2023] Open
Abstract
Mycobacterium abscessus (Mab) infections are inexplicably intractable to clearing after aggressive and lengthy treatment regimens. Here we discovered that acquisition of a single toxin-antitoxin system enables Mab to activate a phenotypic switch that enhances survival upon treatment with current first-line antibiotics. This switch is tripped when the VapC5 toxin inactivates tRNASerCGA by cleavage at only one site within its anticodon, leading to growth arrest. Concomitant tRNASerCGA depletion then reprograms the transcriptome to favor synthesis of proteins naturally low in the cognate Ser UCG codon including the transcription factor WhiB7 and members of its regulon as well as the ribosomal protein family. This programmed stockpiling of ribosomes is predicted to override the efficacy of ribosome-targeting antibiotics while the growth arrest phenotype attenuates antibiotics targeting cell wall synthesis. In agreement, VapC5 increases Mab persister formation upon exposure to amikacin and the next-generation oxazolidinone tedizolid (both target ribosomes) or cefoxitin (inhibits cell wall synthesis). These findings expand the repertoire of genetic adaptations harnessed by Mab to survive assaults intended to eradicate it, as well as provide a much-needed framework for selection of shorter and more efficacious alternate treatment options for Mab infections using currently available antimicrobials whose targets are not confounded by VapC5.
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Affiliation(s)
- Eduardo A Troian
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Heather M Maldonado
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Unnati Chauhan
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Valdir C Barth
- Immunotherapy Laboratory, Basic Health Sciences Department, Federal University of Health Sciences of Porto Alegre (UFCSPA), R. Sarmento Leite, 245 - Centro Histórico, Porto Alegre, 90050-170, Brazil
| | - Nancy A Woychik
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA.
- Member, Rutgers Cancer Institute of New Jersey, Piscataway, NJ, USA.
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2
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Manole A, Efthymiou S, O'Connor E, Mendes MI, Jennings M, Maroofian R, Davagnanam I, Mankad K, Lopez MR, Salpietro V, Harripaul R, Badalato L, Walia J, Francklyn CS, Athanasiou-Fragkouli A, Sullivan R, Desai S, Baranano K, Zafar F, Rana N, Ilyas M, Horga A, Kara M, Mattioli F, Goldenberg A, Griffin H, Piton A, Henderson LB, Kara B, Aslanger AD, Raaphorst J, Pfundt R, Portier R, Shinawi M, Kirby A, Christensen KM, Wang L, Rosti RO, Paracha SA, Sarwar MT, Jenkins D, Ahmed J, Santoni FA, Ranza E, Iwaszkiewicz J, Cytrynbaum C, Weksberg R, Wentzensen IM, Guillen Sacoto MJ, Si Y, Telegrafi A, Andrews MV, Baldridge D, Gabriel H, Mohr J, Oehl-Jaschkowitz B, Debard S, Senger B, Fischer F, van Ravenwaaij C, Fock AJM, Stevens SJC, Bähler J, Nasar A, Mantovani JF, Manzur A, Sarkozy A, Smith DEC, Salomons GS, Ahmed ZM, Riazuddin S, Riazuddin S, Usmani MA, Seibt A, Ansar M, Antonarakis SE, Vincent JB, Ayub M, Grimmel M, Jelsig AM, Hjortshøj TD, Karstensen HG, Hummel M, Haack TB, Jamshidi Y, Distelmaier F, Horvath R, Gleeson JG, Becker H, Mandel JL, Koolen DA, Houlden H. De Novo and Bi-allelic Pathogenic Variants in NARS1 Cause Neurodevelopmental Delay Due to Toxic Gain-of-Function and Partial Loss-of-Function Effects. Am J Hum Genet 2020; 107:311-324. [PMID: 32738225 PMCID: PMC7413890 DOI: 10.1016/j.ajhg.2020.06.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/23/2020] [Indexed: 12/19/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are ubiquitous, ancient enzymes that charge amino acids to cognate tRNA molecules, the essential first step of protein translation. Here, we describe 32 individuals from 21 families, presenting with microcephaly, neurodevelopmental delay, seizures, peripheral neuropathy, and ataxia, with de novo heterozygous and bi-allelic mutations in asparaginyl-tRNA synthetase (NARS1). We demonstrate a reduction in NARS1 mRNA expression as well as in NARS1 enzyme levels and activity in both individual fibroblasts and induced neural progenitor cells (iNPCs). Molecular modeling of the recessive c.1633C>T (p.Arg545Cys) variant shows weaker spatial positioning and tRNA selectivity. We conclude that de novo and bi-allelic mutations in NARS1 are a significant cause of neurodevelopmental disease, where the mechanism for de novo variants could be toxic gain-of-function and for recessive variants, partial loss-of-function.
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Affiliation(s)
- Andreea Manole
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Emer O'Connor
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Marisa I Mendes
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology and Metabolism, Amsterdam, 1081 the Netherlands
| | - Matthew Jennings
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Indran Davagnanam
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital for Children, London, WC1N 3JH, UK
| | - Maria Rodriguez Lopez
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London (UCL), London, WC1E 6BT, UK
| | - Vincenzo Salpietro
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ricardo Harripaul
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, ON, M5T 1R8, Canada; Institute of Medical Science and Department of Psychiatry, University of Toronto, Toronto, ON, M5T 1R8, Canada
| | - Lauren Badalato
- Department of Pediatrics, Queen's University, Kingston, ON, K7L 2V7, Canada
| | - Jagdeep Walia
- Department of Pediatrics, Queen's University, Kingston, ON, K7L 2V7, Canada
| | - Christopher S Francklyn
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Alkyoni Athanasiou-Fragkouli
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Roisin Sullivan
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Sonal Desai
- Department of Neurology and Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Kristin Baranano
- Department of Neurology and Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Faisal Zafar
- Department of Pediatrics, Multan Hospital, Multan, 60000, Pakistan
| | - Nuzhat Rana
- Department of Pediatrics, Multan Hospital, Multan, 60000, Pakistan
| | | | - Alejandro Horga
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Majdi Kara
- Department of Pediatrics, Tripoli Children's Hospital, Tripoli, Libya
| | - Francesca Mattioli
- Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258, Illkirch, 67404, France
| | - Alice Goldenberg
- Département de Génétique, centre de référence anomalies du développement et syndromes malformatifs, CHU de Rouen, Inserm U1245, UNIROUEN, Normandie Université, Centre Normand de Génomique et de Médecine Personnalisée, Rouen, 76031, France
| | - Helen Griffin
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Amelie Piton
- Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258, Illkirch, 67404, France
| | | | | | | | - Joost Raaphorst
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands; Department of Neurology, Amsterdam Neuroscience Institute, Amsterdam University Medical Center, 1105AZ Amsterdam, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Ruben Portier
- Department of Neurology, Medisch Spectrum Twente, 7512KZ Enschede, the Netherlands
| | - Marwan Shinawi
- Department of Pediatrics, Divisions of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Amelia Kirby
- Division of Medical Genetics, SSM Health Cardinal Glennon Children's Hospital, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Katherine M Christensen
- Division of Medical Genetics, SSM Health Cardinal Glennon Children's Hospital, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Lu Wang
- Howard Hughes Medical Institute, University of California San Diego and Rady Children's Hospital, La Jolla, CA 92130, USA
| | - Rasim O Rosti
- Howard Hughes Medical Institute, University of California San Diego and Rady Children's Hospital, La Jolla, CA 92130, USA
| | - Sohail A Paracha
- Institute of Basic Medical Sciences, Khyber Medical University, 25100 Peshawar, Pakistan
| | - Muhammad T Sarwar
- Institute of Basic Medical Sciences, Khyber Medical University, 25100 Peshawar, Pakistan
| | - Dagan Jenkins
- Institute of Child Health, Guilford Street and Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children, London, WC1N 3JH, UK
| | - Jawad Ahmed
- Institute of Basic Medical Sciences, Khyber Medical University, 25100 Peshawar, Pakistan
| | - Federico A Santoni
- Department of Genetic Medicine and Development, University of Geneva, 1206 Geneva, Switzerland; Department of Endocrinology, Diabetes, and Metabolism, University Hospital of Lausanne, 1011 Lausanne, Switzerland
| | - Emmanuelle Ranza
- Department of Genetic Medicine and Development, University of Geneva, 1206 Geneva, Switzerland; Service of Genetic Medicine, University Hospitals of Geneva, 1205 Geneva, Switzerland; Medigenome, The Swiss Institute of Genomic Medicine, Geneva, CH-1207, Switzerland
| | - Justyna Iwaszkiewicz
- Swiss Institute of Bioinformatics, Molecular Modeling Group, Batiment Genopode, Unil Sorge, Lausanne, CH-1015, Switzerland
| | - Cheryl Cytrynbaum
- Hospital for Sick Children, Division of Clinical and Metabolic Genetics, 555 University Ave., Toronto, M5G 1X8, Canada
| | - Rosanna Weksberg
- Hospital for Sick Children, Division of Clinical and Metabolic Genetics, 555 University Ave., Toronto, M5G 1X8, Canada
| | | | | | - Yue Si
- GeneDx, 207 Perry Parkway Gaithersburg, MD 20877, USA
| | | | - Marisa V Andrews
- Department of Pediatrics, Divisions of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Dustin Baldridge
- Department of Pediatrics, Divisions of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Heinz Gabriel
- CeGaT GmbH and Praxis für Humangenetik Tuebingen, Tuebingen, 72076, Germany
| | - Julia Mohr
- CeGaT GmbH and Praxis für Humangenetik Tuebingen, Tuebingen, 72076, Germany
| | | | - Sylvain Debard
- University of Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, 67083, France
| | - Bruno Senger
- University of Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, 67083, France
| | - Frédéric Fischer
- University of Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, 67083, France
| | - Conny van Ravenwaaij
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, 9713, the Netherlands
| | - Annemarie J M Fock
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, 9713, the Netherlands
| | - Servi J C Stevens
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, 6211, the Netherlands
| | - Jürg Bähler
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London (UCL), London, WC1E 6BT, UK
| | - Amina Nasar
- Department of Pediatrics, Queen's University, Kingston, ON, K7L 2V7, Canada
| | - John F Mantovani
- Division of Child Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Adnan Manzur
- Institute of Child Health, Guilford Street and Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children, London, WC1N 3JH, UK
| | - Anna Sarkozy
- Institute of Child Health, Guilford Street and Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children, London, WC1N 3JH, UK
| | - Desirée E C Smith
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology and Metabolism, Amsterdam, 1081 the Netherlands
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology and Metabolism, Amsterdam, 1081 the Netherlands
| | - Zubair M Ahmed
- Department of Biochemistry and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Shaikh Riazuddin
- Jinnah Burn and Reconstructive Surgery Center, Allama Iqbal Medical College, University of Health Sciences, Lahore 54550, Pakistan
| | - Saima Riazuddin
- Department of Biochemistry and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Muhammad A Usmani
- Department of Biochemistry and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Annette Seibt
- Department of General Pediatrics, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Muhammad Ansar
- Department of Genetic Medicine and Development, University of Geneva, 1206 Geneva, Switzerland; Institute of Molecular and Clinical Ophthalmology Basel, Basel Switzerland
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva, 1206 Geneva, Switzerland; Service of Genetic Medicine, University Hospitals of Geneva, 1205 Geneva, Switzerland; iGE3 Institute of Genetics and Genomics of Geneva, 1211 Geneva, Switzerland
| | - John B Vincent
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, ON, M5T 1R8, Canada; Institute of Medical Science and Department of Psychiatry, University of Toronto, Toronto, ON, M5T 1R8, Canada
| | - Muhammad Ayub
- Department of Pediatrics, Queen's University, Kingston, ON, K7L 2V7, Canada
| | - Mona Grimmel
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany
| | - Anne Marie Jelsig
- Department of Clinical Genetics, University Hospital of Copenhagen, Rigshospitalet, 2100, Denmark
| | - Tina Duelund Hjortshøj
- Department of Clinical Genetics, University Hospital of Copenhagen, Rigshospitalet, 2100, Denmark
| | - Helena Gásdal Karstensen
- Department of Clinical Genetics, University Hospital of Copenhagen, Rigshospitalet, 2100, Denmark
| | - Marybeth Hummel
- Department of Pediatrics, Section of Medical Genetics, West Virginia University, Morgantown, WV 26506-9600, USA
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany; Centre for Rare Diseases, University of Tuebingen, 72076 Tübingen, Germany
| | - Yalda Jamshidi
- Genetics Centre, Molecular and Clinical Sciences Institute, St George's University of London, London, SW17 0RE, UK
| | - Felix Distelmaier
- Department of General Pediatrics, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Joseph G Gleeson
- Howard Hughes Medical Institute, University of California San Diego and Rady Children's Hospital, La Jolla, CA 92130, USA
| | - Hubert Becker
- University of Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, 67083, France
| | - Jean-Louis Mandel
- Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258, Illkirch, 67404, France
| | - David A Koolen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Henry Houlden
- Department of Neuromuscular Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
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Jurėnas D, Van Melderen L. The Variety in the Common Theme of Translation Inhibition by Type II Toxin-Antitoxin Systems. Front Genet 2020; 11:262. [PMID: 32362907 PMCID: PMC7180214 DOI: 10.3389/fgene.2020.00262] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
Type II Toxin-antitoxin (TA) modules are bacterial operons that encode a toxic protein and its antidote, which form a self-regulating genetic system. Antitoxins put a halter on toxins in many ways that distinguish different types of TA modules. In type II TA modules, toxin and antitoxin are proteins that form a complex which physically sequesters the toxin, thereby preventing its toxic activity. Type II toxins inhibit various cellular processes, however, the translation process appears to be their favorite target and nearly every step of this complex process is inhibited by type II toxins. The structural features, enzymatic activities and target specificities of the different toxin families are discussed. Finally, this review emphasizes that the structural folds presented by these toxins are not restricted to type II TA toxins or to one particular cellular target, and discusses why so many of them evolved to target translation as well as the recent developments regarding the role(s) of these systems in bacterial physiology and evolution.
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Affiliation(s)
- Dukas Jurėnas
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, Aix-Marseille Université, Marseille, France
| | - Laurence Van Melderen
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Gosselies, Belgium
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Nachiappan M, Jain V, Sharma A, Manickam Y, Jeyakanthan J. Conformational changes in glutaminyl-tRNA synthetases upon binding of the substrates and analogs using molecular docking and molecular dynamics approaches. J Biomol Struct Dyn 2019; 38:1575-1589. [PMID: 31084346 DOI: 10.1080/07391102.2019.1617787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are considered as important components in protein translation as they facilitate the attachment of specific transfer RNA (tRNA) to form aminoacyl-tRNAs. Our study focused on understanding the crystal structure of Glutaminyl-tRNA synthetase (GlnRS) from Thermus thermophilus HB8 (PDB ID:5ZDO) and mechanism of formation of enzyme-substrate complex using substrates and its analogs by applying molecular dynamics simulation (MDS) to investigate the conformational changes. Least energy structure of TtGlnRS was considered to dock the enzyme substrates such as glutamine (Gln), glutamic acid (Glu), adenosine monophosphate (AMP), adenosine triphosphate (ATP), QSI and various substrate analogs (2MA, 4SU and 5MU) onto the active site of the enzyme. We focused on comparative analysis of binding specificity between Gln and Glu; similarly, ATP and AMP. Active site organization as observed by MDS analysis showed interactive changes associated with substrate and catalytically important loops. Study found that when tRNAGln specific for GlnRS was docked into the active site of the TtGlnRS enzyme it interacts with 2' OH on the ribose acceptor end of the tRNA. Upon validation with 50 ns MDS, the maximum deviations and conformational changes of secondary structural elements were observed to be high in the loop regions of enzyme-substrate complexes. Binding affinity of ATP to TtGlnRS was further proved by isothermal titration calorimetry. AbbreviationsaaRSsaminoacyl-tRNA synthetasesAMPadenosine monophosphateATPadenosine triphosphateGlideGrid-based LIgand Docking with EnergeticGlnRSglutaminyl-tRNA synthetaseGRAVYGRand AVerage of hydropathicitYGROMACSGROingen Machine for Chemical SimulationsHADDOCKHigh Ambiguity Driven protein-protein DOCKingITCisothermal titration calorimetry2MA2-methyladenosine 5'-(dihydrogen phosphate)MDSmolecular dynamics simulation5MU5-methyluridine 5'-monophosphateNPTnumber of particles, pressure and temperatureNVTnumber of particles, volume and temperatureOPLS-AAoptimized potential for liquid simulation all atomPDBBrookhaven Protein DatabankPMEParticle-Mesh EwaldQSI5'-o-[n-(l-Glutaminyl)-sulfamoyl]adenosineRgradius of gyrationRMSDroot mean square deviationRMSFroot mean square fluctuation4SU4-thiouracil 5'-monophosphateSPCsimple point chargetRNAtransfer ribo nucleic acidTtThermus thermophilusXPextra precisionCommunicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mutharasappan Nachiappan
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, India
| | - Vitul Jain
- Molecular Medicine - Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Amit Sharma
- Molecular Medicine - Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Yogavel Manickam
- Molecular Medicine - Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Jeyaraman Jeyakanthan
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, India
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5
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Growth-regulating Mycobacterium tuberculosis VapC-mt4 toxin is an isoacceptor-specific tRNase. Nat Commun 2015; 6:7480. [PMID: 26158745 DOI: 10.1038/ncomms8480] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 05/13/2015] [Indexed: 11/09/2022] Open
Abstract
Toxin-antitoxin (TA) systems are implicated in the downregulation of bacterial cell growth associated with stress survival and latent tuberculosis infection, yet the activities and intracellular targets of these TA toxins are largely uncharacterized. Here, we use a specialized RNA-seq approach to identify targets of a Mycobacterium tuberculosis VapC TA toxin, VapC-mt4 (also known as VapC4), which have eluded detection using conventional approaches. Distinct from the one other characterized VapC toxin in M. tuberculosis that cuts 23S rRNA at the sarcin-ricin loop, VapC-mt4 selectively targets three of the 45 M. tuberculosis tRNAs (tRNA(Ala2), tRNA(Ser26) and tRNA(Ser24)) for cleavage at, or adjacent to, their anticodons, resulting in the generation of tRNA halves. While tRNA cleavage is sometimes enlisted as a bacterial host defense mechanism, VapC-mt4 instead alters specific tRNAs to inhibit translation and modulate growth. This stress-linked activity of VapC-mt4 mirrors basic features of eukaryotic tRNases that also generate tRNA halves and inhibit translation in response to stress.
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6
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Fagan CE, Maehigashi T, Dunkle JA, Miles SJ, Dunham CM. Structural insights into translational recoding by frameshift suppressor tRNASufJ. RNA (NEW YORK, N.Y.) 2014; 20:1944-54. [PMID: 25352689 PMCID: PMC4238358 DOI: 10.1261/rna.046953.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/02/2014] [Indexed: 05/25/2023]
Abstract
The three-nucleotide mRNA reading frame is tightly regulated during translation to ensure accurate protein expression. Translation errors that lead to aberrant protein production can result from the uncoupled movement of the tRNA in either the 5' or 3' direction on mRNA. Here, we report the biochemical and structural characterization of +1 frameshift suppressor tRNA(SufJ), a tRNA known to decode four, instead of three, nucleotides. Frameshift suppressor tRNA(SufJ) contains an insertion 5' to its anticodon, expanding the anticodon loop from seven to eight nucleotides. Our results indicate that the expansion of the anticodon loop of either ASL(SufJ) or tRNA(SufJ) does not affect its affinity for the A site of the ribosome. Structural analyses of both ASL(SufJ) and ASL(Thr) bound to the Thermus thermophilus 70S ribosome demonstrate both ASLs decode in the zero frame. Although the anticodon loop residues 34-37 are superimposable with canonical seven-nucleotide ASLs, the single C31.5 insertion between nucleotides 31 and 32 in ASL(SufJ) imposes a conformational change of the anticodon stem, that repositions and tilts the ASL toward the back of the A site. Further modeling analyses reveal that this tilting would cause a distortion in full-length A-site tRNA(SufJ) during tRNA selection and possibly impede gripping of the anticodon stem by 16S rRNA nucleotides in the P site. Together, these data implicate tRNA distortion as a major driver of noncanonical translation events such as frameshifting.
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MESH Headings
- Anticodon/genetics
- Anticodon/ultrastructure
- Crystallography, X-Ray
- Escherichia coli
- Genes, Suppressor
- Nucleic Acid Conformation
- Nucleotides/chemistry
- Nucleotides/genetics
- Protein Biosynthesis/genetics
- RNA, Messenger/genetics
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/ultrastructure
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/ultrastructure
- Ribosomes/genetics
- Thermus thermophilus/genetics
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Affiliation(s)
- Crystal E Fagan
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Tatsuya Maehigashi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Jack A Dunkle
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Stacey J Miles
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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7
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Nikolajewa S, Friedel M, Beyer A, Wilhelm T. THE NEW CLASSIFICATION SCHEME OF THE GENETIC CODE, ITS EARLY EVOLUTION, AND tRNA USAGE. J Bioinform Comput Biol 2011; 4:609-20. [PMID: 16819806 DOI: 10.1142/s0219720006001825] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 12/09/2005] [Accepted: 12/23/2005] [Indexed: 11/18/2022]
Abstract
We present a new classification scheme of the genetic code. In contrast to the standard form it clearly shows five codon symmetries: codon-anticodon, codon-reverse codon, and sense-antisense symmetry, as well as symmetries with respect to purine-pyrimidine (A versus G, U versus C) and keto-aminobase (G versus U, A versus C) exchanges. We study the number of tRNA genes of 16 archaea, 81 bacteria and 7 eucaryotes to analyze whether these symmetries are reflected in the corresponding tRNA usage patterns. Two features are especially striking: reverse stop codons do not have their own tRNAs (just one exception in human), and A** anticodons are significantly suppressed. Our classification scheme of the genetic code and the identified tRNA usage patterns support recent speculations about the early evolution of the genetic code. In particular, pre-tRNAs might have had the ability to bind their codons in two directions to the corresponding codons.
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Affiliation(s)
- Swetlana Nikolajewa
- Theoretical Systems Biology, Institute of Molecular Biotechnology Beutenbergstr, 11, Jena, D-07745, Germany
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8
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Gagnon MG, Boutorine YI, Steinberg SV. Recurrent RNA motifs as probes for studying RNA-protein interactions in the ribosome. Nucleic Acids Res 2010; 38:3441-53. [PMID: 20139416 PMCID: PMC2879513 DOI: 10.1093/nar/gkq031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To understand how the nucleotide sequence of ribosomal RNA determines its tertiary structure, we developed a new approach for identification of those features of rRNA sequence that are responsible for formation of different short- and long-range interactions. The approach is based on the co-analysis of several examples of a particular recurrent RNA motif. For different cases of the motif, we design combinatorial gene libraries in which equivalent nucleotide positions are randomized. Through in vivo expression of the designed libraries we select those variants that provide for functional ribosomes. Then, analysis of the nucleotide sequences of the selected clones would allow us to determine the sequence constraints imposed on each case of the motif. The constraints shared by all cases are interpreted as providing for the integrity of the motif, while those ones specific for individual cases would enable the motif to fit into the particular structural context. Here we demonstrate the validity of this approach for three examples of the so-called along-groove packing motif found in different parts of ribosomal RNA.
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Affiliation(s)
- Matthieu G Gagnon
- Département de Biochimie, Université de Montréal, Montréal, CP 6128, Succursale Centre-Ville, QC H3C 3J7, Canada
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9
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Shaul S, Berel D, Benjamini Y, Graur D. Revisiting the operational RNA code for amino acids: Ensemble attributes and their implications. RNA (NEW YORK, N.Y.) 2010; 16:141-153. [PMID: 19952117 PMCID: PMC2802024 DOI: 10.1261/rna.1745910] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 09/30/2009] [Indexed: 05/28/2023]
Abstract
It has been suggested that tRNA acceptor stems specify an operational RNA code for amino acids. In the last 20 years several attributes of the putative code have been elucidated for a small number of model organisms. To gain insight about the ensemble attributes of the code, we analyzed 4925 tRNA sequences from 102 bacterial and 21 archaeal species. Here, we used a classification and regression tree (CART) methodology, and we found that the degrees of degeneracy or specificity of the RNA codes in both Archaea and Bacteria differ from those of the genetic code. We found instances of taxon-specific alternative codes, i.e., identical acceptor stem determinants encrypting different amino acids in different species, as well as instances of ambiguity, i.e., identical acceptor stem determinants encrypting two or more amino acids in the same species. When partitioning the data by class of synthetase, the degree of code ambiguity was significantly reduced. In cryptographic terms, a plausible interpretation of this result is that the class distinction in synthetases is an essential part of the decryption rules for resolving the subset of RNA code ambiguities enciphered by identical acceptor stem determinants of tRNAs acylated by enzymes belonging to the two classes. In evolutionary terms, our findings lend support to the notion that in the pre-DNA world, interactions between tRNA acceptor stems and synthetases formed the basis for the distinction between the two classes; hence, ambiguities in the ancient RNA code were pivotal for the fixation of these enzymes in the genomes of ancestral prokaryotes.
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Affiliation(s)
- Shaul Shaul
- Department of Zoology, Tel Aviv University, Tel Aviv 69978, Israel
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10
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Computational analysis of tRNA identity. FEBS Lett 2009; 584:325-33. [PMID: 19944694 DOI: 10.1016/j.febslet.2009.11.084] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 11/20/2009] [Accepted: 11/20/2009] [Indexed: 11/22/2022]
Abstract
I review recent developments in computational analysis of tRNA identity. I suggest that the tRNA-protein interaction network is hierarchically organized, and coevolutionarily flexible. Its functional specificity of recognition and discrimination persists despite generic structural constraints and perturbative evolutionary forces. This flexibility comes from its arbitrary nature as a self-recognizing shape code. A revisualization of predicted Proteobacterial tRNA identity highlights open research problems. tRNA identity elements and their coevolution with proteins must be mapped structurally over the Tree of Life. These traits can also resolve deep roots in the Tree. I show that histidylation identity elements phylogenetically reposition Pelagibacter ubique within alpha-Proteobacteria.
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11
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Geslain R, Pan T. Functional analysis of human tRNA isodecoders. J Mol Biol 2009; 396:821-31. [PMID: 20026070 DOI: 10.1016/j.jmb.2009.12.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 12/02/2009] [Accepted: 12/10/2009] [Indexed: 11/16/2022]
Abstract
tRNA isodecoders share the same anticodon but have differences in their body sequence. An unexpected result from genome sequencing projects is the identification of a large number of tRNA isodecoder genes in mammalian genomes. In the reference human genome, more than 270 isodecoder genes are present among the approximately 450 tRNA genes distributed among 49 isoacceptor families. Whether sequence diversity among isodecoder tRNA genes reflects functional variability is an open question. To address this, we developed a method to quantify the efficiency of tRNA isodecoders in stop-codon suppression in human cell lines. First, a green fluorescent protein (GFP) gene that contains a single UAG stop codon at two distinct locations is introduced. GFP is only produced when a tRNA suppressor containing CUA anticodon is co-transfected with the GFP gene. The suppression efficiency is examined for 31 tRNA isodecoders (all contain CUA anticodon), 21 derived from four isoacceptor families of tRNASer genes, 7 from five families of tRNALeu genes, and 3 from three families of tRNAAla genes. We found that isodecoder tRNAs display a large difference in their suppression efficiency. Among those with above background suppression activity, differences of up to 20-fold were observed. We were able to tune tRNA suppression efficiency by subtly adjusting the tRNA sequence and inter-convert poor suppressors into potent ones. We also demonstrate that isodecoder tRNAs with varying suppression efficiencies have similar stability and exhibit similar levels of aminoacylation in vivo. Our results indicate that naturally occurring tRNA isodecoders can have large functional variations and suggest that some tRNA isodecoders may perform a function distinct from translation.
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Affiliation(s)
- Renaud Geslain
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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12
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A sequence element that tunes Escherichia coli tRNA(Ala)(GGC) to ensure accurate decoding. Nat Struct Mol Biol 2009; 16:359-64. [PMID: 19305403 PMCID: PMC2769084 DOI: 10.1038/nsmb.1581] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 02/20/2009] [Indexed: 11/08/2022]
Abstract
Mutating the rare A32-U38 nucleotide pair at the top of the anticodon loop of Escherichia coli tRNA(Ala)(GGC) to a more common U32-A38 pair results in a tRNA that performs almost normally on cognate codons but is unusually efficient in reading near-cognate codons. Pre-steady state kinetic measurements on E. coli ribosomes show that, unlike the wild-type tRNA(Ala)(GGC), the misreading mutant tRNA(Ala)(GGC) shows rapid GTP hydrolysis and no detectable proofreading on near-cognate codons. Similarly, tRNA(Ala)(GGC) mutated to contain C32-G38, a pair that is found in some bacterial tRNA(Ala)(GGC) sequences, was able to decode only the cognate codons, whereas tRNA(Ala)(GGC) containing a more common C32-A38 pair was able to decode all cognate and near-cognate codons tested. We propose that many of the phylogenetically conserved sequence elements present in each tRNA have evolved to suppress translation of near-cognate codons.
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13
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Ledoux S, Uhlenbeck OC. Different aa-tRNAs are selected uniformly on the ribosome. Mol Cell 2008; 31:114-23. [PMID: 18614050 DOI: 10.1016/j.molcel.2008.04.026] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 01/16/2008] [Accepted: 04/25/2008] [Indexed: 10/21/2022]
Abstract
Ten E. coli aminoacyl-tRNAs (aa-tRNAs) were assessed for their ability to decode cognate codons on E. coli ribosomes by using three assays that evaluate the key steps in the decoding pathway. Despite a wide variety of structural features, each aa-tRNA exhibited similar kinetic and thermodynamic properties in each assay. This surprising kinetic and thermodynamic uniformity is likely to reflect the importance of ribosome conformational changes in defining the rates and affinities of the decoding process as well as the evolutionary "tuning" of each aa-tRNA sequence to modify their individual interactions with the ribosome at each step.
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Affiliation(s)
- Sarah Ledoux
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA
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14
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Rodriguez EA, Lester HA, Dougherty DA. Improved amber and opal suppressor tRNAs for incorporation of unnatural amino acids in vivo. Part 1: minimizing misacylation. RNA (NEW YORK, N.Y.) 2007; 13:1703-14. [PMID: 17698638 PMCID: PMC1986802 DOI: 10.1261/rna.666807] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The incorporation of unnatural amino acids site-specifically is a valuable technique for structure-function studies, incorporation of biophysical probes, and determining protein-protein interactions. THG73 is an amber suppressor tRNA used extensively for the incorporation of >100 different residues in over 20 proteins, but under certain conditions THG73 is aminoacylated in vivo by endogenous aminoacyl-tRNA synthetase. Similar aminoacylation is seen with the Escherichia coli Asn amber suppressor tRNA, which has also been used to incorporate UAAs in many studies. We now find that the natural amino acid placed on THG73 is Gln. Since the E. coli GlnRS recognizes positions in the acceptor stem, we made several acceptor stem mutations in the second to fourth positions on THG73. All mutations reduce aminoacylation in vivo and allow for the selection of highly orthogonal tRNAs. To show the generality of these mutations, we created opal suppressor tRNAs that show less aminoacylation in Xenopus oocytes relative to THG73. We have created a library of Tetrahymena thermophila Gln amber suppressor tRNAs that will be useful for determining optimal suppressor tRNAs for use in other eukaryotic cells.
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Affiliation(s)
- Erik A Rodriguez
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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15
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Rodriguez EA, Lester HA, Dougherty DA. Improved amber and opal suppressor tRNAs for incorporation of unnatural amino acids in vivo. Part 2: evaluating suppression efficiency. RNA (NEW YORK, N.Y.) 2007; 13:1715-22. [PMID: 17698637 PMCID: PMC1986817 DOI: 10.1261/rna.667607] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The incorporation of unnatural amino acids into proteins is a valuable tool for addition of biophysical probes, bio-orthogonal functionalities, and photoreactive cross-linking agents, although these approaches often require quantities of protein that are difficult to access with chemically aminoacylated tRNAs. THG73 is an amber suppressor tRNA that has been used extensively, incorporating over 100 residues in 20 proteins. In vitro studies have shown that the Escherichia coli Asn amber suppressor (ENAS) suppresses better than THG73. However, we report here that ENAS suppresses with <26% of the efficiency of THG73 in Xenopus oocytes. We then tested the newly developed Tetrahymena thermophila Gln amber suppressor (TQAS) tRNA library, which contains mutations in the second to fourth positions of the acceptor stem. The acceptor stem mutations have no adverse effect on suppression efficiency and, in fact, can increase the suppression efficiency. Combining mutations causes an averaging of suppression efficiency, and increased suppression efficiency does not correlate with increased DeltaG of the acceptor stem. We created a T. thermophila opal suppressor, TQOpS', which shows approximately 50% suppression efficiency relative to THG73. The TQAS tRNA library, composed of functional suppressor tRNAs, has been created and will allow for screening in eukaryotic cells, where rapid analysis of large libraries is not feasible.
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Affiliation(s)
- Erik A Rodriguez
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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16
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Jakó É, Ittzés P, Szenes Á, Kun Á, Szathmáry E, Pál G. In silico detection of tRNA sequence features characteristic to aminoacyl-tRNA synthetase class membership. Nucleic Acids Res 2007; 35:5593-609. [PMID: 17704131 PMCID: PMC2018626 DOI: 10.1093/nar/gkm598] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aminoacyl tRNA synthetases (aaRS) are grouped into Class I and II based on primary and tertiary structure and enzyme properties suggesting two independent phylogenetic lineages. Analogously, tRNA molecules can also form two respective classes, based on the class membership of their corresponding aaRS. Although some aaRS–tRNA interactions are not extremely specific and require editing mechanisms to avoid misaminoacylation, most aaRS–tRNA interactions are rather stereospecific. Thus, class-specific aaRS features could be mirrored by class-specific tRNA features. However, previous investigations failed to detect conserved class-specific nucleotides. Here we introduce a discrete mathematical approach that evaluates not only class-specific ‘strictly present’, but also ‘strictly absent’ nucleotides. The disjoint subsets of these elements compose a unique partition, named extended consensus partition (ECP). By analyzing the ECP for both Class I and II tDNA sets from 50 (13 archaeal, 30 bacterial and 7 eukaryotic) species, we could demonstrate that class-specific tRNA sequence features do exist, although not in terms of strictly conserved nucleotides as it had previously been anticipated. This finding demonstrates that important information was hidden in tRNA sequences inaccessible for traditional statistical methods. The ECP analysis might contribute to the understanding of tRNA evolution and could enrich the sequence analysis tool repertoire.
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Affiliation(s)
- Éena Jakó
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Péter Ittzés
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Áron Szenes
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Ádám Kun
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Eörs Szathmáry
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Gábor Pál
- Theoretical Biology and Ecology Research Group of the Hungarian Academy of Sciences, Department of Plant Taxonomy and Ecology, eScience Regional Knowledge Center, at Eötvös Loránd University, Collegium Budapest, Institute for Advanced Study, Budapest, Hungary, Department of Biochemistry and Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Budapest, Hungary
- *To whom correspondence should be addressed. +36 1 2090555/8577+36 1 3812172
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17
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Vasil'eva IA, Moor NA. Interaction of aminoacyl-tRNA synthetases with tRNA: general principles and distinguishing characteristics of the high-molecular-weight substrate recognition. BIOCHEMISTRY (MOSCOW) 2007; 72:247-63. [PMID: 17447878 DOI: 10.1134/s0006297907030029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review summarizes results of numerous (mainly functional) studies that have been accumulated over recent years on the problem of tRNA recognition by aminoacyl-tRNA synthetases. Development and employment of approaches that use synthetic mutant and chimeric tRNAs have demonstrated general principles underlying highly specific interaction in different systems. The specificity of interaction is determined by a certain number of nucleotides and structural elements of tRNA (constituting the set of recognition elements or specificity determinants), which are characteristic of each pair. Crystallographic structures available for many systems provide the details of the molecular basis of selective interaction. Diversity and identity of biochemical functions of the recognition elements make substantial contribution to the specificity of such interactions.
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Affiliation(s)
- I A Vasil'eva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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18
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Lue SW, Kelley SO. A single residue in leucyl-tRNA synthetase affecting amino acid specificity and tRNA aminoacylation. Biochemistry 2007; 46:4466-72. [PMID: 17378584 PMCID: PMC2518062 DOI: 10.1021/bi0618215] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human mitochondrial leucyl-tRNA synthetase (hs mt LeuRS) achieves high aminoacylation fidelity without a functional editing active site, representing a rare example of a class I aminoacyl-tRNA synthetase (aaRS) that does not proofread its products. Previous studies demonstrated that the enzyme achieves high selectivity by using a more specific synthetic active site that is not prone to errors under physiological conditions. Interestingly, the synthetic active site of hs mt LeuRS displays a high degree of homology with prokaryotic, lower eukaryotic, and other mitochondrial LeuRSs that are less specific. However, there is one residue that differs between hs mt and Escherichia coli LeuRSs located on a flexible closing loop near the signature KMSKS motif. Here we describe studies indicating that this particular residue (K600 in hs mt LeuRS and L570 in E. coli LeuRS) strongly impacts aminoacylation in two ways: it affects both amino acid discrimination and transfer RNA (tRNA) binding. While this residue may not be in direct contact with the amino acid or tRNA substrate, substitutions of this position in both enzymes lead to altered catalytic efficiency and perturbations to the discrimination of leucine and isoleucine. In addition, tRNA recognition and aminoacylation is affected. These findings indicate that the conformation of the synthetic active site, modulated by this residue, may be coupled to specificity and provide new insights into the origins of selectivity without editing.
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Affiliation(s)
- Stanley W Lue
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
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19
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Konevega AL, Soboleva NG, Makhno VI, Peshekhonov AV, Katunin VI. Effect of modification of tRNA nucleotide 37 on the tRNA interaction with the A and P sites of the Escherichia coli 70S ribosome. Mol Biol 2006. [DOI: 10.1134/s0026893306040121] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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McClain WH. Surprising contribution to aminoacylation and translation of non-Watson-Crick pairs in tRNA. Proc Natl Acad Sci U S A 2006; 103:4570-5. [PMID: 16537400 PMCID: PMC1450212 DOI: 10.1073/pnas.0600592103] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecules of transfer RNA (tRNA) typically contain four stems composed of Watson-Crick (W-C) base pairs and infrequent mispairs such as G-U and A-C. The latter mispairs are fundamental units of RNA secondary structure found in nearly every class of RNA and are nearly isomorphic to W-C pairs. Therefore, they often substitute for G-C or A-U base pairs. The mispairs also have unique chemical, structural, and dynamic conformational properties, which can only be partially mimicked by W-C base pairs. Here, I characterize the identities and tasks of six mutant G-U and A-C mispairs in Escherichia coli tRNA(Gly) using genetic and bioinformatic tools and show that mispairs are significantly more important for aminoacylation and translation than previously realized. Mispairs boost aminoacylation and translation primarily because they activate tRNA by means of their conformational flexibility. The statistical preservation of the six mutant mispair sites across tRNA(Gly) in many organisms points to a fundamental structure-function signature within tRNA(Gly) with possible analogous missions in other RNAs.
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Affiliation(s)
- William H McClain
- Department of Bacteriology, University of Wisconsin, 420 Henry Mall, Madison, WI 53706-1569, USA.
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21
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Roy H, Ling J, Alfonzo J, Ibba M. Loss of editing activity during the evolution of mitochondrial phenylalanyl-tRNA synthetase. J Biol Chem 2005; 280:38186-92. [PMID: 16162501 DOI: 10.1074/jbc.m508281200] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accurate selection of amino acids is essential for faithful translation of the genetic code. Errors during amino acid selection are usually corrected by the editing activity of aminoacyl-tRNA synthetases such as phenylalanyl-tRNA synthetases (PheRS), which edit misactivated tyrosine. Comparison of cytosolic and mitochondrial PheRS from the yeast Saccharomyces cerevisiae suggested that the organellar protein might lack the editing activity. Yeast cytosolic PheRS was found to contain an editing site, which upon disruption abolished both cis and trans editing of Tyr-tRNA(Phe). Wild-type mitochondrial PheRS lacked cis and trans editing and could synthesize Tyr-tRNA(Phe), an activity enhanced in active site variants with improved tyrosine recognition. Possible trans editing was investigated in isolated mitochondrial extracts, but no such activity was detected. These data indicate that the mitochondrial protein synthesis machinery lacks the tyrosine proofreading activity characteristic of cytosolic translation. This difference between the mitochondria and the cytosol suggests that either organellar protein synthesis quality control is focused on another step or that translation in this compartment is inherently less accurate than in the cytosol.
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Affiliation(s)
- Hervé Roy
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210-1292, USA
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22
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Olejniczak M, Dale T, Fahlman RP, Uhlenbeck OC. Idiosyncratic tuning of tRNAs to achieve uniform ribosome binding. Nat Struct Mol Biol 2005; 12:788-93. [PMID: 16116437 DOI: 10.1038/nsmb978] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 07/22/2005] [Indexed: 11/09/2022]
Abstract
The binding of seven tRNA anticodons to their complementary codons on Escherichia coli ribosomes was substantially impaired, as compared with the binding of their natural tRNAs, when they were transplanted into tRNA(2)(Ala). An analysis of chimeras composed of tRNA(2)(Ala) and various amounts of either tRNA(3)(Gly) or tRNA(2)(Arg) indicates that the presence of the parental 32-38 nucleotide pair is sufficient to restore ribosome binding of the transplanted anticodons. Furthermore, mutagenesis of tRNA(2)(Ala) showed that its highly conserved A32-U38 pair serves to weaken ribosome affinity. We propose that this negative binding determinant is used to offset the very tight codon-anticodon interaction of tRNA(2)(Ala). This suggests that each tRNA sequence has coevolved with its anticodon to tune ribosome affinity to a value that is the same for all tRNAs.
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Affiliation(s)
- Mikołaj Olejniczak
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
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23
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Uter NT, Perona JJ. Long-range intramolecular signaling in a tRNA synthetase complex revealed by pre-steady-state kinetics. Proc Natl Acad Sci U S A 2004; 101:14396-401. [PMID: 15452355 PMCID: PMC521953 DOI: 10.1073/pnas.0404017101] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pre-steady-state kinetic studies of Escherichia coli glutaminyl-tRNA synthetase conclusively demonstrate the existence of long-distance pathways of communication through the protein-RNA complex. Measurements of aminoacyl-tRNA synthesis reveal a rapid burst of product formation followed by a slower linear increase corresponding to k(cat). Thus, a step after chemistry but before regeneration of active enzyme is rate-limiting for synthesis of Gln-tRNA(Gln). Single-turnover kinetics validates these observations, confirming that the rate of the chemical step for tRNA aminoacylation (k(chem)) exceeds the steady-state rate by nearly 10-fold. The concentration dependence of the single-turnover reaction further reveals that the glutamine K(d) is significantly higher than the steady-state K(m) value. The separation of binding from catalytic events by transient kinetics now allows precise interpretation of how alterations in tRNA structure affect the aminoacylation reaction. Mutation of U35 in the tRNA anticodon loop decreases k(chem) by 30-fold and weakens glutamine binding affinity by 20-fold, demonstrating that the active-site configuration depends on enzyme-tRNA contacts some 40 A distant. By contrast, mutation of the adjacent G36 has very small effects on k(chem) and K(d) for glutamine. Together with x-ray crystallographic data, these findings allow a comparative evaluation of alternative long-range signaling pathways and lay the groundwork for systematic exploration of how induced-fit conformational transitions may control substrate selection in this model enzyme-RNA complex.
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Affiliation(s)
- Nathan T Uter
- Interdepartmental Program in Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106, USA
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24
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Choi H, Gabriel K, Schneider J, Otten S, McClain WH. Recognition of acceptor-stem structure of tRNA(Asp) by Escherichia coli aspartyl-tRNA synthetase. RNA (NEW YORK, N.Y.) 2003; 9:386-393. [PMID: 12649491 PMCID: PMC1370406 DOI: 10.1261/rna.2139703] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2002] [Accepted: 12/16/2002] [Indexed: 05/23/2023]
Abstract
Protein-RNA recognition between aminoacyl-tRNA synthetases and tRNA is highly specific and essential for cell viability. We investigated the structure-function relationships involved in the interaction of the Escherichia coli tRNA(Asp) acceptor stem with aspartyl-tRNA synthetase. The goal was to isolate functionally active mutants and interpret them in terms of the crystal structure of the synthetase-tRNA(Asp) complex. Mutants were derived from Saccharomyces cerevisiae tRNA(Asp), which is inactive with E. coli aspartyl-tRNA synthetase, allowing a genetic selection of active tRNAs in a tRNA(Asp) knockout strain of E. coli. The mutants were obtained by directed mutagenesis or library selections that targeted the acceptor stem of the yeast tRNA(Asp) gene. The mutants provide a rich source of tRNA(Asp) sequences, which show that the sequence of the acceptor stem can be extensively altered while allowing the tRNA to retain substantial aminoacylation and cell-growth functions. The predominance of tRNA backbone-mediated interactions observed between the synthetase and the acceptor stem of the tRNA in the crystal and the mutability of the acceptor stem suggest that many of the corresponding wild-type bases are replaceable by alternative sequences, so long as they preserve the initial backbone structure of the tRNA. Backbone interactions emerge as an important functional component of the tRNA-synthetase interaction.
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Affiliation(s)
- Hyunsic Choi
- Department of Bacteriology, University of Wisconsin, Madison, Madison, Wisconsin 53706-1567, USA
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25
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Choi H, Otten S, Schneider J, McClain WH. Genetic perturbations of RNA reveal structure-based recognition in protein-RNA interaction. J Mol Biol 2002; 324:573-6. [PMID: 12460561 DOI: 10.1016/s0022-2836(02)01098-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Protein-RNA recognition is an essential foundation of cellular processes, yet much remains unknown about these important interactions. The recognition between aminoacyl-tRNA synthetases and their cognate tRNA substrates is highly specific and essential for cell viability, due to the necessity for accurate translation of the genetic code into protein sequences. We selected an active tRNA that is highly mutated in the recognition nucleotides of the acceptor stem region in the alanine system. The functional properties of this mutant and its secondary derivatives demonstrate that recognition cannot be reduced to isolated structural elements, but rather the amino acid acceptor stem is being recognized as a unit.
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MESH Headings
- Amino Acyl-tRNA Synthetases/chemistry
- Amino Acyl-tRNA Synthetases/genetics
- Amino Acyl-tRNA Synthetases/metabolism
- Bacterial Proteins/chemistry
- Bacterial Proteins/metabolism
- Escherichia coli/genetics
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Conformation
- Protein Structure, Secondary
- RNA/genetics
- RNA, Bacterial/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Structure-Activity Relationship
- Substrate Specificity
- Transformation, Bacterial
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Affiliation(s)
- Hyunsic Choi
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, E.B. Fred Hall, Madison, WI 53706-1567, USA
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26
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Abstract
Aminoacyl-tRNAs are substrates for translation and are pivotal in determining how the genetic code is interpreted as amino acids. The function of aminoacyl-tRNA synthesis is to precisely match amino acids with tRNAs containing the corresponding anticodon. This is primarily achieved by the direct attachment of an amino acid to the corresponding tRNA by an aminoacyl-tRNA synthetase, although intrinsic proofreading and extrinsic editing are also essential in several cases. Recent studies of aminoacyl-tRNA synthesis, mainly prompted by the advent of whole genome sequencing and the availability of a vast body of structural data, have led to an expanded and more detailed picture of how aminoacyl-tRNAs are synthesized. This article reviews current knowledge of the biochemical, structural, and evolutionary facets of aminoacyl-tRNA synthesis.
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Affiliation(s)
- M Ibba
- Center for Biomolecular Recognition, IMBG Laboratory B, The Panum Institute, DK-2200, Copenhagen N, Denmark.
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27
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Nissan TA, Perona JJ. Alternative designs for construction of the class II transfer RNA tertiary core. RNA (NEW YORK, N.Y.) 2000; 6:1585-1596. [PMID: 11105758 PMCID: PMC1370028 DOI: 10.1017/s1355838200001126] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The structural requirements for assembly of functional class II transfer RNA core regions have been examined by sequence analysis and tested by reconstruction of alternative folds into the tertiary domain of Escherichia coli tRNA(2)Gln. At least four distinct designs have been identified that permit stable folding and efficient synthetase recognition, as assessed by thermal melting profiles and glutaminylation kinetics. Although most large variable-arm tRNAs found in nature possess an enlarged D-loop, lack of this feature can be compensated for by insertion of nucleotides either 3' to the variable loop or within the short acceptor/D-stem connector region. Rare pyrimidines at nt 9 in the core region can be accommodated in the class II framework, but only if specific nucleotides are present either in the D-loop or 3' to the variable arm. Glutaminyl-tRNA synthetase requires one or two unpaired uridines 3' to the variable arm to efficiently aminoacylate several of the class II frameworks. Because there are no specific enzyme contacts in the tRNAGln core region, these data suggest that tRNA discrimination by GlnRS depends in part on indirect readout of RNA sequence information.
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Affiliation(s)
- T A Nissan
- Department of Chemistry and Biochemistry, and Interdepartmental Program in Biochemistry and Molecular Biology, University of California at Santa Barbara, 93106-9510, USA
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28
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Abstract
Transfer RNAs (tRNAs) are grouped into two classes based on the structure of their variable loop. In Escherichia coli, tRNAs from three isoaccepting groups are classified as type II. Leucine tRNAs comprise one such group. We used both in vivo and in vitro approaches to determine the nucleotides that are required for tRNA(Leu) function. In addition, to investigate the role of the tRNA fold, we compared the in vivo and in vitro characteristics of type I tRNA(Leu) variants with their type II counterparts.A minimum of six conserved tRNA(Leu) nucleotides were required to change the amino acid identity and recognition of a type II tRNA(Ser) amber suppressor from a serine to a leucine residue. Five of these nucleotides affect tRNA tertiary structure; the G15-C48 tertiary "Levitt base-pair" in tRNA(Ser) was changed to A15-U48; the number of nucleotides in the alpha and beta regions of the D-loop was changed to achieve the positioning of G18 and G19 that is found in all tRNA(Leu); a base was inserted at position 47n between the base-paired extra stem and the T-stem; in addition the G73 "discriminator" base of tRNA(Ser) was changed to A73. This minimally altered tRNA(Ser) exclusively inserted leucine residues and was an excellent in vitro substrate for LeuRS. In a parallel experiment, nucleotide substitutions were made in a glutamine-inserting type I tRNA (RNA(SerDelta); an amber suppressor in which the tRNA(Ser) type II extra-stem-loop is replaced by a consensus type I loop). This "type I" swap experiment was successful both in vivo and in vitro but required more nucleotide substitutions than did the type II swap. The type I and II swaps revealed differences in the contributions of the tRNA(Leu) acceptor stem base-pairs to tRNA(Leu) function: in the type I, but not the type II fold, leucine specificity was contingent on the presence of the tRNA(Leu) acceptor stem sequence. The type I and II tRNAs used in this study differed only in the sequence and structure of the variable loop. By altering this loop, and thereby possibly introducing subtle changes into the overall tRNA fold, it became possible to detect otherwise cryptic contributions of the acceptor stem sequence to recognition by LeuRS. Possible reasons for this effect are discussed.
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MESH Headings
- Amino Acyl-tRNA Synthetases/metabolism
- Anticodon/genetics
- Base Pairing/genetics
- Base Sequence
- Conserved Sequence/genetics
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Genes, Suppressor/genetics
- Genetic Engineering
- Glutamine/metabolism
- Kinetics
- Leucine/metabolism
- Mutation/genetics
- Nucleic Acid Conformation
- RNA, Transfer, Leu/chemistry
- RNA, Transfer, Leu/classification
- RNA, Transfer, Leu/genetics
- RNA, Transfer, Leu/metabolism
- RNA, Transfer, Ser/chemistry
- RNA, Transfer, Ser/classification
- RNA, Transfer, Ser/genetics
- RNA, Transfer, Ser/metabolism
- Serine/metabolism
- Structure-Activity Relationship
- Substrate Specificity
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29
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Chang KY, Varani G, Bhattacharya S, Choi H, McClain WH. Correlation of deformability at a tRNA recognition site and aminoacylation specificity. Proc Natl Acad Sci U S A 1999; 96:11764-9. [PMID: 10518524 PMCID: PMC18360 DOI: 10.1073/pnas.96.21.11764] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The fidelity of protein synthesis depends on specific tRNA aminoacylation by aminoacyl-tRNA synthetase enzymes, which in turn depends on the recognition of the identity of particular nucleotides and structural features in the substrate tRNA. These features generally reside within the acceptor helix, the anticodon stem-loop, and in some systems the variable pocket of the tRNA. In the alanine system, fidelity is ensured by a G.U wobble base pair located at the third position within the acceptor helix of alanine tRNA. We have investigated the activity of mutant alanine tRNAs to explore the mechanism of enzyme recognition. Here we show that the mismatched pair C-C is an excellent substitute for G.U in alanine-tRNA-knockout cells. A structural investigation by NMR spectroscopy of the C-C RNA acceptor end reveals that the two cytosines are intercalated into the helix, and that C-C exists in multiple conformations. Structural heterogeneity also is present in the wild-type G.U RNA, whereas inactive Watson-Crick helices are structurally rigid. The correlation between functional and structural data suggests that the G.U pair provides a distinctive structure and a point of deformability that allow the tRNA acceptor end to fit into the active site of the alanyl-tRNA synthetase. Fidelity is ensured because noncognate and inactive mutant tRNAs are bound in the active site in an incorrect conformation that reduces enzymatic activity.
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Affiliation(s)
- K Y Chang
- Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom
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30
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Auffinger P, Westhof E. Singly and bifurcated hydrogen-bonded base-pairs in tRNA anticodon hairpins and ribozymes. J Mol Biol 1999; 292:467-83. [PMID: 10497015 DOI: 10.1006/jmbi.1999.3080] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The tRNA anticodon loops always comprise seven nucleotides and is involved in many recognition processes with proteins and RNA fragments. We have investigated the nature and the possible interactions between the first (32) and last (38) residues of the loop on the basis of the available sequences and crystal structures. The data demonstrate the conservation of a bifurcated hydrogen bond interaction between residues 32 and 38, located at the stem/loop junction. This interaction leads to the formation of a non-canonical base-pair which is preserved in the known crystal structures of tRNA/synthetase complexes. Among the tRNA and tDNA sequences, 93 % of the 32.38 oppositions can be assigned to two families of isosteric base-pairs, one with a large (86 %) and the other with a much smaller (7 %) population. The remainder (7 %) of the oppositions have been assigned to a third family due to the lack of evidence for assigning them into the first two sets. In all families, the Y32.R38 base-pairs are not isosteric upon reversal (like the sheared G.A or wobble G.U pairs), explaining the strong conservation of a pyrimidine at position 32. Thus, the 32.38 interaction extends the sequence signature of the anticodon loop beyond the conserved U-turn at position 33 and the usually modified purine at position 37. A comparison with other loops containing both a singly hydrogen-bonded base-pair and a U-turn suggests that the 32.38 pair could be involved in the formation of a base triple with a residue in a ribosomal RNA component. It is also observed that two crystal structures of ribozymes (hammerhead and leadzyme) present similar base-pairs at the cleavage site.
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Affiliation(s)
- P Auffinger
- Modélisations et Simulations des Acides Nucléiques, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 rue René Descartes, Strasbourg Cedex, 67084, France
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31
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McClain WH, Jou YY, Bhattacharya S, Gabriel K, Schneider J. The reliability of in vivo structure-function analysis of tRNA aminoacylation. J Mol Biol 1999; 290:391-409. [PMID: 10390340 DOI: 10.1006/jmbi.1999.2884] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The G.U wobble base-pair in the acceptor helix of Escherichia coli tRNAAlais critical for aminoacylation by the alanine synthetase. Previous work by several groups probed the mechanism of enzyme recognition of G.U by a structure-function analysis of mutant tRNAs using either a cell assay (amber suppressor tRNA) or a test tube assay (phage T7 tRNA substrate and purified enzyme). However, the aminoacylation capacity of particular mutant tRNAs was about 10(4)-fold higher in the cell assay. This led us to scrutinize the cell assay to determine if any parameter exaggerates the extent of aminoacylation in mutants forming substantial amounts of alanyl-tRNAAla. In doing so, we have refined and developed experimental designs to analyze tRNA function. We examined the level of aminoacylation of amber suppressor tRNAAlawith respect to the method of isolating aminoacyl-tRNA, the rate of cell growth, the cellular levels of alanine synthetase and elongation factor TU (EF-Tu), the amount of tRNA and the characteristics of EF-Tu binding. Within the precision of our measurements, none of these parameters varied in a way that could significantly amplify cellular alanyl-tRNAAla. A key observation is that the extent of aminoacylation of tRNAAlawas independent of tRNAAlaconcentration over a 75-fold range. Therefore, the cellular assay of tRNAAlareflects the substrate quality of the molecule for formation of alanyl-tRNAAla. These experiments support the authenticity of the cellular assay and imply that a condition or factor present in the cell assay may be absent in the test tube assay.
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MESH Headings
- Acylation
- Alanine-tRNA Ligase/metabolism
- Base Sequence
- Blotting, Northern
- Escherichia coli/cytology
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Escherichia coli/growth & development
- Genes, Suppressor/genetics
- Guanosine Triphosphate/metabolism
- Lysine/analysis
- Mutation
- Peptide Elongation Factor Tu/metabolism
- Protein Binding
- RNA, Bacterial/genetics
- RNA, Bacterial/isolation & purification
- RNA, Bacterial/metabolism
- RNA, Transfer, Ala/genetics
- RNA, Transfer, Ala/isolation & purification
- RNA, Transfer, Ala/metabolism
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/isolation & purification
- RNA, Transfer, Amino Acyl/metabolism
- Reproducibility of Results
- Structure-Activity Relationship
- Suppression, Genetic
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Affiliation(s)
- W H McClain
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706-1567, USA.
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32
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McClain WH, Gabriel K, Bhattacharya S, Jou YY, Schneider J. Functional compensation by particular nucleotide substitutions of a critical G*U wobble base-pair during aminoacylation of transfer RNA. J Mol Biol 1999; 286:1025-32. [PMID: 10047479 DOI: 10.1006/jmbi.1999.2542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Expression of the genetic code depends on precise tRNA aminoacylation by cognate aminoacyl-tRNA synthetase enzymes. The G.U wobble base-pair in the acceptor helix of Escherichia coli alanine tRNA is the primary aminoacylation determinant of this molecule. Previous work on the process of synthetase recognition of the G.U pair showed that replacing G.U by a G.C Watson-Crick base-pair inactivates alanine acceptance by the tRNA, but that C.A and G.A wobble pair replacements preserve acceptance. Work by another group reported that the effects of a G.C replacement were reversed by a distal wobble base-pair in the anticodon helix. This result is potentially interesting because it suggests that distant regions in alanine tRNA are functionally coupled during synthetase recognition and more generally because recognition determinants of many other tRNAs lie in both the acceptor helix and anticodon helix region. Here, we have conducted an extensive in vivo analysis of the distal wobble pair in alanine tRNA and report that it does not behave like a compensating mutation. Restoration of alanine acceptance was not detected even when the synthetase enzyme was overproduced. We discuss the previous experimental evidence and suggest how the distal wobble pair was incorrectly analyzed. The available data indicate that all principal recognition determinants of alanine tRNA lie in the molecule's acceptor helix.
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Affiliation(s)
- W H McClain
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706-1567, USA.
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33
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Giegé R, Sissler M, Florentz C. Universal rules and idiosyncratic features in tRNA identity. Nucleic Acids Res 1998; 26:5017-35. [PMID: 9801296 PMCID: PMC147952 DOI: 10.1093/nar/26.22.5017] [Citation(s) in RCA: 599] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Correct expression of the genetic code at translation is directly correlated with tRNA identity. This survey describes the molecular signals in tRNAs that trigger specific aminoacylations. For most tRNAs, determinants are located at the two distal extremities: the anticodon loop and the amino acid accepting stem. In a few tRNAs, however, major identity signals are found in the core of the molecule. Identity elements have different strengths, often depend more on k cat effects than on K m effects and exhibit additive, cooperative or anti-cooperative interplay. Most determinants are in direct contact with cognate synthetases, and chemical groups on bases or ribose moieties that make functional interactions have been identified in several systems. Major determinants are conserved in evolution; however, the mechanisms by which they are expressed are species dependent. Recent studies show that alternate identity sets can be recognized by a single synthetase, and emphasize the importance of tRNA architecture and anti-determinants preventing false recognition. Identity rules apply to tRNA-like molecules and to minimalist tRNAs. Knowledge of these rules allows the manipulation of identity elements and engineering of tRNAs with switched, altered or multiple specificities.
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MESH Headings
- Amino Acyl-tRNA Synthetases/metabolism
- Evolution, Molecular
- Genetic Code
- Humans
- Kinetics
- Models, Molecular
- Nucleic Acid Conformation
- Protein Biosynthesis
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
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Affiliation(s)
- R Giegé
- Unité Propre de Recherche 9002, 'Structure des Macromolécules Biologiques et Mécanismes de Reconnaissance', Scientifique, 15 rue René Descartes, F-67084, Strasbourg Cedex, France.
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34
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Vörtler CS, Fedorova O, Persson T, Kutzke U, Eckstein F. Determination of 2'-hydroxyl and phosphate groups important for aminoacylation of Escherichia coli tRNAAsp: a nucleotide analogue interference study. RNA (NEW YORK, N.Y.) 1998; 4:1444-1454. [PMID: 9814764 PMCID: PMC1369716 DOI: 10.1017/s1355838298980967] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
2'-Deoxynucleoside 5'-a-thiotriphosphates have been incorporated randomly, replacing any of the four nucleotides separately and at a low level in Escherichia colitRNA(AsP)transcripts. After some tRNAs were charged with the cognate aminoacyl-tRNA synthetase and biotinylated, charged and uncharged tRNAs were separated by binding to Streptavidin. A comparison of the iodine cleavage pattern of charged and uncharged tRNAs indicated positions of 2'-deoxyphosphorothioate interference with charging. To separate the 2'-deoxy from the phosphorothioate effect, the same sequence of reactions was performed with the corresponding NTPalphaS. Several positions were identified with a 2'-deoxy or a phosphorothioate effect. tRNAs with single deoxy substitutions at the identified positions were prepared by enzymatic ligation of chemically synthesized halves. The kinetics of charging these tRNAs were determined. The 2'-deoxy effects identified by the interference assay were confirmed, showing a reduction in charging efficiency of between 2.5-6-fold, except for the terminal A76 with a 25-fold reduction. Inspection of the X-ray structure of the tRNA-synthetase complex showed consistency of most of these findings. Critical 2'-deoxy groups are localized mainly on the proposed contact surface with the synthetase or at the interface of the two tRNA domains. The same overall picture emerged for critical phosphorothioates. With the exception of 2'-deoxy-adenosine-containing tRNAs, multiple 2'-deoxy-substituted tRNAs, prepared by ligation of halves, showed a much larger reduction in charging efficiency than the mono-substituted tRNAs, indicating an additive effect.
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Affiliation(s)
- C S Vörtler
- Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany
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35
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Wolfson AD, Pleiss JA, Uhlenbeck OC. A new assay for tRNA aminoacylation kinetics. RNA (NEW YORK, N.Y.) 1998; 4:1019-23. [PMID: 9701292 PMCID: PMC1369678 DOI: 10.1017/s1355838298980700] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
An improved quantitative assay for tRNA aminoacylation is presented based on charging of a nicked tRNA followed by separation of an aminoacylated 3'-fragment on an acidic denaturing polyacrylamide gel. Kinetic parameters of tRNA aminoacylation by Escherichia coli AlaRS obtained by the new method are in excellent agreement with those measured by the conventional method. This assay provides several advantages over the traditional methods of measuring tRNA aminoacylation: (1) the fraction of aminoacyl-tRNA is measured directly; (2) data can be obtained at saturating amino acid concentrations; and (3) the assay is significantly more sensitive.
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Affiliation(s)
- A D Wolfson
- Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215, USA
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