1
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Douglas J, Cui H, Perona JJ, Vargas-Rodriguez O, Tyynismaa H, Carreño CA, Ling J, Ribas de Pouplana L, Yang XL, Ibba M, Becker H, Fischer F, Sissler M, Carter CW, Wills PR. AARS Online: A collaborative database on the structure, function, and evolution of the aminoacyl-tRNA synthetases. IUBMB Life 2024. [PMID: 39247978 DOI: 10.1002/iub.2911] [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: 05/14/2024] [Accepted: 08/07/2024] [Indexed: 09/10/2024]
Abstract
The aminoacyl-tRNA synthetases (aaRS) are a large group of enzymes that implement the genetic code in all known biological systems. They attach amino acids to their cognate tRNAs, moonlight in various translational and non-translational activities beyond aminoacylation, and are linked to many genetic disorders. The aaRS have a subtle ontology characterized by structural and functional idiosyncrasies that vary from organism to organism, and protein to protein. Across the tree of life, the 22 coded amino acids are handled by 16 evolutionary families of Class I aaRS and 21 families of Class II aaRS. We introduce AARS Online, an interactive Wikipedia-like tool curated by an international consortium of field experts. This platform systematizes existing knowledge about the aaRS by showcasing a taxonomically diverse selection of aaRS sequences and structures. Through its graphical user interface, AARS Online facilitates a seamless exploration between protein sequence and structure, providing a friendly introduction to the material for non-experts and a useful resource for experts. Curated multiple sequence alignments can be extracted for downstream analyses. Accessible at www.aars.online, AARS Online is a free resource to delve into the world of the aaRS.
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Affiliation(s)
- Jordan Douglas
- Department of Physics, University of Auckland, New Zealand
- Centre for Computational Evolution, University of Auckland, New Zealand
| | - Haissi Cui
- Department of Chemistry, University of Toronto, Canada
| | - John J Perona
- Department of Chemistry, Portland State University, Portland, Oregon, USA
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biology and Biophysics, University of Connecticut, Storrs, Connecticut, USA
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | | | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Catalonia, Spain
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Michael Ibba
- Biological Sciences, Chapman University, Orange, California, USA
| | - Hubert Becker
- Génétique Moléculaire, Génomique Microbiologique, University of Strasbourg, France
| | - Frédéric Fischer
- Génétique Moléculaire, Génomique Microbiologique, University of Strasbourg, France
| | - Marie Sissler
- Génétique Moléculaire, Génomique Microbiologique, University of Strasbourg, France
| | - Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter R Wills
- Department of Physics, University of Auckland, New Zealand
- Centre for Computational Evolution, University of Auckland, New Zealand
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2
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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] [MESH Headings] [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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3
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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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4
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Nasim F, Qureshi IA. Aminoacyl tRNA Synthetases: Implications of Structural Biology in Drug Development against Trypanosomatid Parasites. ACS OMEGA 2023; 8:14884-14899. [PMID: 37151504 PMCID: PMC10157851 DOI: 10.1021/acsomega.3c00826] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/29/2023] [Indexed: 05/09/2023]
Abstract
The ensemble of aminoacyl tRNA synthetases is regarded as a key component of the protein translation machinery. With the progressive increase in structure-based studies on tRNA synthetase-ligand complexes, the detailed picture of these enzymes is becoming clear. Having known their critical role in deciphering the genetic code in a living system, they have always been chosen as one of the important targets for development of antimicrobial drugs. Later on, the role of aminoacyl tRNA synthetases (aaRSs) on the survivability of trypanosomatids has also been validated. It became evident through several gene knockout studies that targeting even one of these enzymes affected parasitic growth drastically. Such successful studies have inspired researchers to search for inhibitors that could specifically target trypanosomal aaRSs, and their never-ending efforts have provided fruitful results. Taking all such studies into consideration, these macromolecules of prime importance deserve further investigation for the development of drugs that cure spectrum of infections caused by trypanosomatids. In this review, we have compiled advancements of over a decade that have taken place in the pursuit of devising drugs by using trypanosomatid aaRSs as a major target of interest. Several of these inhibitors work on an exemplary low concentration range without posing any threat to the mammalian cells which is a very critical aspect of the drug discovery process. Advancements have been made in terms of using structural biology as an important tool to analyze the architecture of the trypanosomatids aaRSs and concoction of inhibitors with augmented specificities toward their targets. Some of the inhibitors that have been tested on other parasites successfully but their efficacy has so far not been validated against these trypanosomatids have also been appended.
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5
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Dutta S, Chandra A. A Multiple Proton Transfer Mechanism for the Charging Step of the Aminoacylation Reaction at the Active Site of Aspartyl tRNA Synthetase. J Chem Inf Model 2023; 63:1819-1832. [PMID: 36893463 DOI: 10.1021/acs.jcim.2c01332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Aspartyl-tRNA synthetase catalyzes the attachment of aspartic acid to its cognate tRNA by the aminoacylation reaction during the initiation of the protein biosynthesis process. In the second step of the aminoacylation reaction, known as the charging step, the aspartate moiety is transferred from aspartyl-adenylate to the 3'-OH of A76 of tRNA through a proton transfer process. We have investigated different pathways for the charging step through three separate QM/MM simulations combined with the enhanced sampling method of well-sliced metadynamics and found out the most feasible pathway for the reaction at the active site of the enzyme. In the charging reaction, both the phosphate group and the ammonium group after deprotonation can potentially act as a base for proton transfer in the substrate-assisted mechanism. We have considered three possible mechanisms involving different pathways of proton transfer, and only one of them is determined to be enzymatically feasible. The free energy landscape along reaction coordinates where the phosphate group acts as the general base showed that, in the absence of water, the barrier height is 52.6 kcal/mol. The free energy barrier is reduced to 39.7 kcal/mol when the active site water molecules are also treated quantum mechanically, thus allowing a water mediated proton transfer. The charging reaction involving the ammonium group of the aspartyl adenylate is found to follow a path where first a proton from the ammonium group moves to a water in the vicinity forming a hydronium ion (H3O+) and NH2 group. The hydronium ion subsequently passes the proton to the Asp233 residue, thus minimizing the chance of back proton transfer from hydronium to the NH2 group. The neutral NH2 group subsequently takes the proton from the O3' of A76 with a free energy barrier of 10.7 kcal/mol. In the next step, the deprotonated O3' makes a nucleophilic attack to the carbonyl carbon forming a tetrahedral transition state with a free energy barrier of 24.8 kcal/mol. Thus, the present work shows that the charging step proceeds through a multiple proton transfer mechanism where the amino group formed after deprotonation acts as the base to capture a proton from O3' of A76 rather than the phosphate group. The current study also shows the important role played by Asp233 in the proton transfer process.
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Affiliation(s)
- Saheb Dutta
- Department of Chemistry, Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
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6
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Mukai T, Amikura K, Fu X, Söll D, Crnković A. Indirect Routes to Aminoacyl-tRNA: The Diversity of Prokaryotic Cysteine Encoding Systems. Front Genet 2022; 12:794509. [PMID: 35047015 PMCID: PMC8762117 DOI: 10.3389/fgene.2021.794509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/18/2021] [Indexed: 01/23/2023] Open
Abstract
Universally present aminoacyl-tRNA synthetases (aaRSs) stringently recognize their cognate tRNAs and acylate them with one of the proteinogenic amino acids. However, some organisms possess aaRSs that deviate from the accurate translation of the genetic code and exhibit relaxed specificity toward their tRNA and/or amino acid substrates. Typically, these aaRSs are part of an indirect pathway in which multiple enzymes participate in the formation of the correct aminoacyl-tRNA product. The indirect cysteine (Cys)-tRNA pathway, originally thought to be restricted to methanogenic archaea, uses the unique O-phosphoseryl-tRNA synthetase (SepRS), which acylates the non-proteinogenic amino acid O-phosphoserine (Sep) onto tRNACys. Together with Sep-tRNA:Cys-tRNA synthase (SepCysS) and the adapter protein SepCysE, SepRS forms a transsulfursome complex responsible for shuttling Sep-tRNACys to SepCysS for conversion of the tRNA-bound Sep to Cys. Here, we report a comprehensive bioinformatic analysis of the diversity of indirect Cys encoding systems. These systems are present in more diverse groups of bacteria and archaea than previously known. Given the occurrence and distribution of some genes consistently flanking SepRS, it is likely that this gene was part of an ancient operon that suffered a gradual loss of its original components. Newly identified bacterial SepRS sequences strengthen the suggestion that this lineage of enzymes may not rely on the m1G37 identity determinant in tRNA. Some bacterial SepRSs possess an N-terminal fusion resembling a threonyl-tRNA synthetase editing domain, which interestingly is frequently observed in the vicinity of archaeal SepCysS genes. We also found several highly degenerate SepRS genes that likely have altered amino acid specificity. Cross-analysis of selenocysteine (Sec)-utilizing traits confirmed the co-occurrence of SepCysE and the Sec-utilizing machinery in archaea, but also identified an unusual O-phosphoseryl-tRNASec kinase fusion with an archaeal Sec elongation factor in some lineages, where it may serve in place of SepCysE to prevent crosstalk between the two minor aminoacylation systems. These results shed new light on the variations in SepRS and SepCysS enzymes that may reflect adaptation to lifestyle and habitat, and provide new information on the evolution of the genetic code.
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Affiliation(s)
- Takahito Mukai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Kazuaki Amikura
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Xian Fu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- Department of Chemistry, Yale University, New Haven, CT, United States
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
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7
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Chuawong P, Likittrakulwong W, Suebka S, Wiriyatanakorn N, Saparpakorn P, Taweesablamlert A, Sudprasert W, Hendrickson T, Svasti J. Anticodon-binding domain swapping in a nondiscriminating aspartyl-tRNA synthetase reveals contributions to tRNA specificity and catalytic activity. Proteins 2020; 88:1133-1142. [PMID: 32067260 DOI: 10.1002/prot.25881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/15/2019] [Accepted: 02/12/2020] [Indexed: 11/10/2022]
Abstract
The nondiscriminating aspartyl-tRNA synthetase (ND-AspRS), found in many archaea and bacteria, covalently attaches aspartic acid to tRNAAsp and tRNAAsn generating a correctly charged Asp-tRNAAsp and an erroneous Asp-tRNAAsn . This relaxed tRNA specificity is governed by interactions between the tRNA and the enzyme. In an effort to assess the contributions of the anticodon-binding domain to tRNA specificity, we constructed two chimeric enzymes, Chimera-D and Chimera-N, by replacing the native anticodon-binding domain in the Helicobacter pylori ND-AspRS with that of a discriminating AspRS (Chimera-D) and an asparaginyl-tRNA synthetase (AsnRS, Chimera-N), both from Escherichia coli. Both chimeric enzymes showed similar secondary structure compared to wild-type (WT) ND-AspRS and maintained the ability to form dimeric complexes in solution. Although less catalytically active than WT, Chimera-D was more discriminating as it aspartylated tRNAAsp over tRNAAsn with a specificity ratio of 7.0 compared to 2.9 for the WT enzyme. In contrast, Chimera-N exhibited low catalytic activity toward tRNAAsp and was unable to aspartylate tRNAAsn . The observed catalytic activities for the two chimeras correlate with their heterologous toxicity when expressed in E. coli. Molecular dynamics simulations show a reduced hydrogen bond network at the interface between the anticodon-binding domain and the catalytic domain in Chimera-N compared to Chimera-D or WT, explaining its lower stability and catalytic activity.
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Affiliation(s)
- Pitak Chuawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Wirot Likittrakulwong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.,Faculty of Agricultural Technology, Pibulsongkram Rajabhat University, Phitsanulok, Thailand
| | - Suwimon Suebka
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.,Faculty of Science and Technology, Valaya Alongkorn Rajabhat University, Pathum Thani, Thailand
| | | | | | - Amata Taweesablamlert
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Wanwisa Sudprasert
- Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | | | - Jisnuson Svasti
- Laboratory of Biochemistry, Chulabhorn Research Institute, Bangkok, Thailand
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8
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Florentz C, Giegé R. History of tRNA research in strasbourg. IUBMB Life 2019; 71:1066-1087. [PMID: 31185141 DOI: 10.1002/iub.2079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/06/2019] [Indexed: 01/03/2023]
Abstract
The tRNA molecules, in addition to translating the genetic code into protein and defining the second genetic code via their aminoacylation by aminoacyl-tRNA synthetases, act in many other cellular functions and dysfunctions. This article, illustrated by personal souvenirs, covers the history of ~60 years tRNA research in Strasbourg. Typical examples point up how the work in Strasbourg was a two-way street, influenced by and at the same time influencing investigators outside of France. All along, research in Strasbourg has nurtured the structural and functional diversity of tRNA. It produced massive sequence and crystallographic data on tRNA and its partners, thereby leading to a deeper physicochemical understanding of tRNA architecture, dynamics, and identity. Moreover, it emphasized the role of nucleoside modifications and in the last two decades, highlighted tRNA idiosyncrasies in plants and organelles, together with cellular and health-focused aspects. The tRNA field benefited from a rich local academic heritage and a strong support by both university and CNRS. Its broad interlinks to the worldwide community of tRNA researchers opens to an exciting future. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1066-1087, 2019.
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Affiliation(s)
- Catherine Florentz
- Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire, CNRS and Université de Strasbourg, F-67084, 15 rue René Descartes, Strasbourg, France.,Direction de la Recherche et de la Valorisation, Université de Strasbourg, F-67084, 4 rue Blaise Pascal, Strasbourg, France
| | - Richard Giegé
- Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire, CNRS and Université de Strasbourg, F-67084, 15 rue René Descartes, Strasbourg, France
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9
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Songsiriritthigul C, Suebka S, Chen CJ, Fuengfuloy P, Chuawong P. Crystal structure of the N-terminal anticodon-binding domain of the nondiscriminating aspartyl-tRNA synthetase from Helicobacter pylori. Acta Crystallogr F Struct Biol Commun 2017; 73:62-69. [PMID: 28177315 PMCID: PMC5297925 DOI: 10.1107/s2053230x16020586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/28/2016] [Indexed: 01/25/2023] Open
Abstract
The N-terminal anticodon-binding domain of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) plays a crucial role in the recognition of both tRNAAsp and tRNAAsn. Here, the first X-ray crystal structure of the N-terminal domain of this enzyme (ND-AspRS1-104) from the human-pathogenic bacterium Helicobacter pylori is reported at 2.0 Å resolution. The apo form of H. pylori ND-AspRS1-104 shares high structural similarity with the N-terminal anticodon-binding domains of the discriminating aspartyl-tRNA synthetase (D-AspRS) from Escherichia coli and ND-AspRS from Pseudomonas aeruginosa, allowing recognition elements to be proposed for tRNAAsp and tRNAAsn. It is proposed that a long loop (Arg77-Lys90) in this H. pylori domain influences its relaxed tRNA specificity, such that it is classified as nondiscriminating. A structural comparison between D-AspRS from E. coli and ND-AspRS from P. aeruginosa suggests that turns E and F (78GAGL81 and 83NPKL86) in H. pylori ND-AspRS play a crucial role in anticodon recognition. Accordingly, the conserved Pro84 in turn F facilitates the recognition of the anticodons of tRNAAsp (34GUC36) and tRNAAsn (34GUU36). The absence of the amide H atom allows both C and U bases to be accommodated in the tRNA-recognition site.
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MESH Headings
- Amino Acid Sequence
- Anticodon/chemistry
- Anticodon/metabolism
- Apoproteins/chemistry
- Apoproteins/genetics
- Apoproteins/metabolism
- Aspartate-tRNA Ligase/chemistry
- Aspartate-tRNA Ligase/genetics
- Aspartate-tRNA Ligase/metabolism
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Binding Sites
- Cloning, Molecular
- Crystallography, X-Ray
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Gene Expression
- Helicobacter pylori/chemistry
- Helicobacter pylori/enzymology
- Models, Molecular
- Plasmids/chemistry
- Plasmids/metabolism
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Pseudomonas aeruginosa/enzymology
- Pseudomonas aeruginosa/genetics
- RNA, Transfer, Asn/chemistry
- RNA, Transfer, Asn/genetics
- RNA, Transfer, Asn/metabolism
- RNA, Transfer, Asp/chemistry
- RNA, Transfer, Asp/genetics
- RNA, Transfer, Asp/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Structural Homology, Protein
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Affiliation(s)
- Chomphunuch Songsiriritthigul
- Synchrotron Light Research Institute (Public Organization), 111 University Avenue, Nakhon Ratchasima 30000, Thailand
- Center for Biomolecular Structure, Function and Application, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Suwimon Suebka
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, and Special Research Unit for Advanced Magnetic Resonance, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok 10900, Thailand
| | - Chun-Jung Chen
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Pitchayada Fuengfuloy
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, and Special Research Unit for Advanced Magnetic Resonance, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok 10900, Thailand
| | - Pitak Chuawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, and Special Research Unit for Advanced Magnetic Resonance, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok 10900, Thailand
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10
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Aboelnga MM, Hayward JJ, Gauld JW. A water-mediated and substrate-assisted aminoacylation mechanism in the discriminating aminoacyl-tRNA synthetase GlnRS and non-discriminating GluRS. Phys Chem Chem Phys 2017; 19:25598-25609. [DOI: 10.1039/c7cp02969a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computational methods have been used to elucidate key differences and similarities between the distinct aminoacyl-tRNA synthetases (aaRS) GlnRS and non-discriminating-GluRS.
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Affiliation(s)
- Mohamed M. Aboelnga
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
- Department of Chemistry and Biochemistry
| | - John J. Hayward
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
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11
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) are modular enzymes globally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation. Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g., in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show huge structural plasticity related to function and limited idiosyncrasies that are kingdom or even species specific (e.g., the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS). Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably between distant groups such as Gram-positive and Gram-negative Bacteria. The review focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation, and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulated in last two decades is reviewed, showing how the field moved from essentially reductionist biology towards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRS paralogs (e.g., during cell wall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointed throughout the review and distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Mathias Springer
- Université Paris Diderot, Sorbonne Cité, UPR9073 CNRS, IBPC, 75005 Paris, France
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12
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Datt M, Sharma A. Novel and unique domains in aminoacyl-tRNA synthetases from human fungal pathogens Aspergillus niger, Candida albicans and Cryptococcus neoformans. BMC Genomics 2014; 15:1069. [PMID: 25479903 PMCID: PMC4301749 DOI: 10.1186/1471-2164-15-1069] [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] [Received: 06/18/2014] [Accepted: 11/20/2014] [Indexed: 12/15/2022] Open
Abstract
Background Some species of fungi can cause serious human diseases, particularly to immuno-compromised individuals. Opportunistic fungal infections are a leading cause of mortality, and present an emerging challenge that requires development of new and effective therapeutics. Aminoacyl-tRNA synthetases (aaRSs) are indispensable components of cellular protein translation machinery and can be targeted for discovery of novel anti-fungal agents. Results Validation of aaRSs as potential drug targets in pathogenic microbes prompted us to investigate the genomic distribution of aaRSs within three fungi that infect humans – A. niger, C. albicans and C. neoformans. Hidden Markov Models were built for aaRSs and related proteins to search for homologues in these fungal genomes. Here, we provide a detailed and comprehensive annotation for 3 fungal genome aaRSs and their associated proteins. We delineate predicted localizations, subdomain architectures and prevalence of unusual motifs within these aaRSs. Several fungal aaRSs have unique domain appendages of unknown function e.g. A. niger AsxRS and C. neoformans TyrRS have additional domains that are absent from human homologs. Conclusions Detailed comparisons of fungal aaRSs with human homologs suggest key differences that could be exploited for specific drug targeting. Our cataloging and structural analyses provide a comprehensive foundation for experimentally dissecting fungal aaRSs that may enable development of new anti-fungal agents. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1069) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Amit Sharma
- Structural and Computational Biology group, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
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13
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Santos-Garcia D, Latorre A, Moya A, Gibbs G, Hartung V, Dettner K, Kuechler SM, Silva FJ. Small but powerful, the primary endosymbiont of moss bugs, Candidatus Evansia muelleri, holds a reduced genome with large biosynthetic capabilities. Genome Biol Evol 2014; 6:1875-93. [PMID: 25115011 PMCID: PMC4122945 DOI: 10.1093/gbe/evu149] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Moss bugs (Coleorrhyncha: Peloridiidae) are members of the order Hemiptera, and like many hemipterans, they have symbiotic associations with intracellular bacteria to fulfill nutritional requirements resulting from their unbalanced diet. The primary endosymbiont of the moss bugs, Candidatus Evansia muelleri, is phylogenetically related to Candidatus Carsonella ruddii and Candidatus Portiera aleyrodidarum, primary endosymbionts of psyllids and whiteflies, respectively. In this work, we report the genome of Candidatus Evansia muelleri Xc1 from Xenophyes cascus, which is the only obligate endosymbiont present in the association. This endosymbiont possesses an extremely reduced genome similar to Carsonella and Portiera. It has crossed the borderline to be considered as an autonomous cell, requiring the support of the insect host for some housekeeping cell functions. Interestingly, in spite of its small genome size, Evansia maintains enriched amino acid (complete or partial pathways for ten essential and six nonessential amino acids) and sulfur metabolisms, probably related to the poor diet of the insect, based on bryophytes, which contains very low levels of nitrogenous and sulfur compounds. Several facts, including the congruence of host (moss bugs, whiteflies, and psyllids) and endosymbiont phylogenies and the retention of the same ribosomal RNA operon during genome reduction in Evansia, Portiera, and Carsonella, suggest the existence of an ancient endosymbiotic Halomonadaceae clade associated with Hemiptera. Three possible scenarios for the origin of these three primary endosymbiont genera are proposed and discussed.
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Affiliation(s)
- Diego Santos-Garcia
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
| | - George Gibbs
- School of Biological Science, Victoria University, Wellington, New Zealand
| | - Viktor Hartung
- Museum für Naturkunde, Leibniz-Institute for Research on Evolution and Biodiversity, Berlin, Germany
| | - Konrad Dettner
- Department of Animal Ecology II, University of Bayreuth, Germany
| | - Stefan Martin Kuechler
- Department of Animal Ecology II, University of Bayreuth, Germany
- *Corresponding author: E-mail: ;
| | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
- *Corresponding author: E-mail: ;
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14
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Zhou X, Wang E. Transfer RNA: a dancer between charging and mis-charging for protein biosynthesis. SCIENCE CHINA-LIFE SCIENCES 2013; 56:921-32. [PMID: 23982864 DOI: 10.1007/s11427-013-4542-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/13/2013] [Indexed: 01/17/2023]
Abstract
Transfer RNA plays a fundamental role in the protein biosynthesis as an adaptor molecule by functioning as a biological link between the genetic nucleotide sequence in the mRNA and the amino acid sequence in the protein. To perform its role in protein biosynthesis, it has to be accurately recognized by aminoacyl-tRNA synthetases (aaRSs) to generate aminoacyl-tRNAs (aa-tRNAs). The correct pairing between an amino acid with its cognate tRNA is crucial for translational quality control. Production and utilization of mis-charged tRNAs are usually detrimental for all the species, resulting in cellular dysfunctions. Correct aa-tRNAs formation is collectively controlled by aaRSs with distinct mechanisms and/or other trans-factors. However, in very limited instances, mis-charged tRNAs are intermediate for specific pathways or essential components for the translational machinery. Here, from the point of accuracy in tRNA charging, we review our understanding about the mechanism ensuring correct aa-tRNA generation. In addition, some unique mis-charged tRNA species necessary for the organism are also briefly described.
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Affiliation(s)
- Xiaolong Zhou
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
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15
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Fuengfuloy P, Chuawong P, Suebka S, Wattana-amorn P, Williams C, Crump MP, Songsiriritthigul C. Overproduction of the N-terminal anticodon-binding domain of the non-discriminating aspartyl-tRNA synthetase from Helicobacter pylori for crystallization and NMR measurements. Protein Expr Purif 2013; 89:25-32. [DOI: 10.1016/j.pep.2013.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/06/2013] [Accepted: 02/13/2013] [Indexed: 10/27/2022]
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16
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Gowri VS, Ghosh I, Sharma A, Madhubala R. Unusual domain architecture of aminoacyl tRNA synthetases and their paralogs from Leishmania major. BMC Genomics 2012; 13:621. [PMID: 23151081 PMCID: PMC3532385 DOI: 10.1186/1471-2164-13-621] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 10/30/2012] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Leishmania major, a protozoan parasite, is the causative agent of cutaneous leishmaniasis. Due to the development of resistance against the currently available anti-leishmanial drugs, there is a growing need for specific inhibitors and novel drug targets. In this regards, aminoacyl tRNA synthetases, the linchpins of protein synthesis, have received recent attention among the kinetoplastid research community. This is the first comprehensive survey of the aminoacyl tRNA synthetases, their paralogs and other associated proteins from L. major. RESULTS A total of 26 aminoacyl tRNA synthetases were identified using various computational and bioinformatics tools. Phylogenetic analysis and domain architectures of the L. major aminoacyl tRNA synthetases suggest a probable archaeal/eukaryotic origin. Presence of additional domains or N- or C-terminal extensions in 11 aminoacyl tRNA synthetases from L. major suggests possibilities such as additional tRNA binding or oligomerization or editing activity. Five freestanding editing domains were identified in L. major. Domain assignment revealed a novel asparagine tRNA synthetase paralog, asparagine synthetase A which has been so far reported from prokaryotes and archaea. CONCLUSIONS A comprehensive bioinformatic analysis revealed 26 aminoacyl tRNA synthetases and five freestanding editing domains in L. major. Identification of two EMAP (endothelial monocyte-activating polypeptide) II-like proteins similar to human EMAP II-like proteins suggests their participation in multisynthetase complex formation. While the phylogeny of tRNA synthetases suggests a probable archaeal/eukaryotic origin, phylogeny of asparagine synthetase A strongly suggests a bacterial origin. The unique features identified in this work provide rationale for designing inhibitors against parasite aminoacyl tRNA synthetases and their paralogs.
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Affiliation(s)
- V S Gowri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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17
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Abstract
Aminoacyl-tRNAsynthetases (aaRSs) are modular enzymesglobally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation.Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g.,in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show hugestructural plasticity related to function andlimited idiosyncrasies that are kingdom or even speciesspecific (e.g.,the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS).Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably betweendistant groups such as Gram-positive and Gram-negative Bacteria.Thereview focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation,and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulatedin last two decades is reviewed,showing how thefield moved from essentially reductionist biologytowards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRSparalogs (e.g., during cellwall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointedthroughout the reviewand distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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18
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Perona JJ, Hadd A. Structural diversity and protein engineering of the aminoacyl-tRNA synthetases. Biochemistry 2012; 51:8705-29. [PMID: 23075299 DOI: 10.1021/bi301180x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRS) are the enzymes that ensure faithful transmission of genetic information in all living cells, and are central to the developing technologies for expanding the capacity of the translation apparatus to incorporate nonstandard amino acids into proteins in vivo. The 24 known aaRS families are divided into two classes that exhibit functional evolutionary convergence. Each class features an active site domain with a common fold that binds ATP, the amino acid, and the 3'-terminus of tRNA, embellished by idiosyncratic further domains that bind distal portions of the tRNA and enhance specificity. Fidelity in the expression of the genetic code requires that the aaRS be selective for both amino acids and tRNAs, a substantial challenge given the presence of structurally very similar noncognate substrates of both types. Here we comprehensively review central themes concerning the architectures of the protein structures and the remarkable dual-substrate selectivities, with a view toward discerning the most important issues that still substantially limit our capacity for rational protein engineering. A suggested general approach to rational design is presented, which should yield insight into the identities of the protein-RNA motifs at the heart of the genetic code, while also offering a basis for improving the catalytic properties of engineered tRNA synthetases emerging from genetic selections.
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Affiliation(s)
- John J Perona
- Department of Chemistry, Portland State University, Portland, Oregon 97207, United States.
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19
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Rational design of an evolutionary precursor of glutaminyl-tRNA synthetase. Proc Natl Acad Sci U S A 2011; 108:20485-90. [PMID: 22158897 DOI: 10.1073/pnas.1117294108] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The specificity of most aminoacyl-tRNA synthetases for an amino acid and cognate tRNA pair evolved before the divergence of the three domains of life. Glutaminyl-tRNA synthetase (GlnRS) evolved later and is derived from the archaeal-type nondiscriminating glutamyl-tRNA synthetase (GluRS), an enzyme with relaxed tRNA specificity capable of forming both Glu-tRNA(Glu) and Glu-tRNA(Gln). The archaea lack GlnRS and use a specialized amidotransferase to convert Glu-tRNA(Gln) to Gln-tRNA(Gln) needed for protein synthesis. We show that the Methanothermobacter thermautotrophicus GluRS is active toward tRNA(Glu) and the two tRNA(Gln) isoacceptors the organism encodes, but with a significant catalytic preference for tRNA(Gln2)(CUG). The less active tRNA(Gln1)(UUG) responds to the less common CAA codon for Gln. From a biochemical characterization of M. thermautotrophicus GluRS variants, we found that the evolution of tRNA specificity in GlnRS could be recapitulated by converting the M. thermautotrophicus GluRS to a tRNA(Gln) specific enzyme, solely through the addition of an acceptor stem loop present in bacterial GlnRS. One designed GluRS variant is also highly specific for the tRNA(Gln2)(CUG) isoacceptor, which responds to the CAG codon, and shows no activity toward tRNA(Gln1)(UUG). Because it is now possible to eliminate particular codons from the genome of Escherichia coli, additional codons will become available for genetic code engineering. Isoacceptor-specific aminoacyl-tRNA synthetases will enable the reassignment of more open codons while preserving accurate encoding of the 20 canonical amino acids.
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20
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Rubio MAT, Hopper AK. Transfer RNA travels from the cytoplasm to organelles. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:802-17. [PMID: 21976284 DOI: 10.1002/wrna.93] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Transfer RNAs (tRNAs) encoded by the nuclear genome are surprisingly dynamic. Although tRNAs function in protein synthesis occurring on cytoplasmic ribosomes, tRNAs can transit from the cytoplasm to the nucleus and then again return to the cytoplasm by a process known as the tRNA retrograde process. Subsets of the cytoplasmic tRNAs are also imported into mitochondria and function in mitochondrial protein synthesis. The numbers of tRNA species that are imported into mitochondria differ among organisms, ranging from just a few to the entire set needed to decode mitochondrially encoded mRNAs. For some tRNAs, import is dependent on the mitochondrial protein import machinery, whereas the majority of tRNA mitochondrial import is independent of this machinery. Although cytoplasmic proteins and proteins located on the mitochondrial surface participating in the tRNA import process have been described for several organisms, the identity of these proteins differ among organisms. Likewise, the tRNA determinants required for mitochondrial import differ among tRNA species and organisms. Here, we present an overview and discuss the current state of knowledge regarding the mechanisms involved in the tRNA retrograde process and continue with an overview of tRNA import into mitochondria. Finally, we highlight areas of future research to understand the function and regulation of movement of tRNAs between the cytoplasm and organelles.
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Affiliation(s)
- Mary Anne T Rubio
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
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21
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Liao JC, Lam R, Brazda V, Duan S, Ravichandran M, Ma J, Xiao T, Tempel W, Zuo X, Wang YX, Chirgadze NY, Arrowsmith CH. Interferon-inducible protein 16: insight into the interaction with tumor suppressor p53. Structure 2011; 19:418-29. [PMID: 21397192 PMCID: PMC3760383 DOI: 10.1016/j.str.2010.12.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Revised: 12/14/2010] [Accepted: 12/16/2010] [Indexed: 02/09/2023]
Abstract
IFI16 is a member of the interferon-inducible HIN-200 family of nuclear proteins. It has been implicated in transcriptional regulation by modulating protein-protein interactions with p53 tumor suppressor protein and other transcription factors. However, the mechanisms of interaction remain unknown. Here, we report the crystal structures of both HIN-A and HIN-B domains of IFI16 determined at 2.0 and 2.35 Å resolution, respectively. Each HIN domain comprises a pair of tightly packed OB-fold subdomains that appear to act as a single unit. We show that both HIN domains of IFI16 are capable of enhancing p53-DNA complex formation and transcriptional activation via distinctive means. HIN-A domain binds to the basic C terminus of p53, whereas the HIN-B domain binds to the core DNA-binding region of p53. Both interactions are compatible with the DNA-bound state of p53 and together contribute to the effect of full-length IFI16 on p53-DNA complex formation and transcriptional activation.
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Affiliation(s)
- Jack C.C. Liao
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Robert Lam
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L5, Canada
| | - Vaclav Brazda
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Shili Duan
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Mani Ravichandran
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L5, Canada
| | - Justin Ma
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Ting Xiao
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L5, Canada
| | - Wolfram Tempel
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L5, Canada
| | - Xiaobing Zuo
- Protein–Nucleic Acid Interaction Section, Structural Biophysics Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA
| | - Yun-Xing Wang
- Protein–Nucleic Acid Interaction Section, Structural Biophysics Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA
| | - Nickolay Y. Chirgadze
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Cheryl H. Arrowsmith
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L5, Canada
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22
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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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23
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Chang KM, Hendrickson TL. Recognition of tRNAGln by Helicobacter pylori GluRS2--a tRNAGln-specific glutamyl-tRNA synthetase. Nucleic Acids Res 2009; 37:6942-9. [PMID: 19755501 PMCID: PMC2777447 DOI: 10.1093/nar/gkp754] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Accurate aminoacylation of tRNAs by the aminoacyl-tRNA synthetases (aaRSs) plays a critical role in protein translation. However, some of the aaRSs are missing in many microorganisms. Helicobacter pylori does not have a glutaminyl-tRNA synthetase (GlnRS) but has two divergent glutamyl-tRNA synthetases: GluRS1 and GluRS2. Like a canonical GluRS, GluRS1 aminoacylates tRNAGlu1 and tRNAGlu2. In contrast, GluRS2 only misacylates tRNAGln to form Glu-tRNAGln. It is not clear how GluRS2 achieves specific recognition of tRNAGln while rejecting the two H. pylori tRNAGlu isoacceptors. Here, we show that GluRS2 recognizes major identity elements clustered in the tRNAGln acceptor stem. Mutations in the tRNA anticodon or at the discriminator base had little to no impact on enzyme specificity and activity.
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Affiliation(s)
- Keng-Ming Chang
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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24
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Bailly M, Blaise M, Lorber B, Thirup S, Kern D. Isolation, crystallization and preliminary X-ray analysis of the transamidosome, a ribonucleoprotein involved in asparagine formation. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:577-81. [PMID: 19478435 DOI: 10.1107/s1744309109015000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 04/22/2009] [Indexed: 11/10/2022]
Abstract
Thermus thermophilus deprived of asparagine synthetase synthesizes Asn on tRNA(Asn) via a tRNA-dependent pathway involving a nondiscriminating aspartyl-tRNA synthetase that charges Asp onto tRNA(Asn) prior to conversion of the Asp to Asn by GatCAB, a tRNA-dependent amidotransferase. This pathway also constitutes the route of Asn-tRNA(Asn) formation by bacteria and archaea deprived of asparaginyl-tRNA synthetase. The partners involved in tRNA-dependent Asn formation in T. thermophilus assemble into a ternary complex called the transamidosome. This particule produces Asn-tRNA(Asn) in the presence of free Asp, ATP and an amido-group donor. Crystals of the transamidosome from T. thermophilus were obtained in the presence of PEG 4000 in MES-NaOH buffer pH 6.5. They belonged to the primitive monoclinic space group P2(1), with unit-cell parameters a = 115.9, b = 214.0, c = 127.8 A, beta = 93.3 degrees . A complete data set was collected to 3 A resolution. Here, the isolation and crystallization of the transamidosome from T. thermophilus and preliminary crystallographic data are reported.
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Affiliation(s)
- Marc Bailly
- UPR 9002 'Architecture et Réactivité de l'ARN', Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 Rue René Descartes, F-67084 Strasbourg CEDEX, France
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25
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Cathopoulis TJT, Chuawong P, Hendrickson TL. Conserved discrimination against misacylated tRNAs by two mesophilic elongation factor Tu orthologs. Biochemistry 2008; 47:7610-6. [PMID: 18627126 DOI: 10.1021/bi800369q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Elongation factor Tu (EF-Tu) binds and loads elongating aminoacyl-tRNAs (aa-tRNAs) onto the ribosome for protein biosynthesis. Many bacteria biosynthesize Gln-tRNA (Gln) and Asn-tRNA (Asn) by an indirect, two-step pathway that relies on the misacylated tRNAs Glu-tRNA (Gln) and Asp-tRNA (Asn) as intermediates. Previous thermodynamic and experimental analyses have demonstrated that Thermus thermophilus EF-Tu does not bind Asp-tRNA (Asn) and predicted a similar discriminatory response against Glu-tRNA (Gln) [Asahara, H., and Uhlenbeck, O. (2005) Biochemistry 46, 6194-6200; Roy, H., et al. (2007) Nucleic Acids Res. 35, 3420-3430]. By discriminating against these misacylated tRNAS, EF-Tu plays a direct role in preventing misincorporation of aspartate and glutamate into proteins at asparagine and glutamine codons. Here we report the characterization of two different mesophilic EF-Tu orthologs, one from Escherichia coli, a bacterium that does not utilize either Glu-tRNA (Gln) or Asp-tRNA (Asn), and the second from Helicobacter pylori, an organism in which both misacylated tRNAs are essential. Both EF-Tu orthologs discriminate against these misacylated tRNAs, confirming the prediction that Glu-tRNA (Gln), like Asp-tRNA (Asn), will not form a complex with EF-Tu. These results also demonstrate that the capacity of EF-Tu to discriminate against both of these aminoacyl-tRNAs is conserved even in bacteria like E. coli that do not generate either misacylated tRNA.
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Affiliation(s)
- Terry J T Cathopoulis
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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26
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Bailly M, Blaise M, Roy H, Deniziak M, Lorber B, Birck C, Becker HD, Kern D. tRNA-dependent asparagine formation in prokaryotes: characterization, isolation and structural and functional analysis of a ribonucleoprotein particle generating Asn-tRNA(Asn). Methods 2008; 44:146-63. [PMID: 18241796 DOI: 10.1016/j.ymeth.2007.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 11/23/2007] [Accepted: 11/29/2007] [Indexed: 11/29/2022] Open
Abstract
In some living organisms the 20 aa-tRNA species participating in protein synthesis are not charged by a complete set of 20 aminoacyl-tRNA synthetases. In prokaryotes, the deficiency of asparaginyl- and/or glutaminyl-tRNA synthetases is compensated by another aminoacyl-tRNA synthetase of relaxed specificity that mischarges the orphan tRNA and by an enzyme that converts the amino acid into that homologous to the tRNA. In Thermus thermophilus Asn-tRNA(Asn) is formed indirectly via a two-step pathway whereby tRNA(Asn) is mischarged with Asp that will subsequently be amidated into Asn by an amidotransferase. The non-discriminating aspartyl-tRNA synthetase, the trimeric GatCAB tRNA-dependent amidotransferase and the tRNA(Asn) promoting this pathway assemble into a ribonucleoprotein particle termed transamidosome. This article deals with the methods and techniques employed to clone the genes encoding the enzymes and the tRNA involved in this pathway, to express them in Escherichia coli, to isolate them on a large scale, and to transcribe and produce mg quantities of pure tRNA(Asn)in vitro. The approaches designed especially for this system include (i) clustering of the ORFs encoding the subunits of the heterotrimeric GatCAB that are sprinkled in the genome into an artificial operon, and (ii) the self-cleavage of the tRNA(Asn) transcript starting with U in 5' position through fusion with a hammerhead ribozyme. Further, the crystallization of the free enzymes is described and the characterization of their assembly with tRNA(Asn) into a ribonucleoprotein particle, as well as the investigation of the catalytic mechanism of Asn-tRNA(Asn) formation by the complex are reported.
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Affiliation(s)
- Marc Bailly
- UPR 9002 Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 Rue René Descartes and Université Louis Pasteur, F-67084 Strasbourg Cedex, France
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27
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Bailly M, Blaise M, Lorber B, Becker HD, Kern D. The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis. Mol Cell 2008; 28:228-39. [PMID: 17964262 DOI: 10.1016/j.molcel.2007.08.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 07/09/2007] [Accepted: 08/13/2007] [Indexed: 11/28/2022]
Abstract
Asparagine, one of the 22 genetically encoded amino acids, can be synthesized by a tRNA-dependent mechanism. So far, this type of pathway was believed to proceed via two independent steps. A nondiscriminating aspartyl-tRNA synthetase (ND-DRS) first generates a mischarged aspartyl-tRNAAsn that dissociates from the enzyme and binds to a tRNA-dependent amidotransferase (AdT), which then converts the tRNA-bound aspartate into asparagine. We show herein that the ND-DRS, tRNAAsn, and AdT assemble into a specific ribonucleoprotein complex called transamidosome that remains stable during the overall catalytic process. Our results indicate that the tRNAAsn-mediated linkage between the ND-DRS and AdT enables channeling of the mischarged aspartyl-tRNAAsn intermediate between DRS and AdT active sites to prevent challenging of the genetic code integrity. We propose that formation of a ribonucleoprotein is a general feature for tRNA-dependent amino acid biosynthetic pathways that are remnants of earlier stages when amino acid synthesis and tRNA aminoacylation were coupled.
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Affiliation(s)
- Marc Bailly
- UPR Architecture et Réactivité de l'ARN, Université Louis Pasteur de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15, Rue René Descartes, F-67084 Strasbourg Cédex, France
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28
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Suzuki K, Sato Y, Maeda Y, Shimizu S, Hossain MT, Ubukata S, Sekiguchi T, Takénaka A. Crystallization and preliminary X-ray crystallographic study of a putative aspartyl-tRNA synthetase from the crenarchaeon Sulfolobus tokodaii strain 7. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:608-12. [PMID: 17620724 PMCID: PMC2335148 DOI: 10.1107/s1744309107026905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 06/01/2007] [Indexed: 11/10/2022]
Abstract
Genome analysis suggests that the aspartyl-tRNA synthetase of the crenarchaeon Sulfolobus tokodaii strain 7 belongs to the nondiscriminating type that is believed to catalyze aspartylation of tRNA(Asp) and tRNA(Asn). This protein has been overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method from 100 mM sodium HEPES buffer pH 7.5 containing 100 mM NaCl and 1.6 M (NH4)2SO4 as the crystallizing reagent. Diffraction data were collected to 2.3 A resolution using synchrotron radiation. The crystal belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 116.0, b = 139.3, c = 75.3 A. The estimated Matthews coefficient (3.10 A3 Da(-1); 60.3% solvent content) suggests the presence of two subunits in the asymmetric unit. The structure has been successfully solved by the molecular-replacement method. Full refinement of the structure may reveal it to be the original ancestor of the nondiscriminating AspRS.
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Affiliation(s)
- Kaoru Suzuki
- College of Science and Engineering, Iwaki-Meisei University, Chuou-dai-Iino, Iwaki, Fukushima 970-8551, Japan
| | - Yoshiteru Sato
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
| | - Yohei Maeda
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
| | - Satoru Shimizu
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
| | - Md Tofazzal Hossain
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
| | - Souichirou Ubukata
- College of Science and Engineering, Iwaki-Meisei University, Chuou-dai-Iino, Iwaki, Fukushima 970-8551, Japan
| | - Takeshi Sekiguchi
- College of Science and Engineering, Iwaki-Meisei University, Chuou-dai-Iino, Iwaki, Fukushima 970-8551, Japan
| | - Akio Takénaka
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
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29
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Cathopoulis T, Chuawong P, Hendrickson TL. Novel tRNA aminoacylation mechanisms. MOLECULAR BIOSYSTEMS 2007; 3:408-18. [PMID: 17533454 DOI: 10.1039/b618899k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In nature, ribosomally synthesized proteins can contain at least 22 different amino acids: the 20 common amino acids as well as selenocysteine and pyrrolysine. Each of these amino acids is inserted into proteins codon-specifically via an aminoacyl-transfer RNA (aa-tRNA). In most cases, these aa-tRNAs are biosynthesized directly by a set of highly specific and accurate aminoacyl-tRNA synthetases (aaRSs). However, in some cases aaRSs with relaxed or novel substrate specificities cooperate with other enzymes to generate specific canonical and non-canonical aminoacyl-tRNAs.
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MESH Headings
- Amino Acyl-tRNA Synthetases/metabolism
- Aspartate-tRNA Ligase/metabolism
- Bacteria/enzymology
- RNA, Transfer, Amino Acyl/biosynthesis
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/metabolism
- RNA, Transfer, Asn/biosynthesis
- RNA, Transfer, Asn/chemistry
- RNA, Transfer, Cys/biosynthesis
- RNA, Transfer, Cys/chemistry
- RNA, Transfer, Gln/biosynthesis
- RNA, Transfer, Gln/chemistry
- Transfer RNA Aminoacylation
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Affiliation(s)
- Terry Cathopoulis
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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30
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Chuawong P, Hendrickson TL. The nondiscriminating aspartyl-tRNA synthetase from Helicobacter pylori: anticodon-binding domain mutations that impact tRNA specificity and heterologous toxicity. Biochemistry 2006; 45:8079-87. [PMID: 16800632 PMCID: PMC2654173 DOI: 10.1021/bi060189c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Divergent tRNA substrate recognition patterns distinguish the two distinct forms of aspartyl-tRNA synthetase (AspRS) that exist in different bacteria. In some cases, a canonical, discriminating AspRS (D-AspRS) specifically generates Asp-tRNA(Asp) and usually coexists with asparaginyl-tRNA synthetase (AsnRS). In other bacteria, particularly those that lack AsnRS, AspRS is nondiscriminating (ND-AspRS) and generates both Asp-tRNA(Asp) and the noncanonical, misacylated Asp-tRNA(Asn); this misacylated tRNA is subsequently repaired by the glutamine-dependent Asp-tRNA(Asn)/Glu-tRNA(Gln) amidotransferase (Asp/Glu-Adt). The molecular features that distinguish the closely related bacterial D-AspRS and ND-AspRS are not well-understood. Here, we report the first characterization of the ND-AspRS from the human pathogen Helicobacter pylori (H. pylori or Hp). This enzyme is toxic when heterologously overexpressed in Escherichia coli. This toxicity is rescued upon coexpression of the Hp Asp/Glu-Adt, indicating that Hp Asp/Glu-Adt can utilize E. coli Asp-tRNA(Asn) as a substrate. Finally, mutations in the anticodon-binding domain of Hp ND-AspRS reduce this enzyme's ability to misacylate tRNA(Asn), in a manner that correlates with the toxicity of the enzyme in E. coli.
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31
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Schulze JO, Masoumi A, Nickel D, Jahn M, Jahn D, Schubert WD, Heinz DW. Crystal structure of a non-discriminating glutamyl-tRNA synthetase. J Mol Biol 2006; 361:888-97. [PMID: 16876193 DOI: 10.1016/j.jmb.2006.06.054] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 06/20/2006] [Accepted: 06/21/2006] [Indexed: 11/22/2022]
Abstract
Error-free protein biosynthesis is dependent on the reliable charging of each tRNA with its cognate amino acid. Many bacteria, however, lack a glutaminyl-tRNA synthetase. In these organisms, tRNA(Gln) is initially mischarged with glutamate by a non-discriminating glutamyl-tRNA synthetase (ND-GluRS). This enzyme thus charges both tRNA(Glu) and tRNA(Gln) with glutamate. Discriminating GluRS (D-GluRS), found in some bacteria and all eukaryotes, exclusively generates Glu-tRNA(Glu). Here we present the first crystal structure of a non-discriminating GluRS from Thermosynechococcus elongatus (ND-GluRS(Tel)) in complex with glutamate at a resolution of 2.45 A. Structurally, the enzyme shares the overall architecture of the discriminating GluRS from Thermus thermophilus (D-GluRS(Tth)). We confirm experimentally that GluRS(Tel) is non-discriminating and present kinetic parameters for synthesis of Glu-tRNA(Glu) and of Glu-tRNA(Gln). Anticodons of tRNA(Glu) (34C/UUC36) and tRNA(Gln) (34C/UUG36) differ only in base 36. The pyrimidine base of C36 is specifically recognized in D-GluRS(Tth) by the residue Arg358. In ND-GluRS(Tel) this arginine residue is replaced by glycine (Gly366) presumably allowing both cytosine and the bulkier purine base G36 of tRNA(Gln) to be tolerated. Most other ND-GluRS share this structural feature, leading to relaxed substrate specificity.
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Affiliation(s)
- Jörg O Schulze
- Division of Structural Biology, German Research Centre for Biotechnology (GBF), Mascheroder Weg 1, D-38124 Braunschweig, Germany
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32
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Iwasaki W, Sekine SI, Kuroishi C, Kuramitsu S, Shirouzu M, Yokoyama S. Structural basis of the water-assisted asparagine recognition by asparaginyl-tRNA synthetase. J Mol Biol 2006; 360:329-42. [PMID: 16753178 DOI: 10.1016/j.jmb.2006.04.068] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 04/24/2006] [Accepted: 04/26/2006] [Indexed: 11/30/2022]
Abstract
Asparaginyl-tRNA synthetase (AsnRS) is a member of the class-II aminoacyl-tRNA synthetases, and is responsible for catalyzing the specific aminoacylation of tRNA(Asn) with asparagine. Here, the crystal structure of AsnRS from Pyrococcus horikoshii, complexed with asparaginyl-adenylate (Asn-AMP), was determined at 1.45 A resolution, and those of free AsnRS and AsnRS complexed with an Asn-AMP analog (Asn-SA) were solved at 1.98 and 1.80 A resolutions, respectively. All of the crystal structures have many solvent molecules, which form a network of hydrogen-bonding interactions that surrounds the entire AsnRS molecule. In the AsnRS/Asn-AMP complex (or the AsnRS/Asn-SA), one side of the bound Asn-AMP (or Asn-SA) is completely covered by the solvent molecules, which complement the binding site. In particular, two of these water molecules were found to interact directly with the asparagine amide and carbonyl groups, respectively, and to contribute to the formation of a pocket highly complementary to the asparagine side-chain. Thus, these two water molecules appear to play a key role in the strict recognition of asparagine and the discrimination against aspartic acid by the AsnRS. This water-assisted asparagine recognition by the AsnRS strikingly contrasts with the fact that the aspartic acid recognition by the closely related aspartyl-tRNA synthetase is achieved exclusively through extensive interactions with protein amino acid residues. Furthermore, based on a docking model of AsnRS and tRNA, a single arginine residue (Arg83) in the AsnRS was postulated to be involved in the recognition of the third position of the tRNA(Asn) anticodon (U36). We performed a mutational analysis of this particular arginine residue, and confirmed its significance in the tRNA recognition.
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Affiliation(s)
- Wataru Iwasaki
- 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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33
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Bernard D, Akochy PM, Beaulieu D, Lapointe J, Roy PH. Two residues in the anticodon recognition domain of the aspartyl-tRNA synthetase from Pseudomonas aeruginosa are individually implicated in the recognition of tRNAAsn. J Bacteriol 2006; 188:269-74. [PMID: 16352843 PMCID: PMC1317590 DOI: 10.1128/jb.188.1.269-274.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In many organisms, the formation of asparaginyl-tRNA is not done by direct aminoacylation of tRNA(Asn) but by specific tRNA-dependent transamidation of aspartyl-tRNA(Asn). This transamidation pathway involves a nondiscriminating aspartyl-tRNA synthetase (AspRS) that charges both tRNA(Asp) and tRNA(Asn) with aspartic acid. Recently, it has been shown for the first time in an organism (Pseudomonas aeruginosa PAO1) that the transamidation pathway is the only route of synthesis of Asn-tRNA(Asn) but does not participate in Gln-tRNA(Gln) formation. P. aeruginosa PAO1 has a nondiscriminating AspRS. We report here the identification of two residues in the anticodon recognition domain (H31 and G83) which are implicated in the recognition of tRNA(Asn). Sequence comparisons of putative discriminating and nondiscriminating AspRSs (based on the presence or absence of the AdT operon and of AsnRS) revealed that bacterial nondiscriminating AspRSs possess a histidine at position 31 and usually a glycine at position 83, whereas discriminating AspRSs possess a leucine at position 31 and a residue other than a glycine at position 83. Mutagenesis of these residues of P. aeruginosa AspRS from histidine to leucine and from glycine to lysine increased the specificity of tRNA(Asp) charging over that of tRNA(Asn) by 3.5-fold and 4.2-fold, respectively. Thus, we show these residues to be determinants of the relaxed specificity of this nondiscriminating AspRS. Using available crystallographic data, we found that the H31 residue could interact with the central bases of the anticodons of the tRNA(Asp) and tRNA(Asn). Therefore, these two determinants of specificity of P. aeruginosa AspRS could be important for all bacterial AspRSs.
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Affiliation(s)
- Dominic Bernard
- Centre de Recherche en Infectiologie, CHU Laval, 2705 Boulevard Laurier, RC-709, Sainte-Foy, Quebec, Canada G1V 4G2
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34
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Wu HL, Bagby S, van den Elsen JMH. Evolution of the Genetic Triplet Code via Two Types of Doublet Codons. J Mol Evol 2005; 61:54-64. [PMID: 16059752 DOI: 10.1007/s00239-004-0224-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 02/21/2005] [Indexed: 10/25/2022]
Abstract
Explaining the apparent non-random codon distribution and the nature and number of amino acids in the 'standard' genetic code remains a challenge, despite the various hypotheses so far proposed. In this paper we propose a simple new hypothesis for code evolution involving a progression from singlet to doublet to triplet codons with a reading mechanism that moves three bases each step. We suggest that triplet codons gradually evolved from two types of ambiguous doublet codons, those in which the first two bases of each three-base window were read ('prefix' codons) and those in which the last two bases of each window were read ('suffix' codons). This hypothesis explains multiple features of the genetic code such as the origin of the pattern of four-fold degenerate and two-fold degenerate triplet codons, the origin of its error minimising properties, and why there are only 20 amino acids.
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Affiliation(s)
- Huan-Lin Wu
- Department of Biology and Biochemistry, University of Bath, 4 South, Claverton Down, Bath BA2 7AY, UK
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35
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Feng L, Yuan J, Toogood H, Tumbula-Hansen D, Söll D. Aspartyl-tRNA Synthetase Requires a Conserved Proline in the Anticodon-binding Loop for tRNAAsn Recognition in Vivo. J Biol Chem 2005; 280:20638-41. [PMID: 15781458 DOI: 10.1074/jbc.m500874200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most prokaryotes require Asp-tRNA(Asn) for the synthesis of Asn-tRNA(Asn). This misacylated tRNA species is synthesized by a non-discriminating aspartyl-tRNA synthetase (AspRS) that acylates both tRNA(Asp) and tRNA(Asn) with aspartate. In contrast, a discriminating AspRS forms only Asp-tRNA(Asp). Here we show that a conserved proline (position 77) in the L1 loop of the non-discriminating Deinococcus radiodurans AspRS2 is required for tRNA(Asn) recognition in vivo. Escherichia coli trpA34 was transformed with DNA from a library of D. radiodurans aspS2 genes with a randomized codon 77 and then subjected to in vivo selection for Asp-tRNA(Asn) formation by growth in minimal medium. Only proline codons were found at position 77 in the aspS2 genes isolated from 21 of the resulting viable colonies. However, when the aspS temperature-sensitive E. coli strain CS89 was transformed with the same DNA library and then screened for Asp-tRNA(Asp) formation in vivo by growth at the non-permissive temperature, codons for seven other amino acids besides proline were identified at position 77 in the isolates examined. Thus, replacement of proline 77 by cysteine, isoleucine, leucine, lysine, phenylalanine, serine, or valine resulted in mutant D. radiodurans AspRS2 enzymes still capable of forming Asp-tRNA(Asp) but unable to recognize tRNA(Asn). This strongly suggests that proline 77 is responsible for the non-discriminatory tRNA recognition properties of this enzyme.
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Affiliation(s)
- Liang Feng
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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36
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Rinehart J, Krett B, Rubio MAT, Alfonzo JD, Söll D. Saccharomyces cerevisiae imports the cytosolic pathway for Gln-tRNA synthesis into the mitochondrion. Genes Dev 2005; 19:583-92. [PMID: 15706032 PMCID: PMC551578 DOI: 10.1101/gad.1269305] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Accepted: 01/06/2005] [Indexed: 11/25/2022]
Abstract
Aminoacyl-tRNA (aa-tRNA) formation, an essential process in protein biosynthesis, is generally achieved by direct attachment of an amino acid to tRNA by the aa-tRNA synthetases. An exception is Gln-tRNA synthesis, which in eukaryotes is catalyzed by glutaminyl-tRNA synthetase (GlnRS), while most bacteria, archaea, and chloroplasts employ the transamidation pathway, in which a tRNA-dependent glutamate modification generates Gln-tRNA. Mitochondrial protein synthesis is carried out normally by mitochondrial enzymes and organelle-encoded tRNAs that are different from their cytoplasmic counterparts. Early work suggested that mitochondria use the transamidation pathway for Gln-tRNA formation. We found no biochemical support for this in Saccharomyces cerevisiae mitochondria, but demonstrated the presence of the cytoplasmic GlnRS in the organelle and its involvement in mitochondrial Gln-tRNA synthesis. In addition, we showed in vivo localization of cytoplasmic tRNAGln in mitochondria and demonstrated its role in mitochondrial translation. We furthermore reconstituted in vitro cytoplasmic tRNAGln import into mitochondria by a novel mechanism. This tRNA import mechanism expands our knowledge of RNA trafficking in the eukaryotic cell. These findings change our view of the evolution of organellar protein synthesis.
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MESH Headings
- Amino Acyl-tRNA Synthetases/genetics
- Amino Acyl-tRNA Synthetases/metabolism
- Biological Transport, Active/genetics
- Biological Transport, Active/physiology
- Gene Expression Regulation, Fungal/genetics
- Gene Expression Regulation, Fungal/physiology
- Mitochondria/genetics
- Mitochondria/physiology
- Protein Biosynthesis/genetics
- Protein Biosynthesis/physiology
- Protein Transport/genetics
- Protein Transport/physiology
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- RNA, Transfer, Gln/genetics
- RNA, Transfer, Gln/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/physiology
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
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Affiliation(s)
- Jesse Rinehart
- Department of Molecular Biophysics and Biochemistry, and Department of Chemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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37
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Lee J, Hendrickson TL. Divergent anticodon recognition in contrasting glutamyl-tRNA synthetases. J Mol Biol 2005; 344:1167-74. [PMID: 15561136 PMCID: PMC2897014 DOI: 10.1016/j.jmb.2004.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 09/30/2004] [Accepted: 10/11/2004] [Indexed: 10/26/2022]
Abstract
The pathogenic bacterium Helicobacter pylori utilizes two essential glutamyl-tRNA synthetases (GluRS1 and GluRS2). These two enzymes are closely related in evolution and yet they aminoacylate contrasting tRNAs. GluRS1 is a canonical discriminating GluRS (D-GluRS) that biosynthesizes Glu-tRNA(Glu) and cannot make Glu-tRNA(Gln). In contrast, GluRS2 is non-canonical as it is only essential for the production of misacylated Glu-tRNA(Gln). The co-existence and evident divergence of these two enzymes was capitalized upon to directly examine how GluRS2 acquired tRNA(Gln) specificity. One key feature that distinguishes tRNA(Glu) from tRNA(Gln) is the third position in the anticodon of each tRNA (C36 versus G36, respectively). By comparing sequence alignments of different GluRSs, including GluRS1s and GluRS2s, to the crystal structure of the Thermus thermophilus D-GluRS:tRNA(Glu) complex, a divergent pattern of conservation in enzymes that aminoacylate tRNA(Glu)versus those specific for tRNA(Gln) emerged and was experimentally validated. In particular, when an arginine conserved in discriminating GluRSs and GluRS1s was inserted into Hp GluRS2 (Glu334Arg GluRS2), the catalytic efficiency of the mutant enzyme (k(cat)/K(Mapp)) was reduced by approximately one order of magnitude towards tRNA(Gln). However, this mutation did not introduce activity towards tRNA(Glu). In contrast, disruption of a glycine that is conserved in all GluRS2s but not in other GluRSs (Gly417Thr GluRS2) generated a mutant GluRS2 with weak activity towards tRNA(Glu1). Synergy between these two mutations was observed in the double mutant (Glu334Arg/Gly417Thr GluRS2), which specifically and more robustly aminoacylates tRNA(Glu1) instead of tRNA(Gln). As GluRS1 and GluRS2 are related by an apparent gene duplication event, these results demonstrate that we can experimentally map critical evolutionary events in the emergence of new tRNA specificities.
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Affiliation(s)
- Joohee Lee
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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38
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Affiliation(s)
- Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210-1292, USA.
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O'Donoghue P, Luthey-Schulten Z. On the evolution of structure in aminoacyl-tRNA synthetases. Microbiol Mol Biol Rev 2004; 67:550-73. [PMID: 14665676 PMCID: PMC309052 DOI: 10.1128/mmbr.67.4.550-573.2003] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aminoacyl-tRNA synthetases are one of the major protein components in the translation machinery. These essential proteins are found in all forms of life and are responsible for charging their cognate tRNAs with the correct amino acid. The evolution of the tRNA synthetases is of fundamental importance with respect to the nature of the biological cell and the transition from an RNA world to the modern world dominated by protein-enzymes. We present a structure-based phylogeny of the aminoacyl-tRNA synthetases. By using structural alignments of all of the aminoacyl-tRNA synthetases of known structure in combination with a new measure of structural homology, we have reconstructed the evolutionary history of these proteins. In order to derive unbiased statistics from the structural alignments, we introduce a multidimensional QR factorization which produces a nonredundant set of structures. Since protein structure is more highly conserved than protein sequence, this study has allowed us to glimpse the evolution of protein structure that predates the root of the universal phylogenetic tree. The extensive sequence-based phylogenetic analysis of the tRNA synthetases (Woese et al., Microbiol. Mol. Biol. Rev. 64:202-236, 2000) has further enabled us to reconstruct the complete evolutionary profile of these proteins and to make connections between major evolutionary events and the resulting changes in protein shape. We also discuss the effect of functional specificity on protein shape over the complex evolutionary course of the tRNA synthetases.
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Affiliation(s)
- Patrick O'Donoghue
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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O'Donoghue P, Luthey-Schulten Z. On the evolution of structure in aminoacyl-tRNA synthetases. Microbiol Mol Biol Rev 2003; 67:550-573. [PMID: 14665676 DOI: 10.1128/mmbr.67.4.550-573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
The aminoacyl-tRNA synthetases are one of the major protein components in the translation machinery. These essential proteins are found in all forms of life and are responsible for charging their cognate tRNAs with the correct amino acid. The evolution of the tRNA synthetases is of fundamental importance with respect to the nature of the biological cell and the transition from an RNA world to the modern world dominated by protein-enzymes. We present a structure-based phylogeny of the aminoacyl-tRNA synthetases. By using structural alignments of all of the aminoacyl-tRNA synthetases of known structure in combination with a new measure of structural homology, we have reconstructed the evolutionary history of these proteins. In order to derive unbiased statistics from the structural alignments, we introduce a multidimensional QR factorization which produces a nonredundant set of structures. Since protein structure is more highly conserved than protein sequence, this study has allowed us to glimpse the evolution of protein structure that predates the root of the universal phylogenetic tree. The extensive sequence-based phylogenetic analysis of the tRNA synthetases (Woese et al., Microbiol. Mol. Biol. Rev. 64:202-236, 2000) has further enabled us to reconstruct the complete evolutionary profile of these proteins and to make connections between major evolutionary events and the resulting changes in protein shape. We also discuss the effect of functional specificity on protein shape over the complex evolutionary course of the tRNA synthetases.
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Affiliation(s)
- Patrick O'Donoghue
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Brevet A, Chen J, Commans S, Lazennec C, Blanquet S, Plateau P. Anticodon recognition in evolution: switching tRNA specificity of an aminoacyl-tRNA synthetase by site-directed peptide transplantation. J Biol Chem 2003; 278:30927-35. [PMID: 12766171 DOI: 10.1074/jbc.m302618200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The highly conserved aspartyl-, asparaginyl-, and lysyl-tRNA synthetases compose one subclass of aminoacyl-tRNA synthetases, called IIb. The three enzymes possess an OB-folded extension at their N terminus. The function of this extension is to specifically recognize the anticodon triplet of the tRNA. Three-dimensional models of bacterial aspartyl- and lysyl-tRNA synthetases complexed to tRNA indicate that a rigid scaffold of amino acid residues along the five beta-strands of the OB-fold accommodates the base U at the center of the anticodon. The binding of the adjacent anticodon bases occurs through interactions with a flexible loop joining strands 4 and 5 (L45). As a result, a switching of the specificity of lysyl-tRNA synthetase from tRNALys (anticodon UUU) toward tRNAAsp (GUC) could be attempted by transplanting the small loop L45 of aspartyl-tRNA synthetase inside lysyl-tRNA synthetase. Upon this transplantation, lysyl-tRNA synthetase loses its capacity to aminoacylate tRNALys. In exchange, the chimeric enzyme acquires the capacity to charge tRNAAsp with lysine. Upon giving the tRNAAsp substrate the discriminator base of tRNALys, the specificity shift is improved. The change of specificity was also established in vivo. Indeed, the transplanted lysyl-tRNA synthetase succeeds in suppressing a missense Lys --> Asp mutation inserted into the beta-lactamase gene. These results functionally establish that sequence variation in a small peptide region of subclass IIb aminoacyl-tRNA synthetases contributes to specification of nucleic acid recognition. Because this peptide element is not part of the core catalytic structure, it may have evolved independently of the active sites of these synthetases.
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Affiliation(s)
- Annie Brevet
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex, France
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