1
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Kompatscher M, Bartosik K, Erharter K, Plangger R, Juen F, Kreutz C, Micura R, Westhof E, Erlacher M. Contribution of tRNA sequence and modifications to the decoding preferences of E. coli and M. mycoides tRNAGlyUCC for synonymous glycine codons. Nucleic Acids Res 2024; 52:1374-1386. [PMID: 38050960 PMCID: PMC10853795 DOI: 10.1093/nar/gkad1136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/06/2023] [Accepted: 11/10/2023] [Indexed: 12/07/2023] Open
Abstract
tRNA superwobbling, used by certain bacteria and organelles, is an intriguing decoding concept in which a single tRNA isoacceptor is used to decode all synonymous codons of a four-fold degenerate codon box. While Escherichia coli relies on three tRNAGly isoacceptors to decode the four glycine codons (GGN), Mycoplasma mycoides requires only a single tRNAGly. Both organisms express tRNAGly with the anticodon UCC, which are remarkably similar in sequence but different in their decoding ability. By systematically introducing mutations and altering the number and type of tRNA modifications using chemically synthesized tRNAs, we elucidated the contribution of individual nucleotides and chemical groups to decoding by the E. coli and M. mycoides tRNAGly. The tRNA sequence was identified as the key factor for superwobbling, revealing the T-arm sequence as a novel pivotal element. In addition, the presence of tRNA modifications, although not essential for providing superwobbling, was shown to delicately fine-tune and balance the decoding of synonymous codons. This emphasizes that the tRNA sequence and its modifications together form an intricate system of high complexity that is indispensable for accurate and efficient decoding.
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Affiliation(s)
- Maria Kompatscher
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Karolina Bartosik
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Kevin Erharter
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Raphael Plangger
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Fabian Sebastian Juen
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Eric Westhof
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l’ARN, CNRS UPR 9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France
| | - Matthias D Erlacher
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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2
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Dulic M, Godinic-Mikulcic V, Kekez M, Evic V, Rokov-Plavec J. Protein-Protein Interactions of Seryl-tRNA Synthetases with Emphasis on Human Counterparts and Their Connection to Health and Disease. Life (Basel) 2024; 14:124. [PMID: 38255739 PMCID: PMC10817482 DOI: 10.3390/life14010124] [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: 12/06/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
Seryl-tRNA synthetases (SerRSs), members of the aminoacyl-tRNA synthetase family, interact with diverse proteins, enabling SerRSs to enhance their role in the translation of the genetic message or to perform alternative functions in cellular processes beyond translation. Atypical archaeal SerRS interacts with arginyl-tRNA synthetase and proteins of the ribosomal P-stalk to optimize translation through tRNA channeling. The complex between yeast SerRS and peroxin Pex21p provides a connection between translation and peroxisome function. The partnership between Arabidopsis SerRS and BEN1 indicates a link between translation and brassinosteroid metabolism and may be relevant in plant stress response mechanisms. In Drosophila, the unusual heterodimeric mitochondrial SerRS coordinates mitochondrial translation and replication via interaction with LON protease. Evolutionarily conserved interactions of yeast and human SerRSs with m3C32 tRNA methyltransferases indicate coordination between tRNA modification and aminoacylation in the cytosol and mitochondria. Human cytosolic SerRS is a cellular hub protein connecting translation to vascular development, angiogenesis, lipogenesis, and telomere maintenance. When translocated to the nucleus, SerRS acts as a master negative regulator of VEGFA gene expression. SerRS alone or in complex with YY1 and SIRT2 competes with activating transcription factors NFκB1 and c-Myc, resulting in balanced VEGFA expression important for proper vascular development and angiogenesis. In hypoxia, SerRS phosphorylation diminishes its binding to the VEGFA promoter, while the lack of nutrients triggers SerRS glycosylation, reducing its nuclear localization. Additionally, SerRS binds telomeric DNA and cooperates with the shelterin protein POT1 to regulate telomere length and cellular senescence. As an antitumor and antiangiogenic factor, human cytosolic SerRS appears to be a promising drug target and therapeutic agent for treating cancer, cardiovascular diseases, and possibly obesity and aging.
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Affiliation(s)
| | | | | | | | - Jasmina Rokov-Plavec
- Division of Biochemistry, Department of Chemistry, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia; (M.D.); (V.G.-M.); (M.K.); (V.E.)
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3
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Kuhle B, Chen Q, Schimmel P. tRNA renovatio: Rebirth through fragmentation. Mol Cell 2023; 83:3953-3971. [PMID: 37802077 PMCID: PMC10841463 DOI: 10.1016/j.molcel.2023.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/15/2023] [Accepted: 09/12/2023] [Indexed: 10/08/2023]
Abstract
tRNA function is based on unique structures that enable mRNA decoding using anticodon trinucleotides. These structures interact with specific aminoacyl-tRNA synthetases and ribosomes using 3D shape and sequence signatures. Beyond translation, tRNAs serve as versatile signaling molecules interacting with other RNAs and proteins. Through evolutionary processes, tRNA fragmentation emerges as not merely random degradation but an act of recreation, generating specific shorter molecules called tRNA-derived small RNAs (tsRNAs). These tsRNAs exploit their linear sequences and newly arranged 3D structures for unexpected biological functions, epitomizing the tRNA "renovatio" (from Latin, meaning renewal, renovation, and rebirth). Emerging methods to uncover full tRNA/tsRNA sequences and modifications, combined with techniques to study RNA structures and to integrate AI-powered predictions, will enable comprehensive investigations of tRNA fragmentation products and new interaction potentials in relation to their biological functions. We anticipate that these directions will herald a new era for understanding biological complexity and advancing pharmaceutical engineering.
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Affiliation(s)
- Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA; Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Qi Chen
- Molecular Medicine Program, Department of Human Genetics, and Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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4
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Kuhle B, Hirschi M, Doerfel LK, Lander GC, Schimmel P. Structural basis for a degenerate tRNA identity code and the evolution of bimodal specificity in human mitochondrial tRNA recognition. Nat Commun 2023; 14:4794. [PMID: 37558671 PMCID: PMC10412605 DOI: 10.1038/s41467-023-40354-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/22/2023] [Indexed: 08/11/2023] Open
Abstract
Animal mitochondrial gene expression relies on specific interactions between nuclear-encoded aminoacyl-tRNA synthetases and mitochondria-encoded tRNAs. Their evolution involves an antagonistic interplay between strong mutation pressure on mtRNAs and selection pressure to maintain their essential function. To understand the molecular consequences of this interplay, we analyze the human mitochondrial serylation system, in which one synthetase charges two highly divergent mtRNASer isoacceptors. We present the cryo-EM structure of human mSerRS in complex with mtRNASer(UGA), and perform a structural and functional comparison with the mSerRS-mtRNASer(GCU) complex. We find that despite their common function, mtRNASer(UGA) and mtRNASer(GCU) show no constrain to converge on shared structural or sequence identity motifs for recognition by mSerRS. Instead, mSerRS evolved a bimodal readout mechanism, whereby a single protein surface recognizes degenerate identity features specific to each mtRNASer. Our results show how the mutational erosion of mtRNAs drove a remarkable innovation of intermolecular specificity rules, with multiple evolutionary pathways leading to functionally equivalent outcomes.
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Affiliation(s)
- Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA.
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073, Göttingen, Germany.
| | - Marscha Hirschi
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Lili K Doerfel
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- The Scripps Florida Research Institute at the University of Florida, Jupiter, FL, 33458, USA
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5
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Lee D, Kim MK, Choi JI. Development of Orthogonal Aminoacyl tRNA Synthetase Mutant with Enhanced Incorporation Ability with Para-azido-L-phenylalanine. BIOTECHNOL BIOPROC E 2023. [DOI: 10.1007/s12257-022-0252-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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6
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Jin D, Zhu Y, Schubert HL, Goff SP, Musier-Forsyth K. HIV-1 Gag Binds the Multi-Aminoacyl-tRNA Synthetase Complex via the EPRS Subunit. Viruses 2023; 15:474. [PMID: 36851687 PMCID: PMC9967848 DOI: 10.3390/v15020474] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/31/2023] [Accepted: 01/31/2023] [Indexed: 02/11/2023] Open
Abstract
Host factor tRNAs facilitate the replication of retroviruses such as human immunodeficiency virus type 1 (HIV-1). HIV-1 uses human tRNALys3 as the primer for reverse transcription, and the assembly of HIV-1 structural protein Gag at the plasma membrane (PM) is regulated by matrix (MA) domain-tRNA interactions. A large, dynamic multi-aminoacyl-tRNA synthetase complex (MSC) exists in the cytosol and consists of eight aminoacyl-tRNA synthetases (ARSs) and three other cellular proteins. Proteomic studies to identify HIV-host interactions have identified the MSC as part of the HIV-1 Gag and MA interactomes. Here, we confirmed that the MA domain of HIV-1 Gag forms a stable complex with the MSC, mapped the primary interaction site to the linker domain of bi-functional human glutamyl-prolyl-tRNA synthetase (EPRS), and showed that the MA-EPRS interaction was RNA dependent. MA mutations that significantly reduced the EPRS interaction reduced viral infectivity and mapped to MA residues that also interact with phosphatidylinositol-(4,5)-bisphosphate. Overexpression of EPRS or EPRS fragments did not affect susceptibility to HIV-1 infection, and knockdown of EPRS reduced both a control reporter gene and HIV-1 protein translation. EPRS knockdown resulted in decreased progeny virion production, but the decrease could not be attributed to selective effects on virus gene expression, and the specific infectivity of the virions remained unchanged. While the precise function of the Gag-EPRS interaction remains uncertain, we discuss possible effects of the interaction on either virus or host activities.
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Affiliation(s)
- Danni Jin
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Yiping Zhu
- Departments of Biochemistry and Molecular Biophysics, and Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Heidi L. Schubert
- Department of Biochemistry, University of Utah, Salt Lake City, UT 841122, USA
| | - Stephen P. Goff
- Departments of Biochemistry and Molecular Biophysics, and Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
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7
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Giegé R, Eriani G. The tRNA identity landscape for aminoacylation and beyond. Nucleic Acids Res 2023; 51:1528-1570. [PMID: 36744444 PMCID: PMC9976931 DOI: 10.1093/nar/gkad007] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 12/21/2022] [Accepted: 01/03/2023] [Indexed: 02/07/2023] Open
Abstract
tRNAs are key partners in ribosome-dependent protein synthesis. This process is highly dependent on the fidelity of tRNA aminoacylation by aminoacyl-tRNA synthetases and relies primarily on sets of identities within tRNA molecules composed of determinants and antideterminants preventing mischarging by non-cognate synthetases. Such identity sets were discovered in the tRNAs of a few model organisms, and their properties were generalized as universal identity rules. Since then, the panel of identity elements governing the accuracy of tRNA aminoacylation has expanded considerably, but the increasing number of reported functional idiosyncrasies has led to some confusion. In parallel, the description of other processes involving tRNAs, often well beyond aminoacylation, has progressed considerably, greatly expanding their interactome and uncovering multiple novel identities on the same tRNA molecule. This review highlights key findings on the mechanistics and evolution of tRNA and tRNA-like identities. In addition, new methods and their results for searching sets of multiple identities on a single tRNA are discussed. Taken together, this knowledge shows that a comprehensive understanding of the functional role of individual and collective nucleotide identity sets in tRNA molecules is needed for medical, biotechnological and other applications.
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Affiliation(s)
- Richard Giegé
- Correspondence may also be addressed to Richard Giegé.
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8
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Zhang J. Probing RNA Structures and Interactions Using Fluorescence Lifetime Analyses. Methods Mol Biol 2023; 2568:13-23. [PMID: 36227559 PMCID: PMC11268537 DOI: 10.1007/978-1-0716-2687-0_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Structural analyses of large, complex noncoding RNAs continue to lag behind their rapid discovery and functional descriptions. Site-specifically incorporated, minimally invasive fluorescent probes such as 2-aminopurine (2AP) and pyrrolo-cytosine (PyC) have provided essential complementary information about local RNA structure, conformational dynamics, and interactions. Here I describe a protocol that benchmarks and correlates local RNA conformations with their respective fluorescence lifetimes, as a general technique that confers key advantages over fluorescence intensity-based methods. The observation that fluorescence lifetimes are more sensitive to local structures than sequence contexts suggests broad utility across diverse RNA and ribonucleoprotein systems.
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Affiliation(s)
- Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
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9
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Byun JK, Vu JA, He SL, Jang JC, Musier-Forsyth K. Plant-exclusive domain of trans-editing enzyme ProXp-ala confers dimerization and enhanced tRNA binding. J Biol Chem 2022; 298:102255. [PMID: 35835222 PMCID: PMC9425024 DOI: 10.1016/j.jbc.2022.102255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/26/2022] Open
Abstract
Faithful translation of the genetic code is critical for the viability of all living organisms. The trans-editing enzyme ProXp-ala prevents Pro to Ala mutations during translation by hydrolyzing misacylated Ala-tRNAPro that has been synthesized by prolyl-tRNA synthetase. Plant ProXp-ala sequences contain a conserved C-terminal domain (CTD) that is absent in other organisms; the origin, structure, and function of this extra domain are unknown. To characterize the plant-specific CTD, we performed bioinformatics and computational analyses that provided a model consistent with a conserved α-helical structure. We also expressed and purified wildtype Arabidopsis thaliana (At) ProXp-ala in Escherichia coli, as well as variants lacking the CTD or containing only the CTD. Circular dichroism spectroscopy confirmed a loss of α-helical signal intensity upon CTD truncation. Size-exclusion chromatography with multiangle laser-light scattering revealed that wildtype At ProXp-ala was primarily dimeric and CTD truncation abolished dimerization in vitro. Furthermore, bimolecular fluorescence complementation assays in At protoplasts support a role for the CTD in homodimerization in vivo. The deacylation rate of Ala-tRNAPro by At ProXp-ala was also significantly reduced in the absence of the CTD, and kinetic assays indicated that the reduction in activity is primarily due to a tRNA binding defect. Overall, these results broaden our understanding of eukaryotic translational fidelity in the plant kingdom. Our study reveals that the plant-specific CTD plays a significant role in substrate binding and canonical editing function. Through its ability to facilitate protein-protein interactions, we propose the CTD may also provide expanded functional potential for trans-editing enzymes in plants.
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Affiliation(s)
- Jun-Kyu Byun
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - John A Vu
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Siou-Luan He
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Jyan-Chyun Jang
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA.
| | - Karin Musier-Forsyth
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.
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10
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Kuhle B, Hirschi M, Doerfel LK, Lander GC, Schimmel P. Structural basis for shape-selective recognition and aminoacylation of a D-armless human mitochondrial tRNA. Nat Commun 2022; 13:5100. [PMID: 36042193 PMCID: PMC9427863 DOI: 10.1038/s41467-022-32544-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/04/2022] [Indexed: 02/05/2023] Open
Abstract
Human mitochondrial gene expression relies on the specific recognition and aminoacylation of mitochondrial tRNAs (mtRNAs) by nuclear-encoded mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs). Despite their essential role in cellular energy homeostasis, strong mutation pressure and genetic drift have led to an unparalleled sequence erosion of animal mtRNAs. The structural and functional consequences of this erosion are not understood. Here, we present cryo-EM structures of the human mitochondrial seryl-tRNA synthetase (mSerRS) in complex with mtRNASer(GCU). These structures reveal a unique mechanism of substrate recognition and aminoacylation. The mtRNASer(GCU) is highly degenerated, having lost the entire D-arm, tertiary core, and stable L-shaped fold that define canonical tRNAs. Instead, mtRNASer(GCU) evolved unique structural innovations, including a radically altered T-arm topology that serves as critical identity determinant in an unusual shape-selective readout mechanism by mSerRS. Our results provide a molecular framework to understand the principles of mito-nuclear co-evolution and specialized mechanisms of tRNA recognition in mammalian mitochondrial gene expression.
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Affiliation(s)
- Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA.
| | - Marscha Hirschi
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Lili K Doerfel
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92121, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- The Scripps Florida Research Institute at the University of Florida, Jupiter, FL, 33458, USA
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11
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Wusiman W, Zhang Z, Ding Q, Liu M. The pathophyiological role of aminoacyl-tRNA synthetases in digestive system diseases. Front Physiol 2022; 13:935576. [PMID: 36017335 PMCID: PMC9396140 DOI: 10.3389/fphys.2022.935576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/05/2022] [Indexed: 12/24/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) catalyze the ligation of amino acids to their cognate transfer RNAs and are indispensable enzymes for protein biosynthesis in all the cells. Previously, ARSs were considered simply as housekeeping enzymes, however, they are now known to be involved in a variety of physiological and pathological processes, such as tumorigenesis, angiogenesis, and immune response. In this review, we summarize the role of ARSs in the digestive system, including the esophagus, stomach, small intestine, colon, as well as the auxiliary organs such as the pancreas, liver, and the gallbladder. Furthermore, we specifically focus on the diagnostic and prognostic value of ARSs in cancers, aiming to provide new insights into the pathophysiological implications of ARSs in tumorigenesis.
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Affiliation(s)
- Wugelanmu Wusiman
- Department of Gastroenterology, Institute of Liver and Gastrointestinal Diseases, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zerui Zhang
- Department of Gastroenterology, Institute of Liver and Gastrointestinal Diseases, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiang Ding
- Department of Gastroenterology, Institute of Liver and Gastrointestinal Diseases, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mei Liu
- Department of Gastroenterology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- *Correspondence: Mei Liu,
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12
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Garin S, Levi O, Forrest ME, Antonellis A, Arava YS. Comprehensive characterization of mRNAs associated with yeast cytosolic aminoacyl-tRNA synthetases. RNA Biol 2021; 18:2605-2616. [PMID: 34039240 PMCID: PMC8632134 DOI: 10.1080/15476286.2021.1935116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 12/27/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are a conserved family of enzymes with an essential role in protein synthesis: ligating amino acids to cognate tRNA molecules for translation. In addition to their role in tRNA charging, aaRSs have acquired non-canonical functions, including post-transcriptional regulation of mRNA expression. Yet, the extent and mechanisms of these post-transcriptional functions are largely unknown. Herein, we performed a comprehensive transcriptome analysis to define the mRNAs that are associated with almost all aaRSs present in S. cerevisiae cytosol. Nineteen (out of twenty) isogenic strains of GFP-tagged cytosolic aaRSs were subjected to immunoprecipitation with anti-GFP beads along with an untagged control. mRNAs associated with each aaRS were then identified by RNA-seq. The extent of mRNA association varied significantly between aaRSs, from MetRS in which none appeared to be statistically significant, to PheRS that binds hundreds of different mRNAs. Interestingly, many target mRNAs are bound by multiple aaRSs, suggesting co-regulation by this family of enzymes. Gene Ontology analyses for aaRSs with a considerable number of target mRNAs discovered an enrichment for pathways of amino acid metabolism and of ribosome biosynthesis. Furthermore, sequence and structure motif analysis revealed for some aaRSs an enrichment for motifs that resemble the anticodon stem loop of cognate tRNAs. These data suggest that aaRSs coordinate mRNA expression in response to amino acid availability and may utilize RNA elements that mimic their canonical tRNA binding partners.
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Affiliation(s)
- Shahar Garin
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Ofri Levi
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Megan E. Forrest
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Yoav S. Arava
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
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13
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Abstract
A nonsense suppressor tRNA (sup-tRNA) allows a natural or non-natural amino acid to be assigned to a nonsense codon in mRNA. Sup-tRNAs were utilized initially for studying tRNA functions but lately are used more for protein engineering and gene regulation. In the latter application, a sup-tRNA that is aminoacylated with a natural amino acid by the corresponding aminoacyl-tRNA synthetase is used to express a full-length natural protein from its mutated gene with a nonsense codon in the middle. This type of sup-tRNA has recently been artificially evolved to develop biosensors. In these biosensors, an analyte induces the processing of an engineered premature sup-tRNA into a mature sup-tRNA, which suppresses the corresponding nonsense codon incorporated into a gene, encoding an easily detectable reporter protein. This review introduces sup-tRNA-based biosensors that the author's group has developed by utilizing bacterial and eukaryotic cell-free translation systems.
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14
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Abstract
The aminoacyl-tRNA synthetases are an essential and universally distributed family of enzymes that plays a critical role in protein synthesis, pairing tRNAs with their cognate amino acids for decoding mRNAs according to the genetic code. Synthetases help to ensure accurate translation of the genetic code by using both highly accurate cognate substrate recognition and stringent proofreading of noncognate products. While alterations in the quality control mechanisms of synthetases are generally detrimental to cellular viability, recent studies suggest that in some instances such changes facilitate adaption to stress conditions. Beyond their central role in translation, synthetases are also emerging as key players in an increasing number of other cellular processes, with far-reaching consequences in health and disease. The biochemical versatility of the synthetases has also proven pivotal in efforts to expand the genetic code, further emphasizing the wide-ranging roles of the aminoacyl-tRNA synthetase family in synthetic and natural biology.
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Affiliation(s)
- Miguel Angel Rubio Gomez
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Michael Ibba
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
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15
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Mohanty BK, Agrawal A, Kushner SR. Generation of pre-tRNAs from polycistronic operons is the essential function of RNase P in Escherichia coli. Nucleic Acids Res 2020; 48:2564-2578. [PMID: 31993626 PMCID: PMC7049720 DOI: 10.1093/nar/gkz1188] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 12/05/2019] [Accepted: 01/27/2020] [Indexed: 11/14/2022] Open
Abstract
Ribonuclease P (RNase P) is essential for the 5′-end maturation of tRNAs in all kingdoms of life. In Escherichia coli, temperature sensitive mutations in either its protein (rnpA49) and or RNA (rnpB709) subunits lead to inviability at nonpermissive temperatures. Using the rnpA49 temperature sensitive allele, which encodes a partially defective RNase P at the permissive temperature, we show here for the first time that the processing of RNase P-dependent polycistronic tRNA operons to release pre-tRNAs is the essential function of the enzyme, since the majority of 5′-immature tRNAs can be aminoacylated unless their 5′-extensions ≥8 nt. Surprisingly, the failure of 5′-end maturation elicits increased polyadenylation of some pre-tRNAs by poly(A) polymerase I (PAP I), which exacerbates inviability. The absence of PAP I led to improved aminoacylation of 5′-immature tRNAs. Our data suggest a more dynamic role for PAP I in maintaining functional tRNA levels in the cell.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Ankit Agrawal
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Sidney R Kushner
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- To whom correspondence should be addressed. Tel: +706 542 1440; Fax: +706 542 1439;
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16
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Srivastava A, Yesudhas D, Ramakrishnan C, Ahmad S, Gromiha MM. Role of disordered regions in transferring tyrosine to its cognate tRNA. Int J Biol Macromol 2020; 150:705-713. [PMID: 32057853 DOI: 10.1016/j.ijbiomac.2020.02.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/16/2020] [Accepted: 02/08/2020] [Indexed: 10/25/2022]
Abstract
Aminoacyl tRNA synthetase (AARS) plays an important role in transferring each amino acid to its cognate tRNA. Specifically, tyrosyl tRNA synthetase (TyrRS) is involved in various functions including protection from DNA damage due to oxidative stress, protein synthesis and cell signaling and can be an attractive target for controlling the pathogens by early inhibition of translation. TyrRS has two disordered regions, which lack a stable 3D structure in solution, and are involved in tRNA synthetase catalysis and stability. One of the disordered regions undergoes disorder-to-order transition (DOT) upon complex formation with tRNA whereas the other remains disordered (DR). In this work, we have explored the importance of these disordered regions using molecular dynamics simulations of both free and RNA-complexed states. We observed that the DOT and DR regions of the first subunit acts as a flap and interact with the acceptor arm of the tRNA. The DOT-DR flap closes when tyrosine (TyrRSTyr) is present at the active site of the complex and opens in the presence of tyrosine monophosphate (TyrRSYMP). The DOT and DR regions of the second subunit interact with the anticodon stem as well as D-loop of the tRNA, which might be involved in stabilizing the complex. The anticodon loop of the tRNA binds to the structured region present in the C-terminal of the protein, which is observed to be flexible during simulations. Detailed energy calculations also show that TyrRSTyr complex has stronger binding energy between tRNA and protein compared to TyrRSYMP; on the contrary, the anticodon is strongly bound in TyrRSYMP. The results obtained in the present study provide additional insights for understanding catalysis and the involvement of disordered regions in Tyr transfer to cognate tRNA.
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Affiliation(s)
- Ambuj Srivastava
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - Dhanusha Yesudhas
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - Chandrasekaran Ramakrishnan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - Shandar Ahmad
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - M Michael Gromiha
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India.
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17
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Li S, Su Z, Lehmann J, Stamatopoulou V, Giarimoglou N, Henderson FE, Fan L, Pintilie GD, Zhang K, Chen M, Ludtke SJ, Wang YX, Stathopoulos C, Chiu W, Zhang J. Structural basis of amino acid surveillance by higher-order tRNA-mRNA interactions. Nat Struct Mol Biol 2019; 26:1094-1105. [PMID: 31740854 PMCID: PMC6899168 DOI: 10.1038/s41594-019-0326-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/07/2019] [Indexed: 12/11/2022]
Abstract
Amino acid availability in Gram-positive bacteria is monitored by T-box riboswitches. T-boxes directly bind tRNAs, assess their aminoacylation state, and regulate the transcription or translation of downstream genes to maintain nutritional homeostasis. Here, we report cocrystal and cryo-EM structures of Geobacillus kaustophilus and Bacillus subtilis T-box-tRNA complexes, detailing their multivalent, exquisitely selective interactions. The T-box forms a U-shaped molecular vise that clamps the tRNA, captures its 3' end using an elaborate 'discriminator' structure, and interrogates its aminoacylation state using a steric filter fashioned from a wobble base pair. In the absence of aminoacylation, T-boxes clutch tRNAs and form a continuously stacked central spine, permitting transcriptional readthrough or translation initiation. A modeled aminoacyl disrupts tRNA-T-box stacking, severing the central spine and blocking gene expression. Our data establish a universal mechanism of amino acid sensing on tRNAs and gene regulation by T-box riboswitches and exemplify how higher-order RNA-RNA interactions achieve multivalency and specificity.
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Affiliation(s)
- Shuang Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Zhaoming Su
- Department of Bioengineering and Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA, USA
| | - Jean Lehmann
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Campus Paris-Saclay, Gif-sur-Yvette, France
| | | | - Nikoleta Giarimoglou
- Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Lixin Fan
- Small-Angle X-ray Scattering Core Facility, Center for Cancer Research of the National Cancer Institute, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc, Frederick, MD, USA
| | - Grigore D Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA, USA
| | - Kaiming Zhang
- Department of Bioengineering and Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA, USA
| | - Muyuan Chen
- Verna Marrs and McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Steven J Ludtke
- Verna Marrs and McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Yun-Xing Wang
- Small-Angle X-ray Scattering Core Facility, Center for Cancer Research of the National Cancer Institute, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc, Frederick, MD, USA.,Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | | | - Wah Chiu
- Department of Bioengineering and Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA, USA. .,Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, Stanford University, Stanford, CA, USA.
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
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18
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Cao KY, Pan Y, Yan TM, Jiang ZH. Purification, characterization and cytotoxic activities of individual tRNAs from Escherichia coli. Int J Biol Macromol 2019; 142:355-365. [PMID: 31593735 DOI: 10.1016/j.ijbiomac.2019.09.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 01/20/2023]
Abstract
Transfer RNAs (tRNAs) are the most abundant class in small non-coding RNAs which have been proved to be pharmacologically active. In the present study, we evaluated the potential anticancer activities of tRNAs from Escherichia coli MRE 600 to investigate the relationship between non-pathogenic Escherichia coli strain and colorectal cancer. To purify individual tRNAs, we firstly developed a two-dimensional liquid chromatography (2D-LC) and successfully obtained two pure tRNAs. Nuclease mediated base-specific digestions coupled with UHPLC-MS/MS techniques led to an identification of these two tRNAs as tRNA-Val(UAC) and tRNA-Leu(CAG) with typical cloverleaf-like secondary structure. MTT assay demonstrated that both tRNA-1 and tRNA-2 exhibit strong cytotoxicity with IC50 of 113.0 nM and 124.8 nM on HCT-8 cells in a dose-dependent manner. Further clonogenic assay revealed that the purified tRNAs exhibit significant inhibition in colony formation with survival percentage of 79.0 ± 1.6 and 71.2 ± 2.2 at the concentration of 100 nM. These findings provided evidences of anticancer activities of tRNAs from non-pathogenic Escherichia coli strain, indicating that the pharmacological effects of these neglected biomacromolecules from microorganisms should be emphasized. This study put new insights into the therapeutic effects of intestinal microorganism on human diseases, therefore broadened our knowledge of the biological functions of gut microbiota.
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Affiliation(s)
- Kai-Yue Cao
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau; Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau
| | - Yu Pan
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau; Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau
| | - Tong-Meng Yan
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau; Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau
| | - Zhi-Hong Jiang
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau; Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau.
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19
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Kumar A, Åqvist J, Satpati P. Principles of tRNA Ala Selection by Alanyl-tRNA Synthetase Based on the Critical G3·U70 Base Pair. ACS OMEGA 2019; 4:15539-15548. [PMID: 31572855 PMCID: PMC6761608 DOI: 10.1021/acsomega.9b01827] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
Throughout evolution, the presence of a single G3·U70 mismatch in the acceptor stem of tRNAAla is the major determinant for aminoacylation with alanine by alanyl-tRNA synthetase (AlaRS). Recently reported crystal structures of the complexes AlaRS-tRNAAla/G3·U70 and AlaRS-tRNAAla/A3·U70 suggest two very different conformations, representing a reactive and a nonreactive state, respectively. On the basis of these structures, it has been proposed that the G3·U70 base pair guides the -CCA end of the tRNA acceptor stem into the active site of AlaRS, thereby enabling aminoacylation. The crystal structures open up the possibility of directly computing the energetics of tRNA specificity by AlaRS. We have carried out molecular dynamics free-energy simulations to quantitatively estimate tRNA discrimination by AlaRS, focusing on the mutations of the single critical base pair G3·U70 to uncover the energetics underlying the accuracy of tRNA selection. The calculations show that the reactive complex is highly selective in favor of the cognate tRNAAla/G3·U70 over its noncognate analogues (A3·U70/G3·C70/A3·C70). In contrast, the nonreactive complex is predicted to be unselective between tRNAAla/G3·U70 and tRNAAla/A3·U70. Utilizing our calculated relative binding free energies, we show how a simple three-step kinetic scheme for aminoacylation, involving both an initial nonspecific binding step and a subsequent transition to a selective reactive complex, accounts for the observed kinetics of the process.
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Affiliation(s)
- Amit Kumar
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Johan Åqvist
- Department
of Cell and Molecular Biology, Uppsala University,
Biomedical Center, Box 596, Uppsala SE-751 24, Sweden
| | - Priyadarshi Satpati
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Guwahati, Guwahati 781039, Assam, India
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20
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Serrão VHB, Silva IR, da Silva MTA, Scortecci JF, de Freitas Fernandes A, Thiemann OH. The unique tRNASec and its role in selenocysteine biosynthesis. Amino Acids 2018; 50:1145-1167. [DOI: 10.1007/s00726-018-2595-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/26/2018] [Indexed: 12/26/2022]
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21
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Schmitt MA, Biddle W, Fisk JD. Mapping the Plasticity of the Escherichia coli Genetic Code with Orthogonal Pair-Directed Sense Codon Reassignment. Biochemistry 2018; 57:2762-2774. [PMID: 29668270 DOI: 10.1021/acs.biochem.8b00177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The relative quantitative importance of the factors that determine the fidelity of translation is largely unknown, which makes predicting the extent to which the degeneracy of the genetic code can be broken challenging. Our strategy of using orthogonal tRNA/aminoacyl tRNA synthetase pairs to precisely direct the incorporation of a single amino acid in response to individual sense and nonsense codons provides a suite of related data with which to examine the plasticity of the code. Each directed sense codon reassignment measurement is an in vivo competition experiment between the introduced orthogonal translation machinery and the natural machinery in Escherichia coli. This report discusses 20 new, related genetic codes, in which a targeted E. coli wobble codon is reassigned to tyrosine utilizing the orthogonal tyrosine tRNA/aminoacyl tRNA synthetase pair from Methanocaldococcus jannaschii. One at a time, reassignment of each targeted sense codon to tyrosine is quantified in cells by measuring the fluorescence of GFP variants in which the essential tyrosine residue is encoded by a non-tyrosine codon. Significantly, every wobble codon analyzed may be partially reassigned with efficiencies ranging from 0.8 to 41%. The accumulation of the suite of data enables a qualitative dissection of the relative importance of the factors affecting the fidelity of translation. While some correlation was observed between sense codon reassignment and either competing endogenous tRNA abundance or changes in aminoacylation efficiency of the altered orthogonal system, no single factor appears to predominately drive translational fidelity. Evaluation of relative cellular fitness in each of the 20 quantitatively characterized proteome-wide tyrosine substitution systems suggests that at a systems level, E. coli is robust to missense mutations.
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Affiliation(s)
- Margaret A Schmitt
- Department of Chemical and Biological Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - Wil Biddle
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - John D Fisk
- Department of Chemical and Biological Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States.,Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States.,School of Biomedical Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States
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22
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Koh CS, Sarin LP. Transfer RNA modification and infection – Implications for pathogenicity and host responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:419-432. [DOI: 10.1016/j.bbagrm.2018.01.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/04/2018] [Accepted: 01/19/2018] [Indexed: 12/19/2022]
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23
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The emerging complexity of the tRNA world: mammalian tRNAs beyond protein synthesis. Nat Rev Mol Cell Biol 2017; 19:45-58. [PMID: 28875994 DOI: 10.1038/nrm.2017.77] [Citation(s) in RCA: 277] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The discovery of the genetic code and tRNAs as decoders of the code transformed life science. However, after establishing the role of tRNAs in protein synthesis, the field moved to other parts of the RNA world. Now, tRNA research is blooming again, with demonstration of the involvement of tRNAs in various other pathways beyond translation and in adapting translation to environmental cues. These roles are linked to the presence of tRNA sequence variants known as isoacceptors and isodecoders, various tRNA base modifications, the versatility of protein binding partners and tRNA fragmentation events, all of which collectively create an incalculable complexity. This complexity provides a vast repertoire of tRNA species that can serve various functions in cellular homeostasis and in adaptation of cellular functions to changing environments, and it likely arose from the fundamental role of RNAs in early evolution.
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24
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Hoffman KS, Berg MD, Shilton BH, Brandl CJ, O'Donoghue P. Genetic selection for mistranslation rescues a defective co-chaperone in yeast. Nucleic Acids Res 2017; 45:3407-3421. [PMID: 27899648 PMCID: PMC5389508 DOI: 10.1093/nar/gkw1021] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022] Open
Abstract
Despite the general requirement for translation fidelity, mistranslation can be an adaptive response. We selected spontaneous second site mutations that suppress the stress sensitivity caused by a Saccharomyces cerevisiae tti2 allele with a Leu to Pro mutation at residue 187, identifying a single nucleotide mutation at the same position (C70U) in four tRNAProUGG genes. Linkage analysis and suppression by SUF9G3:U70 expressed from a centromeric plasmid confirmed the causative nature of the suppressor mutation. Since the mutation incorporates the G3:U70 identity element for alanyl-tRNA synthetase into tRNAPro, we hypothesized that suppression results from mistranslation of Pro187 in Tti2L187P as Ala. A strain expressing Tti2L187A was not stress sensitive. In vitro, tRNAProUGG (C70U) was mis-aminoacylated with alanine by alanyl–tRNA synthetase, but was not a substrate for prolyl–tRNA synthetase. Mass spectrometry from protein expressed in vivo and a novel GFP reporter for mistranslation confirmed substitution of alanine for proline at a rate of ∼6%. Mistranslating cells expressing SUF9G3:U70 induce a partial heat shock response but grow nearly identically to wild-type. Introducing the same G3:U70 mutation in SUF2 (tRNAProAGG) suppressed a second tti2 allele (tti2L50P). We have thus identified a strategy that allows mistranslation to suppress deleterious missense Pro mutations in Tti2.
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Affiliation(s)
- Kyle S Hoffman
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Matthew D Berg
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Brian H Shilton
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Christopher J Brandl
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada.,Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
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25
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Abstract
All types of nucleic acids in cells undergo naturally occurring chemical modifications, including DNA, rRNA, mRNA, snRNA, and most prominently tRNA. Over 100 different modifications have been described and every position in the purine and pyrimidine bases can be modified; often the sugar is also modified [1]. In tRNA, the function of modifications varies; some modulate global and/or local RNA structure, and others directly impact decoding and may be essential for viability. Whichever the case, the overall importance of modifications is highlighted by both their evolutionary conservation and the fact that organisms use a substantial portion of their genomes to encode modification enzymes, far exceeding what is needed for the de novo synthesis of the canonical nucleotides themselves [2]. Although some modifications occur at exactly the same nucleotide position in tRNAs from the three domains of life, many can be found at various positions in a particular tRNA and their location may vary between and within different tRNAs. With this wild array of chemical diversity and substrate specificities, one of the big challenges in the tRNA modification field has been to better understand at a molecular level the modes of substrate recognition by the different modification enzymes; in this realm RNA binding rests at the heart of the problem. This chapter will focus on several examples of modification enzymes where their mode of RNA binding is well understood; from these, we will try to draw general conclusions and highlight growing themes that may be applicable to the RNA modification field at large.
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26
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Self-Referential Encoding on Modules of Anticodon Pairs-Roots of the Biological Flow System. Life (Basel) 2017; 7:life7020016. [PMID: 28383509 PMCID: PMC5492138 DOI: 10.3390/life7020016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/24/2017] [Accepted: 03/26/2017] [Indexed: 12/22/2022] Open
Abstract
The proposal that the genetic code was formed on the basis of (proto)tRNA Dimer-Directed Protein Synthesis is reviewed and updated. The tRNAs paired through the anticodon loops are an indication on the process. Dimers are considered mimics of the ribosomes-structures that hold tRNAs together and facilitate the transferase reaction, and of the translation process-anticodons are at the same time codons for each other. The primitive protein synthesis system gets stabilized when the product peptides are stable and apt to bind the producers therewith establishing a self-stimulating production cycle. The chronology of amino acid encoding starts with Glycine and Serine, indicating the metabolic support of the Glycine-Serine C1-assimilation pathway, which is also consistent with evidence on origins of bioenergetics mechanisms. Since it is not possible to reach for substrates simpler than C1 and compounds in the identified pathway are apt for generating the other central metabolic routes, it is considered that protein synthesis is the beginning and center of a succession of sink-effective mechanisms that drive the formation and evolution of the metabolic flow system. Plasticity and diversification of proteins construct the cellular system following the orientation given by the flow and implementing it. Nucleic acid monomers participate in bioenergetics and the polymers are conservative memory systems for the synthesis of proteins. Protoplasmic fission is the final sink-effective mechanism, part of cell reproduction, guaranteeing that proteins don't accumulate to saturation, which would trigger inhibition.
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27
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What Froze the Genetic Code? Life (Basel) 2017; 7:life7020014. [PMID: 28379164 PMCID: PMC5492136 DOI: 10.3390/life7020014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 03/27/2017] [Accepted: 04/03/2017] [Indexed: 11/16/2022] Open
Abstract
The frozen accident theory of the Genetic Code was a proposal by Francis Crick that attempted to explain the universal nature of the Genetic Code and the fact that it only contains information for twenty amino acids. Fifty years later, it is clear that variations to the universal Genetic Code exist in nature and that translation is not limited to twenty amino acids. However, given the astonishing diversity of life on earth, and the extended evolutionary time that has taken place since the emergence of the extant Genetic Code, the idea that the translation apparatus is for the most part immobile remains true. Here, we will offer a potential explanation to the reason why the code has remained mostly stable for over three billion years, and discuss some of the mechanisms that allow species to overcome the intrinsic functional limitations of the protein synthesis machinery.
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28
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Macé K, Gillet R. Origins of tmRNA: the missing link in the birth of protein synthesis? Nucleic Acids Res 2016; 44:8041-51. [PMID: 27484476 PMCID: PMC5041485 DOI: 10.1093/nar/gkw693] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 12/20/2022] Open
Abstract
The RNA world hypothesis refers to the early period on earth in which RNA was central in assuring both genetic continuity and catalysis. The end of this era coincided with the development of the genetic code and protein synthesis, symbolized by the apparition of the first non-random messenger RNA (mRNA). Modern transfer-messenger RNA (tmRNA) is a unique hybrid molecule which has the properties of both mRNA and transfer RNA (tRNA). It acts as a key molecule during trans-translation, a major quality control pathway of modern bacterial protein synthesis. tmRNA shares many common characteristics with ancestral RNA. Here, we present a model in which proto-tmRNAs were the first molecules on earth to support non-random protein synthesis, explaining the emergence of early genetic code. In this way, proto-tmRNA could be the missing link between the first mRNA and tRNA molecules and modern ribosome-mediated protein synthesis.
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Affiliation(s)
- Kevin Macé
- Université de Rennes 1, CNRS UMR 6290 IGDR, Translation and Folding Team, 35042 Rennes cedex, France
| | - Reynald Gillet
- Université de Rennes 1, CNRS UMR 6290 IGDR, Translation and Folding Team, 35042 Rennes cedex, France Institut Universitaire de France
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29
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Sun L, Gomes AC, He W, Zhou H, Wang X, Pan DW, Schimmel P, Pan T, Yang XL. Evolutionary Gain of Alanine Mischarging to Noncognate tRNAs with a G4:U69 Base Pair. J Am Chem Soc 2016; 138:12948-12955. [PMID: 27622773 DOI: 10.1021/jacs.6b07121] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fidelity of translation, which is predominately dictated by the accuracy of aminoacyl-tRNA synthetases in pairing amino acids with correct tRNAs, is of central importance in biology. Yet, deliberate modifications of translational fidelity can be beneficial. Here we found human and not E. coli AlaRS has an intrinsic capacity for mispairing alanine onto nonalanyl-tRNAs including tRNACys. Consistently, a cysteine-to-alanine substitution was found in a reporter protein expressed in human cells. All human AlaRS-mischarged tRNAs have a G4:U69 base pair in the acceptor stem. The base pair is required for the mischarging. By solving the crystal structure of human AlaRS and comparing it to that of E. coli AlaRS, we identified a key sequence divergence between eukaryotes and bacteria that influences mischarging. Thus, the expanded tRNA specificity of AlaRS appears to be an evolutionary gain-of-function to provide posttranscriptional alanine substitutions in eukaryotic proteins for potential regulations.
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Affiliation(s)
- Litao Sun
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Ana Cristina Gomes
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Weiwei He
- Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Huihao Zhou
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Xiaoyun Wang
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - David W Pan
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Paul Schimmel
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Xiang-Lei Yang
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States.,Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92037, United States
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30
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Abstract
Contact-dependent growth inhibition (CDI) is a widespread mechanism of bacterial competition. CDI(+) bacteria deliver the toxic C-terminal region of contact-dependent inhibition A proteins (CdiA-CT) into neighboring target bacteria and produce CDI immunity proteins (CdiI) to protect against self-inhibition. The CdiA-CT(EC536) deployed by uropathogenic Escherichia coli 536 (EC536) is a bacterial toxin 28 (Ntox28) domain that only exhibits ribonuclease activity when bound to the cysteine biosynthetic enzyme O-acetylserine sulfhydrylase A (CysK). Here, we present crystal structures of the CysK/CdiA-CT(EC536) binary complex and the neutralized ternary complex of CysK/CdiA-CT/CdiI(EC536) CdiA-CT(EC536) inserts its C-terminal Gly-Tyr-Gly-Ile peptide tail into the active-site cleft of CysK to anchor the interaction. Remarkably, E. coli serine O-acetyltransferase uses a similar Gly-Asp-Gly-Ile motif to form the "cysteine synthase" complex with CysK. The cysteine synthase complex is found throughout bacteria, protozoa, and plants, indicating that CdiA-CT(EC536) exploits a highly conserved protein-protein interaction to promote its toxicity. CysK significantly increases CdiA-CT(EC536) thermostability and is required for toxin interaction with tRNA substrates. These observations suggest that CysK stabilizes the toxin fold, thereby organizing the nuclease active site for substrate recognition and catalysis. By contrast, Ntox28 domains from Gram-positive bacteria lack C-terminal Gly-Tyr-Gly-Ile motifs, suggesting that they do not interact with CysK. We show that the Ntox28 domain from Ruminococcus lactaris is significantly more thermostable than CdiA-CT(EC536), and its intrinsic tRNA-binding properties support CysK-independent nuclease activity. The striking differences between related Ntox28 domains suggest that CDI toxins may be under evolutionary pressure to maintain low global stability.
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31
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Katz A, Elgamal S, Rajkovic A, Ibba M. Non-canonical roles of tRNAs and tRNA mimics in bacterial cell biology. Mol Microbiol 2016; 101:545-58. [PMID: 27169680 DOI: 10.1111/mmi.13419] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2016] [Indexed: 12/27/2022]
Abstract
Transfer RNAs (tRNAs) are the macromolecules that transfer activated amino acids from aminoacyl-tRNA synthetases to the ribosome, where they are used for the mRNA guided synthesis of proteins. Transfer RNAs are ancient molecules, perhaps even predating the existence of the translation machinery. Albeit old, these molecules are tremendously conserved, a characteristic that is well illustrated by the fact that some bacterial tRNAs are efficient and specific substrates of eukaryotic aminoacyl-tRNA synthetases and ribosomes. Considering their ancient origin and high structural conservation, it is not surprising that tRNAs have been hijacked during evolution for functions outside of translation. These roles beyond translation include synthetic, regulatory and information functions within the cell. Here we provide an overview of the non-canonical roles of tRNAs and their mimics in bacteria, and discuss some of the common themes that arise when comparing these different functions.
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Affiliation(s)
- Assaf Katz
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, 8380453, Chile
| | - Sara Elgamal
- Department of Microbiology and The Center for RNA Biology, Ohio State University, Columbus, Ohio, 43210, USA
| | - Andrei Rajkovic
- Department of Microbiology and The Center for RNA Biology, Ohio State University, Columbus, Ohio, 43210, USA
| | - Michael Ibba
- Department of Microbiology and The Center for RNA Biology, Ohio State University, Columbus, Ohio, 43210, USA
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32
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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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33
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McKenney KM, Alfonzo JD. From Prebiotics to Probiotics: The Evolution and Functions of tRNA Modifications. Life (Basel) 2016; 6:E13. [PMID: 26985907 PMCID: PMC4810244 DOI: 10.3390/life6010013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/27/2016] [Accepted: 03/07/2016] [Indexed: 12/13/2022] Open
Abstract
All nucleic acids in cells are subject to post-transcriptional chemical modifications. These are catalyzed by a myriad of enzymes with exquisite specificity and that utilize an often-exotic array of chemical substrates. In no molecule are modifications more prevalent than in transfer RNAs. In the present document, we will attempt to take a chemical rollercoaster ride from prebiotic times to the present, with nucleoside modifications as key players and tRNA as the centerpiece that drove the evolution of biological systems to where we are today. These ideas will be put forth while touching on several examples of tRNA modification enzymes and their modus operandi in cells. In passing, we submit that the choice of tRNA is not a whimsical one but rather highlights its critical function as an essential invention for the evolution of protein enzymes.
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Affiliation(s)
- Katherine M McKenney
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | - Juan D Alfonzo
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
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34
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Rozov A, Demeshkina N, Khusainov I, Westhof E, Yusupov M, Yusupova G. Novel base-pairing interactions at the tRNA wobble position crucial for accurate reading of the genetic code. Nat Commun 2016; 7:10457. [PMID: 26791911 PMCID: PMC4736104 DOI: 10.1038/ncomms10457] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/13/2015] [Indexed: 02/07/2023] Open
Abstract
Posttranscriptional modifications at the wobble position of transfer RNAs play a substantial role in deciphering the degenerate genetic code on the ribosome. The number and variety of modifications suggest different mechanisms of action during messenger RNA decoding, of which only a few were described so far. Here, on the basis of several 70S ribosome complex X-ray structures, we demonstrate how Escherichia coli tRNA(Lys)(UUU) with hypermodified 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U) at the wobble position discriminates between cognate codons AAA and AAG, and near-cognate stop codon UAA or isoleucine codon AUA, with which it forms pyrimidine-pyrimidine mismatches. We show that mnm(5)s(2)U forms an unusual pair with guanosine at the wobble position that expands general knowledge on the degeneracy of the genetic code and specifies a powerful role of tRNA modifications in translation. Our models consolidate the translational fidelity mechanism proposed previously where the steric complementarity and shape acceptance dominate the decoding mechanism.
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Affiliation(s)
- Alexey Rozov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964; CNRS/University of Strasbourg, UMR7104, 1 rue Laurent Fries, BP 10142, Illkirch 67404, France
| | - Natalia Demeshkina
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964; CNRS/University of Strasbourg, UMR7104, 1 rue Laurent Fries, BP 10142, Illkirch 67404, France
| | - Iskander Khusainov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964; CNRS/University of Strasbourg, UMR7104, 1 rue Laurent Fries, BP 10142, Illkirch 67404, France.,Institute of Fundamental Medicine and Biology, Kazan Federal University, Karl Marx 18, Kazan 420012, Russia
| | - Eric Westhof
- Architecture and Reactivity of RNA, Institute of Molecular and Cellular Biology of the CNRS, University of Strasbourg, UPR9002, 15 rue Rene Descartes, Strasbourg 67084, France
| | - Marat Yusupov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964; CNRS/University of Strasbourg, UMR7104, 1 rue Laurent Fries, BP 10142, Illkirch 67404, France
| | - Gulnara Yusupova
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964; CNRS/University of Strasbourg, UMR7104, 1 rue Laurent Fries, BP 10142, Illkirch 67404, France
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35
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Post-Transcriptional Modifications of RNA: Impact on RNA Function and Human Health. MODIFIED NUCLEIC ACIDS IN BIOLOGY AND MEDICINE 2016. [DOI: 10.1007/978-3-319-34175-0_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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36
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Grzybkowska A, Jędrzejczyk D, Rostkowski M, Chworos A, Dybala-Defratyka A. RNA model evaluation based on MD simulation of four tRNA analogs. RSC Adv 2016. [DOI: 10.1039/c6ra14933b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Characteristic of 3D structures of tRNA analogs generated from primary sequence, subjected to all-atom MD simulation and assessed using selected RNA model evaluation methods.
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Affiliation(s)
- Anna Grzybkowska
- Institute of Applied Radiation Chemistry
- Faculty of Chemistry
- Lodz University of Technology
- Lodz
- Poland
| | - Dominika Jędrzejczyk
- Center of Molecular and Macromolecular Studies
- Polish Academy of Sciences
- 90-363 Lodz
- Poland
| | - Michał Rostkowski
- Institute of Applied Radiation Chemistry
- Faculty of Chemistry
- Lodz University of Technology
- Lodz
- Poland
| | - Arkadiusz Chworos
- Center of Molecular and Macromolecular Studies
- Polish Academy of Sciences
- 90-363 Lodz
- Poland
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37
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Fang P, Guo M. Evolutionary Limitation and Opportunities for Developing tRNA Synthetase Inhibitors with 5-Binding-Mode Classification. Life (Basel) 2015; 5:1703-25. [PMID: 26670257 PMCID: PMC4695845 DOI: 10.3390/life5041703] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 12/30/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are enzymes that catalyze the transfer of amino acids to their cognate tRNAs as building blocks for translation. Each of the aaRS families plays a pivotal role in protein biosynthesis and is indispensable for cell growth and survival. In addition, aaRSs in higher species have evolved important non-translational functions. These translational and non-translational functions of aaRS are attractive for developing antibacterial, antifungal, and antiparasitic agents and for treating other human diseases. The interplay between amino acids, tRNA, ATP, EF-Tu and non-canonical binding partners, had shaped each family with distinct pattern of key sites for regulation, with characters varying among species across the path of evolution. These sporadic variations in the aaRSs offer great opportunity to target these essential enzymes for therapy. Up to this day, growing numbers of aaRS inhibitors have been discovered and developed. Here, we summarize the latest developments and structural studies of aaRS inhibitors, and classify them with distinct binding modes into five categories.
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Affiliation(s)
- Pengfei Fang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA.
| | - Min Guo
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA.
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38
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Guimarães RC. The Self-Referential Genetic Code is Biologic and Includes the Error Minimization Property. ORIGINS LIFE EVOL B 2015; 45:69-75. [PMID: 25773583 DOI: 10.1007/s11084-015-9417-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/24/2014] [Indexed: 11/26/2022]
Abstract
The distribution of the triplet to amino acid correspondences in the genetic code matrix contains blocks of similarity. There are (a) groups of similar triplets coding for the same amino acid, which is called code degeneracy, and (b) clusters of similar amino acids corresponding to similar triplets. Processes that led to this regionalization have been investigated through a variety of perspectives but no consensus has been reached and no model has been convincing enough to drive experimental tests. Most traditional has been the hypothesis that the code was derived from the standard evolutionary processes of testing variations in the correspondences through the fitness measure of reaching distributions in the matrix space in an optimal manner so that the effects of mutations on protein phenotypes would be minimized, that is, with reduction of the intensity or of the deviant quality of the functional alterations associated with variations. In contrast, the self-referential model for the formation of the code is based on an original regionalization of characters through the concerted superposition of the two components of the encodings: the four modules of dimers of tRNAs are occupied sequentially by sets of amino acids that are also sequentially devoted to fulfilling specific functions in the protein sites and motifs to which they preferentially belong. Therewith, part (b) of the error-minimizing property follows. Part (a) of the property, the code degeneracy, is derived from the synthetase character of developing specificities directed initially to the principal dinucleotides of the triplets, resulting in tetracodonic degeneracy. This was later partly modified during evolution according to the developments of codon usage and the introduction of new amino acids.
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Affiliation(s)
- Romeu Cardoso Guimarães
- Lab. Biodiversidade e Evolução Molecular, Dept. Biologia Geral, Inst. Ciências Biológicas, Univ. Federal de Minas Gerais, 31270.901, Belo Horizonte, MG, Brazil,
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39
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Dutta S, Nandi N. Dynamics of the Active Sites of Dimeric Seryl tRNA Synthetase from Methanopyrus kandleri. J Phys Chem B 2015; 119:10832-48. [PMID: 25794108 DOI: 10.1021/jp511585w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Saheb Dutta
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Nilashis Nandi
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
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40
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New method for the orthogonal labeling and purification of Toxoplasma gondii proteins while inside the host cell. mBio 2015; 6:e01628. [PMID: 25759504 PMCID: PMC4453564 DOI: 10.1128/mbio.01628-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite that is capable of causing severe disease in immunocompromised humans. How T. gondii is able to modulate the host cell to support itself is still poorly understood. Knowledge pertaining to the host-parasite interaction could be bolstered by developing a system to specifically label parasite proteins while the parasite grows inside the host cell. For this purpose, we have created a strain of T. gondii that expresses a mutant Escherichia coli methionyl-tRNA synthetase (MetRSNLL) that allows methionine tRNA to be loaded with the azide-containing methionine analog azidonorleucine (Anl). Anl-containing proteins are susceptible to a copper-catalyzed “click” reaction to attach affinity tags for purification or fluorescent tags for visualization. The MetRSNLL-Anl system labels nascent T. gondii proteins in an orthogonal fashion, labeling proteins only in MetRSNLL-expressing parasites. This system should be useful for nonradioactive pulse-chase studies and purification of nascently translated proteins. Although this approach allows labeling of a diverse array of parasite proteins, secreted parasite proteins appear to be only minimally labeled in MetRSNLL-expressing T. gondii. The minimal labeling of secreted proteins is likely a consequence of the selective charging of the initiator tRNA (and not the elongator methionine tRNA) by the heterologously expressed bacterial MetRS. Studying how T. gondii modifies the host cell to permit its survival is complicated by the complex protein environment of the host cell. The approach presented in this article provides the first method for specific labeling of T. gondii proteins while the parasite grows inside the host cell. We show that this approach is useful for pulse-chase labeling of parasite proteins during in vitro growth. It should also be applicable during in vivo infections and in other apicomplexan parasites, including Plasmodium spp.
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41
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Crofts TS, Hazra AB, Tran JLA, Sokolovskaya OM, Osadchiy V, Ad O, Pelton J, Bauer S, Taga ME. Regiospecific Formation of Cobamide Isomers Is Directed by CobT. Biochemistry 2014; 53:7805-15. [DOI: 10.1021/bi501147d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Terence S. Crofts
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Amrita B. Hazra
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Jennifer LA Tran
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Olga M. Sokolovskaya
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Vadim Osadchiy
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Omer Ad
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Jeffrey Pelton
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Stefan Bauer
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
| | - Michiko E. Taga
- Department of Plant and Microbial Biology, ∥Department of Chemistry, ⊥QB3 Institute, and #Energy Biosciences Institute, University of California, Berkeley, United States
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42
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Panwar B, Raghava GPS. Prediction of uridine modifications in tRNA sequences. BMC Bioinformatics 2014; 15:326. [PMID: 25272949 PMCID: PMC4287530 DOI: 10.1186/1471-2105-15-326] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 09/24/2014] [Indexed: 12/31/2022] Open
Abstract
Background In past number of methods have been developed for predicting post-translational modifications in proteins. In contrast, limited attempt has been made to understand post-transcriptional modifications. Recently it has been shown that tRNA modifications play direct role in the genome structure and codon usage. This study is an attempt to understand kingdom-wise tRNA modifications particularly uridine modifications (UMs), as majority of modifications are uridine-derived. Results A three-steps strategy has been applied to develop an efficient method for the prediction of UMs. In the first step, we developed a common prediction model for all the kingdoms using a dataset from MODOMICS-2008. Support Vector Machine (SVM) based prediction models were developed and evaluated by five-fold cross-validation technique. Different approaches were applied and found that a hybrid approach of binary and structural information achieved highest Area under the curve (AUC) of 0.936. In the second step, we used newly added tRNA sequences (as independent dataset) of MODOMICS-2012 for the kingdom-wise prediction performance evaluation of previously developed (in the first step) common model and achieved performances between the AUC of 0.910 to 0.949. In the third and last step, we used different datasets from MODOMICS-2012 for the kingdom-wise individual prediction models development and achieved performances between the AUC of 0.915 to 0.987. Conclusions The hybrid approach is efficient not only to predict kingdom-wise modifications but also to classify them into two most prominent UMs: Pseudouridine (Y) and Dihydrouridine (D). A webserver called tRNAmod (http://crdd.osdd.net/raghava/trnamod/) has been developed, which predicts UMs from both tRNA sequences and whole genome. Electronic supplementary material The online version of this article (doi:10.1186/1471-2105-15-326) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Gajendra P S Raghava
- Bioinformatics Centre, CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India.
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43
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Moghal A, Mohler K, Ibba M. Mistranslation of the genetic code. FEBS Lett 2014; 588:4305-10. [PMID: 25220850 DOI: 10.1016/j.febslet.2014.08.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 01/02/2023]
Abstract
During mRNA decoding at the ribosome, deviations from stringent codon identity, or "mistranslation," are generally deleterious and infrequent. Observations of organisms that decode some codons ambiguously, and the discovery of a compensatory increase in mistranslation frequency to combat environmental stress have changed the way we view "errors" in decoding. Modern tools for the study of the frequency and phenotypic effects of mistranslation can provide quantitative and sensitive measurements of decoding errors that were previously inaccessible. Mistranslation with non-protein amino acids, in particular, is an enticing prospect for new drug therapies and the study of molecular evolution.
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Affiliation(s)
- Adil Moghal
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210-1292, USA; Department of Microbiology, The Ohio State University, Columbus, OH 43210-1292, USA
| | - Kyle Mohler
- Department of Microbiology, The Ohio State University, Columbus, OH 43210-1292, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA
| | - Michael Ibba
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210-1292, USA; Department of Microbiology, The Ohio State University, Columbus, OH 43210-1292, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA.
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44
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Vargas-Rodriguez O, Musier-Forsyth K. Structural biology: wobble puts RNA on target. Nature 2014; 510:480-1. [PMID: 24919145 DOI: 10.1038/nature13502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Oscar Vargas-Rodriguez
- Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
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45
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Naganuma M, Sekine SI, Chong YE, Guo M, Yang XL, Gamper H, Hou YM, Schimmel P, Yokoyama S. The selective tRNA aminoacylation mechanism based on a single G•U pair. Nature 2014; 510:507-11. [PMID: 24919148 DOI: 10.1038/nature13440] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/06/2014] [Indexed: 11/09/2022]
Abstract
Ligation of tRNAs with their cognate amino acids, by aminoacyl-tRNA synthetases, establishes the genetic code. Throughout evolution, tRNA(Ala) selection by alanyl-tRNA synthetase (AlaRS) has depended predominantly on a single wobble base pair in the acceptor stem, G3•U70, mainly on the kcat level. Here we report the crystal structures of an archaeal AlaRS in complex with tRNA(Ala) with G3•U70 and its A3•U70 variant. AlaRS interacts with both the minor- and the major-groove sides of G3•U70, widening the major groove. The geometry difference between G3•U70 and A3•U70 is transmitted along the acceptor stem to the 3'-CCA region. Thus, the 3'-CCA region of tRNA(Ala) with G3•U70 is oriented to the reactive route that reaches the active site, whereas that of the A3•U70 variant is folded back into the non-reactive route. This novel mechanism enables the single wobble pair to dominantly determine the specificity of tRNA selection, by an approximate 100-fold difference in kcat.
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Affiliation(s)
- Masahiro Naganuma
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Shun-ichi Sekine
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yeeting Esther Chong
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] aTyr Pharma, 3545 John Hopkins Court, San Diego, California 92121, USA (Y.E.C.); Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, USA (M.G.)
| | - Min Guo
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] aTyr Pharma, 3545 John Hopkins Court, San Diego, California 92121, USA (Y.E.C.); Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, USA (M.G.)
| | - Xiang-Lei Yang
- The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Howard Gamper
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Paul Schimmel
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] The Scripps Florida Research Institute, 130 Scripps Way, 3B3 Jupiter, Florida 33458-5284, USA
| | - Shigeyuki Yokoyama
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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Optimized orthogonal translation of unnatural amino acids enables spontaneous protein double-labelling and FRET. Nat Chem 2014; 6:393-403. [PMID: 24755590 DOI: 10.1038/nchem.1919] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 03/12/2014] [Indexed: 12/13/2022]
Abstract
The ability to introduce different biophysical probes into defined positions in target proteins will provide powerful approaches for interrogating protein structure, function and dynamics. However, methods for site-specifically incorporating multiple distinct unnatural amino acids are hampered by their low efficiency. Here we provide a general solution to this challenge by developing an optimized orthogonal translation system that uses amber and evolved quadruplet-decoding transfer RNAs to encode numerous pairs of distinct unnatural amino acids into a single protein expressed in Escherichia coli with a substantial increase in efficiency over previous methods. We also provide a general strategy for labelling pairs of encoded unnatural amino acids with different probes via rapid and spontaneous reactions under physiological conditions. We demonstrate the utility of our approach by genetically directing the labelling of several pairs of sites in calmodulin with fluorophores and probing protein structure and dynamics by Förster resonance energy transfer.
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Bartholow TG, Sanford BL, Cao B, Schmit HL, Johnson JM, Meitzner J, Bhattacharyya S, Musier-Forsyth K, Hati S. Strictly conserved lysine of prolyl-tRNA Synthetase editing domain facilitates binding and positioning of misacylated tRNA(Pro.). Biochemistry 2014; 53:1059-68. [PMID: 24450765 PMCID: PMC3986007 DOI: 10.1021/bi401279r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To ensure high fidelity in translation, many aminoacyl-tRNA synthetases, enzymes responsible for attaching specific amino acids to cognate tRNAs, require proof-reading mechanisms. Most bacterial prolyl-tRNA synthetases (ProRSs) misactivate alanine and employ a post-transfer editing mechanism to hydrolyze Ala-tRNA(Pro). This reaction occurs in a second catalytic site (INS) that is distinct from the synthetic active site. The 2'-OH of misacylated tRNA(Pro) and several conserved residues in the Escherichia coli ProRS INS domain are directly involved in Ala-tRNA(Pro) deacylation. Although mutation of the strictly conserved lysine 279 (K279) results in nearly complete loss of post-transfer editing activity, this residue does not directly participate in Ala-tRNA(Pro) hydrolysis. We hypothesized that the role of K279 is to bind the phosphate backbone of the acceptor stem of misacylated tRNA(Pro) and position it in the editing active site. To test this hypothesis, we carried out pKa, charge neutralization, and free-energy of binding calculations. Site-directed mutagenesis and kinetic studies were performed to verify the computational results. The calculations revealed a considerably higher pKa of K279 compared to an isolated lysine and showed that the protonated state of K279 is stabilized by the neighboring acidic residue. However, substitution of this acidic residue with a positively charged residue leads to a significant increase in Ala-tRNA(Pro) hydrolysis, suggesting that enhancement in positive charge density in the vicinity of K279 favors tRNA binding. A charge-swapping experiment and free energy of binding calculations support the conclusion that the positive charge at position 279 is absolutely necessary for tRNA binding in the editing active site.
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Affiliation(s)
- Thomas G Bartholow
- Department of Chemistry, University of Wisconsin-Eau Claire , Eau Claire, Wisconsin, 54702, United States
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48
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Cameron SL. Insect mitochondrial genomics: implications for evolution and phylogeny. ANNUAL REVIEW OF ENTOMOLOGY 2013; 59:95-117. [PMID: 24160435 DOI: 10.1146/annurev-ento-011613-162007] [Citation(s) in RCA: 873] [Impact Index Per Article: 79.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The mitochondrial (mt) genome is, to date, the most extensively studied genomic system in insects, outnumbering nuclear genomes tenfold and representing all orders versus very few. Phylogenomic analysis methods have been tested extensively, identifying compositional bias and rate variation, both within and between lineages, as the principal issues confronting accurate analyses. Major studies at both inter- and intraordinal levels have contributed to our understanding of phylogenetic relationships within many groups. Genome rearrangements are an additional data type for defining relationships, with rearrangement synapomorphies identified across multiple orders and at many different taxonomic levels. Hymenoptera and Psocodea have greatly elevated rates of rearrangement offering both opportunities and pitfalls for identifying rearrangement synapomorphies in each group. Finally, insects are model systems for studying aberrant mt genomes, including truncated tRNAs and multichromosomal genomes. Greater integration of nuclear and mt genomic studies is necessary to further our understanding of insect genomic evolution.
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Affiliation(s)
- Stephen L Cameron
- Earth, Environmental & Biological Sciences School, Science & Engineering Faculty, Queensland University of Technology, Brisbane, QLD 4001, Australia;
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49
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A metabolic prototype for eliminating tryptophan from the genetic code. Sci Rep 2013; 3:1359. [PMID: 23447021 PMCID: PMC3584311 DOI: 10.1038/srep01359] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/13/2013] [Indexed: 11/13/2022] Open
Abstract
We set out to reduce the chemical constitution of a living organism to 19 amino acids. A strain was constructed for reassigning the tryptophan codon UGG to histidine and eliminating tryptophan from Escherichia coli. Histidine codons in the gene for an essential enzyme were replaced with tryptophan codons and the restoration of catalytic activity by missense suppressor His-tRNA bearing a CCA anticodon was selected. We used automated cultivation to assess the stability of this genetic construct during evolution. Histidine to tryptophan mutation at codon 30 in the transketolase gene from yeast and its cognate suppressor tRNA were stably propagated in a tktAB deletant of E. coli over 2500 generations. The ratio of histidine misincorporation at tryptophan sites in the proteome increased from 0.0007 to 0.03 over 300 days of continuous culture. This result demonstrated that the genetic code can be forced to evolve by permanent metabolic selection.
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50
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tRNA tKUUU, tQUUG, and tEUUC wobble position modifications fine-tune protein translation by promoting ribosome A-site binding. Proc Natl Acad Sci U S A 2013; 110:12289-94. [PMID: 23836657 DOI: 10.1073/pnas.1300781110] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
tRNA modifications are crucial to ensure translation efficiency and fidelity. In eukaryotes, the URM1 and ELP pathways increase cellular resistance to various stress conditions, such as nutrient starvation and oxidative agents, by promoting thiolation and methoxycarbonylmethylation, respectively, of the wobble uridine of cytoplasmic (tK(UUU)), (tQ(UUG)), and (tE(UUC)). Although in vitro experiments have implicated these tRNA modifications in modulating wobbling capacity and translation efficiency, their exact in vivo biological roles remain largely unexplored. Using a combination of quantitative proteomics and codon-specific translation reporters, we find that translation of a specific gene subset enriched for AAA, CAA, and GAA codons is impaired in the absence of URM1- and ELP-dependent tRNA modifications. Moreover, in vitro experiments using native tRNAs demonstrate that both modifications enhance binding of tK(UUU) to the ribosomal A-site. Taken together, our data suggest that tRNA thiolation and methoxycarbonylmethylation regulate translation of genes with specific codon content.
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