1
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Lu W, Terasaka N, Sakaguchi Y, Suzuki T, Suzuki T, Suga H. An anticodon-sensing T-boxzyme generates the elongator nonproteinogenic aminoacyl-tRNA in situ of a custom-made translation system for incorporation. Nucleic Acids Res 2024; 52:3938-3949. [PMID: 38477328 DOI: 10.1093/nar/gkae151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/24/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
In the hypothetical RNA world, ribozymes could have acted as modern aminoacyl-tRNA synthetases (ARSs) to charge tRNAs, thus giving rise to the peptide synthesis along with the evolution of a primitive translation apparatus. We previously reported a T-boxzyme, Tx2.1, which selectively charges initiator tRNA with N-biotinyl-phenylalanine (BioPhe) in situ in a Flexible In-vitro Translation (FIT) system to produce BioPhe-initiating peptides. Here, we performed in vitro selection of elongation-capable T-boxzymes (elT-boxzymes), using para-azido-l-phenylalanine (PheAZ) as an acyl-donor. We implemented a new strategy to enrich elT-boxzyme-tRNA conjugates that self-aminoacylated on the 3'-terminus selectively. One of them, elT32, can charge PheAZ onto tRNA in trans in response to its cognate anticodon. Further evolution of elT32 resulted in elT49, with enhanced aminoacylation activity. We have demonstrated the translation of a PheAZ-containing peptide in an elT-boxzyme-integrated FIT system, revealing that elT-boxzymes are able to generate the PheAZ-tRNA in response to the cognate anticodon in situ of a custom-made translation system. This study, together with Tx2.1, illustrates a scenario where a series of ribozymes could have overseen aminoacylation and co-evolved with a primitive RNA-based translation system.
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Affiliation(s)
- Wei Lu
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naohiro Terasaka
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takeo Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Medical Biochemistry, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0125, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Padhiar NH, Katneni U, Komar AA, Motorin Y, Kimchi-Sarfaty C. Advances in methods for tRNA sequencing and quantification. Trends Genet 2024; 40:276-290. [PMID: 38123442 DOI: 10.1016/j.tig.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 12/23/2023]
Abstract
In the past decade tRNA sequencing (tRNA-seq) has attracted considerable attention as an important tool for the development of novel approaches to quantify highly modified tRNA species and to propel tRNA research aimed at understanding the cellular physiology and disease and development of tRNA-based therapeutics. Many methods are available to quantify tRNA abundance while accounting for modifications and tRNA charging/acylation. Advances in both library preparation methods and bioinformatic workflows have enabled developments in next-generation sequencing (NGS) workflows. Other approaches forgo NGS applications in favor of hybridization-based approaches. In this review we provide a brief comparative overview of various tRNA quantification approaches, focusing on the advantages and disadvantages of these methods, which together facilitate reliable tRNA quantification.
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Affiliation(s)
- Nigam H Padhiar
- Hemostasis Branch 1, Division of Hemostasis, Office of Plasma Protein Therapeutics, Office of Therapeutic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Upendra Katneni
- Hemostasis Branch 1, Division of Hemostasis, Office of Plasma Protein Therapeutics, Office of Therapeutic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Anton A Komar
- Department of Biological, Geological, and Environmental Sciences, Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH, USA
| | - Yuri Motorin
- CNRS-Université de Lorraine, UAR 2008, IBSLor UMR 7365 IMoPA, Nancy, France.
| | - Chava Kimchi-Sarfaty
- Hemostasis Branch 1, Division of Hemostasis, Office of Plasma Protein Therapeutics, Office of Therapeutic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
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3
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Zhang XD, Wang YS, Xiang H, Bai LW, Cheng P, Li K, Huang R, Wang X, Lei X. Nucleoside modification-based flexizymes with versatile activity for tRNA aminoacylation. Chem Commun (Camb) 2024; 60:1607-1610. [PMID: 38230513 DOI: 10.1039/d3cc05673b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Extensive research has focused on genetic code reprogramming using flexizymes (Fxs), ribozymes enabling diverse tRNA acylation. Here we describe a nucleoside-modification strategy for the preparation of flexizyme variants derived from 2'-OMe, 2'-F, and 2'-MOE modifications with unique and versatile activities, enabling the charging of tRNAs with a broad range of substrates. This innovative strategy holds promise for synthetic biology applications, offering a robust pathway to expand the genetic code for diverse substrate incorporation.
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Affiliation(s)
- Xin-Dan Zhang
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Yi-Shen Wang
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Hua Xiang
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Li-Wen Bai
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Peng Cheng
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Kai Li
- College of Life Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Rong Huang
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
| | - Xiaolei Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China.
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
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4
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Krahn N, Zhang J, Melnikov SV, Tharp JM, Villa A, Patel A, Howard R, Gabir H, Patel T, Stetefeld J, Puglisi J, Söll D. tRNA shape is an identity element for an archaeal pyrrolysyl-tRNA synthetase from the human gut. Nucleic Acids Res 2024; 52:513-524. [PMID: 38100361 PMCID: PMC10810272 DOI: 10.1093/nar/gkad1188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/23/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023] Open
Abstract
Protein translation is orchestrated through tRNA aminoacylation and ribosomal elongation. Among the highly conserved structure of tRNAs, they have distinguishing features which promote interaction with their cognate aminoacyl tRNA synthetase (aaRS). These key features are referred to as identity elements. In our study, we investigated the tRNA:aaRS pair that installs the 22nd amino acid, pyrrolysine (tRNAPyl:PylRS). Pyrrolysyl-tRNA synthetases (PylRSs) are naturally encoded in some archaeal and bacterial genomes to acylate tRNAPyl with pyrrolysine. Their large amino acid binding pocket and poor recognition of the tRNA anticodon have been instrumental in incorporating >200 noncanonical amino acids. PylRS enzymes can be divided into three classes based on their genomic structure. Two classes contain both an N-terminal and C-terminal domain, however the third class (ΔpylSn) lacks the N-terminal domain. In this study we explored the tRNA identity elements for a ΔpylSn tRNAPyl from Candidatus Methanomethylophilus alvus which drives the orthogonality seen with its cognate PylRS (MaPylRS). From aminoacylation and translation assays we identified five key elements in ΔpylSn tRNAPyl necessary for MaPylRS activity. The absence of a base (position 8) and a G-U wobble pair (G28:U42) were found to affect the high-resolution structure of the tRNA, while molecular dynamic simulations led us to acknowledge the rigidity imparted from the G-C base pairs (G3:C70 and G5:C68).
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Affiliation(s)
- Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Jingji Zhang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sergey V Melnikov
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Jeffery M Tharp
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Alessandra Villa
- PDC-Center for High Performance Computing, KTH-Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Armaan Patel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, SE-171 65, Sweden
| | - Haben Gabir
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB T1K 2E1, Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Department of Microbiology, Immunology & Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Joseph Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
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5
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Malnar Črnigoj M, Čerček U, Yin X, Ho MT, Repic Lampret B, Neumann M, Hermann A, Rouleau G, Suter B, Mayr M, Rogelj B. Phenylalanine-tRNA aminoacylation is compromised by ALS/FTD-associated C9orf72 C4G2 repeat RNA. Nat Commun 2023; 14:5764. [PMID: 37717009 PMCID: PMC10505166 DOI: 10.1038/s41467-023-41511-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 09/07/2023] [Indexed: 09/18/2023] Open
Abstract
The expanded hexanucleotide GGGGCC repeat mutation in the C9orf72 gene is the main genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Under one disease mechanism, sense and antisense transcripts of the repeat are predicted to bind various RNA-binding proteins, compromise their function and cause cytotoxicity. Here we identify phenylalanine-tRNA synthetase (FARS) subunit alpha (FARSA) as the main interactor of the CCCCGG antisense repeat RNA in cytosol. The aminoacylation of tRNAPhe by FARS is inhibited by antisense RNA, leading to decreased levels of charged tRNAPhe. Remarkably, this is associated with global reduction of phenylalanine incorporation in the proteome and decrease in expression of phenylalanine-rich proteins in cellular models and patient tissues. In conclusion, this study reveals functional inhibition of FARSA in the presence of antisense RNA repeats. Compromised aminoacylation of tRNA could lead to impairments in protein synthesis and further contribute to C9orf72 mutation-associated pathology.
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Affiliation(s)
- Mirjana Malnar Črnigoj
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, 1000, Slovenia
- Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, Ljubljana, 1000, Slovenia
| | - Urša Čerček
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, 1000, Slovenia
- Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, Ljubljana, 1000, Slovenia
| | - Xiaoke Yin
- King's BHF Centre, King's College London, London, SE5 9NU, UK
| | - Manh Tin Ho
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | - Barbka Repic Lampret
- Clinical Institute of Special Laboratory Diagnostics, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, 1000, Slovenia
| | - Manuela Neumann
- Molecular Neuropathology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases, Tübingen, 72076, Germany
- Department of Neuropathology, University Hospital of Tübingen, Tübingen, 72076, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section "Albrecht-Kossel", Department of Neurology and Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, University of Rostock, 18147, Rostock, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Rostock/Greifswald, 18147, Rostock, Germany
| | - Guy Rouleau
- Department of Human Genetics, McGill University, Montréal, QC, H3A 0G4, Canada
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, QC, H3A 0G4, Canada
| | - Beat Suter
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | - Manuel Mayr
- King's BHF Centre, King's College London, London, SE5 9NU, UK
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, 1000, Slovenia.
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, 1000, Slovenia.
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6
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Tijaro-Bulla S, Nyandwi SP, Cui H. Physiological and engineered tRNA aminoacylation. Wiley Interdiscip Rev RNA 2023; 14:e1789. [PMID: 37042417 DOI: 10.1002/wrna.1789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Aminoacyl-tRNA synthetases form the protein family that controls the interpretation of the genetic code, with tRNA aminoacylation being the key chemical step during which an amino acid is assigned to a corresponding sequence of nucleic acids. In consequence, aminoacyl-tRNA synthetases have been studied in their physiological context, in disease states, and as tools for synthetic biology to enable the expansion of the genetic code. Here, we review the fundamentals of aminoacyl-tRNA synthetase biology and classification, with a focus on mammalian cytoplasmic enzymes. We compile evidence that the localization of aminoacyl-tRNA synthetases can be critical in health and disease. In addition, we discuss evidence from synthetic biology which made use of the importance of subcellular localization for efficient manipulation of the protein synthesis machinery. This article is categorized under: RNA Processing Translation > Translation Regulation RNA Processing > tRNA Processing RNA Export and Localization > RNA Localization.
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Affiliation(s)
| | | | - Haissi Cui
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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7
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Tang GQ, Elder JJH, Douglas J, Carter CW. Domain acquisition by class I aminoacyl-tRNA synthetase urzymes coordinated the catalytic functions of HVGH and KMSKS motifs. Nucleic Acids Res 2023; 51:8070-8084. [PMID: 37470821 PMCID: PMC10450160 DOI: 10.1093/nar/gkad590] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/23/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023] Open
Abstract
Leucyl-tRNA synthetase (LeuRS) is a Class I aminoacyl-tRNA synthetase (aaRS) that synthesizes leucyl-tRNAleu for codon-directed protein synthesis. Two signature sequences, HxGH and KMSKS help stabilize transition-states for amino acid activation and tRNA aminoacylation by all Class I aaRS. Separate alanine mutants of each signature, together with the double mutant, behave in opposite ways in Pyrococcus horikoshii LeuRS and the 129-residue urzyme ancestral model generated from it (LeuAC). Free energy coupling terms, Δ(ΔG‡), for both reactions are large and favourable for LeuRS, but unfavourable for LeuAC. Single turnover assays with 32Pα-ATP show correspondingly different internal products. These results implicate domain motion in catalysis by full-length LeuRS. The distributed thermodynamic cycle of mutational changes authenticates LeuAC urzyme catalysis far more convincingly than do single point mutations. Most importantly, the evolutionary gain of function induced by acquiring the anticodon-binding (ABD) and multiple insertion modules in the catalytic domain appears to be to coordinate the catalytic function of the HxGH and KMSKS signature sequences. The implication that backbone elements of secondary structures achieve a major portion of the overall transition-state stabilization by LeuAC is also consistent with coevolution of the genetic code and metabolic pathways necessary to produce histidine and lysine sidechains.
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Affiliation(s)
- Guo Qing Tang
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, USA
| | - Jessica J H Elder
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, USA
| | - Jordan Douglas
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, USA
- Department of Physics, The University of Auckland, New Zealand
| | - Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, USA
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8
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Choi H, Covert MW. Whole-cell modeling of E. coli confirms that in vitro tRNA aminoacylation measurements are insufficient to support cell growth and predicts a positive feedback mechanism regulating arginine biosynthesis. Nucleic Acids Res 2023; 51:5911-5930. [PMID: 37224536 PMCID: PMC10325894 DOI: 10.1093/nar/gkad435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/26/2023] Open
Abstract
In Escherichia coli, inconsistencies between in vitro tRNA aminoacylation measurements and in vivo protein synthesis demands were postulated almost 40 years ago, but have proven difficult to confirm. Whole-cell modeling can test whether a cell behaves in a physiologically correct manner when parameterized with in vitro measurements by providing a holistic representation of cellular processes in vivo. Here, a mechanistic model of tRNA aminoacylation, codon-based polypeptide elongation, and N-terminal methionine cleavage was incorporated into a developing whole-cell model of E. coli. Subsequent analysis confirmed the insufficiency of aminoacyl-tRNA synthetase kinetic measurements for cellular proteome maintenance, and estimated aminoacyl-tRNA synthetase kcats that were on average 7.6-fold higher. Simulating cell growth with perturbed kcats demonstrated the global impact of these in vitro measurements on cellular phenotypes. For example, an insufficient kcat for HisRS caused protein synthesis to be less robust to the natural variability in aminoacyl-tRNA synthetase expression in single cells. More surprisingly, insufficient ArgRS activity led to catastrophic impacts on arginine biosynthesis due to underexpressed N-acetylglutamate synthase, where translation depends on repeated CGG codons. Overall, the expanded E. coli model deepens understanding of how translation operates in an in vivo context.
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Affiliation(s)
- Heejo Choi
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA
| | - Markus W Covert
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA
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9
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Ma X, Bakhtina M, Shulgina I, Cantara WA, Kuzmishin Nagy A, Goto Y, Suga H, Foster MP, Musier-Forsyth K. Structural basis of tRNAPro acceptor stem recognition by a bacterial trans-editing domain. Nucleic Acids Res 2023; 51:3988-3999. [PMID: 36951109 PMCID: PMC10164551 DOI: 10.1093/nar/gkad192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/24/2023] Open
Abstract
High fidelity tRNA aminoacylation by aminoacyl-tRNA synthetases is essential for cell viability. ProXp-ala is a trans-editing protein that is present in all three domains of life and is responsible for hydrolyzing mischarged Ala-tRNAPro and preventing mistranslation of proline codons. Previous studies have shown that, like bacterial prolyl-tRNA synthetase, Caulobacter crescentus ProXp-ala recognizes the unique C1:G72 terminal base pair of the tRNAPro acceptor stem, helping to ensure deacylation of Ala-tRNAPro but not Ala-tRNAAla. The structural basis for C1:G72 recognition by ProXp-ala is still unknown and was investigated here. NMR spectroscopy, binding, and activity assays revealed two conserved residues, K50 and R80, that likely interact with the first base pair, stabilizing the initial protein-RNA encounter complex. Modeling studies are consistent with direct interaction between R80 and the major groove of G72. A third key contact between A76 of tRNAPro and K45 of ProXp-ala was essential for binding and accommodating the CCA-3' end in the active site. We also demonstrated the essential role that the 2'OH of A76 plays in catalysis. Eukaryotic ProXp-ala proteins recognize the same acceptor stem positions as their bacterial counterparts, albeit with different nucleotide base identities. ProXp-ala is encoded in some human pathogens; thus, these results have the potential to inform new antibiotic drug design.
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Affiliation(s)
- Xiao Ma
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Irina Shulgina
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - William A Cantara
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Alexandra B Kuzmishin Nagy
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Yuki Goto
- Department of Chemistry, Graduate School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Mark P Foster
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
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10
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Avcilar-Kucukgoze I, Kashina AS. Enzymatic Aminoacylation of tRNA Arg Using Recombinant Arg-tRNA Synthetase. Methods Mol Biol 2023; 2620:107-111. [PMID: 37010755 DOI: 10.1007/978-1-0716-2942-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
This chapter describes the preparation of pre-charged Arg-tRNA that can be used in arginylation reaction. While in a typical arginylation reaction arginyl-tRNA synthetase (RARS) is normally included as a component of the reaction and continually charges tRNA during arginylation, it is sometimes necessary to separate the charging and the arginylation step, in order to perform each reaction under controlled conditions, e.g., for measuring the kinetics or determining the effect of different compounds and chemicals on the reaction. In such cases, tRNAArg can be pre-charged with Arg and purified away from the RARS enzyme prior to arginylation.
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Affiliation(s)
- Irem Avcilar-Kucukgoze
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Anna S Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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11
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Del Greco C, Antonellis A. The Role of Nuclear-Encoded Mitochondrial tRNA Charging Enzymes in Human Inherited Disease. Genes (Basel) 2022; 13:genes13122319. [PMID: 36553587 PMCID: PMC9777667 DOI: 10.3390/genes13122319] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are highly conserved essential enzymes that charge tRNA with cognate amino acids-the first step of protein synthesis. Of the 37 nuclear-encoded human ARS genes, 17 encode enzymes are exclusively targeted to the mitochondria (mt-ARSs). Mutations in nuclear mt-ARS genes are associated with rare, recessive human diseases with a broad range of clinical phenotypes. While the hypothesized disease mechanism is a loss-of-function effect, there is significant clinical heterogeneity among patients that have mutations in different mt-ARS genes and also among patients that have mutations in the same mt-ARS gene. This observation suggests that additional factors are involved in disease etiology. In this review, we present our current understanding of diseases caused by mutations in the genes encoding mt-ARSs and propose explanations for the observed clinical heterogeneity.
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Affiliation(s)
- Christina Del Greco
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Correspondence:
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12
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Abstract
Increased tRNA abundance and amino acid coupling generally promote increased oncogenesis. By contrast, a new study shows that in breast cancer, the leucyl-tRNA synthetase LARS suppresses transformation and tumour development by increasing tRNA-LeuCAG translation of certain tumour suppressor mRNAs.
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Affiliation(s)
- C Theresa Vincent
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Immunology, Genetics and Pathology (IGP), Uppsala University, Uppsala, Sweden
| | - Robert J Schneider
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY, USA.
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13
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Abstract
Viruses require multifunctional structured RNAs to hijack their host’s biochemistry, but their mechanisms can be obscured by the difficulty of solving conformationally dynamic RNA structures. Using cryo–electron microscopy (cryo-EM), we visualized the structure of the mysterious viral transfer RNA (tRNA)–like structure (TLS) from the brome mosaic virus, which affects replication, translation, and genome encapsidation. Structures in isolation and those bound to tyrosyl-tRNA synthetase (TyrRS) show that this ~55-kilodalton purported tRNA mimic undergoes large conformational rearrangements to bind TyrRS in a form that differs substantially from that of tRNA. Our study reveals how viral RNAs can use a combination of static and dynamic RNA structures to bind host machinery through highly noncanonical interactions, and we highlight the utility of cryo-EM for visualizing small, conformationally dynamic structured RNAs.
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Affiliation(s)
- Steve L. Bonilla
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Madeline E. Sherlock
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrea MacFadden
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jeffrey S. Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA BioScience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 10 80045, USA
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14
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Abstract
As the adaptor that decodes mRNA sequence into protein, the basic aspects of tRNA structure and function are central to all studies of biology. Yet the complexities of their properties and cellular roles go beyond the view of tRNAs as static participants in protein synthesis. Detailed analyses through more than 60 years of study have revealed tRNAs to be a fascinatingly diverse group of molecules in form and function, impacting cell biology, physiology, disease and synthetic biology. This review analyzes tRNA structure, biosynthesis and function, and includes topics that demonstrate their diversity and growing importance.
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Affiliation(s)
- Matthew D. Berg
- Department of Biochemistry, The University of Western Ontario, London, Canada
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15
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Yokosawa T, Sato A, Wakasugi K. Tryptophan Depletion Modulates Tryptophanyl-tRNA Synthetase-Mediated High-Affinity Tryptophan Uptake into Human Cells. Genes (Basel) 2020; 11:genes11121423. [PMID: 33261077 PMCID: PMC7760169 DOI: 10.3390/genes11121423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/07/2020] [Accepted: 11/25/2020] [Indexed: 12/14/2022] Open
Abstract
The novel high-affinity tryptophan (Trp)-selective transport system is present at elevated levels in human interferon-γ (IFN-γ)-treated and indoleamine 2,3-dioxygenase 1 (IDO1)-expressing cells. High-affinity Trp uptake into cells results in extracellular Trp depletion and immune suppression. We have previously shown that both IDO1 and tryptophanyl-tRNA synthetase (TrpRS), whose expression levels are increased by IFN-γ, have a crucial function in high-affinity Trp uptake into human cells. Here, we aimed to elucidate the relationship between TrpRS and IDO1 in high-affinity Trp uptake. We demonstrated that overexpression of IDO1 in HeLa cells drastically enhances high-affinity Trp uptake upon addition of purified TrpRS protein to uptake assay buffer. We also clarified that high-affinity Trp uptake by Trp-starved cells is significantly enhanced by the addition of TrpRS protein to the assay buffer. Moreover, we showed that high-affinity Trp uptake is also markedly elevated by the addition of TrpRS protein to the assay buffer of cells overexpressing another Trp-metabolizing enzyme, tryptophan 2,3-dioxygenase (TDO2). Taken together, we conclude that Trp deficiency is crucial for high-affinity Trp uptake mediated by extracellular TrpRS.
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Affiliation(s)
- Takumi Yokosawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Aomi Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan;
| | - Keisuke Wakasugi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan;
- Correspondence: ; Tel.: +81-3-5454-4392
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16
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Abstract
Aminoacylation of tRNA generates an aminoacyl-tRNA (aa-tRNA) that is active for protein synthesis on the ribosome. Quantification of aminoacylation of tRNA is critical to understand the mechanism of specificity and the flux of the aa-tRNA into the protein synthesis machinery, which determines the rate of cell growth. Traditional assays for the quantification of tRNA aminoacylation involve radioactivity, either with a radioactive amino acid or with a [3′-32P]-labeled tRNA. We describe here a label-free assay that monitors aminoacylation by biotinylation-streptavidin (SA) conjugation to the α-amine or the α-imine of the aminoacyl group on the aa-tRNA. The conjugated aa-tRNA product is readily separated from the unreacted tRNA by a denaturing polyacrylamide gel, allowing for quantitative measurement of aminoacylation. This label-free assay is applicable to a wide range of amino acids and tRNA sequences and to both classes of aminoacylation. It is more sensitive and robust than the assay with a radioactive amino acid and has the potential to explore a wider range of tRNA than the assay with a [3′-32P]-labeled tRNA. This label-free assay reports kinetic parameters of aminoacylation quantitatively similar to those reported by using a radioactive amino acid, suggesting its broad applicability to research relevant to human health and disease.
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17
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Lee J, Schwieter KE, Watkins AM, Kim DS, Yu H, Schwarz KJ, Lim J, Coronado J, Byrom M, Anslyn EV, Ellington AD, Moore JS, Jewett MC. Expanding the limits of the second genetic code with ribozymes. Nat Commun 2019; 10:5097. [PMID: 31704912 PMCID: PMC6841967 DOI: 10.1038/s41467-019-12916-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 10/09/2019] [Indexed: 12/16/2022] Open
Abstract
The site-specific incorporation of noncanonical monomers into polypeptides through genetic code reprogramming permits synthesis of bio-based products that extend beyond natural limits. To better enable such efforts, flexizymes (transfer RNA (tRNA) synthetase-like ribozymes that recognize synthetic leaving groups) have been used to expand the scope of chemical substrates for ribosome-directed polymerization. The development of design rules for flexizyme-catalyzed acylation should allow scalable and rational expansion of genetic code reprogramming. Here we report the systematic synthesis of 37 substrates based on 4 chemically diverse scaffolds (phenylalanine, benzoic acid, heteroaromatic, and aliphatic monomers) with different electronic and steric factors. Of these substrates, 32 were acylated onto tRNA and incorporated into peptides by in vitro translation. Based on the design rules derived from this expanded alphabet, we successfully predicted the acylation of 6 additional monomers that could uniquely be incorporated into peptides and direct N-terminal incorporation of an aldehyde group for orthogonal bioconjugation reactions.
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Affiliation(s)
- Joongoo Lee
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, 60208, IL, USA
| | - Kenneth E Schwieter
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Andrew M Watkins
- Departments of Biochemistry and Physics, Stanford University, Stanford, 94305, CA, USA
| | - Do Soon Kim
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, 60208, IL, USA
| | - Hao Yu
- Departments of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Kevin J Schwarz
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Jongdoo Lim
- Department of Chemistry, University of Texas at Austin, Austin, 78712, TX, USA
| | - Jaime Coronado
- Department of Chemistry, University of Texas at Austin, Austin, 78712, TX, USA
| | - Michelle Byrom
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, 78712, TX, USA
| | - Eric V Anslyn
- Department of Chemistry, University of Texas at Austin, Austin, 78712, TX, USA
| | - Andrew D Ellington
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, 78712, TX, USA
| | - Jeffrey S Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA.
- The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, 60208, IL, USA.
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18
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Crnković A, Vargas-Rodriguez O, Söll D. Plasticity and Constraints of tRNA Aminoacylation Define Directed Evolution of Aminoacyl-tRNA Synthetases. Int J Mol Sci 2019; 20:ijms20092294. [PMID: 31075874 PMCID: PMC6540133 DOI: 10.3390/ijms20092294] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
Genetic incorporation of noncanonical amino acids (ncAAs) has become a powerful tool to enhance existing functions or introduce new ones into proteins through expanded chemistry. This technology relies on the process of nonsense suppression, which is made possible by directing aminoacyl-tRNA synthetases (aaRSs) to attach an ncAA onto a cognate suppressor tRNA. However, different mechanisms govern aaRS specificity toward its natural amino acid (AA) substrate and hinder the engineering of aaRSs for applications beyond the incorporation of a single l-α-AA. Directed evolution of aaRSs therefore faces two interlinked challenges: the removal of the affinity for cognate AA and improvement of ncAA acylation. Here we review aspects of AA recognition that directly influence the feasibility and success of aaRS engineering toward d- and β-AAs incorporation into proteins in vivo. Emerging directed evolution methods are described and evaluated on the basis of aaRS active site plasticity and its inherent constraints.
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Affiliation(s)
- Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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19
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Abstract
Diabetes mellitus (DM) is a complex endocrine and metabolic disorder for human health and well-being. Deregulated glucose and lipid metabolism are the primary underlying manifestations associated with this disease. Transfer RNAs (tRNAs) are considered to mainly participate in protein translation and may contribute to complex human pathologies. Although the molecular mechanisms remain, for the most part, unknown, accumulating evidence indicates that tRNAs play a vital role in the pathogenesis of DM. This paper reviews different aspects of tRNA-associated dysregulation in DM, such as tRNA mutations, tRNA modifications, tRNA aminoacylation and tRNA derivatives, aiming at a better understanding of the pathogenesis of DM and providing new ideas for the personalized treatment of this metabolism-associated disease.
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Affiliation(s)
- Zheng Zhou
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Bao Sun
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410000, China; Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha 410000, China
| | - Shiqiong Huang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410000, China; Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha 410000, China
| | - Wenrui Jia
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Dongsheng Yu
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China.
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20
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Li W, Meng D, Gu Z, Yang Q, Yuan H, Li Y, Chen Q, Yu J, Liu C, Li T. Apple S-RNase triggers inhibition of tRNA aminoacylation by interacting with a soluble inorganic pyrophosphatase in growing self-pollen tubes in vitro. New Phytol 2018; 218:579-593. [PMID: 29424440 DOI: 10.1111/nph.15028] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 01/04/2018] [Indexed: 05/21/2023]
Abstract
Apple exhibits S-RNase-based self-incompatibility (SI), in which S-RNase plays a central role in rejecting self-pollen. It has been proposed that the arrest of pollen growth in SI of Solanaceae plants is a consequence of the degradation of pollen rRNA by S-RNase; however, the underlying mechanism in Rosaceae is still unclear. Here, we used S2 -RNase as a bait to screen an apple pollen cDNA library and characterized an apple soluble inorganic pyrophosphatase (MdPPa) that physically interacted with S-RNases. When treated with self S-RNases, apple pollen tubes showed a marked growth inhibition, as well as a decrease in endogenous soluble pyrophosphatase activity and elevated levels of inorganic pyrophosphate (PPi). In addition, S-RNase was found to bind to two variable regions of MdPPa, resulting in a noncompetitive inhibition of its activity. Silencing of MdPPa expression led to a reduction in pollen tube growth. Interestingly, tRNA aminoacylation was inhibited in self S-RNase-treated or MdPPa-silenced pollen tubes, resulting in the accumulation of uncharged tRNA. Furthermore, we provide evidence showing that this disturbance of tRNA aminoacylation is independent of RNase activity. We propose an alternative mechanism differing from RNA degradation to explain the cytotoxicity of the S-RNase apple SI process.
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Affiliation(s)
- Wei Li
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Dong Meng
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Zhaoyu Gu
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Qing Yang
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Hui Yuan
- College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China
| | - Yang Li
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Qiuju Chen
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Jie Yu
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Chunsheng Liu
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Tianzhong Li
- Laboratory of Fruit Cell and Molecular Breeding, College of Horticulture, China Agricultural University, Beijing, 100193, China
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21
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Paley EL, Perry G. Towards an Integrative Understanding of tRNA Aminoacylation-Diet-Host-Gut Microbiome Interactions in Neurodegeneration. Nutrients 2018; 10:nu10040410. [PMID: 29587458 PMCID: PMC5946195 DOI: 10.3390/nu10040410] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 02/07/2023] Open
Abstract
Transgenic mice used for Alzheimer’s disease (AD) preclinical experiments do not recapitulate the human disease. In our models, the dietary tryptophan metabolite tryptamine produced by human gut microbiome induces tryptophanyl-tRNA synthetase (TrpRS) deficiency with consequent neurodegeneration in cells and mice. Dietary supplements, antibiotics and certain drugs increase tryptamine content in vivo. TrpRS catalyzes tryptophan attachment to tRNAtrp at initial step of protein biosynthesis. Tryptamine that easily crosses the blood–brain barrier induces vasculopathies, neurodegeneration and cell death via TrpRS competitive inhibition. TrpRS inhibitor tryptophanol produced by gut microbiome also induces neurodegeneration. TrpRS inhibition by tryptamine and its metabolites preventing tryptophan incorporation into proteins lead to protein biosynthesis impairment. Tryptophan, a least amino acid in food and proteins that cannot be synthesized by humans competes with frequent amino acids for the transport from blood to brain. Tryptophan is a vulnerable amino acid, which can be easily lost to protein biosynthesis. Some proteins marking neurodegenerative pathology, such as tau lack tryptophan. TrpRS exists in cytoplasmic (WARS) and mitochondrial (WARS2) forms. Pathogenic gene variants of both forms cause TrpRS deficiency with consequent intellectual and motor disabilities in humans. The diminished tryptophan-dependent protein biosynthesis in AD patients is a proof of our model-based disease concept.
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Affiliation(s)
- Elena L Paley
- Expert Biomed, Inc., 11933 SW 271st TER Homestead, Miami Dade, FL 33032-3305, USA.
- Stop Alzheimers Corp., Miami Dade, FL 33032, USA.
- Nova Southeastern University, 3301 College Ave, Fort Lauderdale, FL 33314, USA.
| | - George Perry
- Stop Alzheimers Corp., Miami Dade, FL 33032, USA.
- University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
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22
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Cantara WA, Olson ED, Musier-Forsyth K. Analysis of RNA structure using small-angle X-ray scattering. Methods 2017; 113:46-55. [PMID: 27777026 PMCID: PMC5253320 DOI: 10.1016/j.ymeth.2016.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/10/2016] [Accepted: 10/20/2016] [Indexed: 11/22/2022] Open
Abstract
In addition to their role in correctly attaching specific amino acids to cognate tRNAs, aminoacyl-tRNA synthetases (aaRS) have been found to possess many alternative functions and often bind to and act on other nucleic acids. In contrast to the well-defined 3D structure of tRNA, the structures of many of the other RNAs recognized by aaRSs have not been solved. Despite advances in the use of X-ray crystallography (XRC), nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (cryo-EM) for structural characterization of biomolecules, significant challenges to solving RNA structures still exist. Recently, small-angle X-ray scattering (SAXS) has been increasingly employed to characterize the 3D structures of RNAs and RNA-protein complexes. SAXS is capable of providing low-resolution tertiary structure information under physiological conditions and with less intensive sample preparation and data analysis requirements than XRC, NMR and cryo-EM. In this article, we describe best practices involved in the process of RNA and RNA-protein sample preparation, SAXS data collection, data analysis, and structural model building.
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Affiliation(s)
- William A Cantara
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States.
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23
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Saint-Léger A, Ribas de Pouplana L. A new set of assays for the discovery of aminoacyl-tRNA synthetase inhibitors. Methods 2016; 113:34-45. [PMID: 27989759 DOI: 10.1016/j.ymeth.2016.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023] Open
Abstract
Current biochemical methods available to monitor the activity of aminoacyl-tRNA synthetases (ARS) are ill-suited to high-throughput screening approaches for the identification of small-molecule inhibitors of these enzymes. In an attempt to improve the limitations of current assays we have developed a suite of new methods designed to streamline the discovery of new ARS antagonists. This set of assays includes approaches to monitor ARS activity in vitro, in human cells, and in bacteria. They are applicable to several ARSs from any given organism, can be easily adapted to very high-throughput set-ups, and allow for a multi-factorial selection of drug candidates.
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Affiliation(s)
- Adélaïde Saint-Léger
- Omnia Molecular S.L., c/ Baldiri Reixac 15-21, 08028 Barcelona, Catalonia, Spain
| | - Lluís Ribas de Pouplana
- Omnia Molecular S.L., c/ Baldiri Reixac 15-21, 08028 Barcelona, Catalonia, Spain; Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Catalonia, Spain.
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24
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Cvetesic N, Gruic-Sovulj I. Synthetic and editing reactions of aminoacyl-tRNA synthetases using cognate and non-cognate amino acid substrates. Methods 2016; 113:13-26. [PMID: 27713080 DOI: 10.1016/j.ymeth.2016.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 11/19/2022] Open
Abstract
The covalent coupling of cognate amino acid-tRNA pairs by corresponding aminoacyl-tRNA synthetases (aaRS) defines the genetic code and provides aminoacylated tRNAs for ribosomal protein synthesis. Besides the cognate substrate, some non-cognate amino acids may also compete for tRNA aminoacylation. However, their participation in protein synthesis is generally prevented by an aaRS proofreading activity located in the synthetic site and in a separate editing domain. These mechanisms, coupled with the ability of certain aaRSs to discriminate well against non-cognate amino acids in the synthetic reaction alone, define the accuracy of the aminoacylation reaction. aaRS quality control may also act as a gatekeeper for the standard genetic code and prevents infiltration by natural amino acids that are not normally coded for protein biosynthesis. This latter finding has reinforced interest in understanding the principles that govern discrimination against a range of potential non-cognate amino acids. This paper presents an overview of the kinetic assays that have been established for monitoring synthetic and editing reactions with cognate and non-cognate amino acid substrates. Taking into account the peculiarities of non-cognate reactions, the specific controls needed and the dedicated experimental designs are discussed in detail. Kinetic partitioning within the synthetic and editing sites controls the balance between editing and aminoacylation. We describe in detail steady-state and single-turnover approaches for the analysis of synthetic and editing reactions, which ultimately enable mechanisms of amino acid discrimination to be determined.
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Affiliation(s)
- Nevena Cvetesic
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
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25
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Wanders D, Stone KP, Forney LA, Cortez CC, Dille KN, Simon J, Xu M, Hotard EC, Nikonorova IA, Pettit AP, Anthony TG, Gettys TW. Role of GCN2-Independent Signaling Through a Noncanonical PERK/NRF2 Pathway in the Physiological Responses to Dietary Methionine Restriction. Diabetes 2016; 65:1499-510. [PMID: 26936965 PMCID: PMC4878423 DOI: 10.2337/db15-1324] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 02/23/2016] [Indexed: 01/11/2023]
Abstract
Restricting availability of essential amino acids (EAAs) limits aminoacylation of tRNAs by their cognate EAAs and activates the nutrient-sensing kinase, general control nonderepressible 2 (GCN2). Activated GCN2 phosphorylates eukaryotic initiation factor 2 (eIF2), altering gene-specific translation and initiating a transcriptional program collectively described as the integrated stress response (ISR). Central GCN2 activation by EAA deprivation is also linked to an acute aversive feeding response. Dietary methionine restriction (MR) produces a well-documented series of physiological responses (increased energy intake and expenditure, decreased adiposity, and increased insulin sensitivity), but the role of GCN2 in mediating them is unknown. Using Gcn2(-/-) mice, we found that the absence of GCN2 had no effect on the ability of MR to reduce body weight or adiposity, increase energy intake and expenditure, increase hepatic transcription and release of fibroblast growth factor 21, or improve insulin sensitivity. Interestingly, hepatic eIF2 phosphorylation by MR was uncompromised in Gcn2(-/-) mice. Instead, protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) was activated in both intact and Gcn2(-/-) mice. PERK activation corresponded with induction of the ISR and the nuclear respiratory factor 2 antioxidant program but not ER stress. These data uncover a novel glutathione-sensing mechanism that functions independently of GCN2 to link dietary MR to its metabolic phenotype.
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Affiliation(s)
- Desiree Wanders
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Kirsten P Stone
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Laura A Forney
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Cory C Cortez
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Kelly N Dille
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Jacob Simon
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Mark Xu
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Elisabeth C Hotard
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Inna A Nikonorova
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Ashley P Pettit
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Tracy G Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Thomas W Gettys
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
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26
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McShane A, Hok E, Tomberlin J, Eriani G, Geslain R. The Enzymatic Paradox of Yeast Arginyl-tRNA Synthetase: Exclusive Arginine Transfer Controlled by a Flexible Mechanism of tRNA Recognition. PLoS One 2016; 11:e0148460. [PMID: 26844776 PMCID: PMC4742068 DOI: 10.1371/journal.pone.0148460] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/18/2016] [Indexed: 11/18/2022] Open
Abstract
Identity determinants are essential for the accurate recognition of transfer RNAs by aminoacyl-tRNA synthetases. To date, arginine determinants in the yeast Saccharomyces cerevisiae have been identified exclusively in vitro and only on a limited number of tRNA Arginine isoacceptors. In the current study, we favor a full cellular approach and expand the investigation of arginine determinants to all four tRNA Arg isoacceptors. More precisely, this work scrutinizes the relevance of the tRNA nucleotides at position 20, 35 and 36 in the yeast arginylation reaction. We built 21 mutants by site-directed mutagenesis and tested their functionality in YAL5, a previously engineered yeast knockout deficient for the expression of tRNA Arg CCG. Arginylation levels were also monitored using Northern blot. Our data collected in vivo correlate with previous observations. C35 is the prominent arginine determinant followed by G36 or U36 (G/U36). In addition, although there is no major arginine determinant in the D loop, the recognition of tRNA Arg ICG relies to some extent on the nucleotide at position 20. This work refines the existing model for tRNA Arg recognition. Our observations indicate that yeast Arginyl-tRNA synthetase (yArgRS) relies on distinct mechanisms to aminoacylate the four isoacceptors. Finally, according to our refined model, yArgRS is able to accommodate tRNA Arg scaffolds presenting N34, C/G35 and G/A/U36 anticodons while maintaining specificity. We discuss the mechanistic and potential physiological implications of these findings.
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Affiliation(s)
- Ariel McShane
- Laboratory of tRNA biology, Department of Biology, College of Charleston, Charleston, South Carolina, United States of America
| | - Eveline Hok
- Laboratory of tRNA biology, Department of Biology, College of Charleston, Charleston, South Carolina, United States of America
| | - Jensen Tomberlin
- Laboratory of tRNA biology, Department of Biology, College of Charleston, Charleston, South Carolina, United States of America
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084, Strasbourg CEDEX, France
| | - Renaud Geslain
- Laboratory of tRNA biology, Department of Biology, College of Charleston, Charleston, South Carolina, United States of America
- * E-mail:
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Koubek J, Chen YR, Cheng RP, Huang JJT. Nonorthogonal tRNA(cys)(Amber) for protein and nascent chain labeling. RNA 2015; 21:1672-82. [PMID: 26194135 PMCID: PMC4536326 DOI: 10.1261/rna.051805.115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/08/2015] [Indexed: 05/14/2023]
Abstract
In vitro-transcribed suppressor tRNAs are commonly used in site-specific fluorescence labeling for protein and ribosome-bound nascent chains (RNCs) studies. Here, we describe the production of nonorthogonal Bacillus subtilis tRNA(cys)(Amber) from Escherichia coli, a process that is superior to in vitro transcription in terms of yield, ease of manipulation, and tRNA stability. As cysteinyl-tRNA synthetase was previously shown to aminoacylate tRNA(cys)(Amber) with lower efficiency, multiple tRNA synthetase mutants were designed to optimize aminoacylation. Aminoacylated tRNA was conjugated to a fluorophore to produce BODIPY FL-cysteinyl-tRNA(cys)(Amber), which was used to generate ribosome-bound nascent chains of different lengths with the fluorophore incorporated at various predetermined sites. This tRNA tool may be beneficial in the site-specific labeling of full-length proteins as well as RNCs for biophysical and biological research.
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MESH Headings
- Amino Acyl-tRNA Synthetases/genetics
- Amino Acyl-tRNA Synthetases/metabolism
- Bacillus subtilis/genetics
- Cell-Free System
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Fluorescent Dyes/chemistry
- In Vitro Techniques
- Models, Molecular
- Protein Biosynthesis
- RNA Stability
- RNA, Bacterial/biosynthesis
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Transfer, Cys/biosynthesis
- RNA, Transfer, Cys/chemistry
- RNA, Transfer, Cys/genetics
- Transfer RNA Aminoacylation
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Affiliation(s)
- Jiří Koubek
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Nankang, Taipei 11529, Taiwan Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yet-Ran Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Richard Ping Cheng
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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Rao BS, Jackman JE. Life without post-transcriptional addition of G-1: two alternatives for tRNAHis identity in Eukarya. RNA 2015; 21:243-53. [PMID: 25505023 PMCID: PMC4338351 DOI: 10.1261/rna.048389.114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/06/2014] [Indexed: 05/23/2023]
Abstract
The identity of tRNA(His) is strongly associated with the presence of an additional 5'-guanosine residue (G-1) in all three domains of life. The critical nature of the G-1 residue is underscored by the fact that two entirely distinct mechanisms for its acquisition are observed, with cotranscriptional incorporation observed in Bacteria, while post-transcriptional addition of G-1 occurs in Eukarya. Here, through our investigation of eukaryotes that lack obvious homologs of the post-transcriptional G-1-addition enzyme Thg1, we identify alternative pathways to tRNA(His) identity that controvert these well-established rules. We demonstrate that Trypanosoma brucei, like Acanthamoeba castellanii, lacks the G-1 identity element on tRNA(His) and utilizes a noncanonical G-1-independent histidyl-tRNA synthetase (HisRS). Purified HisRS enzymes from A. castellanii and T. brucei exhibit a mechanism of tRNA(His) recognition that is distinct from canonical G-1-dependent synthetases. Moreover, noncanonical HisRS enzymes genetically complement the loss of THG1 in Saccharomyces cerevisiae, demonstrating the biological relevance of the G-1-independent aminoacylation activity. In contrast, in Caenorhabditis elegans, which is another Thg1-independent eukaryote, the G-1 residue is maintained, but here its acquisition is noncanonical. In this case, the G-1 is encoded and apparently retained after 5' end processing, which has so far only been observed in Bacteria and organelles. Collectively, these observations unearth a widespread and previously unappreciated diversity in eukaryotic tRNA(His) identity mechanisms.
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Affiliation(s)
- Bhalchandra S Rao
- Molecular, Cellular and Developmental Biology Program, Center for RNA Biology and Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jane E Jackman
- Molecular, Cellular and Developmental Biology Program, Center for RNA Biology and Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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29
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Zhou XL, Ruan ZR, Wang M, Fang ZP, Wang Y, Chen Y, Liu RJ, Eriani G, Wang ED. A minimalist mitochondrial threonyl-tRNA synthetase exhibits tRNA-isoacceptor specificity during proofreading. Nucleic Acids Res 2014; 42:13873-86. [PMID: 25414329 PMCID: PMC4267643 DOI: 10.1093/nar/gku1218] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Yeast mitochondria contain a minimalist threonyl-tRNA synthetase (ThrRS) composed only of the catalytic core and tRNA binding domain but lacking the entire editing domain. Besides the usual tRNAThr2, some budding yeasts, such as Saccharomyces cerevisiae, also contain a non-canonical tRNAThr1 with an enlarged 8-nucleotide anticodon loop, reprograming the usual leucine CUN codons to threonine. This raises interesting questions about the aminoacylation fidelity of such ThrRSs and the possible contribution of the two tRNAThrs during editing. Here, we found that, despite the absence of the editing domain, S. cerevisiae mitochondrial ThrRS (ScmtThrRS) harbors a tRNA-dependent pre-transfer editing activity. Remarkably, only the usual tRNAThr2 stimulated pre-transfer editing, thus, establishing the first example of a synthetase exhibiting tRNA-isoacceptor specificity during pre-transfer editing. We also showed that the failure of tRNAThr1 to stimulate tRNA-dependent pre-transfer editing was due to the lack of an editing domain. Using assays of the complementation of a ScmtThrRS gene knockout strain, we showed that the catalytic core and tRNA binding domain of ScmtThrRS co-evolved to recognize the unusual tRNAThr1. In combination, the results provide insights into the tRNA-dependent editing process and suggest that tRNA-dependent pre-transfer editing takes place in the aminoacylation catalytic core.
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Affiliation(s)
- Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Zhi-Rong Ruan
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Meng Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Zhi-Peng Fang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Yong Wang
- School of Life Science and Technology, ShanghaiTech University, 319 Yue Yang Road, 200031 Shanghai, China
| | - Yun Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Ru-Juan Liu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, Université de Strasbourg, UPR9002 CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg, France
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, China School of Life Science and Technology, ShanghaiTech University, 319 Yue Yang Road, 200031 Shanghai, China
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30
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Abstract
Portions of E. coli tRNA(Glu) having identity determinants for glutamyl-tRNA synthetase (ERS, EC 6.1.1.17) have been designed to be the first RNA inhibitors of a Class I synthetase. ERS recognizes the 2-thionyl group of 2-thio-5-methylaminomethyluridine (mnm(5)s(2)U(34)) in the first or wobble anticodon position of E. coli tRNA(Glu). The interaction, as revealed by structural analysis, though specific, appears tenuous. Thus, it is surprising that RNAs designed from this tRNA's anticodon stem and loop domain with (ASL(Glu)-s(2)U(34)) and without s(2)U(34) are bound by ERS and inhibit aminoacylation of the native tRNA. ASL(Glu), ASL(Glu)-s(2)U(34), and a minihelix(Glu) composed of identity determinants of the amino acid accepting stem were thermally stable under conditions of aminoacylation (T(m)s = 75 +/- 1.5, 76 +/- 0.9 and 83 +/- 2.0 degrees C, respectively). In binding competition, the modified ASL(Glu)-s(2)U(34) bound ERS with a higher affinity (half maximal inhibiting concentration, IC(50), 5.1 +/- 0.4 microM) than its unmodified counterpart, ASL(Glu) (IC(50), 10.3 +/- 0.6 microM). The minihelix(Glu), ASL(Glu)-s(2)U(34) and ASL(Glu) bound ERS with K(d)s of 9.9 +/- 3.3, 6.5 +/- 1.7 and 20.5 +/- 3.8 microM. ERS aminoacylation of tRNA(Glu) was inhibited by the tRNA fragments. Unmodified ASL(Glu), minihelix(Glu), and ASL(Glu)-s(2)U(34) exhibited a K(ic) of 1.9 +/- 0.2 microM, 4.1 +/- 0.2 microM, and 6.5 +/- 0.1 microM, respectively. The modified ASL(Glu)-s(2)U(34), though having a higher affinity for ERS, may be released more readily and thus, not be as good an inhibitor as the unmodified ASL. Thus, the RNA constructs are effective tools to study RNA-protein interaction.
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Affiliation(s)
- Estella M Gustilo
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622, USA
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Alperstein A, Ulrich B, Garofalo DM, Dreisbach R, Raff H, Sheppard K. The predatory bacterium Bdellovibrio bacteriovorus aspartyl-tRNA synthetase recognizes tRNAAsn as a substrate. PLoS One 2014; 9:e110842. [PMID: 25338061 PMCID: PMC4206432 DOI: 10.1371/journal.pone.0110842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/20/2014] [Indexed: 11/29/2022] Open
Abstract
The predatory bacterium Bdellovibrio bacteriovorus preys on other Gram-negative bacteria and was predicted to be an asparagine auxotroph. However, despite encoding asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase, B. bacteriovorus also contains the amidotransferase GatCAB. Deinococcus radiodurans, and Thermus thermophilus also encode both of these aminoacyl-tRNA synthetases with GatCAB. Both also code for a second aspartyl-tRNA synthetase and use the additional aspartyl-tRNA synthetase with GatCAB to synthesize asparagine on tRNAAsn. Unlike those two bacteria, B. bacteriovorus encodes only one aspartyl-tRNA synthetase. Here we demonstrate the lone B. bacteriovorus aspartyl-tRNA synthetase catalyzes aspartyl-tRNAAsn formation that GatCAB can then amidate to asparaginyl-tRNAAsn. This non-discriminating aspartyl-tRNA synthetase with GatCAB thus provides B. bacteriovorus a second route for Asn-tRNAAsn formation with the asparagine synthesized in a tRNA-dependent manner. Thus, in contrast to a previous prediction, B. bacteriovorus codes for a biosynthetic route for asparagine. Analysis of bacterial genomes suggests a significant number of other bacteria may also code for both routes for Asn-tRNAAsn synthesis with only a limited number encoding a second aspartyl-tRNA synthetase.
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Affiliation(s)
- Ariel Alperstein
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
| | - Brittany Ulrich
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
| | - Denise M. Garofalo
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
| | - Ruth Dreisbach
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
| | - Hannah Raff
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
| | - Kelly Sheppard
- Chemistry Department, Skidmore College, Saratoga Springs, New York, United States of America
- * E-mail:
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32
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Fung AWS, Leung CCY, Fahlman RP. The determination of tRNALeu recognition nucleotides for Escherichia coli L/F transferase. RNA 2014; 20:1210-1222. [PMID: 24935875 PMCID: PMC4105747 DOI: 10.1261/rna.044529.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/28/2014] [Indexed: 06/03/2023]
Abstract
Escherichia coli leucyl/phenylalanyl-tRNA protein transferase catalyzes the tRNA-dependent post-translational addition of amino acids onto the N-terminus of a protein polypeptide substrate. Based on biochemical and structural studies, the current tRNA recognition model by L/F transferase involves the identity of the 3' aminoacyl adenosine and the sequence-independent docking of the D-stem of an aminoacyl-tRNA to the positively charged cluster on L/F transferase. However, this model does not explain the isoacceptor preference observed 40 yr ago. Using in vitro-transcribed tRNA and quantitative MALDI-ToF MS enzyme activity assays, we have confirmed that, indeed, there is a strong preference for the most abundant leucyl-tRNA, tRNA(Leu) (anticodon 5'-CAG-3') isoacceptor for L/F transferase activity. We further investigate the molecular mechanism for this preference using hybrid tRNA constructs. We identified two independent sequence elements in the acceptor stem of tRNA(Leu) (CAG)-a G₃:C₇₀ base pair and a set of 4 nt (C₇₂, A₄:U₆₉, C₆₈)-that are important for the optimal binding and catalysis by L/F transferase. This maps a more specific, sequence-dependent tRNA recognition model of L/F transferase than previously proposed.
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Affiliation(s)
- Angela Wai Shan Fung
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | | - Richard Peter Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7 Department of Oncology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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33
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Mandal D, Köhrer C, Su D, Babu IR, Chan CT, Liu Y, Söll D, Blum P, Kuwahara M, Dedon PC, RajBhandary UL. Identification and codon reading properties of 5-cyanomethyl uridine, a new modified nucleoside found in the anticodon wobble position of mutant haloarchaeal isoleucine tRNAs. RNA 2014; 20:177-88. [PMID: 24344322 PMCID: PMC3895270 DOI: 10.1261/rna.042358.113] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Most archaea and bacteria use a modified C in the anticodon wobble position of isoleucine tRNA to base pair with A but not with G of the mRNA. This allows the tRNA to read the isoleucine codon AUA without also reading the methionine codon AUG. To understand why a modified C, and not U or modified U, is used to base pair with A, we mutated the C34 in the anticodon of Haloarcula marismortui isoleucine tRNA (tRNA2(Ile)) to U, expressed the mutant tRNA in Haloferax volcanii, and purified and analyzed the tRNA. Ribosome binding experiments show that although the wild-type tRNA2(Ile) binds exclusively to the isoleucine codon AUA, the mutant tRNA binds not only to AUA but also to AUU, another isoleucine codon, and to AUG, a methionine codon. The G34 to U mutant in the anticodon of another H. marismortui isoleucine tRNA species showed similar codon binding properties. Binding of the mutant tRNA to AUG could lead to misreading of the AUG codon and insertion of isoleucine in place of methionine. This result would explain why most archaea and bacteria do not normally use U or a modified U in the anticodon wobble position of isoleucine tRNA for reading the codon AUA. Biochemical and mass spectrometric analyses of the mutant tRNAs have led to the discovery of a new modified nucleoside, 5-cyanomethyl U in the anticodon wobble position of the mutant tRNAs. 5-Cyanomethyl U is present in total tRNAs from euryarchaea but not in crenarchaea, eubacteria, or eukaryotes.
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MESH Headings
- Anticodon/genetics
- Base Pairing
- Base Sequence
- Codon/genetics
- Escherichia coli/genetics
- Haloarcula marismortui/genetics
- Haloferax/genetics
- Molecular Structure
- Point Mutation
- RNA, Archaeal/chemistry
- RNA, Archaeal/genetics
- RNA, Archaeal/metabolism
- RNA, Bacterial/genetics
- RNA, Fungal/genetics
- RNA, Transfer, Ile/chemistry
- RNA, Transfer, Ile/genetics
- RNA, Transfer, Ile/metabolism
- Ribosomes/chemistry
- Saccharomyces cerevisiae/genetics
- Sulfolobus/genetics
- Transfer RNA Aminoacylation
- Uridine/analogs & derivatives
- Uridine/chemistry
- Uridine/genetics
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Affiliation(s)
- Debabrata Mandal
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Caroline Köhrer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Dan Su
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - I. Ramesh Babu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Clement T.Y. Chan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yuchen Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Paul Blum
- School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, Nebraska 68508, USA
| | - Masayasu Kuwahara
- Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Uttam L. RajBhandary
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Corresponding authorE-mail
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34
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Shepherd J, Ibba M. Direction of aminoacylated transfer RNAs into antibiotic synthesis and peptidoglycan-mediated antibiotic resistance. FEBS Lett 2013; 587:2895-904. [PMID: 23907010 DOI: 10.1016/j.febslet.2013.07.036] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 12/30/2022]
Abstract
Prokaryotic aminoacylated-transfer RNAs often need to be efficiently segregated between translation and other cellular biosynthetic pathways. Many clinically relevant bacteria, including Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa direct some aminoacylated-tRNA species into peptidoglycan biosynthesis and/or membrane phospholipid modification. Subsequent indirect peptidoglycan cross-linkage or change in membrane permeability is often a prerequisite for high-level antibiotic resistance. In Streptomycetes, aminoacylated-tRNA species are used for antibiotic synthesis as well as antibiotic resistance. The direction of coding aminoacylated-tRNA molecules away from translation and into antibiotic resistance and synthesis pathways are discussed in this review.
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Affiliation(s)
- Jennifer Shepherd
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210-1292, USA
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35
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Santos-Cortez RLP, Lee K, Azeem Z, Antonellis PJ, Pollock LM, Khan S, Andrade-Elizondo PB, Chiu I, Adams MD, Basit S, Smith JD, Nickerson DA, McDermott BM, Ahmad W, Leal SM. Mutations in KARS, encoding lysyl-tRNA synthetase, cause autosomal-recessive nonsyndromic hearing impairment DFNB89. Am J Hum Genet 2013; 93:132-40. [PMID: 23768514 DOI: 10.1016/j.ajhg.2013.05.018] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/02/2013] [Accepted: 05/20/2013] [Indexed: 01/27/2023] Open
Abstract
Previously, DFNB89, a locus associated with autosomal-recessive nonsyndromic hearing impairment (ARNSHI), was mapped to chromosomal region 16q21-q23.2 in three unrelated, consanguineous Pakistani families. Through whole-exome sequencing of a hearing-impaired individual from each family, missense mutations were identified at highly conserved residues of lysyl-tRNA synthetase (KARS): the c.1129G>A (p.Asp377Asn) variant was found in one family, and the c.517T>C (p.Tyr173His) variant was found in the other two families. Both variants were predicted to be damaging by multiple bioinformatics tools. The two variants both segregated with the nonsyndromic-hearing-impairment phenotype within the three families, and neither mutation was identified in ethnically matched controls or within variant databases. Individuals homozygous for KARS mutations had symmetric, severe hearing impairment across all frequencies but did not show evidence of auditory or limb neuropathy. It has been demonstrated that KARS is expressed in hair cells of zebrafish, chickens, and mice. Moreover, KARS has strong localization to the spiral ligament region of the cochlea, as well as to Deiters' cells, the sulcus epithelium, the basilar membrane, and the surface of the spiral limbus. It is hypothesized that KARS variants affect aminoacylation in inner-ear cells by interfering with binding activity to tRNA or p38 and with tetramer formation. The identification of rare KARS variants in ARNSHI-affected families defines a gene that is associated with ARNSHI.
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Affiliation(s)
- Regie Lyn P Santos-Cortez
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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36
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Santra M, Bagchi B. Kinetic proofreading at single molecular level: aminoacylation of tRNA(Ile) and the role of water as an editor. PLoS One 2013; 8:e66112. [PMID: 23840412 PMCID: PMC3688713 DOI: 10.1371/journal.pone.0066112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/02/2013] [Indexed: 11/25/2022] Open
Abstract
Proofreading/editing in protein synthesis is essential for accurate translation of information from the genetic code. In this article we present a theoretical investigation of efficiency of a kinetic proofreading mechanism that employs hydrolysis of the wrong substrate as the discriminatory step in enzyme catalytic reactions. We consider aminoacylation of tRNAIle which is a crucial step in protein synthesis and for which experimental results are now available. We present an augmented kinetic scheme and then employ methods of stochastic simulation algorithm to obtain time dependent concentrations of different substances involved in the reaction and their rates of formation. We obtain the rates of product formation and ATP hydrolysis for both correct and wrong substrates (isoleucine and valine in our case, respectively), in single molecular enzyme as well as ensemble enzyme kinetics. The present theoretical scheme correctly reproduces (i) the amplitude of the discrimination factor in the overall rates between isoleucine and valine which is obtained as (1.8×102).(4.33×102) = 7.8×104, (ii) the rates of ATP hydrolysis for both Ile and Val at different substrate concentrations in the aminoacylation of tRNAIle. The present study shows a non-michaelis type dependence of rate of reaction on tRNAIle concentration in case of valine. The overall editing in steady state is found to be independent of amino acid concentration. Interestingly, the computed ATP hydrolysis rate for valine at high substrate concentration is same as the rate of formation of Ile-tRNAIle whereas at intermediate substrate concentration the ATP hydrolysis rate is relatively low. We find that the presence of additional editing domain in class I editing enzyme makes the kinetic proofreading more efficient through enhanced hydrolysis of wrong product at the editing CP1 domain.
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Affiliation(s)
- Mantu Santra
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, India
- * E-mail:
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37
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Preston MA, D’Silva S, Kon Y, Phizicky EM. tRNAHis 5-methylcytidine levels increase in response to several growth arrest conditions in Saccharomyces cerevisiae. RNA 2013; 19:243-56. [PMID: 23249748 PMCID: PMC3543094 DOI: 10.1261/rna.035808.112] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
tRNAs are highly modified, each with a unique set of modifications. Several reports suggest that tRNAs are hypomodified or, in some cases, hypermodified under different growth conditions and in certain cancers. We previously demonstrated that yeast strains depleted of tRNA(His) guanylyltransferase accumulate uncharged tRNA(His) lacking the G(-1) residue and subsequently accumulate additional 5-methylcytidine (m(5)C) at residues C(48) and C(50) of tRNA(His), due to the activity of the m(5)C-methyltransferase Trm4. We show here that the increase in tRNA(His) m(5)C levels does not require loss of Thg1, loss of G(-1) of tRNA(His), or cell death but is associated with growth arrest following different stress conditions. We find substantially increased tRNA(His) m(5)C levels after temperature-sensitive strains are grown at nonpermissive temperature, and after wild-type strains are grown to stationary phase, starved for required amino acids, or treated with rapamycin. We observe more modest accumulations of m(5)C in tRNA(His) after starvation for glucose and after starvation for uracil. In virtually all cases examined, the additional m(5)C on tRNA(His) occurs while cells are fully viable, and the increase is neither due to the GCN4 pathway, nor to increased Trm4 levels. Moreover, the increased m(5)C appears specific to tRNA(His), as tRNA(Val(AAC)) and tRNA(Gly(GCC)) have much reduced additional m(5)C during these growth arrest conditions, although they also have C(48) and C(50) and are capable of having increased m(5)C levels. Thus, tRNA(His) m(5)C levels are unusually responsive to yeast growth conditions, although the significance of this additional m(5)C remains unclear.
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Tan K, Zhou M, Zhang R, Anderson WF, Joachimiak A. The crystal structures of the α-subunit of the α(2)β (2) tetrameric Glycyl-tRNA synthetase. ACTA ACUST UNITED AC 2012; 13:233-9. [PMID: 23054484 DOI: 10.1007/s10969-012-9142-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 09/11/2012] [Indexed: 11/25/2022]
Abstract
Aminoacyl-tRNA synthetases (AARSs) are ligases (EC.6.1.1.-) that catalyze the acylation of amino acids to their cognate tRNAs in the process of translating genetic information from mRNA to protein. Their amino acid and tRNA specificity are crucial for correctly translating the genetic code. Glycine is the smallest amino acid and the glycyl-tRNA synthetase (GlyRS) belongs to Class II AARSs. The enzyme is unusual because it can assume different quaternary structures. In eukaryotes, archaebacteria and some bacteria, it forms an α(2) homodimer. In some bacteria, GlyRS is an α(2)β(2) heterotetramer and shows a distant similarity to α(2) GlyRSs. The human pathogen eubacterium Campylobacter jejuni GlyRS (CjGlyRS) is an α(2)β(2) heterotetramer and is similar to Escherichia coli GlyRS; both are members of Class IIc AARSs. The two-step aminoacylation reaction of tetrameric GlyRSs requires the involvement of both α- and β-subunits. At present, the structure of the GlyRS α(2)β(2) class and the details of the enzymatic mechanism of this enzyme remain unknown. Here we report the crystal structures of the catalytic α-subunit of CjGlyRS and its complexes with ATP, and ATP and glycine. These structures provide detailed information on substrate binding and show evidence for a proposed mechanism for amino acid activation and the formation of the glycyl-adenylate intermediate for Class II AARSs.
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Affiliation(s)
- Kemin Tan
- Center for Structural Genomics of Infectious Diseases, University of Chicago, Chicago, IL 60637, USA
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Aldinger CA, Leisinger AK, Igloi GL. The influence of identity elements on the aminoacylation of tRNA(Arg) by plant and Escherichia coli arginyl-tRNA synthetases. FEBS J 2012; 279:3622-3638. [PMID: 22831759 DOI: 10.1111/j.1742-4658.2012.08722.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Identity elements determine the accurate recognition between tRNAs and aminoacyl-tRNA synthetases. The arginine system from yeast and Escherichia coli has been studied extensively in the past. However, information about the enzymes from higher eukaryotes is limited and plant aminoacyl-tRNA synthetases have been largely ignored in this respect. We have designed in vitro tRNA transcripts, based on the soybean tRNA(Arg) primary structure, aiming to investigate its specific aminoacylation by two recombinant plant arginyl-tRNA synthetases and to compare this with the enzyme from E. coli. Identity elements at positions 20 and 35 in plants parallel those previously established for bacteria. Cryptic identity elements in the plant system that are not revealed within a tRNA(Arg) consensus sequence compiled from isodecoders corresponding to nine distinct cytoplasmic, mitochondrial and plastid isoaccepting sequences are located in the acceptor stem. Additionally, it has been shown that U20a and A38 are essential for a fully efficient cognate E. coli arginylation, whereas, for the plant arginyl-tRNA synthetases, these bases can be replaced by G20a and C38 with full retention of activity. G10, a constituent of the 10:25:45 tertiary interaction, is essential for both plant and E. coli activity. Amino acid recognition in terms of discriminating between arginine and canavanine by the arginyl-tRNA synthetase from both kingdoms may be manipulated by changes at different sites within the tRNA structure.
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Affiliation(s)
| | | | - Gabor L Igloi
- Institut für Biologie III, Universität Freiburg, Germany
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40
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Abstract
Protein biosynthesis requires aminoacyl-transfer RNA (tRNA) synthetases to provide aminoacyl-tRNA substrates for the ribosome. Most bacteria and all archaea lack a glutaminyl-tRNA synthetase (GlnRS); instead, Gln-tRNAGln is produced via an indirect pathway: a glutamyl-tRNA synthetase (GluRS) first attaches glutamate (Glu) to tRNAGln, and an amidotransferase converts Glu-tRNAGln to Gln-tRNAGln. The human pathogen Helicobacter pylori encodes two GluRS enzymes, with GluRS2 specifically aminoacylating Glu onto tRNAGln. It was proposed that GluRS2 is evolving into a bacterial-type GlnRS. Herein, we have combined rational design and directed evolution approaches to test this hypothesis. We show that, in contrast to wild-type (WT) GlnRS2, an engineered enzyme variant (M110) with seven amino acid changes is able to rescue growth of the temperature-sensitive Escherichia coli glnS strain UT172 at its non-permissive temperature. In vitro kinetic analyses reveal that WT GluRS2 selectively acylates Glu over Gln, whereas M110 acylates Gln 4-fold more efficiently than Glu. In addition, M110 hydrolyzes adenosine triphosphate 2.5-fold faster in the presence of Glu than Gln, suggesting that an editing activity has evolved in this variant to discriminate against Glu. These data imply that GluRS2 is a few steps away from evolving into a GlnRS and provides a paradigm for studying aminoacyl-tRNA synthetase evolution using directed engineering approaches.
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Affiliation(s)
- Li-Tao Guo
- Department of Molecular Biophysics and Biochemistry and Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Sunna Helgadóttir
- Department of Molecular Biophysics and Biochemistry and Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry and Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
- *To whom correspondence should be addressed. Tel: +1 203 432 6205; Fax: +1 203 432 6202;
| | - Jiqiang Ling
- Department of Molecular Biophysics and Biochemistry and Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
- Correspondence may also be addressed to Dieter Söll. Tel: +1 203 432 6200; Fax: +1 203 432 6202;
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Mohanty BK, Maples VF, Kushner SR. Polyadenylation helps regulate functional tRNA levels in Escherichia coli. Nucleic Acids Res 2012; 40:4589-603. [PMID: 22287637 PMCID: PMC3378859 DOI: 10.1093/nar/gks006] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/19/2011] [Accepted: 12/23/2011] [Indexed: 12/24/2022] Open
Abstract
Here we demonstrate a new regulatory mechanism for tRNA processing in Escherichia coli whereby RNase T and RNase PH, the two primary 3' → 5' exonucleases involved in the final step of 3'-end maturation, compete with poly(A) polymerase I (PAP I) for tRNA precursors in wild-type cells. In the absence of both RNase T and RNase PH, there is a >30-fold increase of PAP I-dependent poly(A) tails that are ≤10 nt in length coupled with a 2.3- to 4.2-fold decrease in the level of aminoacylated tRNAs and a >2-fold decrease in growth rate. Only 7 out of 86 tRNAs are not regulated by this mechanism and are also not substrates for RNase T, RNase PH or PAP I. Surprisingly, neither PNPase nor RNase II has any effect on tRNA poly(A) tail length. Our data suggest that the polyadenylation of tRNAs by PAP I likely proceeds in a distributive fashion unlike what is observed with mRNAs.
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Affiliation(s)
| | | | - Sidney R. Kushner
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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Chen S, Fahmi NE, Nangreave RC, Mehellou Y, Hecht SM. Synthesis of pdCpAs and transfer RNAs activated with thiothreonine and derivatives. Bioorg Med Chem 2012; 20:2679-89. [PMID: 22405920 PMCID: PMC3575115 DOI: 10.1016/j.bmc.2012.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/05/2012] [Accepted: 02/08/2012] [Indexed: 11/29/2022]
Abstract
N,S-diprotected L-thiothreonine and L-allo-thiothreonine derivatives were synthesized using a novel chemical strategy, and used for esterification of the dinucleotide pdCpA. The aminoacylated dinucleotides were then employed for the preparation of activated suppressor tRNA(CUA) transcripts. Thiothreonine and allo-thiothreonine were incorporated into a predetermined position of a catalytically competent dihydrofolate reductase (DHFR) analogue lacking cysteine, and the elaborated proteins were derivatized site-specifically at the thiothreonine residue with a fluorophore.
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Affiliation(s)
- Shengxi Chen
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Nour Eddine Fahmi
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Ryan C. Nangreave
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Youcef Mehellou
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Sidney M. Hecht
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
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43
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Abstract
We describe a strategy for tracking Mg²⁺-initiated folding of ³²P-labeled tRNA molecules to their native structures based on the capacity for aminoacylation by the cognate aminoacyl-tRNA synthetase enzyme. The approach directly links folding to function, paralleling a common strategy used to study the folding of catalytic RNAs. Incubation of unfolded tRNA with magnesium ions, followed by the addition of aminoacyl-tRNA synthetase and further incubation, yields a rapid burst of aminoacyl-tRNA formation corresponding to the prefolded tRNA fraction. A subsequent slower increase in product formation monitors continued folding in the presence of the enzyme. Further analysis reveals the presence of a parallel fraction of tRNA that folds more rapidly than the majority of the population. The application of the approach to study the influence of post-transcriptional modifications in folding of Escherichia coli tRNA₁(Gln) reveals that the modified bases increase the folding rate but do not affect either the equilibrium between properly folded and misfolded states or the folding pathway. This assay allows the use of ³²P-labeled tRNA in integrated studies combining folding, post-transcriptional processing, and aminoacylation reactions.
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Affiliation(s)
| | | | - John J. Perona
- Department of Chemistry and Biochemistry
- Interdepartmental Program in Biomolecular Science and Engineering, University of California, Santa Barbara, California 93106-9510, USA
- Corresponding author.E-mail .
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Abstract
Genetic code reprogramming is a method for the reassignment of arbitrary codons from proteinogenic amino acids to non-proteinogenic ones, and thus specific sequences of nonstandard peptides can be ribosomally expressed according to their mRNA templates. We here describe a protocol that facilitates the genetic code reprogramming using flexizymes integrated with a custom-made in vitro translation apparatus, referred to as the flexible in vitro translation (FIT) system. Flexizymes are flexible tRNA acylation ribozymes that enable the preparation of a diverse array of non-proteinogenic acyl-tRNAs. These acyl-tRNAs read vacant codons created in the FIT system, yielding the desired nonstandard peptides with diverse exotic structures, such as N-acyl groups, D: -amino acids, N-methyl amino acids, and physiologically stable macrocyclic scaffolds. Facility of the protocol allows for a wide variety of applications in the synthesis of new classes of nonstandard peptides with biological functions.
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Affiliation(s)
- Yuki Goto
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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45
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Miller MR, Liu Z, Cazier DJ, Gebhard GM, Herron SR, Zaher HS, Green R, Buskirk AR. The role of SmpB and the ribosomal decoding center in licensing tmRNA entry into stalled ribosomes. RNA 2011; 17:1727-1736. [PMID: 21795410 PMCID: PMC3162337 DOI: 10.1261/rna.2821711] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/24/2011] [Indexed: 05/31/2023]
Abstract
In bacteria, stalled ribosomes are recycled by a hybrid transfer-messenger RNA (tmRNA). Like tRNA, tmRNA is aminoacylated with alanine and is delivered to the ribosome by EF-Tu, where it reacts with the growing polypeptide chain. tmRNA entry into stalled ribosomes poses a challenge to our understanding of ribosome function because it occurs in the absence of a codon-anticodon interaction. Instead, tmRNA entry is licensed by the binding of its protein partner, SmpB, to the ribosomal decoding center. We analyzed a series of SmpB mutants and found that its C-terminal tail is essential for tmRNA accommodation but not for EF-Tu activation. We obtained evidence that the tail likely functions as a helix on the ribosome to promote accommodation and identified key residues in the tail essential for this step. In addition, our mutational analysis points to a role for the conserved K(131)GKK tail residues in trans-translation after peptidyl transfer to tmRNA, presumably EF-G-mediated translocation or translation of the tmRNA template. Surprisingly, analysis of A1492, A1493, and G530 mutants reveals that while these ribosomal nucleotides are essential for normal tRNA selection, they play little to no role in peptidyl transfer to tmRNA. These studies clarify how SmpB interacts with the ribosomal decoding center to license tmRNA entry into stalled ribosomes.
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Affiliation(s)
- Mickey R. Miller
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Zhu Liu
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - DeAnna J. Cazier
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Grant M. Gebhard
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Steven R. Herron
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Hani S. Zaher
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Allen R. Buskirk
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
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46
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Jakubowski H. Quality control in tRNA charging -- editing of homocysteine. Acta Biochim Pol 2011; 58:149-163. [PMID: 21643559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/02/2011] [Indexed: 05/30/2023]
Abstract
All living organisms conduct protein synthesis with a high degree of accuracy maintained in the transmission and flow of information from a gene to protein product. One crucial 'quality control' point in maintaining a high level of accuracy is the selectivity by which aminoacyl-tRNA synthetases furnish correctly activated amino acids, attached to tRNA species, as the building blocks for growing protein chains. When differences in binding energies of amino acids to an aminoacyl-tRNA synthetase are inadequate, editing is used as a major determinant of enzyme selectivity. Some incorrect amino acids are edited at the active site before the transfer to tRNA (pre-transfer editing), while others are edited after transfer to tRNA at a separate editing site (post-transfer editing). Access of natural non-protein amino acids, such as homocysteine, homoserine, or ornithine to the genetic code is prevented by the editing function of aminoacyl-tRNA synthetases. Disabling editing function leads to tRNA mischarging errors and incorporation of incorrect amino acids into protein, which is detrimental to cell homeostasis and inhibits growth. Continuous homocysteine editing by methionyl-tRNA synthetase, resulting in the synthesis of homocysteine thiolactone, is part of the process of tRNA aminoacylation in living organisms, from bacteria to man. Excessive homocysteine thiolactone synthesis in hyperhomocysteinemia caused by genetic or nutritional deficiencies is linked to human vascular and neurological diseases.
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Affiliation(s)
- Hieronim Jakubowski
- UMDNJ-New Jersey Medical School, Department of Microbiology & Molecular Genetics, International Center for Public Health, Newark, USA.
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47
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Hayashi G, Ohshiro Y, Suga H. [Ribosomal synthesis of nonstandard cyclic peptides and its application to drug discovery]. Seikagaku 2010; 82:505-514. [PMID: 20662259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Gosuke Hayashi
- Bioorganic Chemistry Laboratory, Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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48
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Seligmann H. Do anticodons of misacylated tRNAs preferentially mismatch codons coding for the misloaded amino acid? BMC Mol Biol 2010; 11:41. [PMID: 20509917 PMCID: PMC2887445 DOI: 10.1186/1471-2199-11-41] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/28/2010] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Accurate amino acid insertion during peptide elongation requires tRNAs loaded by cognate amino acids and that anticodons match codons. However, tRNA misloading does not necessarily cause misinsertions: misinsertion is avoided when anticodons mismatch codons coding for misloaded amino acids. PRESENTATION OF THE HYPOTHESIS Occasional compensation of misacylation by codon-anticodon mismatch necessarily occurs. Putatively, occasional error compensation may be enhanced beyond the random combination of independent errors in tRNA loading and codon-anticodon interactions: tRNA misacylation might alter potentials for codon-anticodon mismatches, perhaps specifically increasing potentials for mismatching those codons coding for the misacylated non-cognate amino acid. This hypothetical phenomenon is called 'error coordination', in distinction from 'error compensation' that assumes independence between misacylation and mismatch. TESTING THE HYPOTHESIS Eventually, the hypothesis should be tested for each combination of amino acid misacylation and codon-anticodon mismatch, by comparing stabilities or frequencies of mismatched codon-anticodon duplexes formed by tRNAs loaded by their cognate amino acid with stabilities formed by that tRNA when misloaded with the amino acid coded by the mismatched codon. Competitive mismatching experiments between misloaded and correctly loaded tRNAs could also be useful, yet more sophisticated experiments. IMPLICATIONS OF THE HYPOTHESIS Detecting error coordination implies estimating error compensation, which also promotes protein synthesis accuracy. Hence even in the absence of evidence for error coordination, experiments would yield very useful insights into misacylation and mismatch processes. In case experiments consider post-transcriptional RNA modifications (especially at wobble positions), results on codon-anticodon mismatches would enable significant improvements and sophistications of secondary structure prediction softwares. Positive results would show that protein translation enhances accuracies of products, not of single steps in the production. Ancient translational machineries putatively optimized error coordination, especially before tRNA editing by tRNA synthetases evolved: few primitive, but functionally versatile tRNA species perhaps executed low accuracy translation. Systems artificially designed/selected for low complexity and high efficiency could make use of this property for anticodons with high levels of error compensation and coordination.
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Affiliation(s)
- Hervé Seligmann
- Department of Evolution, Systematics & Ecology, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
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49
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Wang X, Yan Q, Guan MX. Combination of the loss of cmnm5U34 with the lack of s2U34 modifications of tRNALys, tRNAGlu, and tRNAGln altered mitochondrial biogenesis and respiration. J Mol Biol 2010; 395:1038-48. [PMID: 20004207 PMCID: PMC2818684 DOI: 10.1016/j.jmb.2009.12.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 12/01/2009] [Accepted: 12/02/2009] [Indexed: 11/23/2022]
Abstract
Yeast Saccharomyces cerevisiae MTO2, MTO1, and MSS1 genes encoded highly conserved tRNA modifying enzymes for the biosynthesis of carboxymethylaminomethyl (cmnm)(5)s(2)U(34) in mitochondrial tRNA(Lys), tRNA(Glu), and tRNA(Gln). In fact, Mto1p and Mss1p are involved in the biosynthesis of the cmnm(5) group (cmnm(5)U(34)), while Mto2p is responsible for the 2-thiouridylation (s(2)U(34)) of these tRNAs. Previous studies showed that partial modifications at U(34) in mitochondrial tRNA enabled mto1, mto2, and mss1 strains to respire. In this report, we investigated the functional interaction between MTO2, MTO1, and MSS1 genes by using the mto2, mto1, and mss1 single, double, and triple mutants. Strikingly, the deletion of MTO2 was synthetically lethal with a mutation of MSS1 or deletion of MTO1 on medium containing glycerol but not on medium containing glucose. Interestingly, there were no detectable levels of nine tRNAs including tRNA(Lys), tRNA(Glu), and tRNA(Gln) in mto2/mss1, mto2/mto1, and mto2/mto1/mss1 strains. Furthermore, mto2/mss1, mto2/mto1, and mto2/mto1/mss1 mutants exhibited extremely low levels of COX1 and CYTB mRNA and 15S and 21S rRNA as well as the complete loss of mitochondrial protein synthesis. The synthetic enhancement combinations likely resulted from the completely abolished modification at U(34) of tRNA(Lys), tRNA(Glu), and tRNA(Gln), caused by the combination of eliminating the 2-thiouridylation by the mto2 mutation with the absence of the cmnm(5)U(34) by the mto1 or mss1 mutation. The complete loss of modifications at U(34) of tRNAs altered mitochondrial RNA metabolisms, causing a degradation of mitochondrial tRNA, mRNA, and rRNAs. As a result, failures in mitochondrial RNA metabolisms were responsible for the complete loss of mitochondrial translation. Consequently, defects in mitochondrial protein synthesis caused the instability of their mitochondrial genomes, thus producing the respiratory-deficient phenotypes. Therefore, our findings demonstrated a critical role of modifications at U(34) of tRNA(Lys), tRNA(Glu), and tRNA(Gln) in maintenance of mitochondrial genome, mitochondrial RNA stability, translation, and respiratory function.
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MESH Headings
- Alleles
- Base Sequence
- GTP-Binding Proteins/genetics
- GTP-Binding Proteins/metabolism
- Genes, Fungal
- Genome, Mitochondrial
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Mutation
- Oxygen Consumption
- Phenotype
- RNA/chemistry
- RNA/genetics
- RNA/metabolism
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Mitochondrial
- RNA, Transfer, Gln/chemistry
- RNA, Transfer, Gln/genetics
- RNA, Transfer, Gln/metabolism
- RNA, Transfer, Glu/chemistry
- RNA, Transfer, Glu/genetics
- RNA, Transfer, Glu/metabolism
- RNA, Transfer, Lys/chemistry
- RNA, Transfer, Lys/genetics
- RNA, Transfer, Lys/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Transfer RNA Aminoacylation
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Affiliation(s)
- Xinjian Wang
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Qingfeng Yan
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA
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50
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Kresge N, Simoni RD, Hill RL. The mechanism of amino acid activation: the work of Mahlon Hoagland. 1956. J Biol Chem 2009; 284:e7-e8. [PMID: 19785094 PMCID: PMC2719372 DOI: 10.1016/s0021-9258(18)66554-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Enzymatic Carboxyl Activation of Amino Acids (Hoagland, M. B., Keller, E. B., and Zamecnik, P. C. (1956) J. Biol. Chem. 218, 345–358)
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