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Yuan C, Li Z, Luo X, Huang P, Guo L, Lu M, Xia J, Xiao Y, Zhou XL, Chen M. Mammalian trans-editing factor ProX is able to deacylate tRNA Thr mischarged with alanine. Int J Biol Macromol 2023; 253:127121. [PMID: 37778588 DOI: 10.1016/j.ijbiomac.2023.127121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/16/2023] [Accepted: 09/26/2023] [Indexed: 10/03/2023]
Abstract
The precise coupling of tRNAs with their cognate amino acids, known as tRNA aminoacylation, is a stringently regulated process that governs translation fidelity. To ensure fidelity, organisms deploy multiple layers of editing mechanisms to correct mischarged tRNAs. Prior investigations have unveiled the propensity of eukaryotic AlaRS to erroneously attach alanine onto tRNACys and tRNAThr featuring the G4:U69 base pair. In light of this, and given ProXp-ala's capacity in deacylating Ala-tRNAPro, we embarked on exploring whether this trans-editing factor could extend its corrective function to encompass these mischarged tRNAs. Our in vitro deacylation assays demonstrate that murine ProXp-ala (mProXp-ala) is able to efficiently hydrolyze Ala-tRNAThr, while Ala-tRNACys remains unaffected. Subsequently, we determined the first structure of eukaryotic ProXp-ala, revealing a dynamic helix α2 involved in substrate binding. By integrating molecular dynamics simulations and biochemical assays, we pinpointed the pivotal interactions between mProXp-ala and Ala-tRNA, wherein the basic regions of mProXp-ala as well as the C3-G70 plays essential role in recognition. These observations collectively provide a cogent rationale for mProXp-ala's deacylation proficiency against Ala-tRNAThr. Our findings offer valuable insights into the translation quality control within higher eukaryotic organisms, where the fidelity of translation is safeguarded by the multi-functionality of extensively documented proteins.
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Affiliation(s)
- Chen Yuan
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China; Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zihan Li
- Key Laboratory of RNA Science and Engineering, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xinyu Luo
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Pingping Huang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China; Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lijie Guo
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China; Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Meiling Lu
- Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China
| | - Jie Xia
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yibei Xiao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China; Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China; Chongqing Innovation Institute of China Pharmaceutical University, Chongqing 401135, China.
| | - Xiao-Long Zhou
- Key Laboratory of RNA Science and Engineering, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
| | - Meirong Chen
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China; Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
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2
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Byun JK, Vu JA, He SL, Jang JC, Musier-Forsyth K. Plant-exclusive domain of trans-editing enzyme ProXp-ala confers dimerization and enhanced tRNA binding. J Biol Chem 2022; 298:102255. [PMID: 35835222 PMCID: PMC9425024 DOI: 10.1016/j.jbc.2022.102255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/26/2022] Open
Abstract
Faithful translation of the genetic code is critical for the viability of all living organisms. The trans-editing enzyme ProXp-ala prevents Pro to Ala mutations during translation by hydrolyzing misacylated Ala-tRNAPro that has been synthesized by prolyl-tRNA synthetase. Plant ProXp-ala sequences contain a conserved C-terminal domain (CTD) that is absent in other organisms; the origin, structure, and function of this extra domain are unknown. To characterize the plant-specific CTD, we performed bioinformatics and computational analyses that provided a model consistent with a conserved α-helical structure. We also expressed and purified wildtype Arabidopsis thaliana (At) ProXp-ala in Escherichia coli, as well as variants lacking the CTD or containing only the CTD. Circular dichroism spectroscopy confirmed a loss of α-helical signal intensity upon CTD truncation. Size-exclusion chromatography with multiangle laser-light scattering revealed that wildtype At ProXp-ala was primarily dimeric and CTD truncation abolished dimerization in vitro. Furthermore, bimolecular fluorescence complementation assays in At protoplasts support a role for the CTD in homodimerization in vivo. The deacylation rate of Ala-tRNAPro by At ProXp-ala was also significantly reduced in the absence of the CTD, and kinetic assays indicated that the reduction in activity is primarily due to a tRNA binding defect. Overall, these results broaden our understanding of eukaryotic translational fidelity in the plant kingdom. Our study reveals that the plant-specific CTD plays a significant role in substrate binding and canonical editing function. Through its ability to facilitate protein-protein interactions, we propose the CTD may also provide expanded functional potential for trans-editing enzymes in plants.
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Affiliation(s)
- Jun-Kyu Byun
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - John A Vu
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Siou-Luan He
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Jyan-Chyun Jang
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA.
| | - Karin Musier-Forsyth
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.
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3
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Jani J, Pappachan A. A review on quality control agents of protein translation - The role of Trans-editing proteins. Int J Biol Macromol 2022; 199:252-263. [PMID: 34995670 DOI: 10.1016/j.ijbiomac.2021.12.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/18/2021] [Accepted: 12/27/2021] [Indexed: 11/16/2022]
Abstract
Translation of RNA to protein is a key feature of cellular life. The fidelity of this process mainly depends on the availability of correctly charged tRNAs. Different domains of tRNA synthetase (aaRS) maintain translation quality by ensuring the proper attachment of particular amino acid with respective tRNA, thus it establishes the rule of genetic code. However occasional errors by aaRS generate mischarged tRNAs, which can become lethal to the cells. Accurate protein synthesis necessitates hydrolysis of mischarged tRNAs. Various cis and trans-editing proteins are identified which recognize these mischarged products and correct them by hydrolysis. Trans-editing proteins are homologs of cis-editing domains of aaRS. The trans-editing proteins work in close association with aaRS, Ef-Tu, and ribosome to prevent global mistranslation and ensures correct charging of tRNA. In this review, we discuss the major trans-editing proteins and compared them with their cis-editing counterparts. We also discuss their structural features, biochemical activity and role in maintaining cellular protein homeostasis.
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Affiliation(s)
- Jaykumar Jani
- School of Life Sciences, Central University of Gujarat, Sector 30, Gandhinagar 382030, Gujarat, India
| | - Anju Pappachan
- School of Life Sciences, Central University of Gujarat, Sector 30, Gandhinagar 382030, Gujarat, India.
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4
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Vargas-Rodriguez O, Bakhtina M, McGowan D, Abid J, Goto Y, Suga H, Musier-Forsyth K. Human trans-editing enzyme displays tRNA acceptor-stem specificity and relaxed amino acid selectivity. J Biol Chem 2020; 295:16180-16190. [PMID: 33051185 PMCID: PMC7705315 DOI: 10.1074/jbc.ra120.015981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/06/2020] [Indexed: 01/20/2023] Open
Abstract
Accurate translation of genetic information into proteins is vital for cell sustainability. ProXp-ala prevents proteome-wide Pro-to-Ala mutations by hydrolyzing misacylated Ala-tRNAPro, which is synthesized by prolyl-tRNA synthetase. Bacterial ProXp-ala was previously shown to combine a size-based exclusion mechanism with conformational and chemical selection for the recognition of the alanyl moiety, whereas tRNAPro is selected via recognition of tRNA acceptor-stem elements G72 and A73. The identity of these critical bases changed during evolution with eukaryotic cytosolic tRNAPro possessing a cytosine at the corresponding positions. The mechanism by which eukaryotic ProXp-ala adapted to these changes remains unknown. In this work, recognition of the aminoacyl moiety and tRNA acceptor stem by human (Homo sapiens, or Hs) ProXp-ala was examined. Enzymatic assays revealed that Hs ProXp-ala requires C72 and C73 in the context of Hs cytosolic tRNAPro for efficient deacylation of mischarged Ala-tRNAPro The strong dependence on these bases prevents cross-species deacylation of bacterial Ala-tRNAPro or of Hs mitochondrial Ala-tRNAPro by the human enzyme. Similar to the bacterial enzyme, Hs ProXp-ala showed strong tRNA acceptor-stem recognition but differed in its amino acid specificity profile relative to bacterial ProXp-ala. Changes at conserved residues in both the Hs and bacterial ProXp-ala substrate-binding pockets modulated this specificity. These results illustrate how the mechanism of substrate selection diverged during the evolution of the ProXp-ala family, providing the first example of a trans-editing domain whose specificity evolved to adapt to changes in its tRNA substrate.
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Affiliation(s)
- Oscar Vargas-Rodriguez
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Daniel McGowan
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Jawad Abid
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Yuki Goto
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
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5
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Kuzmishin Nagy AB, Bakhtina M, Musier-Forsyth K. Trans-editing by aminoacyl-tRNA synthetase-like editing domains. Enzymes 2020; 48:69-115. [PMID: 33837712 DOI: 10.1016/bs.enz.2020.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRS) are ubiquitous enzymes responsible for aminoacyl-tRNA (aa-tRNA) synthesis. Correctly formed aa-tRNAs are necessary for proper decoding of mRNA and accurate protein synthesis. tRNAs possess specific nucleobases that promote selective recognition by cognate aaRSs. Selecting the cognate amino acid can be more challenging because all amino acids share the same peptide backbone and several are isosteric or have similar side chains. Thus, aaRSs can misactivate non-cognate amino acids and produce mischarged aa-tRNAs. If left uncorrected, mischarged aa-tRNAs deliver their non-cognate amino acid to the ribosome resulting in misincorporation into the nascent polypeptide chain. This changes the primary protein sequence and potentially causes misfolding or formation of non-functional proteins that impair cell survival. A variety of proofreading or editing pathways exist to prevent and correct mistakes in aa-tRNA formation. Editing may occur before the amino acid transfer step of aminoacylation via hydrolysis of the aminoacyl-adenylate. Alternatively, post-transfer editing, which occurs after the mischarged aa-tRNA is formed, may be carried out via a distinct editing site on the aaRS where the mischarged aa-tRNA is deacylated. In recent years, it has become clear that most organisms also encode factors that lack aminoacylation activity but resemble aaRS editing domains and function to clear mischarged aa-tRNAs in trans. This review focuses on these trans-editing factors, which are encoded in all three domains of life and function together with editing domains present within aaRSs to ensure that the accuracy of protein synthesis is sufficient for cell survival.
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Affiliation(s)
- Alexandra B Kuzmishin Nagy
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States.
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6
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Double mimicry evades tRNA synthetase editing by toxic vegetable-sourced non-proteinogenic amino acid. Nat Commun 2017; 8:2281. [PMID: 29273753 PMCID: PMC5741666 DOI: 10.1038/s41467-017-02201-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 11/13/2017] [Indexed: 01/29/2023] Open
Abstract
Hundreds of non-proteinogenic (np) amino acids (AA) are found in plants and can in principle enter human protein synthesis through foods. While aminoacyl-tRNA synthetase (AARS) editing potentially provides a mechanism to reject np AAs, some have pathological associations. Co-crystal structures show that vegetable-sourced azetidine-2-carboxylic acid (Aze), a dual mimic of proline and alanine, is activated by both human prolyl- and alanyl-tRNA synthetases. However, it inserts into proteins as proline, with toxic consequences in vivo. Thus, dual mimicry increases odds for mistranslation through evasion of one but not both tRNA synthetase editing systems.
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7
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Lant JT, Berg MD, Sze DHW, Hoffman KS, Akinpelu IC, Turk MA, Heinemann IU, Duennwald ML, Brandl CJ, O'Donoghue P. Visualizing tRNA-dependent mistranslation in human cells. RNA Biol 2017; 15:567-575. [PMID: 28933646 DOI: 10.1080/15476286.2017.1379645] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
High-fidelity translation and a strictly accurate proteome were originally assumed as essential to life and cellular viability. Yet recent studies in bacteria and eukaryotic model organisms suggest that proteome-wide mistranslation can provide selective advantages and is tolerated in the cell at higher levels than previously thought (one error in 6.9 × 10-4 in yeast) with a limited impact on phenotype. Previously, we selected a tRNAPro containing a single mutation that induces mistranslation with alanine at proline codons in yeast. Yeast tolerate the mistranslation by inducing a heat-shock response and through the action of the proteasome. Here we found a homologous human tRNAPro (G3:U70) mutant that is not aminoacylated with proline, but is an efficient alanine acceptor. In live human cells, we visualized mistranslation using a green fluorescent protein reporter that fluoresces in response to mistranslation at proline codons. In agreement with measurements in yeast, quantitation based on the GFP reporter suggested a mistranslation rate of up to 2-5% in HEK 293 cells. Our findings suggest a stress-dependent phenomenon where mistranslation levels increased during nutrient starvation. Human cells did not mount a detectable heat-shock response and tolerated this level of mistranslation without apparent impact on cell viability. Because humans encode ∼600 tRNA genes and the natural population has greater tRNA sequence diversity than previously appreciated, our data also demonstrate a cell-based screen with the potential to elucidate mutations in tRNAs that may contribute to or alleviate disease.
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Affiliation(s)
- Jeremy T Lant
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Matthew D Berg
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Daniel H W Sze
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Kyle S Hoffman
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | | | - Matthew A Turk
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Ilka U Heinemann
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Martin L Duennwald
- b Department of Pathology , The University of Western Ontario , London , ON , Canada
| | - Christopher J Brandl
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada
| | - Patrick O'Donoghue
- a Department of Biochemistry , The University of Western Ontario , London , ON , Canada.,c Department of Chemistry , The University of Western Ontario , London , ON , Canada
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8
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The emerging complexity of the tRNA world: mammalian tRNAs beyond protein synthesis. Nat Rev Mol Cell Biol 2017; 19:45-58. [PMID: 28875994 DOI: 10.1038/nrm.2017.77] [Citation(s) in RCA: 272] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The discovery of the genetic code and tRNAs as decoders of the code transformed life science. However, after establishing the role of tRNAs in protein synthesis, the field moved to other parts of the RNA world. Now, tRNA research is blooming again, with demonstration of the involvement of tRNAs in various other pathways beyond translation and in adapting translation to environmental cues. These roles are linked to the presence of tRNA sequence variants known as isoacceptors and isodecoders, various tRNA base modifications, the versatility of protein binding partners and tRNA fragmentation events, all of which collectively create an incalculable complexity. This complexity provides a vast repertoire of tRNA species that can serve various functions in cellular homeostasis and in adaptation of cellular functions to changing environments, and it likely arose from the fundamental role of RNAs in early evolution.
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9
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Danhart EM, Bakhtina M, Cantara WA, Kuzmishin AB, Ma X, Sanford BL, Vargas-Rodriguez O, Košutić M, Goto Y, Suga H, Nakanishi K, Micura R, Foster MP, Musier-Forsyth K. Conformational and chemical selection by a trans-acting editing domain. Proc Natl Acad Sci U S A 2017; 114:E6774-E6783. [PMID: 28768811 PMCID: PMC5565427 DOI: 10.1073/pnas.1703925114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Molecular sieves ensure proper pairing of tRNAs and amino acids during aminoacyl-tRNA biosynthesis, thereby avoiding detrimental effects of mistranslation on cell growth and viability. Mischarging errors are often corrected through the activity of specialized editing domains present in some aminoacyl-tRNA synthetases or via single-domain trans-editing proteins. ProXp-ala is a ubiquitous trans-editing enzyme that edits Ala-tRNAPro, the product of Ala mischarging by prolyl-tRNA synthetase, although the structural basis for discrimination between correctly charged Pro-tRNAPro and mischarged Ala-tRNAAla is unclear. Deacylation assays using substrate analogs reveal that size discrimination is only one component of selectivity. We used NMR spectroscopy and sequence conservation to guide extensive site-directed mutagenesis of Caulobacter crescentus ProXp-ala, along with binding and deacylation assays to map specificity determinants. Chemical shift perturbations induced by an uncharged tRNAPro acceptor stem mimic, microhelixPro, or a nonhydrolyzable mischarged Ala-microhelixPro substrate analog identified residues important for binding and deacylation. Backbone 15N NMR relaxation experiments revealed dynamics for a helix flanking the substrate binding site in free ProXp-ala, likely reflecting sampling of open and closed conformations. Dynamics persist on binding to the uncharged microhelix, but are attenuated when the stably mischarged analog is bound. Computational docking and molecular dynamics simulations provide structural context for these findings and predict a role for the substrate primary α-amine group in substrate recognition. Overall, our results illuminate strategies used by a trans-editing domain to ensure acceptance of only mischarged Ala-tRNAPro, including conformational selection by a dynamic helix, size-based exclusion, and optimal positioning of substrate chemical groups.
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Affiliation(s)
- Eric M Danhart
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - William A Cantara
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Alexandra B Kuzmishin
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Xiao Ma
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Brianne L Sanford
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | | | - Marija Košutić
- Institute of Organic Chemistry, Leopold Franzens University, A-6020 Innsbruck, Austria
- Center for Molecular Biosciences, Leopold Franzens University, A-6020 Innsbruck, Austria
| | - Yuki Goto
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kotaro Nakanishi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Ronald Micura
- Institute of Organic Chemistry, Leopold Franzens University, A-6020 Innsbruck, Austria
- Center for Molecular Biosciences, Leopold Franzens University, A-6020 Innsbruck, Austria
| | - Mark P Foster
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210;
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210;
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
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10
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Wende S, Bonin S, Götze O, Betat H, Mörl M. The identity of the discriminator base has an impact on CCA addition. Nucleic Acids Res 2015; 43:5617-29. [PMID: 25958396 PMCID: PMC4477674 DOI: 10.1093/nar/gkv471] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/29/2015] [Indexed: 11/13/2022] Open
Abstract
CCA-adding enzymes synthesize and maintain the C-C-A sequence at the tRNA 3'-end, generating the attachment site for amino acids. While tRNAs are the most prominent substrates for this polymerase, CCA additions on non-tRNA transcripts are described as well. To identify general features for substrate requirement, a pool of randomized transcripts was incubated with the human CCA-adding enzyme. Most of the RNAs accepted for CCA addition carry an acceptor stem-like terminal structure, consistent with tRNA as the main substrate group for this enzyme. While these RNAs show no sequence conservation, the position upstream of the CCA end was in most cases represented by an adenosine residue. In tRNA, this position is described as discriminator base, an important identity element for correct aminoacylation. Mutational analysis of the impact of the discriminator identity on CCA addition revealed that purine bases (with a preference for adenosine) are strongly favoured over pyrimidines. Furthermore, depending on the tRNA context, a cytosine discriminator can cause a dramatic number of misincorporations during CCA addition. The data correlate with a high frequency of adenosine residues at the discriminator position observed in vivo. Originally identified as a prominent identity element for aminoacylation, this position represents a likewise important element for efficient and accurate CCA addition.
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Affiliation(s)
- Sandra Wende
- Institute for Biochemistry, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Sonja Bonin
- Institute for Biochemistry, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Oskar Götze
- Institute for Biochemistry, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Heike Betat
- Institute for Biochemistry, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
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11
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Fang ZP, Wang M, Ruan ZR, Tan M, Liu RJ, Zhou M, Zhou XL, Wang ED. Coexistence of bacterial leucyl-tRNA synthetases with archaeal tRNA binding domains that distinguish tRNA(Leu) in the archaeal mode. Nucleic Acids Res 2014; 42:5109-24. [PMID: 24500203 PMCID: PMC4005665 DOI: 10.1093/nar/gku108] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Leucyl-tRNA (transfer RNA) synthetase (LeuRS) is a multi-domain enzyme, which is divided into bacterial and archaeal/eukaryotic types. In general, one specific LeuRS, the domains of which are of the same type, exists in a single cell compartment. However, some species, such as the haloalkaliphile Natrialba magadii, encode two cytoplasmic LeuRSs, NmLeuRS1 and NmLeuRS2, which are the first examples of naturally occurring chimeric enzymes with different domains of bacterial and archaeal types. Furthermore, N. magadii encodes typical archaeal tRNALeus. The tRNA recognition mode, aminoacylation and translational quality control activities of these two LeuRSs are interesting questions to be addressed. Herein, active NmLeuRS1 and NmLeuRS2 were successfully purified after gene expression in Escherichia coli. Under the optimized aminoacylation conditions, we discovered that they distinguished cognate NmtRNALeu in the archaeal mode, whereas the N-terminal region was of the bacterial type. However, NmLeuRS1 exhibited much higher aminoacylation and editing activity than NmLeuRS2, suggesting that NmLeuRS1 is more likely to generate Leu-tRNALeu for protein biosynthesis. Moreover, using NmLeuRS1 as a model, we demonstrated misactivation of several non-cognate amino acids, and accuracy of protein synthesis was maintained mainly via post-transfer editing. This comprehensive study of the NmLeuRS/tRNALeu system provides a detailed understanding of the coevolution of aminoacyl-tRNA synthetases and tRNA.
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Affiliation(s)
- Zhi-Peng Fang
- Center for RNA Research, 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 200031, China
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12
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Das M, Vargas-Rodriguez O, Goto Y, Suga H, Musier-Forsyth K. Distinct tRNA recognition strategies used by a homologous family of editing domains prevent mistranslation. Nucleic Acids Res 2013; 42:3943-53. [PMID: 24371276 PMCID: PMC3973320 DOI: 10.1093/nar/gkt1332] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Errors in protein synthesis due to mispairing of amino acids with tRNAs jeopardize cell viability. Several checkpoints to prevent formation of Ala- and Cys-tRNAPro have been described, including the Ala-specific editing domain (INS) of most bacterial prolyl-tRNA synthetases (ProRSs) and an autonomous single-domain INS homolog, YbaK, which clears Cys-tRNAPro in trans. In many species where ProRS lacks an INS domain, ProXp-ala, another single-domain INS-like protein, is responsible for editing Ala-tRNAPro. Although the amino acid specificity of these editing domains has been established, the role of tRNA sequence elements in substrate selection has not been investigated in detail. Critical recognition elements for aminoacylation by bacterial ProRS include acceptor stem elements G72/A73 and anticodon bases G35/G36. Here, we show that ProXp-ala and INS require these same acceptor stem and anticodon elements, respectively, whereas YbaK lacks inherent tRNA specificity. Thus, these three related domains use divergent approaches to recognize tRNAs and prevent mistranslation. Whereas some editing domains have borrowed aspects of tRNA recognition from the parent aminoacyl-tRNA synthetase, relaxed tRNA specificity leading to semi-promiscuous editing may offer advantages to cells.
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Affiliation(s)
- Mom Das
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA, Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA and Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
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Zhou X, Wang E. Transfer RNA: a dancer between charging and mis-charging for protein biosynthesis. SCIENCE CHINA-LIFE SCIENCES 2013; 56:921-32. [PMID: 23982864 DOI: 10.1007/s11427-013-4542-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/13/2013] [Indexed: 01/17/2023]
Abstract
Transfer RNA plays a fundamental role in the protein biosynthesis as an adaptor molecule by functioning as a biological link between the genetic nucleotide sequence in the mRNA and the amino acid sequence in the protein. To perform its role in protein biosynthesis, it has to be accurately recognized by aminoacyl-tRNA synthetases (aaRSs) to generate aminoacyl-tRNAs (aa-tRNAs). The correct pairing between an amino acid with its cognate tRNA is crucial for translational quality control. Production and utilization of mis-charged tRNAs are usually detrimental for all the species, resulting in cellular dysfunctions. Correct aa-tRNAs formation is collectively controlled by aaRSs with distinct mechanisms and/or other trans-factors. However, in very limited instances, mis-charged tRNAs are intermediate for specific pathways or essential components for the translational machinery. Here, from the point of accuracy in tRNA charging, we review our understanding about the mechanism ensuring correct aa-tRNA generation. In addition, some unique mis-charged tRNA species necessary for the organism are also briefly described.
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Affiliation(s)
- Xiaolong Zhou
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
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14
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Vargas-Rodriguez O, Musier-Forsyth K. Exclusive use of trans-editing domains prevents proline mistranslation. J Biol Chem 2013; 288:14391-14399. [PMID: 23564458 DOI: 10.1074/jbc.m113.467795] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) catalyze the attachment of specific amino acids to cognate tRNAs. Although the accuracy of this process is critical for overall translational fidelity, similar sizes of many amino acids provide a challenge to ARSs. For example, prolyl-tRNA synthetases (ProRSs) mischarge alanine and cysteine onto tRNA(Pro). Many bacterial ProRSs possess an alanine-specific proofreading domain (INS) but lack the capability to edit Cys-tRNA(Pro). Instead, Cys-tRNA(Pro) is cleared by a single-domain homolog of INS, the trans-editing YbaK protein. A global bioinformatics analysis revealed that there are six types of "INS-like" proteins. In addition to INS and YbaK, four additional single-domain homologs are widely distributed throughout bacteria: ProXp-ala (formerly named PrdX), ProXp-x (annotated as ProX), ProXp-y (annotated as YeaK), and ProXp-z (annotated as PA2301). The last three are domains of unknown function. Whereas many bacteria encode a ProRS containing an INS domain in addition to YbaK, many other combinations of INS-like proteins exist throughout the bacterial kingdom. Here, we focus on Caulobacter crescentus, which encodes a ProRS with a truncated INS domain that lacks catalytic activity, as well as YbaK and ProXp-ala. We show that C. crescentus ProRS can readily form Cys- and Ala-tRNA(Pro), and deacylation studies confirmed that these species are cleared by C. crescentus YbaK and ProXp-ala, respectively. Substrate specificity of C. crescentus ProXp-ala is determined, in part, by elements in the acceptor stem of tRNA(Pro) and further ensured through collaboration with elongation factor Tu. These results highlight the diversity of approaches used to prevent proline mistranslation and reveal a novel triple-sieve mechanism of editing that relies exclusively on trans-editing factors.
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Affiliation(s)
- Oscar Vargas-Rodriguez
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210.
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Abstract
The aminoacyl-tRNA synthetases (aaRSs) are essential components of the protein synthesis machinery responsible for defining the genetic code by pairing the correct amino acids to their cognate tRNAs. The aaRSs are an ancient enzyme family believed to have origins that may predate the last common ancestor and as such they provide insights into the evolution and development of the extant genetic code. Although the aaRSs have long been viewed as a highly conserved group of enzymes, findings within the last couple of decades have started to demonstrate how diverse and versatile these enzymes really are. Beyond their central role in translation, aaRSs and their numerous homologs have evolved a wide array of alternative functions both inside and outside translation. Current understanding of the emergence of the aaRSs, and their subsequent evolution into a functionally diverse enzyme family, are discussed in this chapter.
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