1
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Wulff T, Hahnke K, Lécrivain AL, Schmidt K, Ahmed-Begrich R, Finstermeier K, Charpentier E. Dynamics of diversified A-to-I editing in Streptococcus pyogenes is governed by changes in mRNA stability. Nucleic Acids Res 2024; 52:11234-11253. [PMID: 39087550 PMCID: PMC11472039 DOI: 10.1093/nar/gkae629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 07/01/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing plays an important role in the post-transcriptional regulation of eukaryotic cell physiology. However, our understanding of the occurrence, function and regulation of A-to-I editing in bacteria remains limited. Bacterial mRNA editing is catalysed by the deaminase TadA, which was originally described to modify a single tRNA in Escherichia coli. Intriguingly, several bacterial species appear to perform A-to-I editing on more than one tRNA. Here, we provide evidence that in the human pathogen Streptococcus pyogenes, tRNA editing has expanded to an additional tRNA substrate. Using RNA sequencing, we identified more than 27 editing sites in the transcriptome of S. pyogenes SF370 and demonstrate that the adaptation of S. pyogenes TadA to a second tRNA substrate has also diversified the sequence context and recoding scope of mRNA editing. Based on the observation that editing is dynamically regulated in response to several infection-relevant stimuli, such as oxidative stress, we further investigated the underlying determinants of editing dynamics and identified mRNA stability as a key modulator of A-to-I editing. Overall, our findings reveal the presence and diversification of A-to-I editing in S. pyogenes and provide novel insights into the plasticity of the editome and its regulation in bacteria.
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Affiliation(s)
- Thomas F Wulff
- Max Planck Unit for the Science of Pathogens, 10117 Berlin, Germany
| | - Karin Hahnke
- Max Planck Unit for the Science of Pathogens, 10117 Berlin, Germany
| | | | - Katja Schmidt
- Max Planck Unit for the Science of Pathogens, 10117 Berlin, Germany
| | | | | | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, 10117 Berlin, Germany
- Institute for Biology, Humboldt University Berlin, 10115 Berlin, Germany
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2
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Živković I, Dulic M, Kozulic P, Mocibob M, Gruic-Sovulj I. Kinetic characterization of amino acid activation by aminoacyl-tRNA synthetases using radiolabelled γ-[ 32P]ATP. FEBS Open Bio 2024. [PMID: 39344714 DOI: 10.1002/2211-5463.13903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2024] [Revised: 08/23/2024] [Accepted: 09/16/2024] [Indexed: 10/01/2024] Open
Abstract
Aminoacyl-tRNA synthetases (AARSs) are fundamental enzymes that pair amino acids and tRNAs for protein synthesis. Aminoacylation occurs in two discrete steps. The amino acid is first activated by ATP, leading to an aminoacyl-adenylate intermediate and pyrophosphate (PPi) formation. In a subsequent step, the aminoacyl moiety is transferred to the tRNA. Kinetic assays were developed to follow each of these steps independently, as well as cumulative two-step aminoacylation. The main advantage of following the activation step over two-step aminoacylation is that most AARSs can activate amino acids in the absence of the tRNA, the production of which is laborious. Hence, the activation step is often tested first in the kinetic analysis, including large screens exploring AARS-targeting inhibitors. Since the 1960s, the activation reaction has been routinely followed by the standard ATP/[32P]PPi exchange assay, which relies on the equilibrium exchange of radiolabel between PPi and ATP using [32P]PPi as a labelled compound. However, this method became much less convenient when [32P]PPi was discontinued in 2022. As a solution, we developed a modified assay that uses easily attainable γ-[32P]ATP as a labelled compound in the equilibrium-based assay. Using this assay, herein named the [32P]ATP/PPi assay, we followed the activation step of several AARSs. The obtained data are in good agreement with the previously published kinetic constants obtained with the standard ATP/[32P]PPi exchange assay.
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Affiliation(s)
- Igor Živković
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Morana Dulic
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Petra Kozulic
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Marko Mocibob
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
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3
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Schuntermann DB, Jaskolowski M, Reynolds NM, Vargas-Rodriguez O. The central role of transfer RNAs in mistranslation. J Biol Chem 2024; 300:107679. [PMID: 39154912 PMCID: PMC11415595 DOI: 10.1016/j.jbc.2024.107679] [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: 04/25/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 08/20/2024] Open
Abstract
Transfer RNAs (tRNA) are essential small non-coding RNAs that enable the translation of genomic information into proteins in all life forms. The principal function of tRNAs is to bring amino acid building blocks to the ribosomes for protein synthesis. In the ribosome, tRNAs interact with messenger RNA (mRNA) to mediate the incorporation of amino acids into a growing polypeptide chain following the rules of the genetic code. Accurate interpretation of the genetic code requires tRNAs to carry amino acids matching their anticodon identity and decode the correct codon on mRNAs. Errors in these steps cause the translation of codons with the wrong amino acids (mistranslation), compromising the accurate flow of information from DNA to proteins. Accumulation of mutant proteins due to mistranslation jeopardizes proteostasis and cellular viability. However, the concept of mistranslation is evolving, with increasing evidence indicating that mistranslation can be used as a mechanism for survival and acclimatization to environmental conditions. In this review, we discuss the central role of tRNAs in modulating translational fidelity through their dynamic and complex interplay with translation factors. We summarize recent discoveries of mistranslating tRNAs and describe the underlying molecular mechanisms and the specific conditions and environments that enable and promote mistranslation.
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Affiliation(s)
- Dominik B Schuntermann
- Department of Biology, Institute of Molecular Biology and Biophysics, Zurich, Switzerland
| | - Mateusz Jaskolowski
- Department of Biology, Institute of Molecular Biology and Biophysics, Zurich, Switzerland
| | - Noah M Reynolds
- School of Integrated Sciences, Sustainability, and Public Health, University of Illinois Springfield, Springfield, Illinois, USA
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA.
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4
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Duran AD, Danhart EM, Ma X, Nagy ABK, Musier-Forsyth K, Foster MP. NMR-based solution structure of the Caulobacter crescentus ProXp-ala trans-editing enzyme. BIOMOLECULAR NMR ASSIGNMENTS 2024:10.1007/s12104-024-10193-3. [PMID: 39214936 DOI: 10.1007/s12104-024-10193-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024]
Abstract
ProXp-ala is a key component of the translational machinery in all three Domains of life. This enzyme helps to maintain the fidelity of proline codon translation through aminoacyl-tRNAPro proofreading. In the first step of tRNA aminoacylation, the cognate aminoacyl-tRNA synthetase (aaRS) binds and activates an amino acid in the enzyme's synthetic active site. If a non-cognate amino acid passes this first selection step and is charged onto the tRNA, a distinct aaRS editing active site may recognize the mischarged tRNA and deacylate it. Alternatively, this editing reaction may be carried out by a separate enzyme that deacylates the mischarged tRNA in trans. ProXp-ala is responsible for editing Ala mischarged onto tRNAPro. Since trans-editing domains such as ProXp-ala bind their substrates after release from the synthetase, they must recognize not only the mischarged amino acid, but also the specific tRNA. Previous studies showed that Caulobacter crescentus (Cc) ProXp-ala distinguishes tRNAPro from tRNAAla, in part, based on the unique tRNAPro acceptor stem base pair C1:G72. Previous crystallographic and NMR data also revealed a role for conformational selection by the ProXp-ala α2 helix in Ala- versus Pro-tRNAPro substrate discrimination. The α2 helix makes lattice contacts in the crystal, which left some uncertainty as to its position in solution. We report resonance assignments for the substrate-free Cc ProXp-ala and the NMR-derived three-dimensional structure of the protein. These data reveal the position of the α2 helix in solution, with implications for substrate binding and recognition.
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Affiliation(s)
- Antonia D Duran
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
- , 484 W 12th Ave, Columbus, OH, 43017, USA
| | - Eric M Danhart
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
- , 484 W 12th Ave, Columbus, OH, 43017, USA
| | - Xiao Ma
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
- , 484 W 12th Ave, Columbus, OH, 43017, USA
| | - Alexandra B Kuzmishin Nagy
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
- , 484 W 12th Ave, Columbus, OH, 43017, USA
| | - Karin Musier-Forsyth
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
- , 484 W 12th Ave, Columbus, OH, 43017, USA
| | - Mark P Foster
- Center for RNA Biology, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA.
- , 484 W 12th Ave, Columbus, OH, 43017, USA.
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5
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Watkins RR, Vradi A, Shulgina I, Musier-Forsyth K. Trypanosoma brucei multi-aminoacyl-tRNA synthetase complex formation limits promiscuous tRNA proofreading. Front Microbiol 2024; 15:1445687. [PMID: 39081885 PMCID: PMC11286415 DOI: 10.3389/fmicb.2024.1445687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 07/03/2024] [Indexed: 08/02/2024] Open
Abstract
Faithful mRNA decoding depends on the accuracy of aminoacyl-tRNA synthetases (ARSs). Aminoacyl-tRNA proofreading mechanisms have been well-described in bacteria, humans, and plants. However, our knowledge of translational fidelity in protozoans is limited. Trypanosoma brucei (Tb) is a eukaryotic, protozoan pathogen that causes Human African Trypanosomiasis, a fatal disease if untreated. Tb undergoes many physiological changes that are dictated by nutrient availability throughout its insect-mammal lifecycle. In the glucose-deprived insect vector, the tsetse fly, Tb use proline to make ATP via mitochondrial respiration. Alanine is one of the major by-products of proline consumption. We hypothesize that the elevated alanine pool challenges Tb prolyl-tRNA synthetase (ProRS), an ARS known to misactivate alanine in all three domains of life, resulting in high levels of misaminoacylated Ala-tRNAPro. Tb encodes two domains that are members of the INS superfamily of aminoacyl-tRNA deacylases. One homolog is appended to the N-terminus of Tb ProRS, and a second is the major domain of multi-aminoacyl-tRNA synthetase complex (MSC)-associated protein 3 (MCP3). Both ProRS and MCP3 are housed in the Tb MSC. Here, we purified Tb ProRS and MCP3 and observed robust Ala-tRNAPro deacylation activity from both enzymes in vitro. Size-exclusion chromatography multi-angle light scattering used to probe the oligomerization state of MCP3 revealed that although its unique N-terminal extension confers homodimerization in the absence of tRNA, the protein binds to tRNA as a monomer. Kinetic assays showed MCP3 alone has relaxed tRNA specificity and promiscuously hydrolyzes cognate Ala-tRNAAla; this activity is significantly reduced in the presence of Tb alanyl-tRNA synthetase, also housed in the MSC. Taken together, our results provide insight into translational fidelity mechanisms in Tb and lay the foundation for exploring MSC-associated proteins as novel drug targets.
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Affiliation(s)
| | | | | | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, OH, United States
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6
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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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7
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Lyu Z, Villanueva P, O’Malley L, Murphy P, Augenstreich J, Briken V, Singh A, Ling J. Genome-wide screening reveals metabolic regulation of stop-codon readthrough by cyclic AMP. Nucleic Acids Res 2023; 51:9905-9919. [PMID: 37670559 PMCID: PMC10570021 DOI: 10.1093/nar/gkad725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/12/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023] Open
Abstract
Translational fidelity is critical for microbial fitness, survival and stress responses. Much remains unknown about the genetic and environmental control of translational fidelity and its single-cell heterogeneity. In this study, we used a high-throughput fluorescence-based assay to screen a knock-out library of Escherichia coli and identified over 20 genes critical for stop-codon readthrough. Most of these identified genes were not previously known to affect translational fidelity. Intriguingly, we show that several genes controlling metabolism, including cyaA and crp, enhance stop-codon readthrough. CyaA catalyzes the synthesis of cyclic adenosine monophosphate (cAMP). Combining RNA sequencing, metabolomics and biochemical analyses, we show that deleting cyaA impairs amino acid catabolism and production of ATP, thus repressing the transcription of rRNAs and tRNAs to decrease readthrough. Single-cell analyses further show that cAMP is a major driver of heterogeneity in stop-codon readthrough and rRNA expression. Our results highlight that carbon metabolism is tightly coupled with stop-codon readthrough.
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Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Patricia Villanueva
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Liam O’Malley
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Parker Murphy
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Jacques Augenstreich
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Volker Briken
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering and Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
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8
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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] [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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9
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Byun JK, Vu JA, He SL, Jang JC, Musier-Forsyth K. Plant-exclusive domain of trans-editing enzyme ProXp-ala confers dimerization and enhanced tRNA binding. J Biol Chem 2022; 298:102255. [PMID: 35835222 PMCID: PMC9425024 DOI: 10.1016/j.jbc.2022.102255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/26/2022] Open
Abstract
Faithful translation of the genetic code is critical for the viability of all living organisms. The trans-editing enzyme ProXp-ala prevents Pro to Ala mutations during translation by hydrolyzing misacylated Ala-tRNAPro that has been synthesized by prolyl-tRNA synthetase. Plant ProXp-ala sequences contain a conserved C-terminal domain (CTD) that is absent in other organisms; the origin, structure, and function of this extra domain are unknown. To characterize the plant-specific CTD, we performed bioinformatics and computational analyses that provided a model consistent with a conserved α-helical structure. We also expressed and purified wildtype Arabidopsis thaliana (At) ProXp-ala in Escherichia coli, as well as variants lacking the CTD or containing only the CTD. Circular dichroism spectroscopy confirmed a loss of α-helical signal intensity upon CTD truncation. Size-exclusion chromatography with multiangle laser-light scattering revealed that wildtype At ProXp-ala was primarily dimeric and CTD truncation abolished dimerization in vitro. Furthermore, bimolecular fluorescence complementation assays in At protoplasts support a role for the CTD in homodimerization in vivo. The deacylation rate of Ala-tRNAPro by At ProXp-ala was also significantly reduced in the absence of the CTD, and kinetic assays indicated that the reduction in activity is primarily due to a tRNA binding defect. Overall, these results broaden our understanding of eukaryotic translational fidelity in the plant kingdom. Our study reveals that the plant-specific CTD plays a significant role in substrate binding and canonical editing function. Through its ability to facilitate protein-protein interactions, we propose the CTD may also provide expanded functional potential for trans-editing enzymes in plants.
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Affiliation(s)
- Jun-Kyu Byun
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - John A Vu
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Siou-Luan He
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Jyan-Chyun Jang
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Horticulture and Crop Science and Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA.
| | - Karin Musier-Forsyth
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.
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10
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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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11
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Furukawa R, Yokobori SI, Sato R, Kumagawa T, Nakagawa M, Katoh K, Yamagishi A. Amino Acid Specificity of Ancestral Aminoacyl-tRNA Synthetase Prior to the Last Universal Common Ancestor Commonote commonote. J Mol Evol 2022; 90:73-94. [PMID: 35084522 PMCID: PMC8821087 DOI: 10.1007/s00239-021-10043-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 12/16/2021] [Indexed: 11/24/2022]
Abstract
Extant organisms commonly use 20 amino acids in protein synthesis. In the translation system, aminoacyl-tRNA synthetase (ARS) selectively binds an amino acid and transfers it to the cognate tRNA. It is postulated that the amino acid repertoire of ARS expanded during the development of the translation system. In this study we generated composite phylogenetic trees for seven ARSs (SerRS, ProRS, ThrRS, GlyRS-1, HisRS, AspRS, and LysRS) which are thought to have diverged by gene duplication followed by mutation, before the evolution of the last universal common ancestor. The composite phylogenetic tree shows that the AspRS/LysRS branch diverged from the other five ARSs at the deepest node, with the GlyRS/HisRS branch and the other three ARSs (ThrRS, ProRS and SerRS) diverging at the second deepest node. ThrRS diverged next, and finally ProRS and SerRS diverged from each other. Based on the phylogenetic tree, sequences of the ancestral ARSs prior to the evolution of the last universal common ancestor were predicted. The amino acid specificity of each ancestral ARS was then postulated by comparison with amino acid recognition sites of ARSs of extant organisms. Our predictions demonstrate that ancestral ARSs had substantial specificity and that the number of amino acid types amino-acylated by proteinaceous ARSs was limited before the appearance of a fuller range of proteinaceous ARS species. From an assumption that 10 amino acid species are required for folding and function, proteinaceous ARS possibly evolved in a translation system composed of preexisting ribozyme ARSs, before the evolution of the last universal common ancestor.
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Affiliation(s)
- Ryutaro Furukawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan.,Faculty of Human Science, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama, 359-1192, Japan
| | - Shin-Ichi Yokobori
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Riku Sato
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Taimu Kumagawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Mizuho Nakagawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Kazutaka Katoh
- Department of Genome Informatics, Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akihiko Yamagishi
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan.
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12
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Srinivas P, Steiner RE, Pavelich IJ, Guerrero-Ferreira R, Juneja P, Ibba M, Dunham CM. Oxidation alters the architecture of the phenylalanyl-tRNA synthetase editing domain to confer hyperaccuracy. Nucleic Acids Res 2021; 49:11800-11809. [PMID: 34581811 PMCID: PMC8599791 DOI: 10.1093/nar/gkab856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 11/12/2022] Open
Abstract
High fidelity during protein synthesis is accomplished by aminoacyl-tRNA synthetases (aaRSs). These enzymes ligate an amino acid to a cognate tRNA and have proofreading and editing capabilities that ensure high fidelity. Phenylalanyl-tRNA synthetase (PheRS) preferentially ligates a phenylalanine to a tRNAPhe over the chemically similar tyrosine, which differs from phenylalanine by a single hydroxyl group. In bacteria that undergo exposure to oxidative stress such as Salmonella enterica serovar Typhimurium, tyrosine isomer levels increase due to phenylalanine oxidation. Several residues are oxidized in PheRS and contribute to hyperactive editing, including against mischarged Tyr-tRNAPhe, despite these oxidized residues not being directly implicated in PheRS activity. Here, we solve a 3.6 Å cryo-electron microscopy structure of oxidized S. Typhimurium PheRS. We find that oxidation results in widespread structural rearrangements in the β-subunit editing domain and enlargement of its editing domain. Oxidization also enlarges the phenylalanyl-adenylate binding pocket but to a lesser extent. Together, these changes likely explain why oxidation leads to hyperaccurate editing and decreased misincorporation of tyrosine. Taken together, these results help increase our understanding of the survival of S. Typhimurium during human infection.
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Affiliation(s)
- Pooja Srinivas
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Molecular and Systems Pharmacology Graduate Program, Emory University, Atlanta, GA 30322, USA.,Antibiotic Resistance Center, Emory University, Atlanta, GA 30322, USA
| | - Rebecca E Steiner
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Ian J Pavelich
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Antibiotic Resistance Center, Emory University, Atlanta, GA 30322, USA.,Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Ricardo Guerrero-Ferreira
- Robert P. Apkarian Integrated Electron Microscopy Core, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Puneet Juneja
- Robert P. Apkarian Integrated Electron Microscopy Core, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Antibiotic Resistance Center, Emory University, Atlanta, GA 30322, USA
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13
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Exploiting the fundamentals of biological organization for the advancement of biofabrication. Curr Opin Biotechnol 2021; 74:42-54. [PMID: 34798447 DOI: 10.1016/j.copbio.2021.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/26/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022]
Abstract
The field of biofabrication continues to progress, offering higher levels of spatial control, reproducibility, and functionality. However, we remain far from recapitulating what nature has achieved. Biological systems such as tissues and organs are assembled from the bottom-up through coordinated supramolecular and cellular processes that result in their remarkable structures and functionalities. In this perspective, we propose that incorporating such biological assembling mechanisms within fabrication techniques, offers an opportunity to push the boundaries of biofabrication. We dissect these mechanisms into distinct biological organization principles (BOPs) including self-assembly, compartmentalization, diffusion-reaction, disorder-to-order transitions, and out-of-equilibrium processes. We highlight recent work demonstrating the viability and potential of these approaches to enhance scalability, reproducibility, vascularization, and biomimicry; as well as current challenges to overcome.
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14
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Zhang H, Wu J, Lyu Z, Ling J. Impact of alanyl-tRNA synthetase editing deficiency in yeast. Nucleic Acids Res 2021; 49:9953-9964. [PMID: 34500470 PMCID: PMC8464055 DOI: 10.1093/nar/gkab766] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 11/12/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that provide the ribosome with aminoacyl-tRNA substrates for protein synthesis. Mutations in aaRSs lead to various neurological disorders in humans. Many aaRSs utilize editing to prevent error propagation during translation. Editing defects in alanyl-tRNA synthetase (AlaRS) cause neurodegeneration and cardioproteinopathy in mice and are associated with microcephaly in human patients. The cellular impact of AlaRS editing deficiency in eukaryotes remains unclear. Here we use yeast as a model organism to systematically investigate the physiological role of AlaRS editing. Our RNA sequencing and quantitative proteomics results reveal that AlaRS editing defects surprisingly activate the general amino acid control pathway and attenuate the heatshock response. We have confirmed these results with reporter and growth assays. In addition, AlaRS editing defects downregulate carbon metabolism and attenuate protein synthesis. Supplying yeast cells with extra carbon source partially rescues the heat sensitivity caused by AlaRS editing deficiency. These findings are in stark contrast with the cellular effects caused by editing deficiency in other aaRSs. Our study therefore highlights the idiosyncratic role of AlaRS editing compared with other aaRSs and provides a model for the physiological impact caused by the lack of AlaRS editing.
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Affiliation(s)
- Hong Zhang
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiang Wu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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15
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Muthiah A, Housley GD, Klugmann M, Fröhlich D. The Leukodystrophies HBSL and LBSL-Correlates and Distinctions. Front Cell Neurosci 2021; 14:626610. [PMID: 33574740 PMCID: PMC7870476 DOI: 10.3389/fncel.2020.626610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/21/2020] [Indexed: 12/16/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) accurately charge tRNAs with their respective amino acids. As such, they are vital for the initiation of cytosolic and mitochondrial protein translation. These enzymes have become increasingly scrutinized in recent years for their role in neurodegenerative disorders caused by the mutations of ARS-encoding genes. This review focuses on two such genes-DARS1 and DARS2-which encode cytosolic and mitochondrial aspartyl-tRNA synthetases, and the clinical conditions associated with mutations of these genes. We also describe attempts made at modeling these conditions in mice, which have both yielded important mechanistic insights. Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a disease caused by a range of mutations in the DARS2 gene, initially identified in 2003. Ten years later, hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL), caused by mutations of cytosolic DARS1, was discovered. Multiple parallels have been drawn between the two conditions. The Magnetic Resonance Imaging (MRI) patterns are strikingly similar, but still set these two conditions apart from other leukodystrophies. Clinically, both conditions are characterized by lower limb spasticity, often associated with other pyramidal signs. However, perhaps due to earlier detection, a wider range of symptoms, including peripheral neuropathy, as well as visual and hearing changes have been described in LBSL patients. Both HBSL and LBSL are spectrum disorders lacking genotype to phenotype correlation. While the fatal phenotype of Dars1 or Dars2 single gene deletion mouse mutants revealed that the two enzymes lack functional redundancy, further pursuit of disease modeling are required to shed light onto the underlying disease mechanism, and enable examination of experimental treatments, including gene therapies.
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Affiliation(s)
| | | | | | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
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16
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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: 10] [Impact Index Per Article: 2.5] [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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17
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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: 17] [Impact Index Per Article: 4.3] [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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18
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Hu QH, Williams MT, Shulgina I, Fossum CJ, Weeks KM, Adams LM, Reinhardt CR, Musier-Forsyth K, Hati S, Bhattacharyya S. Editing Domain Motions Preorganize the Synthetic Active Site of Prolyl-tRNA Synthetase. ACS Catal 2020; 10:10229-10242. [PMID: 34295570 DOI: 10.1021/acscatal.0c02381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prolyl-tRNA synthetases (ProRSs) catalyze the covalent attachment of proline onto cognate tRNAs, an indispensable step for protein synthesis in all living organisms. ProRSs are modular enzymes and the "prokaryotic-like" ProRSs are distinguished from "eukaryotic-like" ProRSs by the presence of an editing domain (INS) inserted between motifs 2 and 3 of the main catalytic domain. Earlier studies suggested the presence of coupled-domain dynamics could contribute to catalysis; however, the role that the distal, highly mobile INS domain plays in catalysis at the synthetic active site is not completely understood. In the present study, a combination of theoretical and experimental approaches has been used to elucidate the precise role of INS domain dynamics. Quantum mechanical/molecular mechanical simulations were carried out to model catalytic Pro-AMP formation by Enterococcus faecalis ProRS. The energetics of the adenylate formation by the wild-type enzyme was computed and contrasted with variants containing active site mutations, as well as a deletion mutant lacking the INS domain. The combined results revealed that two distinct types of dynamics contribute to the enzyme's catalytic power. One set of motions is intrinsic to the INS domain and leads to conformational preorganization that is essential for catalysis. A second type of motion, stemming from the electrostatic reorganization of active site residues, impacts the height and width of the energy profile and has a critical role in fine tuning the substrate orientation to facilitate reactive collisions. Thus, motions in a distal domain can preorganize the active site of an enzyme to optimize catalysis.
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Affiliation(s)
- Quin H. Hu
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Murphi T. Williams
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Irina Shulgina
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Carl J. Fossum
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Katelyn M. Weeks
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Lauren M. Adams
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Clorice R. Reinhardt
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sanchita Hati
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Sudeep Bhattacharyya
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
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19
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Zajac J, Anderson H, Adams L, Wangmo D, Suhail S, Almen A, Berns L, Coerber B, Dawson L, Hunger A, Jehn J, Johnson J, Plack N, Strasser S, Williams M, Bhattacharyya S, Hati S. Effects of Distal Mutations on Prolyl-Adenylate Formation of Escherichia coli Prolyl-tRNA Synthetase. Protein J 2020; 39:542-553. [PMID: 32681406 DOI: 10.1007/s10930-020-09910-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enzymes play important roles in many biological processes. Amino acid residues in the active site pocket of an enzyme, which are in direct contact with the substrate(s), are generally believed to be critical for substrate recognition and catalysis. Identifying and understanding how these "catalytic" residues help enzymes achieve enormous rate enhancement has been the focus of many structural and biochemical studies over the past several decades. Recent studies have shown that enzymes are intrinsically dynamic and dynamic coupling between distant structural elements is essential for effective catalysis in modular enzymes. Therefore, distal residues are expected to have impact on enzyme function. However, few studies have investigated the role of distal residues on enzymatic catalysis. In the present study, the effects of distal residue mutations on the catalytic function of an aminoacyl-tRNA synthetase, namely, prolyl-tRNA synthase, were investigated. The present study demonstrates that distal residues significantly contribute to catalysis of the modular Escherichia coli prolyl-tRNA synthetase by maintaining intrinsic protein flexibility.
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Affiliation(s)
- Jonathan Zajac
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Heidi Anderson
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Lauren Adams
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Dechen Wangmo
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Shanzay Suhail
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Aimee Almen
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Lauren Berns
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Breanna Coerber
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Logan Dawson
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Andrea Hunger
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Julia Jehn
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Joseph Johnson
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Naomi Plack
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Steven Strasser
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | - Murphi Williams
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA
| | | | - Sanchita Hati
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, USA.
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20
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Tawfik DS, Gruic-Sovulj I. How evolution shapes enzyme selectivity - lessons from aminoacyl-tRNA synthetases and other amino acid utilizing enzymes. FEBS J 2020; 287:1284-1305. [PMID: 31891445 DOI: 10.1111/febs.15199] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/08/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022]
Abstract
Aminoacyl-tRNA synthetases (AARSs) charge tRNA with their cognate amino acids. Many other enzymes use amino acids as substrates, yet discrimination against noncognate amino acids that threaten the accuracy of protein translation is a hallmark of AARSs. Comparing AARSs to these other enzymes allowed us to recognize patterns in molecular recognition and strategies used by evolution for exercising selectivity. Overall, AARSs are 2-3 orders of magnitude more selective than most other amino acid utilizing enzymes. AARSs also reveal the physicochemical limits of molecular discrimination. For example, amino acids smaller by a single methyl moiety present a discrimination ceiling of ~200, while larger ones can be discriminated by up to 105 -fold. In contrast, substrates larger by a hydroxyl group challenge AARS selectivity, due to promiscuous H-bonding with polar active site groups. This 'hydroxyl paradox' is resolved by editing. Indeed, when the physicochemical discrimination limits are reached, post-transfer editing - hydrolysis of tRNAs charged with noncognate amino acids, evolved. The editing site often selectively recognizes the edited noncognate substrate using the very same feature that the synthetic site could not efficiently discriminate against. Finally, the comparison to other enzymes also reveals that the selectivity of AARSs is an explicitly evolved trait, showing some clear examples of how selection acted not only to optimize catalytic efficiency with the target substrate, but also to abolish activity with noncognate threat substrates ('negative selection').
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Affiliation(s)
- Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Croatia
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21
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Escamilla Y, Hughes CA, Abendroth J, Dranow DM, Balboa S, Dean FB, Bullard JM. Glutaminyl-tRNA Synthetase from Pseudomonas aeruginosa: Characterization, structure, and development as a screening platform. Protein Sci 2019; 29:905-918. [PMID: 31833153 DOI: 10.1002/pro.3800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 11/12/2022]
Abstract
Pseudomonas aeruginosa has a high potential for developing resistance to multiple antibiotics. The gene (glnS) encoding glutaminyl-tRNA synthetase (GlnRS) from P. aeruginosa was cloned and the resulting protein characterized. GlnRS was kinetically evaluated and the KM and kcat obs , governing interactions with tRNA, were 1.0 μM and 0.15 s-1 , respectively. The crystal structure of the α2 form of P. aeruginosa GlnRS was solved to 1.9 Å resolution. The amino acid sequence and structure of P. aeruginosa GlnRS were analyzed and compared to that of GlnRS from Escherichia coli. Amino acids that interact with ATP, glutamine, and tRNA are well conserved and structure overlays indicate that both GlnRS proteins conform to a similar three-dimensional structure. GlnRS was developed into a screening platform using scintillation proximity assay technology and used to screen ~2,000 chemical compounds. Three inhibitory compounds were identified and analyzed for enzymatic inhibition as well as minimum inhibitory concentrations against clinically relevant bacterial strains. Two of the compounds, BM02E04 and BM04H03, were selected for further studies. These compounds displayed broad-spectrum antibacterial activity and exhibited moderate inhibitory activity against mutant efflux deficient strains of P. aeruginosa and E. coli. Growth of wild-type strains was unaffected, indicating that efflux was likely responsible for the lack of sensitivity. The global mode of action was determined using time-kill kinetics. BM04H03 did not inhibit the growth of human cell cultures at any concentration and BM02E04 only inhibit cultures at the highest concentration tested (400 μg/ml). In conclusion, GlnRS from P. aeruginosa is shown to have a structure similar to that of E. coli GlnRS and two natural product compounds were identified as inhibitors of P. aeruginosa GlnRS with the potential for utility as lead candidates in antibacterial drug development in a time of increased antibiotic resistance.
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Affiliation(s)
| | | | - Jan Abendroth
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Biosciences, Bainbridge Island, Washington
| | - David M Dranow
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Biosciences, Bainbridge Island, Washington
| | | | - Frank B Dean
- University of Texas Rio Grande Valley, Edinburg, Texas
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22
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Kuncha SK, Kruparani SP, Sankaranarayanan R. Chiral checkpoints during protein biosynthesis. J Biol Chem 2019; 294:16535-16548. [PMID: 31591268 DOI: 10.1074/jbc.rev119.008166] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Protein chains contain only l-amino acids, with the exception of the achiral glycine, making the chains homochiral. This homochirality is a prerequisite for proper protein folding and, hence, normal cellular function. The importance of d-amino acids as a component of the bacterial cell wall and their roles in neurotransmission in higher eukaryotes are well-established. However, the wider presence and the corresponding physiological roles of these specific amino acid stereoisomers have been appreciated only recently. Therefore, it is expected that enantiomeric fidelity has to be a key component of all of the steps in translation. Cells employ various molecular mechanisms for keeping d-amino acids away from the synthesis of nascent polypeptide chains. The major factors involved in this exclusion are aminoacyl-tRNA synthetases (aaRSs), elongation factor thermo-unstable (EF-Tu), the ribosome, and d-aminoacyl-tRNA deacylase (DTD). aaRS, EF-Tu, and the ribosome act as "chiral checkpoints" by preferentially binding to l-amino acids or l-aminoacyl-tRNAs, thereby excluding d-amino acids. Interestingly, DTD, which is conserved across all life forms, performs "chiral proofreading," as it removes d-amino acids erroneously added to tRNA. Here, we comprehensively review d-amino acids with respect to their occurrence and physiological roles, implications for chiral checkpoints required for translation fidelity, and potential use in synthetic biology.
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Affiliation(s)
- Santosh Kumar Kuncha
- Council of Scientific and Industrial Research (CSIR)-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Telangana 500007, India.,Academy of Scientific and Innovative Research, CSIR-CCMB Campus, Hyderabad, Telangana 500007, India
| | - Shobha P Kruparani
- Council of Scientific and Industrial Research (CSIR)-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Telangana 500007, India
| | - Rajan Sankaranarayanan
- Council of Scientific and Industrial Research (CSIR)-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Telangana 500007, India
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23
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Adams LM, Andrews RJ, Hu QH, Schmit HL, Hati S, Bhattacharyya S. Crowder-Induced Conformational Ensemble Shift in Escherichia coli Prolyl-tRNA Synthetase. Biophys J 2019; 117:1269-1284. [PMID: 31542226 PMCID: PMC6818166 DOI: 10.1016/j.bpj.2019.08.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/27/2019] [Accepted: 08/28/2019] [Indexed: 01/08/2023] Open
Abstract
The effect of molecular crowding on the structure and function of Escherichia coli prolyl-transfer RNA synthetase (Ec ProRS), a member of the aminoacyl-transfer RNA synthetase family, has been investigated using a combined experimental and theoretical method. Ec ProRS is a multidomain enzyme; coupled-domain dynamics are essential for efficient catalysis. To gain insight into the mechanistic detail of the crowding effect, kinetic studies were conducted with varying concentrations and sizes of crowders. In parallel, spectroscopic and quantum chemical studies were employed to probe the "soft interactions" between crowders and protein side chains. Finally, the dynamics of the dimeric protein was examined in the presence of crowders using a long-duration (70 ns) classical molecular dynamic simulations. The results of the simulations revealed a shift in the conformational ensemble, which is consistent with the preferential exclusion of cosolutes. The "soft interactions" model of the crowding effect also explained the alteration in kinetic parameters. In summary, the study found that the effects of molecular crowding on both conformational dynamics and catalytic function are correlated in the multidomain Ec ProRS, an enzyme that is central to protein synthesis in all living cells. This study affirmed that large and small cosolutes have considerable impacts on the structure, dynamics, and function of modular proteins and therefore must be considered for stabilizing protein-based pharmaceuticals and industrial enzymes.
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Affiliation(s)
- Lauren M Adams
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Ryan J Andrews
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Quin H Hu
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Heidi L Schmit
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin
| | - Sanchita Hati
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin.
| | - Sudeep Bhattacharyya
- Department of Chemistry, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin.
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24
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Chen L, Tanimoto A, So BR, Bakhtina M, Magliery TJ, Wysocki VH, Musier-Forsyth K. Stoichiometry of triple-sieve tRNA editing complex ensures fidelity of aminoacyl-tRNA formation. Nucleic Acids Res 2019; 47:929-940. [PMID: 30418624 PMCID: PMC6344894 DOI: 10.1093/nar/gky1153] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/30/2018] [Indexed: 11/13/2022] Open
Abstract
Aminoacyl-tRNA synthetases catalyze the attachment of cognate amino acids onto tRNAs. To avoid mistranslation, editing mechanisms evolved to maintain tRNA aminoacylation fidelity. For instance, while rejecting the majority of non-cognate amino acids via discrimination in the synthetic active site, prolyl-tRNA synthetase (ProRS) misactivates and mischarges Ala and Cys, which are similar in size to cognate Pro. Ala-tRNAPro is specifically hydrolyzed by the editing domain of ProRS in cis, while YbaK, a free-standing editing domain, clears Cys-tRNAPro in trans. ProXp-ala is another editing domain that clears Ala-tRNAPro in trans. YbaK does not appear to possess tRNA specificity, readily deacylating Cys-tRNACysin vitro. We hypothesize that YbaK binds to ProRS to gain specificity for Cys-tRNAPro and avoid deacylation of Cys-tRNACys in the cell. Here, in vivo evidence for ProRS-YbaK interaction was obtained using a split-green fluorescent protein assay. Analytical ultracentrifugation and native mass spectrometry were used to investigate binary and ternary complex formation between ProRS, YbaK, and tRNAPro. Our combined results support the hypothesis that the specificity of YbaK toward Cys-tRNAPro is determined by the formation of a three-component complex with ProRS and tRNAPro and establish the stoichiometry of a 'triple-sieve' editing complex for the first time.
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Affiliation(s)
- Lin Chen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Akiko Tanimoto
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Byung Ran So
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Thomas J Magliery
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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25
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Pena N, Dranow DM, Hu Y, Escamilla Y, Bullard JM. Characterization and structure determination of prolyl-tRNA synthetase from Pseudomonas aeruginosa and development as a screening platform. Protein Sci 2019; 28:727-737. [PMID: 30666738 PMCID: PMC6423717 DOI: 10.1002/pro.3579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/17/2019] [Indexed: 11/09/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic multi-drug resistant pathogen implicated as a causative agent in nosocomial and community acquired bacterial infections. The gene encoding prolyl-tRNA synthetase (ProRS) from P. aeruginosa was overexpressed in Escherichia coli and the resulting protein was characterized. ProRS was kinetically evaluated and the KM values for interactions with ATP, proline, and tRNA were 154, 122, and 5.5 μM, respectively. The turn-over numbers, kcatobs , for interactions with these substrates were calculated to be 5.5, 6.3, and 0.2 s-1 , respectively. The crystal structure of the α2 form of P. aeruginosa ProRS was solved to 2.60 Å resolution. The amino acid sequence and X-ray crystal structure of P. aeruginosa ProRS was analyzed and compared with homologs in which the crystal structures have been solved. The amino acids that interact with ATP and proline are well conserved in the active site region and overlay of the crystal structure with ProRS homologs conforms to a similar overall three-dimensional structure. ProRS was developed into a screening platform using scintillation proximity assay (SPA) technology and used to screen 890 chemical compounds, resulting in the identification of two inhibitory compounds, BT06A02 and BT07H05. This work confirms the utility of a screening system based on the functionality of ProRS from P. aeruginosa.
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Affiliation(s)
- Noah Pena
- The University of Texas – RGVEdinburgTexas 78541
| | - David M. Dranow
- Seattle Structural Genomics Center for Infectious DiseaseSeattleWA 98109
- Beryllium Discovery CorpBainbridge IslandWA 98110
| | - Yanmei Hu
- The University of Texas – RGVEdinburgTexas 78541
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26
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Wang X, Komatsu S. Proteomic approaches to uncover the flooding and drought stress response mechanisms in soybean. J Proteomics 2018; 172:201-215. [PMID: 29133124 DOI: 10.1016/j.jprot.2017.11.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/13/2017] [Accepted: 11/08/2017] [Indexed: 12/20/2022]
Abstract
Soybean is the important crop with abundant protein, vegetable oil, and several phytochemicals. With such predominant values, soybean is cultivated with a long history. However, flooding and drought stresses exert deleterious effects on soybean growth. The present review summarizes the morphological changes and affected events in soybean exposed to such extreme-water conditions. Sensitive organ in stressed soybean at different-developmental stages is presented based on protein profiles. Protein quality control and calcium homeostasis in the endoplasmic reticulum are discussed in soybean under both stresses. In addition, the way of calcium homeostasis in mediating protein folding and energy metabolism is addressed. Finally, stress response to flooding and drought is systematically demonstrated. This review concludes the recent findings of plant response to flooding and drought stresses in soybean employed proteomic approaches. BIOLOGICAL SIGNIFICANCE Soybean is considered as traditional-health food because of nutritional elements and pharmacological values. Flooding and drought exert deleterious effects to soybean growth. Proteomic approaches have been employed to elucidate stress response in soybean exposed to flooding and drought stresses. In this review, stress response is presented on organ-specific manner in the early-stage plant and soybean seedling exposed to combined stresses. The endoplasmic reticulum (ER) stress is induced by both stresses; and stress-response in the ER is addressed in the root tip of early-stage soybean. Moreover, calcium-response processes in stressed plant are described in the ER and in the cytosol. Additionally, stress-dependent response was discussed in flooded and drought-stressed plant. This review depicts stress response in the sensitive organ of stressed soybean and forms the basis to develop molecular markers related to plant defense under flooding and drought stresses.
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Affiliation(s)
- Xin Wang
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Setsuko Komatsu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan.
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27
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Bacusmo JM, Kuzmishin AB, Cantara WA, Goto Y, Suga H, Musier-Forsyth K. Quality control by trans-editing factor prevents global mistranslation of non-protein amino acid α-aminobutyrate. RNA Biol 2017; 15:576-585. [PMID: 28737471 DOI: 10.1080/15476286.2017.1353846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Accuracy in protein biosynthesis is maintained through multiple pathways, with a critical checkpoint occurring at the tRNA aminoacylation step catalyzed by aminoacyl-tRNA synthetases (ARSs). In addition to the editing functions inherent to some synthetases, single-domain trans-editing factors, which are structurally homologous to ARS editing domains, have evolved as alternative mechanisms to correct mistakes in aminoacyl-tRNA synthesis. To date, ARS-like trans-editing domains have been shown to act on specific tRNAs that are mischarged with genetically encoded amino acids. However, structurally related non-protein amino acids are ubiquitous in cells and threaten the proteome. Here, we show that a previously uncharacterized homolog of the bacterial prolyl-tRNA synthetase (ProRS) editing domain edits a known ProRS aminoacylation error, Ala-tRNAPro, but displays even more robust editing of tRNAs misaminoacylated with the non-protein amino acid α-aminobutyrate (2-aminobutyrate, Abu) in vitro and in vivo. Our results indicate that editing by trans-editing domains such as ProXp-x studied here may offer advantages to cells, especially under environmental conditions where concentrations of non-protein amino acids may challenge the substrate specificity of ARSs.
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Affiliation(s)
- Jo Marie Bacusmo
- a Department of Chemistry and Biochemistry , The Ohio State University , Columbus , OH , USA.,b Center for RNA Biology , The Ohio State University , Columbus , OH , USA
| | - Alexandra B Kuzmishin
- a Department of Chemistry and Biochemistry , The Ohio State University , Columbus , OH , USA.,b Center for RNA Biology , The Ohio State University , Columbus , OH , USA
| | - William A Cantara
- a Department of Chemistry and Biochemistry , The Ohio State University , Columbus , OH , USA.,b Center for RNA Biology , The Ohio State University , Columbus , OH , USA
| | - Yuki Goto
- c Department of Chemistry , Graduate School of Science, The University of Tokyo , Bunkyo , Tokyo , Japan
| | - Hiroaki Suga
- c Department of Chemistry , Graduate School of Science, The University of Tokyo , Bunkyo , Tokyo , Japan
| | - Karin Musier-Forsyth
- a Department of Chemistry and Biochemistry , The Ohio State University , Columbus , OH , USA.,b Center for RNA Biology , The Ohio State University , Columbus , OH , USA
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28
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Shin BS, Katoh T, Gutierrez E, Kim JR, Suga H, Dever TE. Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis. Nucleic Acids Res 2017; 45:8392-8402. [PMID: 28637321 PMCID: PMC5737446 DOI: 10.1093/nar/gkx532] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/05/2017] [Accepted: 06/08/2017] [Indexed: 01/20/2023] Open
Abstract
Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline.
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Affiliation(s)
- Byung-Sik Shin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Takayuki Katoh
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Erik Gutierrez
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joo-Ran Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Thomas E. Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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29
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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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30
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Rewiring protein synthesis: From natural to synthetic amino acids. Biochim Biophys Acta Gen Subj 2017; 1861:3024-3029. [PMID: 28095316 DOI: 10.1016/j.bbagen.2017.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/21/2022]
Abstract
BACKGROUND The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. SCOPE OF REVIEW This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome. We will discuss evolution and engineering of such components that allow incorporation of natural and synthetic amino acids at positions that deviate from the standard genetic code. MAJOR CONCLUSIONS The protein synthesis machinery is highly selective, yet not fixed, for the correct amino acids that match the mRNA codons. Ambiguous translation of a codon with multiple amino acids or complete reassignment of a codon with a synthetic amino acid diversifies the proteome. GENERAL SIGNIFICANCE Expanding the genetic code with synthetic amino acids through rewiring protein synthesis has broad applications in synthetic biology and chemical biology. Biochemical, structural, and genetic studies of the translational quality control mechanisms are not only crucial to understand the physiological role of translational fidelity and evolution of the genetic code, but also enable us to better design biological parts to expand the proteomes of synthetic organisms. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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31
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p53-Dependent DNA damage response sensitive to editing-defective tRNA synthetase in zebrafish. Proc Natl Acad Sci U S A 2016; 113:8460-5. [PMID: 27402763 DOI: 10.1073/pnas.1608139113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Brain and heart pathologies are caused by editing defects of transfer RNA (tRNA) synthetases, which preserve genetic code fidelity by removing incorrect amino acids misattached to tRNAs. To extend understanding of the broader impact of synthetase editing reactions on organismal homeostasis, and based on effects in bacteria ostensibly from small amounts of mistranslation of components of the replication apparatus, we investigated the sensitivity to editing of the vertebrate genome. We show here that in zebrafish embryos, transient overexpression of editing-defective valyl-tRNA synthetase (ValRS(ED)) activated DNA break-responsive H2AX and p53-responsive downstream proteins, such as cyclin-dependent kinase (CDK) inhibitor p21, which promotes cell-cycle arrest at DNA damage checkpoints, and Gadd45 and p53R2, with pivotal roles in DNA repair. In contrast, the response of these proteins to expression of ValRS(ED) was abolished in p53-deficient fish. The p53-activated downstream signaling events correlated with suppression of abnormal morphological changes caused by the editing defect and, in adults, reversed a shortened life span (followed for 2 y). Conversely, with normal editing activities, p53-deficient fish have a normal life span and few morphological changes. Whole-fish deep sequencing showed genomic mutations associated with the editing defect. We suggest that the sensitivity of p53 to expression of an editing-defective tRNA synthetase has a critical role in promoting genome integrity and organismal homeostasis.
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32
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) are modular enzymes globally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation. Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g., in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show huge structural plasticity related to function and limited idiosyncrasies that are kingdom or even species specific (e.g., the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS). Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably between distant groups such as Gram-positive and Gram-negative Bacteria. The review focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation, and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulated in last two decades is reviewed, showing how the field moved from essentially reductionist biology towards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRS paralogs (e.g., during cell wall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointed throughout the review and distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Mathias Springer
- Université Paris Diderot, Sorbonne Cité, UPR9073 CNRS, IBPC, 75005 Paris, France
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33
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Boyarshin KS, Priss AE, Rayevskiy AV, Ilchenko MM, Dubey IY, Kriklivyi IA, Yaremchuk AD, Tukalo MA. A new mechanism of post-transfer editing by aminoacyl-tRNA synthetases: catalysis of hydrolytic reaction by bacterial-type prolyl-tRNA synthetase. J Biomol Struct Dyn 2016; 35:669-682. [PMID: 26886480 DOI: 10.1080/07391102.2016.1155171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Aminoacyl tRNA synthetases are enzymes that specifically attach amino acids to cognate tRNAs for use in the ribosomal stage of translation. For many aminoacyl tRNA synthetases, the required level of amino acid specificity is achieved either by specific hydrolysis of misactivated aminoacyl-adenylate intermediate (pre-transfer editing) or by hydrolysis of the mischarged aminoacyl-tRNA (post-transfer editing). To investigate the mechanism of post-transfer editing of alanine by prolyl-tRNA synthetase from the pathogenic bacteria Enterococcus faecalis, we used molecular modeling, molecular dynamic simulations, quantum mechanical (QM) calculations, site-directed mutagenesis of the enzyme, and tRNA modification. The results support a new tRNA-assisted mechanism of hydrolysis of misacylated Ala-tRNAPro. The most important functional element of this catalytic mechanism is the 2'-OH group of the terminal adenosine 76 of Ala-tRNAPro, which forms an intramolecular hydrogen bond with the carbonyl group of the alanine residue, strongly facilitating hydrolysis. Hydrolysis was shown by QM methods to proceed via a general acid-base catalysis mechanism involving two functionally distinct water molecules. The transition state of the reaction was identified. Amino acid residues of the editing active site participate in the coordination of substrate and both attacking and assisting water molecules, performing the proton transfer to the 3'-O atom of A76.
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Affiliation(s)
- Konstantin S Boyarshin
- a Department of Protein Synthesis Enzymology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine.,b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Anastasia E Priss
- b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Alexsey V Rayevskiy
- a Department of Protein Synthesis Enzymology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine.,b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Mykola M Ilchenko
- c Department of Synthetic Bioregulators , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Igor Ya Dubey
- c Department of Synthetic Bioregulators , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Ivan A Kriklivyi
- a Department of Protein Synthesis Enzymology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine.,b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Anna D Yaremchuk
- a Department of Protein Synthesis Enzymology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine.,b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
| | - Michael A Tukalo
- a Department of Protein Synthesis Enzymology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine.,b State Key Laboratory of Molecular and Cellular Biology , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotnogo Str, 03680 Kyiv , Ukraine
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Ahmad S, Muthukumar S, Kuncha SK, Routh SB, Yerabham ASK, Hussain T, Kamarthapu V, Kruparani SP, Sankaranarayanan R. Specificity and catalysis hardwired at the RNA-protein interface in a translational proofreading enzyme. Nat Commun 2015; 6:7552. [PMID: 26113036 PMCID: PMC4491819 DOI: 10.1038/ncomms8552] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/19/2015] [Indexed: 01/28/2023] Open
Abstract
Proofreading modules of aminoacyl-tRNA synthetases are responsible for enforcing a high fidelity during translation of the genetic code. They use strategically positioned side chains for specifically targeting incorrect aminoacyl-tRNAs. Here, we show that a unique proofreading module possessing a D-aminoacyl-tRNA deacylase fold does not use side chains for imparting specificity or for catalysis, the two hallmark activities of enzymes. We show, using three distinct archaea, that a side-chain-stripped recognition site is fully capable of solving a subtle discrimination problem. While biochemical probing establishes that RNA plays the catalytic role, mechanistic insights from multiple high-resolution snapshots reveal that differential remodelling of the catalytic core at the RNA–peptide interface provides the determinants for correct proofreading activity. The functional crosstalk between RNA and protein elucidated here suggests how primordial enzyme functions could have emerged on RNA–peptide scaffolds before recruitment of specific side chains. The editing domain of aminoacyl-tRNA synthetases is responsible for removing non-cognate amino acids from mischarged tRNAs. Here the authors show that the D-aminoacyl-tRNA deacylase fold of archaeal ThrRS does not rely on protein side chains for substrate specificity and catalysis.
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Affiliation(s)
- Sadeem Ahmad
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Sowndarya Muthukumar
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Santosh Kumar Kuncha
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Satya Brata Routh
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Antony S K Yerabham
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Tanweer Hussain
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Venu Kamarthapu
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Shobha P Kruparani
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Rajan Sankaranarayanan
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
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Homologous trans-editing factors with broad tRNA specificity prevent mistranslation caused by serine/threonine misactivation. Proc Natl Acad Sci U S A 2015; 112:6027-32. [PMID: 25918376 DOI: 10.1073/pnas.1423664112] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) establish the rules of the genetic code, whereby each amino acid is attached to a cognate tRNA. Errors in this process lead to mistranslation, which can be toxic to cells. The selective forces exerted by species-specific requirements and environmental conditions potentially shape quality-control mechanisms that serve to prevent mistranslation. A family of editing factors that are homologous to the editing domain of bacterial prolyl-tRNA synthetase includes the previously characterized trans-editing factors ProXp-ala and YbaK, which clear Ala-tRNA(Pro) and Cys-tRNA(Pro), respectively, and three additional homologs of unknown function, ProXp-x, ProXp-y, and ProXp-z. We performed an in vivo screen of 230 conditions in which an Escherichia coli proXp-y deletion strain was grown in the presence of elevated levels of amino acids and specific ARSs. This screen, together with the results of in vitro deacylation assays, revealed Ser- and Thr-tRNA deacylase function for this homolog. A similar activity was demonstrated for Bordetella parapertussis ProXp-z in vitro. These proteins, now renamed "ProXp-ST1" and "ProXp-ST2," respectively, recognize multiple tRNAs as substrates. Taken together, our data suggest that these free-standing editing domains have the ability to prevent mistranslation errors caused by a number of ARSs, including lysyl-tRNA synthetase, threonyl-tRNA synthetase, seryl-tRNA synthetase, and alanyl-tRNA synthetase. The expression of these multifunctional enzymes is likely to provide a selective growth advantage to organisms subjected to environmental stresses and other conditions that alter the amino acid pool.
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Novoa EM, Vargas-Rodriguez O, Lange S, Goto Y, Suga H, Musier-Forsyth K, Ribas de Pouplana L. Ancestral AlaX editing enzymes for control of genetic code fidelity are not tRNA-specific. J Biol Chem 2015; 290:10495-503. [PMID: 25724653 DOI: 10.1074/jbc.m115.640060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Indexed: 01/15/2023] Open
Abstract
Accurate protein synthesis requires the hydrolytic editing of tRNAs incorrectly aminoacylated by aminoacyl-tRNA synthetases (ARSs). Recognition of cognate tRNAs by ARS is less error-prone than amino acid recognition, and, consequently, editing domains are generally believed to act only on the tRNAs cognate to their related ARSs. For example, the AlaX family of editing domains, including the editing domain of alanyl-tRNA synthetase and the related free-standing trans-editing AlaX enzymes, are thought to specifically act on tRNA(Ala), whereas the editing domains of threonyl-tRNA synthetases are specific for tRNA(Thr). Here we show that, contrary to this belief, AlaX-S, the smallest of the extant AlaX enzymes, deacylates Ser-tRNA(Thr) in addition to Ser-tRNA(Ala) and that a single residue is important to determine this behavior. Our data indicate that promiscuous forms of AlaX are ancestral to tRNA-specific AlaXs. We propose that former AlaX domains were used to maintain translational fidelity in earlier stages of genetic code evolution when mis-serylation of several tRNAs was possible.
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Affiliation(s)
- Eva Maria Novoa
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Oscar Vargas-Rodriguez
- the Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Stefanie Lange
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Yuki Goto
- the Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan, and
| | - Hiroaki Suga
- the Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan, and
| | - Karin Musier-Forsyth
- the Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Lluís Ribas de Pouplana
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain, the Catalan Institution for Research and Advanced Studies, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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37
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Bullwinkle T, Lazazzera B, Ibba M. Quality Control and Infiltration of Translation by Amino Acids Outside of the Genetic Code. Annu Rev Genet 2014; 48:149-66. [DOI: 10.1146/annurev-genet-120213-092101] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tammy Bullwinkle
- Department of Microbiology, Ohio State University, Columbus, Ohio 43210
| | - Beth Lazazzera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095
| | - Michael Ibba
- Department of Microbiology, Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program and Center for RNA Biology, Ohio State University, Columbus, Ohio 43210;
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38
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Laporte D, Huot JL, Bader G, Enkler L, Senger B, Becker HD. Exploring the evolutionary diversity and assembly modes of multi-aminoacyl-tRNA synthetase complexes: lessons from unicellular organisms. FEBS Lett 2014; 588:4268-78. [PMID: 25315413 DOI: 10.1016/j.febslet.2014.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 10/24/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous and ancient enzymes, mostly known for their essential role in generating aminoacylated tRNAs. During the last two decades, many aaRSs have been found to perform additional and equally crucial tasks outside translation. In metazoans, aaRSs have been shown to assemble, together with non-enzymatic assembly proteins called aaRSs-interacting multifunctional proteins (AIMPs), into so-called multi-synthetase complexes (MSCs). Metazoan MSCs are dynamic particles able to specifically release some of their constituents in response to a given stimulus. Upon their release from MSCs, aaRSs can reach other subcellular compartments, where they often participate to cellular processes that do not exploit their primary function of synthesizing aminoacyl-tRNAs. The dynamics of MSCs and the expansion of the aaRSs functional repertoire are features that are so far thought to be restricted to higher and multicellular eukaryotes. However, much can be learnt about how MSCs are assembled and function from apparently 'simple' organisms. Here we provide an overview on the diversity of these MSCs, their composition, mode of assembly and the functions that their constituents, namely aaRSs and AIMPs, exert in unicellular organisms.
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Affiliation(s)
- Daphné Laporte
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Jonathan L Huot
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Gaétan Bader
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Ludovic Enkler
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Bruno Senger
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Hubert Dominique Becker
- UMR 'Génétique Moléculaire, Génomique, Microbiologie', CNRS, Université de Strasbourg, 21 rue René Descartes, 67084 Strasbourg Cedex, France.
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Cvetesic N, Palencia A, Halasz I, Cusack S, Gruic-Sovulj I. The physiological target for LeuRS translational quality control is norvaline. EMBO J 2014; 33:1639-53. [PMID: 24935946 DOI: 10.15252/embj.201488199] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The fidelity of protein synthesis depends on the capacity of aminoacyl-tRNA synthetases (AARSs) to couple only cognate amino acid-tRNA pairs. If amino acid selectivity is compromised, fidelity can be ensured by an inherent AARS editing activity that hydrolyses mischarged tRNAs. Here, we show that the editing activity of Escherichia coli leucyl-tRNA synthetase (EcLeuRS) is not required to prevent incorrect isoleucine incorporation. Rather, as shown by kinetic, structural and in vivo approaches, the prime biological function of LeuRS editing is to prevent mis-incorporation of the non-standard amino acid norvaline. This conclusion follows from a reassessment of the discriminatory power of LeuRS against isoleucine and the demonstration that a LeuRS editing-deficient E. coli strain grows normally in high concentrations of isoleucine but not under oxygen deprivation conditions when norvaline accumulates to substantial levels. Thus, AARS-based translational quality control is a key feature for bacterial adaptive response to oxygen deprivation. The non-essential role for editing under normal bacterial growth has important implications for the development of resistance to antimicrobial agents targeting the LeuRS editing site.
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Affiliation(s)
- Nevena Cvetesic
- Department of Chemistry, Faculty of Science University of Zagreb, Zagreb, Croatia
| | - Andrés Palencia
- European Molecular Biology Laboratory, Grenoble Outstation and Unit of Virus Host-Cell Interactions, University of Grenoble Alpes-EMBL-CNRS UMI 3265, France
| | | | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation and Unit of Virus Host-Cell Interactions, University of Grenoble Alpes-EMBL-CNRS UMI 3265, France
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science University of Zagreb, Zagreb, Croatia
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40
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Javahishvili T, Manibusan A, Srinagesh S, Lee D, Ensari S, Shimazu M, Schultz PG. Role of tRNA orthogonality in an expanded genetic code. ACS Chem Biol 2014; 9:874-9. [PMID: 24443971 PMCID: PMC4167058 DOI: 10.1021/cb4005172] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We found that Methanocaldococcus
jannaschii DSM2661
tyrosyl-tRNA synthetase (Mj E9RS), specifically evolved
to charge its cognate tRNA with the unnatural amino acid p-acetylphenylalanine (pAcF) in E. coli, misaminoacylates the endogenous E. coli prolyl-tRNAs
with pAcF at a low level (0.5% per proline frequency)
in both the absence or presence of its co-evolved amber suppressor
tRNA (M. jannaschii tyrosyl-tRNA, tRNACUAMjTyr). In contrast to other E. coli tRNAs, the identity elements for recognition of the proly tRNAs
by the E. coli prolyl-tRNA synthetase (C1, G72, and
A73) are similar to those in tRNACUAMjTyr. Although
the unique acceptor stem identity elements of the prolyl-tRNAs likely
lower their recognition by the other endogenous aaRSs in E.
coli, resulting in enhanced fidelity in the wild type strain,
they lead to misaminoacylation by the archae-derived E9RS. Misincorporation
of pAcF for proline was resolved to below detectable levels by overexpression
of the endogenous E. coli prolyl-tRNA synthetase
(proS) gene in combination with additional genomic
manipulations to further increase the intracellular ratio of the ProS
over its cognate proline tRNAs. These experiments suggest another
mechanism by which the cell maintains the high fidelity of protein
biosynthesis.
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Affiliation(s)
| | | | | | - Darin Lee
- Ambrx, Inc., La Jolla, California 92037, United States
| | - Semsi Ensari
- Ambrx, Inc., La Jolla, California 92037, United States
| | - Mark Shimazu
- Ambrx, Inc., La Jolla, California 92037, United States
| | - Peter G. Schultz
- The Scripps Research Institute, La
Jolla, California 92037, United States
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41
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Wu J, Fan Y, Ling J. Mechanism of oxidant-induced mistranslation by threonyl-tRNA synthetase. Nucleic Acids Res 2014; 42:6523-31. [PMID: 24744241 PMCID: PMC4041444 DOI: 10.1093/nar/gku271] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aminoacyl-tRNA synthetases maintain the fidelity during protein synthesis by selective activation of cognate amino acids at the aminoacylation site and hydrolysis of misformed aminoacyl-tRNAs at the editing site. Threonyl-tRNA synthetase (ThrRS) misactivates serine and utilizes an editing site cysteine (C182 in Escherichia coli) to hydrolyze Ser-tRNAThr. Hydrogen peroxide oxidizes C182, leading to Ser-tRNAThr production and mistranslation of threonine codons as serine. The mechanism of C182 oxidation remains unclear. Here we used a chemical probe to demonstrate that C182 was oxidized to sulfenic acid by air, hydrogen peroxide and hypochlorite. Aminoacylation experiments in vitro showed that air oxidation increased the Ser-tRNAThr level in the presence of elongation factor Tu. C182 forms a putative metal binding site with three conserved histidine residues (H73, H77 and H186). We showed that H73 and H186, but not H77, were critical for activating C182 for oxidation. Addition of zinc or nickel ions inhibited C182 oxidation by hydrogen peroxide. These results led us to propose a model for C182 oxidation, which could serve as a paradigm for the poorly understood activation mechanisms of protein cysteine residues. Our work also suggests that bacteria may use ThrRS editing to sense the oxidant levels in the environment.
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Affiliation(s)
- Jiang Wu
- Department of Microbiology and Molecular Genetics, Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Yongqiang Fan
- Department of Microbiology and Molecular Genetics, Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, Medical School, University of Texas Health Science Center, Houston, TX 77030, USA Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030, USA
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42
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Pang YLJ, Poruri K, Martinis SA. tRNA synthetase: tRNA aminoacylation and beyond. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:461-80. [PMID: 24706556 DOI: 10.1002/wrna.1224] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 01/14/2014] [Accepted: 02/06/2014] [Indexed: 01/20/2023]
Abstract
The aminoacyl-tRNA synthetases are prominently known for their classic function in the first step of protein synthesis, where they bear the responsibility of setting the genetic code. Each enzyme is exquisitely adapted to covalently link a single standard amino acid to its cognate set of tRNA isoacceptors. These ancient enzymes have evolved idiosyncratically to host alternate activities that go far beyond their aminoacylation role and impact a wide range of other metabolic pathways and cell signaling processes. The family of aminoacyl-tRNA synthetases has also been suggested as a remarkable scaffold to incorporate new domains that would drive evolution and the emergence of new organisms with more complex function. Because they are essential, the tRNA synthetases have served as pharmaceutical targets for drug and antibiotic development. The recent unfolding of novel important functions for this family of proteins offers new and promising pathways for therapeutic development to treat diverse human diseases.
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Affiliation(s)
- Yan Ling Joy Pang
- Department of Biochemistry, University of Illinois at Urbana, Urbana, IL, USA
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Bartholow TG, Sanford BL, Cao B, Schmit HL, Johnson JM, Meitzner J, Bhattacharyya S, Musier-Forsyth K, Hati S. Strictly conserved lysine of prolyl-tRNA Synthetase editing domain facilitates binding and positioning of misacylated tRNA(Pro.). Biochemistry 2014; 53:1059-68. [PMID: 24450765 PMCID: PMC3986007 DOI: 10.1021/bi401279r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To ensure high fidelity in translation, many aminoacyl-tRNA synthetases, enzymes responsible for attaching specific amino acids to cognate tRNAs, require proof-reading mechanisms. Most bacterial prolyl-tRNA synthetases (ProRSs) misactivate alanine and employ a post-transfer editing mechanism to hydrolyze Ala-tRNA(Pro). This reaction occurs in a second catalytic site (INS) that is distinct from the synthetic active site. The 2'-OH of misacylated tRNA(Pro) and several conserved residues in the Escherichia coli ProRS INS domain are directly involved in Ala-tRNA(Pro) deacylation. Although mutation of the strictly conserved lysine 279 (K279) results in nearly complete loss of post-transfer editing activity, this residue does not directly participate in Ala-tRNA(Pro) hydrolysis. We hypothesized that the role of K279 is to bind the phosphate backbone of the acceptor stem of misacylated tRNA(Pro) and position it in the editing active site. To test this hypothesis, we carried out pKa, charge neutralization, and free-energy of binding calculations. Site-directed mutagenesis and kinetic studies were performed to verify the computational results. The calculations revealed a considerably higher pKa of K279 compared to an isolated lysine and showed that the protonated state of K279 is stabilized by the neighboring acidic residue. However, substitution of this acidic residue with a positively charged residue leads to a significant increase in Ala-tRNA(Pro) hydrolysis, suggesting that enhancement in positive charge density in the vicinity of K279 favors tRNA binding. A charge-swapping experiment and free energy of binding calculations support the conclusion that the positive charge at position 279 is absolutely necessary for tRNA binding in the editing active site.
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Affiliation(s)
- Thomas G Bartholow
- Department of Chemistry, University of Wisconsin-Eau Claire , Eau Claire, Wisconsin, 54702, United States
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44
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In silico discovery of aminoacyl-tRNA synthetase inhibitors. Int J Mol Sci 2014; 15:1358-73. [PMID: 24447926 PMCID: PMC3907873 DOI: 10.3390/ijms15011358] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/02/2014] [Accepted: 01/07/2014] [Indexed: 11/17/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are enzymes that catalyze the transfer of amino acids to their cognate tRNA. They play a pivotal role in protein synthesis and are essential for cell growth and survival. The aaRSs are one of the leading targets for development of antibiotic agents. In this review, we mainly focused on aaRS inhibitor discovery and development using in silico methods including virtual screening and structure-based drug design. These computational methods are relatively fast and cheap, and are proving to be of great benefit for the rational development of more potent aaRS inhibitors and other pharmaceutical agents that may usher in a much needed generation of new antibiotics.
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45
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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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46
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Boyarshin KS, Priss AE, Kriklivyi IA, Kovalenko OP, Yaremchuk AD, Tukalo MA. Role of tRNAPro in pretransfer editing of alanine by prolyl-tRNA synthetase. ACTA ACUST UNITED AC 2013. [DOI: 10.7124/bc.00082d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- K. S. Boyarshin
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - A. E. Priss
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - I. A. Kriklivyi
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - O. P. Kovalenko
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - A. D. Yaremchuk
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - M. A. Tukalo
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
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Johnson JM, Sanford BL, Strom AM, Tadayon SN, Lehman BP, Zirbes AM, Bhattacharyya S, Musier-Forsyth K, Hati S. Multiple pathways promote dynamical coupling between catalytic domains in Escherichia coli prolyl-tRNA synthetase. Biochemistry 2013; 52:4399-412. [PMID: 23731272 DOI: 10.1021/bi400079h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aminoacyl-tRNA synthetases are multidomain enzymes that catalyze covalent attachment of amino acids to their cognate tRNA. Cross-talk between functional domains is a prerequisite for this process. In this study, we investigate the molecular mechanism of site-to-site communication in Escherichia coli prolyl-tRNA synthetase (Ec ProRS). Earlier studies have demonstrated that evolutionarily conserved and/or co-evolved residues that are engaged in correlated motion are critical for the propagation of functional conformational changes from one site to another in modular proteins. Here, molecular simulation and bioinformatics-based analysis were performed to identify dynamically coupled and evolutionarily constrained residues that form contiguous pathways of residue-residue interactions between the aminoacylation and editing domains of Ec ProRS. The results of this study suggest that multiple pathways exist between these two domains to maintain the dynamic coupling essential for enzyme function. Moreover, residues in these interaction networks are generally highly conserved. Site-directed changes of on-pathway residues have a significant impact on enzyme function and dynamics, suggesting that any perturbation along these pathways disrupts the native residue-residue interactions that are required for effective communication between the two functional domains. Free energy analysis revealed that communication between residues within a pathway and cross-talk between pathways are important for coordinating functions of different domains of Ec ProRS for efficient catalysis.
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Affiliation(s)
- James M Johnson
- Department of Chemistry, University of Wisconsin-Eau Claire, Wisconsin 54702, United States
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Kumar S, Das M, Hadad CM, Musier-Forsyth K. Aminoacyl-tRNA substrate and enzyme backbone atoms contribute to translational quality control by YbaK. J Phys Chem B 2013; 117:4521-7. [PMID: 23185990 PMCID: PMC3601562 DOI: 10.1021/jp308628y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amino acids are covalently attached to their corresponding transfer RNAs (tRNAs) by aminoacyl-tRNA synthetases. Proofreading mechanisms exist to ensure that high fidelity is maintained in this key step in protein synthesis. Prolyl-tRNA synthetase (ProRS) can misacylate cognate tRNA(Pro) with Ala and Cys. The cis-editing domain of ProRS (INS) hydrolyzes Ala-tRNA(Pro), whereas Cys-tRNA(Pro) is hydrolyzed by a single domain editing protein, YbaK, in trans. Previous studies have proposed a model of substrate-binding by bacterial YbaK and elucidated a substrate-assisted mechanism of catalysis. However, the microscopic steps in this mechanism have not been investigated. In this work, we carried out biochemical experiments together with a detailed hybrid quantum mechanics/molecular mechanics study to investigate the mechanism of catalysis by Escherichia coli YbaK. The results support a mechanism wherein cyclization of the substrate Cys results in cleavage of the Cys-tRNA ester bond. Protein side chains do not play a significant role in YbaK catalysis. Instead, protein backbone atoms play crucial roles in stabilizing the transition state, while the product is stabilized by the 2'-OH of the tRNA.
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Affiliation(s)
- Sandeep Kumar
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210
- Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Mom Das
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program, Ohio State University, Columbus, Ohio 43210
- Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Christopher M. Hadad
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program, Ohio State University, Columbus, Ohio 43210
- Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
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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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Yadavalli SS, Ibba M. Selection of tRNA charging quality control mechanisms that increase mistranslation of the genetic code. Nucleic Acids Res 2012; 41:1104-12. [PMID: 23222133 PMCID: PMC3553970 DOI: 10.1093/nar/gks1240] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone, most notably a Mycoplasma example that displayed a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma PheRS was found to lack canonical editing activity, relying instead on discrimination against the non-cognate amino acid by kinetic proofreading. This mechanism of discrimination is inadequate for organisms where translation is more accurate, as Mycoplasma PheRS failed to support Escherichia coli growth. However, minor changes in the defunct editing domain of the Mycoplasma enzyme were sufficient to restore E. coli growth, indicating that translational accuracy is an evolutionarily selectable trait.
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Affiliation(s)
- Srujana S Yadavalli
- Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210-1292, USA
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