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Chen Y, Ruan ZR, Wang Y, Huang Q, Xue MQ, Zhou XL, Wang ED. A threonyl-tRNA synthetase-like protein has tRNA aminoacylation and editing activities. Nucleic Acids Res 2019; 46:3643-3656. [PMID: 29579307 PMCID: PMC5909460 DOI: 10.1093/nar/gky211] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/13/2018] [Indexed: 01/22/2023] Open
Abstract
TARS and TARS2 encode cytoplasmic and mitochondrial threonyl-tRNA synthetases (ThrRSs) in mammals, respectively. Interestingly, in higher eukaryotes, a third gene, TARSL2, encodes a ThrRS-like protein (ThrRS-L), which is highly homologous to cytoplasmic ThrRS but with a different N-terminal extension (N-extension). Whether ThrRS-L has canonical functions is unknown. In this work, we studied the organ expression pattern, cellular localization, canonical aminoacylation and editing activities of mouse ThrRS-L (mThrRS-L). Tarsl2 is ubiquitously but unevenly expressed in mouse tissues. Different from mouse cytoplasmic ThrRS (mThrRS), mThrRS-L is located in both the cytoplasm and nucleus; the nuclear distribution is mediated via a nuclear localization sequence at its C-terminus. Native mThrRS-L enriched from HEK293T cells was active in aminoacylation and editing. To investigate the in vitro catalytic properties of mThrRS-L accurately, we replaced the N-extension of mThrRS-L with that of mThrRS. The chimeric protein (mThrRS-L-NT) has amino acid activation, aminoacylation and editing activities. We compared the activities and cross-species tRNA recognition between mThrRS-L-NT and mThrRS. Despite having a similar aminoacylation activity, mThrRS-L-NT and mThrRS exhibit differences in tRNA recognition and editing capacity. Our results provided the first analysis of the aminoacylation and editing activities of ThrRS-L, and improved our understanding of Tarsl2.
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Affiliation(s)
- Yun Chen
- 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, 320 Yue Yang Road, Shanghai, China
| | - Zhi-Rong Ruan
- 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, 320 Yue Yang Road, Shanghai, China
| | - Yong Wang
- 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, 320 Yue Yang Road, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, China
| | - Qian Huang
- 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, 320 Yue Yang Road, Shanghai, China
| | - Mei-Qin Xue
- 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, 320 Yue Yang Road, Shanghai, China
| | - Xiao-Long Zhou
- 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, 320 Yue Yang Road, Shanghai, China
| | - En-Duo Wang
- 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, 320 Yue Yang Road, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, China
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2
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Ye Q, Ji QQ, Yan W, Yang F, Wang ED. Acetylation of lysine ϵ-amino groups regulates aminoacyl-tRNA synthetase activity in Escherichia coli. J Biol Chem 2017; 292:10709-10722. [PMID: 28455447 DOI: 10.1074/jbc.m116.770826] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 04/16/2017] [Indexed: 11/06/2022] Open
Abstract
Previous proteomic analyses have shown that aminoacyl-tRNA synthetases in many organisms can be modified by acetylation of Lys. In this present study, leucyl-tRNA synthetase and arginyl-tRNA synthetase from Escherichia coli (EcLeuRS and EcArgRS) were overexpressed and purified and found to be acetylated on Lys residues by MS. Gln scanning mutagenesis revealed that Lys619, Lys624, and Lys809 in EcLeuRS and Lys126 and Lys408 in EcArgRS might play important roles in enzyme activity. Furthermore, we utilized a novel protein expression system to obtain enzymes harboring acetylated Lys at specific sites and investigated their catalytic activity. Acetylation of these Lys residues could affect their aminoacylation activity by influencing amino acid activation and/or the affinity for tRNA. In vitro assays showed that acetyl-phosphate nonenzymatically acetylates EcLeuRS and EcArgRS and suggested that the sirtuin class deacetylase CobB might regulate acetylation of these two enzymes. These findings imply a potential regulatory role for Lys acetylation in controlling the activity of aminoacyl-tRNA synthetases and thus protein synthesis.
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Affiliation(s)
- Qing Ye
- From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and
| | - Quan-Quan Ji
- From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and
| | - Wei Yan
- From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and
| | - Fang Yang
- From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and
| | - En-Duo Wang
- From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and .,the School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
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3
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Zhou XL, Chen Y, Fang ZP, Ruan ZR, Wang Y, Liu RJ, Xue MQ, Wang ED. Translational Quality Control by Bacterial Threonyl-tRNA Synthetases. J Biol Chem 2016; 291:21208-21221. [PMID: 27542414 DOI: 10.1074/jbc.m116.740472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Indexed: 11/06/2022] Open
Abstract
Translational fidelity mediated by aminoacyl-tRNA synthetases ensures the generation of the correct aminoacyl-tRNAs, which is critical for most species. Threonyl-tRNA synthetase (ThrRS) contains multiple domains, including an N2 editing domain. Of the ThrRS domains, N1 is the last to be assigned a function. Here, we found that ThrRSs from Mycoplasma species exhibit differences in their domain composition and editing active sites compared with the canonical ThrRSs. The Mycoplasma mobile ThrRS, the first example of a ThrRS naturally lacking the N1 domain, displays efficient post-transfer editing activity. In contrast, the Mycoplasma capricolum ThrRS, which harbors an N1 domain and a degenerate N2 domain, is editing-defective. Only editing-capable ThrRSs were able to support the growth of a yeast thrS deletion strain (ScΔthrS), thus suggesting that ScΔthrS is an excellent tool for studying the in vivo editing of introduced bacterial ThrRSs. On the basis of the presence or absence of an N1 domain, we further revealed the crucial importance of the only absolutely conserved residue within the N1 domain in regulating editing by mediating an N1-N2 domain interaction in Escherichia coli ThrRS. Our results reveal the translational quality control of various ThrRSs and the role of the N1 domain in translational fidelity.
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Affiliation(s)
- Xiao-Long Zhou
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - Yun Chen
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - Zhi-Peng Fang
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - Zhi-Rong Ruan
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - Yong Wang
- the School of Life Science and Technology, ShanghaiTech University, 200031 Shanghai, China
| | - Ru-Juan Liu
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - Mei-Qin Xue
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and
| | - En-Duo Wang
- From the State Key Laboratory of Molecular Biology, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China and the School of Life Science and Technology, ShanghaiTech University, 200031 Shanghai, China
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Ye Q, Wang M, Fang ZP, Ruan ZR, Ji QQ, Zhou XL, Wang ED. Degenerate connective polypeptide 1 (CP1) domain from human mitochondrial leucyl-tRNA synthetase. J Biol Chem 2015; 290:24391-402. [PMID: 26272616 DOI: 10.1074/jbc.m115.672824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 11/06/2022] Open
Abstract
The connective polypeptide 1 (CP1) editing domain of leucyl-tRNA synthetase (LeuRS) from various species either harbors a conserved active site to exclude tRNA mis-charging with noncognate amino acids or is evolutionarily truncated or lost because there is no requirement for high translational fidelity. However, human mitochondrial LeuRS (hmtLeuRS) contains a full-length but degenerate CP1 domain that has mutations in some residues important for post-transfer editing. The significance of such an inactive CP1 domain and a translational accuracy mechanism with different noncognate amino acids are not completely understood. Here, we identified the essential role of the evolutionarily divergent CP1 domain in facilitating hmtLeuRS's catalytic efficiency and endowing enzyme with resistance to AN2690, a broad-spectrum drug acting on LeuRSs. In addition, the canonical core of hmtLeuRS is not stringent for noncognate norvaline (Nva) and valine (Val). hmtLeuRS has a very weak tRNA-independent pre-transfer editing activity for Nva, which is insufficient to remove mis-activated Nva. Moreover, hmtLeuRS chimeras fused with a functional CP1 domain from LeuRSs of other species, regardless of origin, showed restored post-transfer editing activity and acquired fidelity during aminoacylation. This work offers a novel perspective on the role of the CP1 domain in optimizing aminoacylation efficiency.
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Affiliation(s)
- Qing Ye
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - Meng Wang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - Zhi-Peng Fang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - Zhi-Rong Ruan
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - Quan-Quan Ji
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - Xiao-Long Zhou
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and
| | - En-Duo Wang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai and the School of Life Science and Technology, ShanghaiTech University, 319 Yue Yang Road, Shanghai 200031, China
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5
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Yan W, Ye Q, Tan M, Chen X, Eriani G, Wang ED. Modulation of Aminoacylation and Editing Properties of Leucyl-tRNA Synthetase by a Conserved Structural Module. J Biol Chem 2015; 290:12256-67. [PMID: 25817995 DOI: 10.1074/jbc.m115.639492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Indexed: 11/06/2022] Open
Abstract
A conserved structural module following the KMSKS catalytic loop exhibits α-α-β-α topology in class Ia and Ib aminoacyl-tRNA synthetases. However, the function of this domain has received little attention. Here, we describe the effect this module has on the aminoacylation and editing capacities of leucyl-tRNA synthetases (LeuRSs) by characterizing the key residues from various species. Mutation of highly conserved basic residues on the third α-helix of this domain impairs the affinity of LeuRS for the anticodon stem of tRNA(Leu), which decreases both aminoacylation and editing activities. Two glycine residues on this α-helix contribute to flexibility, leucine activation, and editing of LeuRS from Escherichia coli (EcLeuRS). Acidic residues on the β-strand enhance the editing activity of EcLeuRS and sense the size of the tRNA(Leu) D-loop. Incorporation of these residues stimulates the tRNA-dependent editing activity of the chimeric minimalist enzyme Mycoplasma mobile LeuRS fused to the connective polypeptide 1 editing domain and leucine-specific domain from EcLeuRS. Together, these results reveal the stem contact-fold to be a functional as well as a structural linker between the catalytic site and the tRNA binding domain. Sequence comparison of the EcLeuRS stem contact-fold domain with editing-deficient enzymes suggests that key residues of this module have evolved an adaptive strategy to follow the editing functions of LeuRS.
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Affiliation(s)
- Wei Yan
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Qing Ye
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Min Tan
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Xi Chen
- the College of Life Sciences, Wuhan University, 299 Bayi Road, Wuhan 430072, Hubei, China
| | - Gilbert Eriani
- the Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 Rue René Descartes, Strasbourg 67084, France, and
| | - En-Duo Wang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China, the School of Life Science and Technology, Shanghai Tech University, 319 Yue Yang Road, Shanghai 200031,China,
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6
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Hu QH, Liu RJ, Fang ZP, Zhang J, Ding YY, Tan M, Wang M, Pan W, Zhou HC, Wang ED. Discovery of a potent benzoxaborole-based anti-pneumococcal agent targeting leucyl-tRNA synthetase. Sci Rep 2014; 3:2475. [PMID: 23959225 PMCID: PMC3747510 DOI: 10.1038/srep02475] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/18/2013] [Indexed: 01/01/2023] Open
Abstract
Streptococcus pneumoniae causes bacterial pneumonia with high mortality and morbidity. The emergency of multidrug-resistant bacteria threatens the treatment of the disease. Leucyl-tRNA synthetase (LeuRS) plays an essential role in cellular translation and is an attractive drug target for antimicrobial development. Here we report the compound ZCL039, a benzoxaborole-based derivative of AN2690, as a potent anti-pneumococcal agent that inhibits S. pneumoniae LeuRS (SpLeuRS) activity. We show using kinetic, biochemical analyses combined with the crystal structure of ZCL039-AMP in complex with the separated SpLeuRS editing domain, that ZCL039 binds to the LeuRS editing active site which requires the presence of tRNA(Leu), and employs an uncompetitive inhibition mechanism. Further docking models establish that ZCL039 clashes with the eukaryal/archaeal specific insertion I4ae helix within editing domains. These findings demonstrate the potential of benzoxaboroles as effective LeuRS inhibitors for pneumococcus infection therapy, and provide future structure-guided drug design and optimization.
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Affiliation(s)
- Qing-Hua Hu
- 1] State Key Laboratory of Molecular Biology, Center for RNA research, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China [2]
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7
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Zhou XL, Fang ZP, Ruan ZR, Wang M, Liu RJ, Tan M, Anella FM, Wang ED. Aminoacylation and translational quality control strategy employed by leucyl-tRNA synthetase from a human pathogen with genetic code ambiguity. Nucleic Acids Res 2013; 41:9825-38. [PMID: 23969415 PMCID: PMC3834818 DOI: 10.1093/nar/gkt741] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Aminoacyl-tRNA synthetases should ensure high accuracy in tRNA aminoacylation. However, the absence of significant structural differences between amino acids always poses a direct challenge for some aminoacyl-tRNA synthetases, such as leucyl-tRNA synthetase (LeuRS), which require editing function to remove mis-activated amino acids. In the cytoplasm of the human pathogen Candida albicans, the CUG codon is translated as both Ser and Leu by a uniquely evolved CatRNASer(CAG). Its cytoplasmic LeuRS (CaLeuRS) is a crucial component for CUG codon ambiguity and harbors only one CUG codon at position 919. Comparison of the activity of CaLeuRS-Ser919 and CaLeuRS-Leu919 revealed yeast LeuRSs have a relaxed tRNA recognition capacity. We also studied the mis-activation and editing of non-cognate amino acids by CaLeuRS. Interestingly, we found that CaLeuRS is naturally deficient in tRNA-dependent pre-transfer editing for non-cognate norvaline while displaying a weak tRNA-dependent pre-transfer editing capacity for non-cognate α-amino butyric acid. We also demonstrated that post-transfer editing of CaLeuRS is not tRNALeu species-specific. In addition, other eukaryotic but not archaeal or bacterial LeuRSs were found to recognize CatRNASer(CAG). Overall, we systematically studied the aminoacylation and editing properties of CaLeuRS and established a characteristic LeuRS model with naturally deficient tRNA-dependent pre-transfer editing, which increases LeuRS types with unique editing patterns.
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Affiliation(s)
- Xiao-Long Zhou
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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8
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Tan M, Wang M, Zhou XL, Yan W, Eriani G, Wang ED. The Yin and Yang of tRNA: proper binding of acceptor end determines the catalytic balance of editing and aminoacylation. Nucleic Acids Res 2013; 41:5513-23. [PMID: 23585282 PMCID: PMC3664829 DOI: 10.1093/nar/gkt252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Faithful translation of the genetic code depends on accurate coupling of amino acids with cognate transfer RNAs (tRNAs) catalyzed by aminoacyl-tRNA synthetases. The fidelity of leucyl-tRNA synthetase (LeuRS) depends mainly on proofreading at the pre- and post-transfer levels. During the catalytic cycle, the tRNA CCA-tail shuttles between the synthetic and editing domains to accomplish the aminoacylation and editing reactions. Previously, we showed that the Y330D mutation of Escherichia coli LeuRS, which blocks the entry of the tRNA CCA-tail into the connective polypeptide 1domain, abolishes both tRNA-dependent pre- and post-transfer editing. In this study, we identified the counterpart substitutions, which constrain the tRNA acceptor stem binding within the synthetic active site. These mutations negatively impact the tRNA charging activity while retaining the capacity to activate the amino acid. Interestingly, the mutated LeuRSs exhibit increased global editing activity in the presence of a non-cognate amino acid. We used a reaction mimicking post-transfer editing to show that these mutations decrease post-transfer editing owing to reduced tRNA aminoacylation activity. This implied that the increased editing activity originates from tRNA-dependent pre-transfer editing. These results, together with our previous work, provide a comprehensive assessment of how intra-molecular translocation of the tRNA CCA-tail balances the aminoacylation and editing activities of LeuRS.
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Affiliation(s)
- Min Tan
- Center for RNA research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, PR China
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Yan W, Tan M, Eriani G, Wang ED. Leucine-specific domain modulates the aminoacylation and proofreading functional cycle of bacterial leucyl-tRNA synthetase. Nucleic Acids Res 2013; 41:4988-98. [PMID: 23525458 PMCID: PMC3643597 DOI: 10.1093/nar/gkt185] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The leucine-specific domain (LSD) is a compact well-ordered module that participates in positioning of the conserved KMSKS catalytic loop in most leucyl-tRNA synthetases (LeuRSs). However, the LeuRS from Mycoplasma mobile (MmLeuRS) has a tetrapeptide GKDG instead of the LSD. Here, we show that the tetrapeptide GKDG can confer tRNA charging and post-transfer editing activity when transplanted into an inactive Escherichia coli LeuRS (EcLeuRS) that has had its LSD deleted. Reciprocally, the LSD, together with the CP1-editing domain of EcLeuRS, can cooperate when inserted into the scaffold of the minimal MmLeuRS, and this generates an enzyme nearly as active as EcLeuRS. Further, we show that LSD participates in tRNA(Leu) recognition and favours the binding of tRNAs harbouring a large loop in the variable arm. Additional analysis established that the Lys598 in the LSD is the critical residue for tRNA binding. Conversion of Lys598 to Ala simultaneously reduces the tRNA-binding strength and aminoacylation and editing capacities, indicating that these factors are subtly connected and controlled at the level of the LSD. The present work provides a novel framework of co-evolution between LeuRS and its cognate tRNA through LSD.
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Affiliation(s)
- Wei Yan
- State Key Laboratory of Molecular Biology, Center for RNA Research, Institute of Biochemistry and Cell Biology, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, PR China
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Interdomain communication modulates the tRNA-dependent pre-transfer editing of leucyl-tRNA synthetase. Biochem J 2013; 449:123-31. [PMID: 23035846 DOI: 10.1042/bj20121258] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
EcLeuRS [Escherichia coli LeuRS (leucyl-tRNA synthetase)] has evolved both tRNA-dependent pre- and post-transfer editing capabilities to ensure catalytic specificity. Both editing functions rely on the entry of the tRNA CCA tail into the editing domain of the LeuRS enzyme, which, according to X-ray crystal structural studies, leads to a dynamic disordered orientation of the interface between the synthetic and editing domains. The results of the present study show that this tRNA-triggered conformational rearrangement leads to interdomain communication between the editing and synthetic domains through their interface, and this communication mechanism modulates the activity of tRNA-dependent pre-transfer editing. Furthermore, tRNA-dependent editing reaction inhibits misactivating non-cognate amino acids from the synthetic active site. These results also suggested a novel quality control mechanism of EcLeuRS which is achieved through the co-ordination between the synthetic and editing domains.
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11
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Hu QH, Huang Q, Wang ED. Crucial role of the C-terminal domain of Mycobacterium tuberculosis leucyl-tRNA synthetase in aminoacylation and editing. Nucleic Acids Res 2012; 41:1859-72. [PMID: 23268443 PMCID: PMC3561953 DOI: 10.1093/nar/gks1307] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The C-terminal extension of prokaryotic leucyl-tRNA synthetase (LeuRS) has been shown to make contacts with the tertiary structure base pairs of tRNA(Leu) as well as its long variable arm. However, the precise role of the flexibly linked LeuRS C-terminal domain (CTD) in aminoacylation and editing processes has not been clarified. In this study, we carried out aspartic acid scanning within the CTD of Mycobacterium tuberculosis LeuRS (MtbLeuRS) and studied the effects on tRNA(Leu)-binding capacity and enzymatic activity. Several critical residues were identified to impact upon the interactions between LeuRS and tRNA(Leu) due to their contributions in the maintenance of structural stability or a neutral interaction interface between the CTD platform and tRNA(Leu) elbow region. Moreover, we propose Arg921 as a crucial recognition site for the tRNA(Leu) long variable arm in aminoacylation and tRNA-dependent pre-transfer editing. We also show here the CTD flexibility conferred by Val910 in regulation of LeuRS-tRNA(Leu) interaction. Taken together, our results suggest the structural importance of the CTD in modulating precise interactions between LeuRS and tRNA(Leu) during the quality control of leucyl-tRNA(Leu) synthesis. This system for the investigation of the interactions between MtbLeuRS and tRNA(Leu) provides a platform for the development of novel antitubercular drugs.
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Affiliation(s)
- Qing-Hua Hu
- State Key Laboratory of Molecular Biology, Center for RNA research, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
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A naturally occurring nonapeptide functionally compensates for the CP1 domain of leucyl-tRNA synthetase to modulate aminoacylation activity. Biochem J 2012; 443:477-84. [PMID: 22292813 DOI: 10.1042/bj20111925] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
aaRSs (aminoacyl-tRNA synthetases) establish the rules of the genetic code by catalysing the formation of aminoacyl-tRNA. The quality control for aminoacylation is achieved by editing activity, which is usually carried out by a discrete editing domain. For LeuRS (leucyl-tRNA synthetase), the CP1 (connective peptide 1) domain is the editing domain responsible for hydrolysing mischarged tRNA. The CP1 domain is universally present in LeuRSs, except MmLeuRS (Mycoplasma mobile LeuRS). The substitute of CP1 in MmLeuRS is a nonapeptide (MmLinker). In the present study, we show that the MmLinker, which is critical for the aminoacylation activity of MmLeuRS, could confer remarkable tRNA-charging activity on the inactive CP1-deleted LeuRS from Escherichia coli (EcLeuRS) and Aquifex aeolicus (AaLeuRS). Furthermore, CP1 from EcLeuRS could functionally compensate for the MmLinker and endow MmLeuRS with post-transfer editing capability. These investigations provide a mechanistic framework for the modular construction of aaRSs and their co-ordination to achieve catalytic efficiency and fidelity. These results also show that the pre-transfer editing function of LeuRS originates from its conserved synthetic domain and shed light on future study of the mechanism.
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13
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Gene 5.5 protein of bacteriophage T7 in complex with Escherichia coli nucleoid protein H-NS and transfer RNA masks transfer RNA priming in T7 DNA replication. Proc Natl Acad Sci U S A 2012; 109:8050-5. [PMID: 22566619 DOI: 10.1073/pnas.1205990109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA primases provide oligoribonucleotides for DNA polymerase to initiate lagging strand synthesis. A deficiency in the primase of bacteriophage T7 to synthesize primers can be overcome by genetic alterations that decrease the expression of T7 gene 5.5, suggesting an alternative mechanism to prime DNA synthesis. The product of gene 5.5 (gp5.5) forms a stable complex with the Escherichia coli histone-like protein H-NS and transfer RNAs (tRNAs). The 3'-terminal sequence (5'-ACCA-3') of tRNAs is identical to that of a functional primer synthesized by T7 primase. Mutations in T7 that suppress the inability of primase reduce the amount of gp5.5 and thus increase the pool of tRNA to serve as primers. Alterations in T7 gene 3 facilitate tRNA priming by reducing its endonuclease activity that cleaves at the tRNA-DNA junction. The tRNA bound to gp5.5 recruits H-NS. H-NS alone inhibits reactions involved in DNA replication, but the binding to gp5.5-tRNA complex abolishes this inhibition.
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14
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Zhou XL, Du DH, Tan M, Lei HY, Ruan LL, Eriani G, Wang ED. Role of tRNA amino acid-accepting end in aminoacylation and its quality control. Nucleic Acids Res 2011; 39:8857-68. [PMID: 21775341 PMCID: PMC3203616 DOI: 10.1093/nar/gkr595] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Aminoacyl–tRNA synthetases (aaRSs) are remarkable enzymes that are in charge of the accurate recognition and ligation of amino acids and tRNA molecules. The greatest difficulty in accurate aminoacylation appears to be in discriminating between highly similar amino acids. To reduce mischarging of tRNAs by non-cognate amino acids, aaRSs have evolved an editing activity in a second active site to cleave the incorrect aminoacyl–tRNAs. Editing occurs after translocation of the aminoacyl–CCA76 end to the editing site, switching between a hairpin and a helical conformation for aminoacylation and editing. Here, we studied the consequence of nucleotide changes in the CCA76 accepting end of tRNALeu during the aminoacylation and editing reactions. The analysis showed that the terminal A76 is essential for both reactions, suggesting that critical interactions occur in the two catalytic sites. Substitutions of C74 and C75 selectively decreased aminoacylation keeping nearly unaffected editing. These mutations might favor the regular helical conformation required to reach the editing site. Mutating the editing domain residues that contribute to CCA76 binding reduced the aminoacylation fidelity leading to cell-toxicity in the presence of non-cognate amino acids. Collectively, the data show how protein synthesis quality is controlled by the CCA76 homogeneity of tRNAs.
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Affiliation(s)
- Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China
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15
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Hao ZX, Feng R, Wang ED, Zhu G. 1H, 15N chemical shift assignments of the imino groups in the base pairs of Escherichia coli tRNA(Leu) (CAG). BIOMOLECULAR NMR ASSIGNMENTS 2011; 5:71-74. [PMID: 20931304 DOI: 10.1007/s12104-010-9270-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/22/2010] [Indexed: 05/30/2023]
Abstract
tRNA molecules are the adaptors in ribosome-based protein biosynthesis and are stabilized by Mg(2+). However, the detailed mechanism for the Mg(2+) mediated stability is not fully understood. To study the effects of Mg(2+) on conformational flexibility of Escherichia coli tRNA(Leu) (CAG) at millisecond timescale, we applied NMR spectroscopic approach to measure proton exchange rates of imino groups in the presence of different concentration of Mg(2+) and correlated them with the corresponding aminoacylation activity of tRNA(Leu). Here, we report the first part of the above mentioned study, the (1)H, (15)N chemical shift assignments of the imino groups in all base pairs of Escherichia coli tRNA(Leu) (CAG) based on 2D (1)H-(15)N TROSY, 2D NOESY and 3D NOESY-HMQC experiments. This work laid the foundation for the NMR study of tRNA(Leu) (BMRB deposits with accession number 17078).
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Affiliation(s)
- Zhan-Xi Hao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Graduate School of the Chinese Academy of Sciences, Shanghai, China
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16
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Hao ZX, Tan M, Liu CD, Feng R, Wang ED, Zhu G. Studying base pair open-close kinetics of tRNALeu by TROSY-based proton exchange NMR spectroscopy. FEBS Lett 2010; 584:4449-52. [PMID: 20937276 DOI: 10.1016/j.febslet.2010.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 10/05/2010] [Accepted: 10/05/2010] [Indexed: 11/24/2022]
Abstract
The millisecond conformational flexibility is functionally important for nucleic acids and can be studied through probing the base pair open-close kinetics by proton exchange nuclear magnetic resonance (NMR) spectroscopy. Here, the traditional imino proton exchange NMR experiments were modified with transverse relaxation optimized spectroscopy and were applied to accurately measure imino proton exchange rates of all base pairs in Escherichia coli tRNA(Leu) (CAG), and their dependence on magnesium ion concentration. Finally, we correlated millisecond conformational flexibility with aminoacylation of tRNA(Leu) and proposed that the flexibility of the acceptor stem and the core region might contribute to aminoacylation of tRNA(Leu).
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Affiliation(s)
- Zhan-Xi Hao
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Shanghai, China
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17
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Chen X, Ma JJ, Tan M, Yao P, Hu QH, Eriani G, Wang ED. Modular pathways for editing non-cognate amino acids by human cytoplasmic leucyl-tRNA synthetase. Nucleic Acids Res 2010; 39:235-47. [PMID: 20805241 PMCID: PMC3017609 DOI: 10.1093/nar/gkq763] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To prevent potential errors in protein synthesis, some aminoacyl-transfer RNA (tRNA) synthetases have evolved editing mechanisms to hydrolyze misactivated amino acids (pre-transfer editing) or misacylated tRNAs (post-transfer editing). Class Ia leucyl-tRNA synthetase (LeuRS) may misactivate various natural and non-protein amino acids and then mischarge tRNA(Leu). It is known that the fidelity of prokaryotic LeuRS depends on multiple editing pathways to clear the incorrect intermediates and products in the every step of aminoacylation reaction. Here, we obtained human cytoplasmic LeuRS (hcLeuRS) and tRNA(Leu) (hctRNA(Leu)) with high activity from Escherichia coli overproducing strains to study the synthetic and editing properties of the enzyme. We revealed that hcLeuRS could adjust its editing strategy against different non-cognate amino acids. HcLeuRS edits norvaline predominantly by post-transfer editing; however, it uses mainly pre-transfer editing to edit α-amino butyrate, although both amino acids can be charged to tRNA(Leu). Post-transfer editing as a final checkpoint of the reaction was very important to prevent mis-incorporation in vitro. These results provide insight into the modular editing pathways created to prevent genetic code ambiguity by evolution.
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Affiliation(s)
- Xin Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Shanghai 200031, China
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18
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Tan M, Zhu B, Zhou XL, He R, Chen X, Eriani G, Wang ED. tRNA-dependent pre-transfer editing by prokaryotic leucyl-tRNA synthetase. J Biol Chem 2010; 285:3235-44. [PMID: 19940155 PMCID: PMC2823433 DOI: 10.1074/jbc.m109.060616] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 11/20/2009] [Indexed: 11/06/2022] Open
Abstract
To prevent genetic code ambiguity due to misincorporation of amino acids into proteins, aminoacyl-tRNA synthetases have evolved editing activities to eliminate intermediate or final non-cognate products. In this work we studied the different editing pathways of class Ia leucyl-tRNA synthetase (LeuRS). Different mutations and experimental conditions were used to decipher the editing mechanism, including the recently developed compound AN2690 that targets the post-transfer editing site of LeuRS. The study emphasizes the crucial importance of tRNA for the pre- and post-transfer editing catalysis. Both reactions have comparable efficiencies in prokaryotic Aquifex aeolicus and Escherichia coli LeuRSs, although the E. coli enzyme favors post-transfer editing, whereas the A. aeolicus enzyme favors pre-transfer editing. Our results also indicate that the entry of the CCA-acceptor end of tRNA in the editing domain is strictly required for tRNA-dependent pre-transfer editing. Surprisingly, this editing reaction was resistant to AN2690, which inactivates the enzyme by forming a covalent adduct with tRNA(Leu) in the post-transfer editing site. Taken together, these data suggest that the binding of tRNA in the post-transfer editing conformation confers to the enzyme the capacity for pre-transfer editing catalysis, regardless of its capacity to catalyze post-transfer editing.
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Affiliation(s)
- Min Tan
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
| | - Bin Zhu
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
| | - Xiao-Long Zhou
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
| | - Ran He
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
| | - Xin Chen
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, UPR9002 du CNRS, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 15 rue René Descartes, 67084 Strasbourg, France
| | - En-Duo Wang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China and
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19
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Li Y, Chen J, Wang E, Wang Y. T7 RNA polymerase transcription of Escherichia coli isoacceptors tRNA(Leu). ACTA ACUST UNITED AC 2009; 42:185-90. [PMID: 18726472 DOI: 10.1007/bf02880055] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/1998] [Indexed: 10/22/2022]
Abstract
The T7 promoter and the gene encoding tRNA(Leu) were synthesized chemically and cloned into plasmid pUC19, where the gene was transcribed in vitro with T7 RNA polymerase purified. It was found that spermidine had a negative effect on T7 transcription. The amount of transcribed tRNA was about 250 times that of the template DNA under optimal reaction conditions. The unmodified tRNA(1) (Leu) and tRNA(2) (Leu) had similar leucine accepting ability, which however was only one fourth that of the native modified ones. This result indicated that the modified nucleotides of tRNA(Leu) played some though not key roles in its aminoacylation.
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Affiliation(s)
- Y Li
- Shanghai Institute of Biochemistry, Chinese Academy of Sciences, China
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20
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Zhou XL, Yao P, Ruan LL, Zhu B, Luo J, Qu LH, Wang ED. A unique insertion in the CP1 domain of Giardia lamblia leucyl-tRNA synthetase. Biochemistry 2009; 48:1340-7. [PMID: 19170608 DOI: 10.1021/bi801832j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Leucyl-tRNA synthetase (LeuRS) catalyzes the esterification of the tRNA(Leu) isoacceptor with leucine. It contains a large insertion domain, connective peptide 1 (CP1), for amino acid editing. Here, we cloned the gene encoding LeuRS from Giardia lamblia (GlLeuRS), one of the most ancient eukaryotes. GlLeuRS was purified from an Escherichia coli overproduction strain, and its properties were investigated. The isolated CP1 domain of GlLeuRS (GlLeuRS-CP1) was an active protein for editing mischarged G. lamblia tRNA(Leu)(AAG) (GltRNA(Leu)). Insertion of 49 amino acid residues within the CP1 domain (the so-called 49-amino acid motif) was important for the optimal aminoacylation activity of GlLeuRS and was crucial for the editing capacity of GlLeuRS-CP1. Additionally, the motif can confer editing activity on the editing-defective isolated CP1 domain from E. coli LeuRS (EcLeuRS-CP1). We also found that GlLeuRS could not rescue a Saccharomyces cerevisiae leuS null strain, suggesting different recognition modes for these two LeuRSs with respect to tRNA(Leu).
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Affiliation(s)
- Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, People's Republic of China
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21
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He R, Zu LD, Yao P, Chen X, Wang ED. Two non-redundant fragments in the N-terminal peptide of human cytosolic methionyl-tRNA synthetase were indispensable for the multi-synthetase complex incorporation and enzyme activity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:347-54. [PMID: 19064003 DOI: 10.1016/j.bbapap.2008.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/03/2008] [Accepted: 11/04/2008] [Indexed: 10/21/2022]
Abstract
In human cytoplasm, nine aminoacyl-tRNA synthetases (aaRSs) and three protein factors form a multi-synthetase complex (MSC). Human cytosolic methionyl-tRNA synthetase (hcMetRS) is a component of the MSC. Sequence alignment revealed that hcMetRS has an N-terminal extension of 267 amino acid residues. This extension can be divided into three sub-domains: GST-like, GN, and GC sub-domains. The effect of each sub-domain in the N-terminal extension of hcMetRS on enzymatic activity and incorporation into the MSC was studied. The results of cellular assay showed that the GST-like sub-domain was responsible for the incorporation of hcMetRS into the MSC. The entire N-terminal extension of hcMetRS is indispensable for the enzymatic activity. Deletion mutagenesis revealed that a seven-amino acid motif within the sub-domain GC was important for the activity of amino acid activation. A conserved proline residue within the seven-amino acid motif was crucial, while the other six residues were moderately important for the amino acid activation activity. Thus, the last 15 residues of previously defined N-terminal extension of hcMetRS was a part of the catalytic domain; whereas the first 252 residues of hcMetRS constitute the N-terminal extended domain of hcMetRS. The formerly defined N-terminal extension of hcMetRS possesses two functions of two different domains.
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Affiliation(s)
- Ran He
- Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China
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22
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Zhou XL, Zhu B, Wang ED. The CP2 domain of leucyl-tRNA synthetase is crucial for amino acid activation and post-transfer editing. J Biol Chem 2008; 283:36608-16. [PMID: 18955487 DOI: 10.1074/jbc.m806745200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leucyl-tRNA synthetase (LeuRS) has an insertion domain, called connective peptide 2 (CP2), either directly preceding or following the editing domain (CP1 domain), depending on the species. The global structures of the CP2 domains from all LeuRSs are similar. Although the CP1 domain has been extensively explored to be responsible for hydrolysis of mischarged tRNALeu, the role of the CP2 domain remains undefined. In the present work, deletion of the CP2 domain of Giardia lamblia LeuRS (GlLeuRS) showed that the CP2 domain is indispensable for amino acid activation and post-transfer editing and that it contributes to LeuRS-tRNALeu binding affinity. In addition, its functions are conserved in both eukaryotic/archaeal and prokaryotic LeuRSs from G. lamblia, Pyrococcus horikoshii (PhLeuRS), and Escherichia coli (EcLeuRS). Alanine scanning and site-directed mutagenesis assays of the CP2 domain identified several residues that are crucial for its various functions. Data from the chimeric mutants, which replaced the CP2 domain of GlLeuRS with either PhLeuRS or EcLeuRS, showed that the CP2 domain of PhLeuRS but not that of EcLeuRS can partially restore amino acid activation and post-transfer editing functions, suggesting that the functions of the CP2 domain are dependent on its location in the primary sequence of LeuRS.
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Affiliation(s)
- Xiao-Long Zhou
- State Key Laboratory of Molecular Biology and Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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23
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Sun T, Zhang Y. Pentamidine binds to tRNA through non-specific hydrophobic interactions and inhibits aminoacylation and translation. Nucleic Acids Res 2008; 36:1654-64. [PMID: 18263620 PMCID: PMC2275129 DOI: 10.1093/nar/gkm1180] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The selective and potent inhibition of mitochondrial translation in Saccharomyces cerevisiae by pentamidine suggests a novel antimicrobial action for this drug. Electrophoresis mobility shift assay, T1 ribonuclease footprinting, hydroxyl radical footprinting and isothermal titration calorimetry collectively demonstrated that pentamidine non-specifically binds to two distinct classes of sites on tRNA. The binding was driven by favorable entropy changes indicative of a large hydrophobic interaction, suggesting that the aromatic rings of pentamidine are inserted into the stacked base pairs of tRNA helices. Pentamidine binding disrupts the tRNA secondary structure and masks the anticodon loop in the tertiary structure. Consistently, we showed that pentamidine specifically inhibits tRNA aminoacylation but not the cognate amino acid adenylation. Pentamidine inhibited protein translation in vitro with an EC(50) equivalent to that binds to tRNA and inhibits tRNA aminoacylation in vitro, but drastically higher than that inhibits translation in vivo, supporting the established notion that the antimicrobial activity of pentamidine is largely due to its selective accumulation by the pathogen rather than by the host cell. Therefore, interrupting tRNA aminoacylation by the entropy-driven non-specific binding is an important mechanism of pentamidine in inhibiting protein translation, providing new insights into the development of antimicrobial drugs.
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Affiliation(s)
- Tao Sun
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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24
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Ling C, Yao YN, Zheng YG, Wei H, Wang L, Wu XF, Wang ED. The C-terminal appended domain of human cytosolic leucyl-tRNA synthetase is indispensable in its interaction with arginyl-tRNA synthetase in the multi-tRNA synthetase complex. J Biol Chem 2005; 280:34755-63. [PMID: 16055448 DOI: 10.1074/jbc.m413511200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Human cytosolic leucyl-tRNA synthetase is one component of a macromolecular aminoacyl-tRNA synthetase complex. This is unlike prokaryotic and lower eukaryotic LeuRSs that exist as free soluble enzymes. There is little known about it, since the purified enzyme has been unavailable. Herein, human cytosolic leucyl-tRNA synthetase was heterologously expressed in a baculovirus system and purified to homogeneity. The molecular mass (135 kDa) of the enzyme is close to the theoretical value derived from its cDNA. The kinetic constants of the enzyme for ATP, leucine, and tRNA(Leu) in the ATP-PP(i) exchange and tRNA leucylation reactions were determined, and the results showed that it is quite active as a free enzyme. Human cytosolic leucyl-tRNA synthetase expressed in human 293 T cells localizes predominantly to the cytosol. Additionally, it is found to have a long C-terminal extension that is absent from bacterial and yeast LeuRSs. A C-terminal 89-amino acid truncated human cytosolic leucyl-tRNA synthetase was constructed and purified, and the catalytic activities, thermal stability, and subcellular location were found to be almost identical to native enzyme. In vivo and in vitro experiments, however, show that the C-terminal extension of human cytosolic leucyl-tRNA synthetase is indispensable for its interaction with the N-terminal of human cytosolic arginyl-tRNA synthetase in the macromolecular complex. Our results also indicate that the two molecules interact with each other only through their appended domains.
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Affiliation(s)
- Chen Ling
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200031
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25
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Yao YN, Wang L, Wu XF, Wang ED. Human mitochondrial leucyl-tRNA synthetase with high activity produced from Escherichia coli. Protein Expr Purif 2003; 30:112-6. [PMID: 12821328 DOI: 10.1016/s1046-5928(03)00097-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The processing of human mitochondrial leucyl-tRNA synthetase had been previously investigated in insect cell. In the present work, the gene encoding human mitochondrial leucyl-tRNA synthetase with the same N-terminus as that processed in the mitochondria of insect cell was cloned and expressed in Escherichia coli. The enzyme was purified by affinity chromatography on Ni-NTA column. About 6 mg of human mitochondrial leucyl-tRNA synthetase was obtained from 1 liter of culture. The specific activity of the purified enzyme is 127.7 units/mg, the highest activity of the reported results; this enzyme has the potential for characterizing the mitochondrial tRNA mutants associated with some human mitochondrion-related neuromuscular disorders. The kinetic constants for three substrates: leucine, ATP, and E. coli tRNA1Leu (CAG) in the leucylation reaction are also reported herein.
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Affiliation(s)
- Yong-Neng Yao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, PR China
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26
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Yao YN, Wang L, Wu XF, Wang ED. The processing of human mitochondrial leucyl-tRNA synthetase in the insect cells. FEBS Lett 2003; 534:139-42. [PMID: 12527375 DOI: 10.1016/s0014-5793(02)03833-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A His-tagged full-length cDNA of human mitochondrial leucyl-tRNA synthetase was expressed in a baculovirus system. The N-terminal sequence of the enzyme isolated from the mitochondria of insect cells was found to be IYSATGKWTKEYTL, indicating that the mitochondrial targeting signal peptide was cleaved between Ser39 and Ile40 after the enzyme precursor was translocated into mitochondria. The enzyme purified from mitochondria catalyzed the leucylation of Escherichia coli tRNA(1)(Leu)(CAG) and Aquifex aeolicus tRNA(Leu)(GAG) with higher catalytic activity in the leucylation of E. coli tRNA(Leu) than that previously expressed in E. coli without the N-terminal 21 residues.
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Affiliation(s)
- Yong Neng Yao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, PR China
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27
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Xu MG, Chen JF, Martin F, Zhao MW, Eriani G, Wang ED. Leucyl-tRNA synthetase consisting of two subunits from hyperthermophilic bacteria Aquifex aeolicus. J Biol Chem 2002; 277:41590-6. [PMID: 12196521 DOI: 10.1074/jbc.m205126200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In a hyperthermophilic bacterium, Aquifex aeolicus, leucyl-tRNA synthetase (LeuRS) consists of two non-identical polypeptide subunits (alpha and beta), different from the canonical LeuRS, which has a single polypeptide chain. By PCR, using genome DNA of A. aeolicus as a template, genes encoding the alpha and beta subunits were amplified and cloned in Escherichia coli. The alpha subunit could not be expressed stably in vivo, whereas the beta subunit was overproduced and purified by a simple procedure. The beta subunit was inactive in catalysis but was able to bind tRNA(Leu). Interestingly, the heterodimer alphabeta-LeuRS could be overproduced in E. coli cells containing both genes and was purified to 95% homogeneity as a hybrid dimer. The kinetics of A. aeolicus LeuRS in pre-steady and steady states and cross-recognition of LeuRS and tRNA(Leu) from A. aeolicus and E. coli were studied. Magnesium concentration, pH value, and temperature aminoacylation optima were determined to be 12 mm, 7.8, and 70 degrees C, respectively. Under optimal conditions, A. aeolicus alphabeta-LeuRS is stable up to 65 degrees C.
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Affiliation(s)
- Min-Gang Xu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
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28
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Du X, Wang ED. Discrimination of tRNA(Leu) isoacceptors by the mutants of Escherichia coli leucyl-tRNA synthetase in editing. Biochemistry 2002; 41:10623-8. [PMID: 12186547 DOI: 10.1021/bi026000o] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Leucyl-tRNA synthetase (LeuRS), one of the class Ia aminoacyl-tRNA synthetases, joins Leu to tRNA(Leu) and excludes noncognate amino acids in protein synthesis. In this study, Escherichia coli LeuRS mutants at amino acid E292, which was located in the connective polypeptide 1 insertion region, were synthesized. Although mutated LeuRS showed little change in structure compared with wild-type LeuRS, the mutants were impaired in activity to varying extents. It was also showed that mutations did not affect the adenylation reaction. However, mutated LeuRS can mischarge tRNA(Leu) isoacceptors tRN or tRN with isoleucine to different extents. Isoleucylation of tRN was more than that of tRN. The mutant LeuRS-E292S, which was picked out as an example for the investigation of the relationship between tRNA(Leu) isoacceptors and editing function, can discriminate the Watson-Crick base pair of the first base pair of tRNA(Leu) from the wobble base pair. The tRNA(Leu) with the Watson-Crick base pair may result in more isoleucylated product than that with the wobble base pair. The same phenomenon happened to another mutant, LeuRS-A293D. It seems that the flexibility of the first base pair affects the editing reaction of LeuRS. The results indicate that the flexibility of the first base pair of tRNA(Leu) may probably affect the mischarged 3'-end of tRNA(Leu) shuttling from synthetic site to editing site and that the transferred acceptor arm of tRNA(Leu) may interact with LeuRS in the region around E292.
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Affiliation(s)
- Xing Du
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China
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Gene cloning, expression and purification of human mitochondrial tRNALeu(UUR) and its mutant. ACTA ACUST UNITED AC 2001; 44:113-20. [DOI: 10.1007/bf02879315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2000] [Indexed: 10/22/2022]
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Li T, Li Y, Guo N, Wang E, Wang Y. Discrimination of tRNALeu isoacceptors by the insertion mutant of Escherichia coli leucyl-tRNA synthetase. Biochemistry 1999; 38:9084-8. [PMID: 10413482 DOI: 10.1021/bi9901984] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A variant (LeuRS-A) of Escherichia coli leucyl-tRNA synthetase (LeuRS) carrying a 40-residue duplication in its connective peptide 1 (CP1) has a 3-fold lower specificity for than for, whereas wild-type LeuRS has the same specificity for these two isoacceptors. The replacement of the acceptor stem of with yields a chimeric tRNA(Leu) for which wild-type LeuRS has the same specificity as it does for the two normal isoacceptors mentioned, but for which LeuRS-A has a reduced specificity similar to that for, indicating a difference between these two acceptor stems. LeuRS-A is slightly less stable than the native enzyme. Wild-type LeuRS and LeuRS-A have almost same K(d) value for their interaction with as determined by fluorescence quenching. No difference was detected between these two proteins by CD and fluorescence spectroscopy. These results show that LeuRS-A can discriminate between the two isoacceptors of tRNA(Leu).
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Affiliation(s)
- T Li
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, Chinese Academy of Sciences, China
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