1
|
Giegé R, Eriani G. The tRNA identity landscape for aminoacylation and beyond. Nucleic Acids Res 2023; 51:1528-1570. [PMID: 36744444 PMCID: PMC9976931 DOI: 10.1093/nar/gkad007] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 12/21/2022] [Accepted: 01/03/2023] [Indexed: 02/07/2023] Open
Abstract
tRNAs are key partners in ribosome-dependent protein synthesis. This process is highly dependent on the fidelity of tRNA aminoacylation by aminoacyl-tRNA synthetases and relies primarily on sets of identities within tRNA molecules composed of determinants and antideterminants preventing mischarging by non-cognate synthetases. Such identity sets were discovered in the tRNAs of a few model organisms, and their properties were generalized as universal identity rules. Since then, the panel of identity elements governing the accuracy of tRNA aminoacylation has expanded considerably, but the increasing number of reported functional idiosyncrasies has led to some confusion. In parallel, the description of other processes involving tRNAs, often well beyond aminoacylation, has progressed considerably, greatly expanding their interactome and uncovering multiple novel identities on the same tRNA molecule. This review highlights key findings on the mechanistics and evolution of tRNA and tRNA-like identities. In addition, new methods and their results for searching sets of multiple identities on a single tRNA are discussed. Taken together, this knowledge shows that a comprehensive understanding of the functional role of individual and collective nucleotide identity sets in tRNA molecules is needed for medical, biotechnological and other applications.
Collapse
Affiliation(s)
- Richard Giegé
- Correspondence may also be addressed to Richard Giegé.
| | | |
Collapse
|
2
|
Shimoyama Y, Ishikawa T, Kodama Y, Kimura S, Sasaki M. Tyrosine tRNA synthetase as a novel extracellular immunomodulatory protein in Streptococcus anginosus. FEMS Microbiol Lett 2020; 367:5905405. [PMID: 32926111 DOI: 10.1093/femsle/fnaa153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/11/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus anginosus is frequently detected in patients with infective endocarditis, abscesses or oral cancer. Although S. anginosus is considered the causative pathogen of these diseases, the pathogenic mechanisms of the bacterium have remained unclear. Previously, we suggested that an extracellular antigen from S. anginosus (SAA) serves as a pathogenic factor by inducing nitric oxide production in murine macrophages. In the present study, we identified SAA using LC-MS/MS and assessed the biological activities of His-tagged recombinant SAA in murine macrophages. SAA was identified as a tyrosine tRNA synthetase (SaTyrRS) that was isolated from the extracellular fraction of S. anginosus but not from other oral streptococci. In addition, inducible nitric oxide synthase and TNF-α mRNA expression was induced in recombinant SaTyrRS-stimulated murine macrophages. However, their mRNA expression was not induced in macrophages stimulated with truncated or heat-inactivated recombinant SaTyrRS, and the activation motif was identified as Arg264-Thr270. Consequently, these results indicated that SaTyrRS could be a novel and specific immunomodulatory protein in S. anginosus.
Collapse
Affiliation(s)
- Yu Shimoyama
- Division of Molecular Microbiology, Department of Microbiology, Iwate Medical University, 1-1-1 Idai-dori, Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan
| | - Taichi Ishikawa
- Division of Molecular Microbiology, Department of Microbiology, Iwate Medical University, 1-1-1 Idai-dori, Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan
| | - Yoshitoyo Kodama
- Division of Molecular Microbiology, Department of Microbiology, Iwate Medical University, 1-1-1 Idai-dori, Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan
| | - Shigenobu Kimura
- Department of Oral Hygiene, Kansai Women's College, Asahigaoka 3-11-1, Kashiwara, Osaka 582-0026, Japan
| | - Minoru Sasaki
- Division of Molecular Microbiology, Department of Microbiology, Iwate Medical University, 1-1-1 Idai-dori, Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan
| |
Collapse
|
3
|
Control of Food Spoilage Molds Using Lactobacillus Bacteriocins. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.3.39] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
4
|
Ferro I, Chelysheva I, Ignatova Z. Competition for amino acid flux among translation, growth and detoxification in bacteria. RNA Biol 2017; 15:991-994. [PMID: 28296576 DOI: 10.1080/15476286.2017.1306174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Transfer-tRNAs (tRNAs) are central entities for translation that deliver amino acids to the ribosome to translate genetic information in an mRNA-template dependent manner. Recent discoveries from our laboratory show that in E. coli and B. licheniformis, some tRNAs are poorly charged despite the plentiful intracellular cognate amino acid. Specifically, tRNAs carrying amino acids that exert toxicity and inhibit bacterial growth when added separately to the growth medium are poorly charged. Here, we discuss various evolutionary strategies different bacterial cells have adopted to precisely hone the competition between amino acid utilization for translation and proliferation and combat the inhibitory effect toward maximizing bacterial fitness. These data add a new twist to the amino acid flux models and to our understanding of the complex intimate link between dynamics of translation and bacterial growth.
Collapse
Affiliation(s)
- Iolanda Ferro
- a Institute of Biochemistry and Molecular Biology, University of Hamburg , Germany
| | - Irina Chelysheva
- a Institute of Biochemistry and Molecular Biology, University of Hamburg , Germany
| | - Zoya Ignatova
- a Institute of Biochemistry and Molecular Biology, University of Hamburg , Germany
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Fang ZP, Wang M, Ruan ZR, Tan M, Liu RJ, Zhou M, Zhou XL, Wang ED. Coexistence of bacterial leucyl-tRNA synthetases with archaeal tRNA binding domains that distinguish tRNA(Leu) in the archaeal mode. Nucleic Acids Res 2014; 42:5109-24. [PMID: 24500203 PMCID: PMC4005665 DOI: 10.1093/nar/gku108] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Leucyl-tRNA (transfer RNA) synthetase (LeuRS) is a multi-domain enzyme, which is divided into bacterial and archaeal/eukaryotic types. In general, one specific LeuRS, the domains of which are of the same type, exists in a single cell compartment. However, some species, such as the haloalkaliphile Natrialba magadii, encode two cytoplasmic LeuRSs, NmLeuRS1 and NmLeuRS2, which are the first examples of naturally occurring chimeric enzymes with different domains of bacterial and archaeal types. Furthermore, N. magadii encodes typical archaeal tRNALeus. The tRNA recognition mode, aminoacylation and translational quality control activities of these two LeuRSs are interesting questions to be addressed. Herein, active NmLeuRS1 and NmLeuRS2 were successfully purified after gene expression in Escherichia coli. Under the optimized aminoacylation conditions, we discovered that they distinguished cognate NmtRNALeu in the archaeal mode, whereas the N-terminal region was of the bacterial type. However, NmLeuRS1 exhibited much higher aminoacylation and editing activity than NmLeuRS2, suggesting that NmLeuRS1 is more likely to generate Leu-tRNALeu for protein biosynthesis. Moreover, using NmLeuRS1 as a model, we demonstrated misactivation of several non-cognate amino acids, and accuracy of protein synthesis was maintained mainly via post-transfer editing. This comprehensive study of the NmLeuRS/tRNALeu system provides a detailed understanding of the coevolution of aminoacyl-tRNA synthetases and tRNA.
Collapse
Affiliation(s)
- Zhi-Peng Fang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Abstract
Aminoacyl-tRNAsynthetases (aaRSs) are modular enzymesglobally 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 hugestructural plasticity related to function andlimited idiosyncrasies that are kingdom or even speciesspecific (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 betweendistant groups such as Gram-positive and Gram-negative Bacteria.Thereview 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 accumulatedin last two decades is reviewed,showing how thefield moved from essentially reductionist biologytowards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRSparalogs (e.g., during cellwall 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 pinpointedthroughout the reviewand distinctive characteristics of bacterium-like synthetases from organelles are outlined.
Collapse
|
8
|
Ancient origin of the divergent forms of leucyl-tRNA synthetases in the Halobacteriales. BMC Evol Biol 2012; 12:85. [PMID: 22694720 PMCID: PMC3436685 DOI: 10.1186/1471-2148-12-85] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 04/27/2012] [Indexed: 02/01/2023] Open
Abstract
Background Horizontal gene transfer (HGT) has greatly impacted the genealogical history of many lineages, particularly for prokaryotes, with genes frequently moving in and out of a line of descent. Many genes that were acquired by a lineage in the past likely originated from ancestral relatives that have since gone extinct. During the course of evolution, HGT has played an essential role in the origin and dissemination of genetic and metabolic novelty. Results Three divergent forms of leucyl-tRNA synthetase (LeuRS) exist in the archaeal order Halobacteriales, commonly known as haloarchaea. Few haloarchaeal genomes have the typical archaeal form of this enzyme and phylogenetic analysis indicates it clusters within the Euryarchaeota as expected. The majority of sequenced halobacterial genomes possess a bacterial form of LeuRS. Phylogenetic reconstruction puts this larger group of haloarchaea at the base of the bacterial domain. The most parsimonious explanation is that an ancient transfer of LeuRS took place from an organism related to the ancestor of the bacterial domain to the haloarchaea. The bacterial form of LeuRS further underwent gene duplications and/or gene transfers within the haloarchaea, with some genomes possessing two distinct types of bacterial LeuRS. The cognate tRNALeu also reveals two distinct clusters for the haloarchaea; however, these tRNALeu clusters do not coincide with the groupings found in the LeuRS tree, revealing that LeuRS evolved independently of its cognate tRNA. Conclusions The study of leucyl-tRNA synthetase in haloarchaea illustrates the importance of gene transfer originating in lineages that went extinct since the transfer occurred. The haloarchaeal LeuRS and tRNALeu did not co-evolve.
Collapse
|
9
|
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.
Collapse
|
10
|
Functional characterization of leucine-specific domain 1 from eukaryal and archaeal leucyl-tRNA synthetases. Biochem J 2010; 429:505-13. [PMID: 20482517 DOI: 10.1042/bj20100235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
LeuRS (leucyl-tRNA synthetase) catalyses the esterification of tRNAsLeu with leucine. This family of enzymes is divided into prokaryotic and eukaryal/archaeal groups according to the presence and position of specific insertions and extensions. In the present study, we investigated the function of LSD1 (leucine-specific domain 1), which is naturally present in eukaryal/archaeal LeuRSs, but absent from prokaryotic LeuRSs. When mutated in their common domain, the eukaryal and archaeal LeuRSs exhibited defects in the first reaction step of amino acid activation with variations of leucine or ATP-binding strength, whereas the tRNA aminoacylation was moderately affected. When the eukaryal extension was mutated, severe tRNA charging defects were observed, suggesting that eukaryotes evolved this LSD1 extension in order to improve the aminoacylation reaction step. The results also showed that the LSD1s from organisms of both groups are dispensable for post-transfer editing. Together, the data provide us with a further understanding of the organization and structure of LeuRS domains.
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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).
Collapse
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
| | | | | | | | | | | | | |
Collapse
|
13
|
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.
Collapse
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
| | | | | |
Collapse
|
14
|
Yao P, Zhou XL, He R, Xue MQ, Zheng YG, Wang YF, Wang ED. Unique residues crucial for optimal editing in yeast cytoplasmic Leucyl-tRNA synthetase are revealed by using a novel knockout yeast strain. J Biol Chem 2008; 283:22591-600. [PMID: 18550527 DOI: 10.1074/jbc.m801181200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leucyl-tRNA synthetase (LeuRS) contains an editing domain that discriminates leucine from noncognate amino acids to ensure translational fidelity. In this study, a knock-out strain for Saccharomyces cerevisiae LeuRS was constructed to analyze in vivo the tRNA aminoacylation properties of S. cerevisiae and human cytoplasmic LeuRSs. The activities of several editing-defective mutants of ycLeuRS were determined in vitro and compared with those obtained in vivo in a complementation assay performed in the knock-out strain. The editing activities of these mutants were analyzed in the presence of either norvaline, a leucine analogue, or AN2690, a specific inhibitor that targets the editing active site. In general, the in vivo data are consistent with those obtained in vitro. Our results show that ycLeuRS post-transfer editing plays a crucial role in the establishment of the aminoacylation fidelity. When impaired, the viability of cells bearing editing-defective mutants is drastically decreased in the presence of noncognate amino acid. This study also emphasizes the crucial function of some semi-conserved residues around the editing site in modulating the editing efficiency. The assay system can be used to test the effect of compounds that potentially target the aminoacylation or editing active site of fungal LeuRS.
Collapse
Affiliation(s)
- Peng Yao
- 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, Shanghai, China
| | | | | | | | | | | | | |
Collapse
|
15
|
Yao P, Zhu B, Jaeger S, Eriani G, Wang ED. Recognition of tRNALeu by Aquifex aeolicus leucyl-tRNA synthetase during the aminoacylation and editing steps. Nucleic Acids Res 2008; 36:2728-38. [PMID: 18367476 PMCID: PMC2377443 DOI: 10.1093/nar/gkn028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recognition of tRNA by the cognate aminoacyl-tRNA synthetase during translation is crucial to ensure the correct expression of the genetic code. To understand tRNA(Leu) recognition sets and their evolution, the recognition of tRNA(Leu) by the leucyl-tRNA synthetase (LeuRS) from the primitive hyperthermophilic bacterium Aquifex aeolicus was studied by RNA probing and mutagenesis. The results show that the base A73; the core structure of tRNA formed by the tertiary interactions U8-A14, G18-U55 and G19-C56; and the orientation of the variable arm are critical elements for tRNA(Leu) aminoacylation. Although dispensable for aminoacylation, the anticodon arm carries discrete editing determinants that are required for stabilizing the conformation of the post-transfer editing state and for promoting translocation of the tRNA acceptor arm from the synthetic to the editing site.
Collapse
Affiliation(s)
- Peng Yao
- 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, Shanghai, People's Republic of China
| | | | | | | | | |
Collapse
|
16
|
Zhu B, Zhao MW, Eriani G, Wang ED. A present-day aminoacyl-tRNA synthetase with ancestral editing properties. RNA (NEW YORK, N.Y.) 2007; 13:15-21. [PMID: 17095543 PMCID: PMC1705749 DOI: 10.1261/rna.228707] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 10/02/2006] [Indexed: 05/12/2023]
Abstract
Leucyl-, isoleucyl-, and valyl-tRNA synthetases form a subgroup of related aminoacyl-tRNA synthetases that attach similar amino acids to their cognate tRNAs. To prevent amino acid misincorporation during translation, these enzymes also hydrolyze mischarged tRNAs through a post-transfer editing mechanism. Here we show that LeuRS from the deep-branching bacterium Aquifex aeolicus edits the complete set of aminoacylated tRNAs generated by the three enzymes: Ile-tRNA(Ile), Val-tRNA(Ile), Val-tRNA(Val), Thr-tRNA(Val), and Ile-tRNA(Leu). This unusual enlarged editing property was studied in a model of a primitive editing system containing a composite minihelix carrying the triple leucine, isoleucine, and valine identity mimicking the primitive tRNA precursor. We found that the freestanding LeuRS editing domain can edit this precursor in contrast to IleRS and ValRS editing domains. These results suggest that A. aeolicus LeuRS carries editing properties that seem more primitive than those of IleRS and ValRS. They suggest that the A. aeolicus editing domain has preserved the ambiguous editing property from the ancestral common editing domain or, alternatively, that this plasticity results from a specific metabolic adaptation.
Collapse
Affiliation(s)
- Bin Zhu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, People's Republic of China
| | | | | | | |
Collapse
|
17
|
Olieric N, Bey G, Nierengarten H, Wang ED, Moras D, Eriani G, Cavarelli J. Expression, purification, and characterization of a new heterotetramer structure of leucyl-tRNA synthetase from Aquifex aeolicus in Escherichia coli. Protein Expr Purif 2005; 47:1-9. [PMID: 16256368 DOI: 10.1016/j.pep.2005.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 09/02/2005] [Accepted: 09/14/2005] [Indexed: 11/25/2022]
Abstract
Aminoacyl-tRNA synthetases are key players in the interpretation of the genetic code. They constitute a textbook example of multi-domain proteins including insertion and terminal functional modules appended to one of the two class-specific active site domains. The non-catalytic domains usually have distinct roles in the aminoacylation reaction. Aquifex aeolicus leucyl-tRNA synthetase (LeuRS) is composed of a separated catalytic site and tRNA anticodon-binding site, which would represent one of the closest relics of the primordial aminoacyl-tRNA synthetase. Moreover, the essential catalytic site residues are split into the two different subunits. In all other class-I aminoacyl-tRNA synthetases, those two functional polypeptides are nowadays fused into a single protein chain. In this work, we report the isolation and the characterization, in Escherichia coli, of a novel oligomeric form (alphabeta)2 for A. aeolicus LeuRS, which is present in addition to the alphabeta heterodimer. A. aeolicus (alphabeta)2 LeuRS has been characterized by biochemical and biophysical methods. Native gel electrophoresis, mass spectrometry, analytical ultracentrifugation, and kinetic analysis confirmed that the (alphabeta)2 enzyme was a stable and active entity. By mass spectrometry we confirmed that the heterodimer alphabeta can bind one tRNALeu molecule whereas the heterotetramer (alphabeta)2 can bind two tRNALeu molecules. Active site titration and aminoacylation assays showed that two functional active sites are found per heterotetramer, suggesting that this molecular species might exist and be active in vivo. All those data suggest that the existence of the heterotetramer is certainly not an artifact of overexpression in E. coli.
Collapse
Affiliation(s)
- Natacha Olieric
- Département de Biologie et Génomique Structurales, UMR7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur Strasbourg, 1 rue Laurent Fries 67404 Illkirch, France
| | | | | | | | | | | | | |
Collapse
|
18
|
Cura V, Olieric N, Guichard A, Wang ED, Moras D, Eriani G, Cavarelli J. Crystallization and preliminary X-ray crystallographic study of the wild type and two mutants of the CP1 hydrolytic domain from Aquifex aeolicus leucyl-tRNA synthetase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:899-901. [PMID: 16511190 PMCID: PMC1991315 DOI: 10.1107/s1744309105028460] [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: 07/21/2005] [Accepted: 09/09/2005] [Indexed: 11/10/2022]
Abstract
The editing or hydrolytic CP1 domain of leucyl-tRNA synthetase (LeuRS) hydrolyses several misactivated amino acids. The CP1 domain of Aquifex aeolicus LeuRS was expressed, purified and crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as precipitant. Crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 38.8, b = 98.4, c = 116.7 A. Crystals diffract to beyond 1.8 A resolution and contain two monomers in the asymmetric unit. Two CP1 mutants in which a conserved threonine residue essential for the fidelity of the hydrolytic pathway is mutated to alanine or glutamic acid have also been expressed and crystallized. Crystals of the two CP1 mutants are isomorphs of the wild type and diffract to beyond 1.9 A resolution. All structures were solved by molecular-replacement techniques.
Collapse
Affiliation(s)
- Vincent Cura
- Département de Biologie et Génomique Structurales, UMR 7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Natacha Olieric
- Département de Biologie et Génomique Structurales, UMR 7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Alexandre Guichard
- Département de Biologie et Génomique Structurales, UMR 7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People’s Republic of China
| | - Dino Moras
- Département de Biologie et Génomique Structurales, UMR 7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Gilbert Eriani
- Architecture et Réactivité de l’ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 Rue René Descartes, 67084 Strasbourg, France
| | - Jean Cavarelli
- Département de Biologie et Génomique Structurales, UMR 7104, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
| |
Collapse
|
19
|
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.
Collapse
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
| | | | | | | | | | | | | |
Collapse
|
20
|
Hao R, Zhao MW, Hao ZX, Yao YN, Wang ED. A T-stem slip in human mitochondrial tRNALeu(CUN) governs its charging capacity. Nucleic Acids Res 2005; 33:3606-13. [PMID: 15972857 PMCID: PMC1157101 DOI: 10.1093/nar/gki677] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The human mitochondrial tRNALeu(CUN) [hmtRNALeu(CUN)] corresponds to the most abundant codon for leucine in human mitochondrial protein genes. Here, in vitro studies reveal that the U48C substitution in hmtRNALeu(CUN), which corresponds to the pathological T12311C gene mutation, improved the aminoacylation efficiency of hmtRNALeu(CUN). Enzymatic probing suggested a more flexible secondary structure in the wild-type hmtRNALeu(CUN) transcript compared with the U48C mutant. Structural analysis revealed that the flexibility of hmtRNALeu(CUN) facilitates a T-stem slip resulting in two potential tertiary structures. Several rationally designed tRNALeu(CUN) mutants were generated to examine the structural and functional consequences of the T-stem slip. Examination of these hmtRNALeu(CUN) mutants indicated that the T-stem slip governs tRNA accepting activity. These results suggest a novel, self-regulation mechanism of tRNA structure and function.
Collapse
Affiliation(s)
- Rui Hao
- Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Ming-Wei Zhao
- Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Zhan-Xi Hao
- Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | | | - En-Duo Wang
- Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences320 Yue Yang Road, Shanghai 200031, People's Republic of China
- To whom correspondence should be addressed. Tel: +86 21 54921241; Fax: +86 21 54921011;
| |
Collapse
|
21
|
Zhao MW, Zhu B, Hao R, Xu MG, Eriani G, Wang ED. Leucyl-tRNA synthetase from the ancestral bacterium Aquifex aeolicus contains relics of synthetase evolution. EMBO J 2005; 24:1430-9. [PMID: 15775966 PMCID: PMC1142543 DOI: 10.1038/sj.emboj.7600618] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Accepted: 02/15/2005] [Indexed: 11/10/2022] Open
Abstract
The editing reactions catalyzed by aminoacyl-tRNA synthetases are critical for the faithful protein synthesis by correcting misactivated amino acids and misaminoacylated tRNAs. We report that the isolated editing domain of leucyl-tRNA synthetase from the deep-rooted bacterium Aquifex aeolicus (alphabeta-LeuRS) catalyzes the hydrolytic editing of both mischarged tRNA(Leu) and minihelix(Leu). Within the domain, we have identified a crucial 20-amino-acid peptide that confers editing capacity when transplanted into the inactive Escherichia coli LeuRS editing domain. Likewise, fusion of the beta-subunit of alphabeta-LeuRS to the E. coli editing domain activates its editing function. These results suggest that alphabeta-LeuRS still carries the basic features from a primitive synthetase molecule. It has a remarkable capacity to transfer autonomous active modules, which is consistent with the idea that modern synthetases arose after exchange of small idiosyncratic domains. It also has a unique alphabeta-heterodimeric structure with separated catalytic and tRNA-binding sites. Such an organization supports the tRNA/synthetase coevolution theory that predicts sequential addition of tRNA and synthetase domains.
Collapse
Affiliation(s)
- Ming-Wei Zhao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
| | - Bin Zhu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
| | - Rui Hao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
| | - Min-Gang Xu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
| | - Gilbert Eriani
- UPR9002, IBMC du CNRS and Université Louis Pasteur, Strasbourg, France
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, 320 Yeu Yang Road, Shanghai 200031, China. Tel.: +86 21 549 21241; Fax: +86 21 549 21011; E-mail:
| |
Collapse
|
22
|
Korencic D, Ahel I, Schelert J, Sacher M, Ruan B, Stathopoulos C, Blum P, Ibba M, Söll D. A freestanding proofreading domain is required for protein synthesis quality control in Archaea. Proc Natl Acad Sci U S A 2004; 101:10260-5. [PMID: 15240874 PMCID: PMC478561 DOI: 10.1073/pnas.0403926101] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Threonyl-tRNA synthetase (ThrRS) participates in protein synthesis quality control by selectively editing the misacylated species Ser-tRNA(Thr). In bacteria and eukaryotes the editing function of ThrRS resides in a highly conserved N-terminal domain distant from the active site. Most archaeal ThrRS proteins are devoid of this editing domain, suggesting evolutionary divergence of quality-control mechanisms. Here we show that archaeal editing of Ser-tRNAThr is catalyzed by a domain unrelated to, and absent from, bacterial and eukaryotic ThrRSs. Despite the lack of sequence homology, the archaeal and bacterial editing domains are both reliant on a pair of essential histidine residues suggestive of a common catalytic mechanism. Whereas the archaeal editing module is most commonly part of full-length ThrRS, several crenarchaeal species contain individual genes encoding the catalytic (ThrRS-cat) and editing domains (ThrRS-ed). Sulfolobus solfataricus ThrRS-cat was shown to synthesize both Thr-tRNAThr and Ser-tRNAThr and to lack editing activity against Ser-tRNAThr. In contrast, ThrRS-ed lacks aminoacylation activity but can act as an autonomous protein in trans to hydrolyze specifically Ser-tRNAThr, or it can be fused to ThrRS-cat to provide the same function in cis. Deletion analyses indicate that ThrRS-ed is dispensable for growth of S. solfataricus under standard conditions but is required for normal growth in media with elevated serine levels. The growth phenotype of the ThrRS-ed deletion strain suggests that retention of the discontinuous ThrRS quaternary structure relates to specific physiological requirements still evident in certain Archaea.
Collapse
Affiliation(s)
- Dragana Korencic
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Zheng YG, Wei H, Ling C, Martin F, Eriani G, Wang ED. Two distinct domains of the beta subunit of Aquifex aeolicus leucyl-tRNA synthetase are involved in tRNA binding as revealed by a three-hybrid selection. Nucleic Acids Res 2004; 32:3294-303. [PMID: 15208367 PMCID: PMC443541 DOI: 10.1093/nar/gkh665] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Aquifex aeolicus alphabeta-LeuRS is the only known heterodimeric class Ia aminoacyl-tRNA synthetase. In this study, we investigated the function of the beta subunit which is believed to bind tRNA(Leu). A yeast three-hybrid system was constructed on the basis of the interaction of the beta subunit with its cognate tRNA(Leu). Then, seven mutated beta subunits exhibiting impaired tRNA binding capacities were selected out from a randomly mutated library. Two mutations were identified in the class Ia-helix-bundle-domain, which might interact with the D-hairpin of the tRNA analogous to other class Ia tRNA:synthetases complexes. The five other mutations were found in the LeuRS-specific C-terminal domain of which the folding is still unknown. tRNA affinity measurements and kinetic analyses performed on the isolated beta subunits and on the co-expressed alphabeta-heterodimers showed for all the mutants an effect in tRNA affinity in the ground state. In addition, an effect on the transition state of the aminoacylation reaction was observed for a 21-residues deletion mutant of the C-terminal end. These results show that the genetic approach of the three hybrid system is widely applicable and is a powerful tool for the investigation of tRNA:synthetase interactions.
Collapse
Affiliation(s)
- Yong-Gang Zheng
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | | | | | | | | | | |
Collapse
|
24
|
Ling C, Zheng YG, Wang ED. High-level expression and single-step purification of leucyl-tRNA synthetase from Aquifex aeolicus. Protein Expr Purif 2004; 36:146-9. [PMID: 15177296 DOI: 10.1016/j.pep.2004.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Revised: 04/01/2004] [Indexed: 11/25/2022]
Abstract
Aquifex aeolicus leucyl-tRNA synthetase is the only known heterodimeric LeuRS, consisting of two subunits with molecular masses of 74.0 and 33.5 kDa, and named alphabeta-LeuRS. The gene encoding alpha subunit was cloned into pSBET-b vector. Synthetic oligonucleotide encoding six histidine residues was also inserted in front of alpha subunit. PSBET-b vector contains argU gene, which encodes a rare Escherichia coli tRNA(Arg)(AGA/AGG). The argU gene helps A. aeolicus LeuRS, which contains AGA/AGG codons in exceptionally high frequency, express well in E. coli. The gene encoding beta subunit was inserted into pET-15b vector. E. coli BL21-CodonPlus (DE3) cells were transformed with the two recombinant plasmids to produce alphabeta-LeuRS with a His6 tag at the N-terminus of alpha subunit. The enzyme was purified by affinity chromatography on Ni-NTA Superflow. About 7 mg purified alphabeta-LeuRS was obtained from 250 ml culture. The His6-tag at the N-terminus did not affect the aminoacylation activity of the enzyme.
Collapse
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, 320 Yue Yang Road, 200031, PR China
| | | | | |
Collapse
|
25
|
Xu MG, Zhao MW, Wang ED. Leucyl-tRNA synthetase from the hyperthermophilic bacterium Aquifex aeolicus recognizes minihelices. J Biol Chem 2004; 279:32151-8. [PMID: 15161932 DOI: 10.1074/jbc.m403018200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aminoacylation of the minihelix mimicking the amino acid acceptor arm of tRNA has been demonstrated in more than 10 aminoacyl-tRNA synthetase systems. Although Escherichia coli or Homo sapiens cytoplasmic leucyl-tRNA synthetase (LeuRS) is unable to charge the cognate minihelix or microhelix, we show here that minihelix(Leu) is efficiently charged by Aquifex aeolicus synthetase, the only known heterodimeric LeuRS (alpha beta-LeuRS). Aminoacylation of minihelices is strongly dependent on the presence of the A73 identity nucleotide and greatly stimulated by destabilization of the first base pair as reported for the E. coli isoleucyl-tRNA synthetase and methionyl-tRNA synthetase systems. In the E. coli LeuRS system, the anticodon of tRNA(Leu) is not important for recognition by the synthetase. However, the addition of RNA helices that mimic the anticodon domain stimulates minihelix(Leu) charging by alpha beta-LeuRS, indicating possible domain-domain communication within alpha beta-LeuRS. The leucine-specific domain of alpha beta-LeuRS is responsible for minihelix recognition. To ensure accurate translation of the genetic code, LeuRS functions to hydrolyze misactivated amino acids (pretransfer editing) and misaminoacylated tRNA (posttransfer editing). In contrast to tRNA(Leu), minihelix(Leu) is unable to induce posttransfer editing even upon the addition of the anticodon domain of tRNA. Therefore, the context of tRNA is crucial for the editing of mischarged products. However, the minihelix(Leu) cannot be misaminoacylated, perhaps because of the tRNA-independent pretransfer editing activity of alpha beta-LeuRS.
Collapse
Affiliation(s)
- Min-Gang Xu
- 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
| | | | | |
Collapse
|
26
|
Li J, Yao YN, Liu MF, Wang ED. Arginyl-tRNA synthetase with signature sequence KMSK from Bacillus stearothermophilus. Biochem J 2004; 376:773-9. [PMID: 13678419 PMCID: PMC1223815 DOI: 10.1042/bj20030957] [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] [Received: 06/26/2003] [Revised: 08/28/2003] [Accepted: 09/15/2003] [Indexed: 11/17/2022]
Abstract
ArgRS (arginyl-tRNA synthetase) belongs to the class I aaRSs (aminoacyl-tRNA synthetases), though the majority of ArgRS species lack the canonical KMSK sequence characteristic of class I aaRSs. A DNA fragment of the ArgRS gene from Bacillus stearothermophilus was amplified using primers designed according to the conserved regions of known ArgRSs. Through analysis of the amplified DNA sequence and known tRNA(Arg)s with a published genomic sequence of B. stearothermophilus, the gene encoding ArgRS ( argS ') was amplified by PCR and the gene encoding tRNA(Arg) (ACG) was synthesized. ArgRS contained 557 amino acid residues including the canonical KMKS sequence. Recombinant ArgRS and tRNA(Arg) (ACG) were expressed in Escherichia coli. ArgRS purified by nickel-affinity chromatography had no ATPase activity. The kinetics of ArgRS and cross-recognition between ArgRSs and tRNA(Arg)s from B. stearothermophilus and E. coli were studied. The activities of B. stearothermophilus ArgRS mutated at Lys(382) and Lys(385) of the KMSK sequence and at Gly(136) upstream of the HIGH loop were determined. From the mutation results, we concluded that there was mutual compensation of Lys(385) and Gly(136) for the amino acid-activation activity of B. stearothermophilus ArgRS.
Collapse
Affiliation(s)
- Juan Li
- 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, People's Republic of China
| | | | | | | |
Collapse
|
27
|
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.
Collapse
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
| | | | | | | |
Collapse
|