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Onoguchi M, Otsuka R, Koyama M, Ando T, Mutsuro-Aoki H, Umehara T, Tamura K. Elucidation of productive alanine recognition mechanism by Escherichia coli alanyl-tRNA synthetase. Biosystems 2024; 237:105152. [PMID: 38346553 DOI: 10.1016/j.biosystems.2024.105152] [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: 01/09/2024] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/22/2024]
Abstract
Alanyl-tRNA synthetase (AlaRS) incorrectly recognizes both a slightly smaller glycine and a slightly larger serine in addition to alanine, and the probability of incorrect identification is extremely low at 1/300 and 1/170, respectively. Alanine is the second smallest amino acid after glycine; however, the mechanism by which AlaRS specifically identifies small differences in side chains with high accuracy remains unknown. In this study, using a malachite green assay, we aimed to elucidate the alanine recognition mechanism of a fragment (AlaRS368N) containing only the amino acid activation domain of Escherichia coli AlaRS. This method quantifies monophosphate by decomposing pyrophosphate generated during aminoacyl-AMP production. AlaRS368N produced far more pyrophosphate when glycine or serine was used as a substrate than when alanine was used. Among several mutants tested, an AlaRS mutant in which the widely conserved aspartic acid at the 235th position (D235) near the active center was replaced with glutamic acid (D235E) increased pyrophosphate release for the alanine substrate, compared to that from glycine and serine. These results suggested that D235 is optimal for AlaRS to specifically recognize alanine. Alanylation activities of an RNA minihelix by the mutants of valine at the 214th position (V214) of another fragment (AlaRS442N), which is the smallest AlaRS with alanine charging activity, suggest the existence of the van der Waals-like interaction between the side chain of V214 and the methyl group of the alanine substrate.
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Affiliation(s)
- Mayu Onoguchi
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Riku Otsuka
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Miki Koyama
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Tadashi Ando
- Department of Applied Electronics, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Hiromi Mutsuro-Aoki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Takuya Umehara
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Koji Tamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
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2
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Antika TR, Nazilah KR, Chrestella DJ, Wang TL, Tseng YK, Wang SC, Hsu HL, Wang SW, Chuang TH, Pan HC, Horng JC, Wang CC. Sequence-specific targeting of Caenorhabditis elegans C-Ala to the D-loop of tRNA Ala. J Biol Chem 2023; 299:105149. [PMID: 37567477 PMCID: PMC10485164 DOI: 10.1016/j.jbc.2023.105149] [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: 03/13/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023] Open
Abstract
Alanyl-tRNA synthetase retains a conserved prototype structure throughout its biology. Nevertheless, its C-terminal domain (C-Ala) is highly diverged and has been shown to play a role in either tRNA or DNA binding. Interestingly, we discovered that Caenorhabditis elegans cytoplasmic C-Ala (Ce-C-Alac) robustly binds both ligands. How Ce-C-Alac targets its cognate tRNA and whether a similar feature is conserved in its mitochondrial counterpart remain elusive. We show that the N- and C-terminal subdomains of Ce-C-Alac are responsible for DNA and tRNA binding, respectively. Ce-C-Alac specifically recognized the conserved invariant base G18 in the D-loop of tRNAAla through a highly conserved lysine residue, K934. Despite bearing little resemblance to other C-Ala domains, C. elegans mitochondrial C-Ala robustly bound both tRNAAla and DNA and maintained targeting specificity for the D-loop of its cognate tRNA. This study uncovers the underlying mechanism of how C. elegans C-Ala specifically targets the D-loop of tRNAAla.
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Affiliation(s)
- Titi Rindi Antika
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | | | | | - Tzu-Ling Wang
- Graduate Institute of Mathematics and Science Education, National Tsing Hua University, Hsinchu City, Taiwan
| | - Yi-Kuan Tseng
- Graduate Institute of Statistics, National Central University, Taoyuan, Taiwan
| | - Sun-Chong Wang
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan
| | - Hsin-Ling Hsu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Shao-Win Wang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Tsung-Hsien Chuang
- Immunology Research Center, National Health Research Institutes, Miaoli, Taiwan
| | - Hung-Chuan Pan
- Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Jia-Cherng Horng
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Chien-Chia Wang
- Department of Life Sciences, National Central University, Taoyuan, Taiwan.
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3
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Antika TR, Chrestella DJ, Tseng YK, Yeh YH, Hsiao CD, Wang CC. A naturally occurring mini-alanyl-tRNA synthetase. Commun Biol 2023; 6:314. [PMID: 36959394 PMCID: PMC10036535 DOI: 10.1038/s42003-023-04699-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/13/2023] [Indexed: 03/25/2023] Open
Abstract
Alanyl-tRNA synthetase (AlaRS) retains a conserved prototype structure throughout its biology, consisting of catalytic, tRNA-recognition, editing, and C-Ala domains. The catalytic and tRNA-recognition domains catalyze aminoacylation, the editing domain hydrolyzes mischarged tRNAAla, and C-Ala-the major tRNA-binding module-targets the elbow of the L-shaped tRNAAla. Interestingly, a mini-AlaRS lacking the editing and C-Ala domains is recovered from the Tupanvirus of the amoeba Acanthamoeba castellanii. Here we show that Tupanvirus AlaRS (TuAlaRS) is phylogenetically related to its host's AlaRS. Despite lacking the conserved amino acid residues responsible for recognition of the identity element of tRNAAla (G3:U70), TuAlaRS still specifically recognized G3:U70-containing tRNAAla. In addition, despite lacking C-Ala, TuAlaRS robustly binds and charges microAla (an RNA substrate corresponding to the acceptor stem of tRNAAla) as well as tRNAAla, indicating that TuAlaRS exclusively targets the acceptor stem. Moreover, this mini-AlaRS could functionally substitute for yeast AlaRS in vivo. This study suggests that TuAlaRS has developed a new tRNA-binding mode to compensate for the loss of C-Ala.
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Affiliation(s)
- Titi Rindi Antika
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan, 320317, Taiwan
| | - Dea Jolie Chrestella
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan, 320317, Taiwan
| | - Yi-Kuan Tseng
- Graduate Institute of Statistics, National Central University, Zhongli District, Taoyuan, 320317, Taiwan
| | - Yi-Hung Yeh
- Institute of Molecular Biology, Academia Sinica, Nankang District, Taipei, 11529, Taiwan
| | - Chwan-Deng Hsiao
- Institute of Molecular Biology, Academia Sinica, Nankang District, Taipei, 11529, Taiwan
| | - Chien-Chia Wang
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan, 320317, Taiwan.
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4
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Kavoor A, Kelly P, Ibba M. Escherichia coli alanyl-tRNA synthetase maintains proofreading activity and translational accuracy under oxidative stress. J Biol Chem 2022; 298:101601. [PMID: 35065077 PMCID: PMC8857464 DOI: 10.1016/j.jbc.2022.101601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are enzymes that synthesize aminoacyl-tRNAs to facilitate translation of the genetic code. Quality control by aaRS proofreading and other mechanisms maintains translational accuracy, which promotes cellular viability. Systematic disruption of proofreading, as recently demonstrated for alanyl-tRNA synthetase (AlaRS), leads to dysregulation of the proteome and reduced viability. Recent studies showed that environmental challenges such as exposure to reactive oxygen species can also alter aaRS synthetic and proofreading functions, prompting us to investigate if oxidation might positively or negatively affect AlaRS activity. We found that while oxidation leads to modification of several residues in Escherichia coli AlaRS, unlike in other aaRSs, this does not affect proofreading activity against the noncognate substrates serine and glycine and only results in a 1.6-fold decrease in efficiency of cognate Ala-tRNAAla formation. Mass spectrometry analysis of oxidized AlaRS revealed that the critical proofreading residue in the editing site, Cys666, and three methionine residues (M217 in the active site, M658 in the editing site, and M785 in the C-Ala domain) were modified to cysteine sulfenic acid and methionine sulfoxide, respectively. Alanine scanning mutagenesis showed that none of the identified residues were solely responsible for the change in cognate tRNAAla aminoacylation observed under oxidative stress, suggesting that these residues may act as reactive oxygen species “sinks” to protect catalytically critical sites from oxidative damage. Combined, our results indicate that E. coli AlaRS proofreading is resistant to oxidative damage, providing an important mechanism of stress resistance that helps to maintain proteome integrity and cellular viability.
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Affiliation(s)
- Arundhati Kavoor
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, USA
| | - Paul Kelly
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, USA
| | - Michael Ibba
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA; Schmid College of Science and Technology, Chapman University, Orange, California, USA.
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5
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Antika TR, Chrestella DJ, Ivanesthi IR, Rida G, Chen KY, Liu FG, Lee YC, Chen YW, Tseng YK, Wang CC. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2190-2200. [PMID: 35100402 PMCID: PMC8887476 DOI: 10.1093/nar/gkac026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/14/2021] [Accepted: 01/11/2022] [Indexed: 11/14/2022] Open
Abstract
Unlike many other aminoacyl-tRNA synthetases, alanyl-tRNA synthetase (AlaRS) retains a conserved prototype structure throughout biology. While Caenorhabditis elegans cytoplasmic AlaRS (CeAlaRSc) retains the prototype structure, its mitochondrial counterpart (CeAlaRSm) contains only a residual C-terminal domain (C-Ala). We demonstrated herein that the C-Ala domain from CeAlaRSc robustly binds both tRNA and DNA. It bound different tRNAs but preferred tRNAAla. Deletion of this domain from CeAlaRSc sharply reduced its aminoacylation activity, while fusion of this domain to CeAlaRSm selectively and distinctly enhanced its aminoacylation activity toward the elbow-containing (or L-shaped) tRNAAla. Phylogenetic analysis showed that CeAlaRSm once possessed the C-Ala domain but later lost most of it during evolution, perhaps in response to the deletion of the T-arm (part of the elbow) from its cognate tRNA. This study underscores the evolutionary gain of C-Ala for docking AlaRS to the L-shaped tRNAAla.
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Affiliation(s)
- Titi Rindi Antika
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Dea Jolie Chrestella
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Indira Rizqita Ivanesthi
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Gita Riswana Nawung Rida
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Kuan-Yu Chen
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Fu-Guo Liu
- Department of Life Sciences, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Beitou District, Taipei 11217, Taiwan
| | - Yu-Wei Chen
- Department of Neurology, Landseed International Hospital, Pingzhen District, Taoyuan 32449, Taiwan
| | - Yi-Kuan Tseng
- Graduate Institute of Statistics, National Central University, Zhongli District, Taoyuan 32001, Taiwan
| | - Chien-Chia Wang
- To whom correspondence should be addressed. Tel: +886 3 426 0840; Fax: +886 3 422 8482;
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6
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Aggarwal SD, Lloyd AJ, Yerneni SS, Narciso AR, Shepherd J, Roper DI, Dowson CG, Filipe SR, Hiller NL. A molecular link between cell wall biosynthesis, translation fidelity, and stringent response in Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2021; 118:e2018089118. [PMID: 33785594 PMCID: PMC8040666 DOI: 10.1073/pnas.2018089118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Survival in the human host requires bacteria to respond to unfavorable conditions. In the important Gram-positive pathogen Streptococcus pneumoniae, cell wall biosynthesis proteins MurM and MurN are tRNA-dependent amino acyl transferases which lead to the production of branched muropeptides. We demonstrate that wild-type cells experience optimal growth under mildly acidic stressed conditions, but ΔmurMN strain displays growth arrest and extensive lysis. Furthermore, these stress conditions compromise the efficiency with which alanyl-tRNAAla synthetase can avoid noncognate mischarging of tRNAAla with serine, which is toxic to cells. The observed growth defects are rescued by inhibition of the stringent response pathway or by overexpression of the editing domain of alanyl-tRNAAla synthetase that enables detoxification of tRNA misacylation. Furthermore, MurM can incorporate seryl groups from mischarged Seryl-tRNAAlaUGC into cell wall precursors with exquisite specificity. We conclude that MurM contributes to the fidelity of translation control and modulates the stress response by decreasing the pool of mischarged tRNAs. Finally, we show that enhanced lysis of ΔmurMN pneumococci is caused by LytA, and the murMN operon influences macrophage phagocytosis in a LytA-dependent manner. Thus, MurMN attenuates stress responses with consequences for host-pathogen interactions. Our data suggest a causal link between misaminoacylated tRNA accumulation and activation of the stringent response. In order to prevent potential corruption of translation, consumption of seryl-tRNAAla by MurM may represent a first line of defense. When this mechanism is overwhelmed or absent (ΔmurMN), the stringent response shuts down translation to avoid toxic generation of mistranslated/misfolded proteins.
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Affiliation(s)
- Surya D Aggarwal
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adrian J Lloyd
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom;
| | | | - Ana Rita Narciso
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 1099-085 Oeiras, Portugal
- Unidade de Ciências Biomoleculares Aplicadas (UCIBIO), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal
| | - Jennifer Shepherd
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - David I Roper
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Christopher G Dowson
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sergio R Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 1099-085 Oeiras, Portugal;
- Unidade de Ciências Biomoleculares Aplicadas (UCIBIO), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213;
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Vasu K, Ramachandiran I, Terenzi F, Khan D, China A, Khan K, Chechi A, Baleanu-Gogonea C, Gogonea V, Fox PL. The zinc-binding domain of mammalian prolyl-tRNA synthetase is indispensable for catalytic activity and organism viability. iScience 2021; 24:102215. [PMID: 33748704 PMCID: PMC7960942 DOI: 10.1016/j.isci.2021.102215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/26/2021] [Accepted: 02/17/2021] [Indexed: 01/10/2023] Open
Abstract
Aminoacyl-tRNA synthetases (AARS) participate in decoding the genome by catalyzing conjugation of amino acids to their cognate tRNAs. During evolution, biochemical and environmental conditions markedly influenced the sequence and structure of the 20 AARSs, revealing adaptations dictating canonical and orthogonal activities. Here, we investigate the function of the appended Zn2+-binding domain (ZBD) in the bifunctional AARS, glutamyl-prolyl-tRNA synthetase (GluProRS). We developed GluProRS mutant mice by CRISPR-Cas9 with a deletion of 29 C-terminal amino acids, including two of four Zn2+-coordinating cysteines. Homozygous ZBD mutant mice die before embryonic day 12.5, but heterozygous mice are healthy. ZBD disruption profoundly reduces GluProRS canonical function by dual mechanisms: it induces rapid proteasomal degradation of the protein and inhibits ProRS aminoacylation activity, likely by sub-optimal positioning of ATP in the spatially adjacent catalytic domain. Collectively, our studies reveal the ZBD as a critical determinant of ProRS activity and GluProRS stability in vitro and in vivo. Conserved zinc-binding domain (ZBD) of GluProRS is required for Pro-tRNA charging ZBD stabilizes GluProRS and positions C-terminal carboxylate in the catalytic site Embryonic lethality in mice with defective GluProRS ZBD reveals in vivo essentiality Locked nucleic acid qPCR assay for CRISPR-mediated screening of chimeric mutant mice
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Affiliation(s)
- Kommireddy Vasu
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Iyappan Ramachandiran
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Fulvia Terenzi
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Debjit Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Arnab China
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Aayushi Chechi
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | | | - Valentin Gogonea
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.,Department of Chemistry, Cleveland State University, Cleveland, OH, USA
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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8
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Pang L, Weeks SD, Van Aerschot A. Aminoacyl-tRNA Synthetases as Valuable Targets for Antimicrobial Drug Discovery. Int J Mol Sci 2021; 22:1750. [PMID: 33578647 PMCID: PMC7916415 DOI: 10.3390/ijms22041750] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/20/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) catalyze the esterification of tRNA with a cognate amino acid and are essential enzymes in all three kingdoms of life. Due to their important role in the translation of the genetic code, aaRSs have been recognized as suitable targets for the development of small molecule anti-infectives. In this review, following a concise discussion of aaRS catalytic and proof-reading activities, the various inhibitory mechanisms of reported natural and synthetic aaRS inhibitors are discussed. Using the expanding repository of ligand-bound X-ray crystal structures, we classified these compounds based on their binding sites, focusing on their ability to compete with the association of one, or more of the canonical aaRS substrates. In parallel, we examined the determinants of species-selectivity and discuss potential resistance mechanisms of some of the inhibitor classes. Combined, this structural perspective highlights the opportunities for further exploration of the aaRS enzyme family as antimicrobial targets.
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Affiliation(s)
- Luping Pang
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
- KU Leuven, Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Herestraat 49–box 822, 3000 Leuven, Belgium
| | | | - Arthur Van Aerschot
- KU Leuven, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49–box 1041, 3000 Leuven, Belgium;
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9
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Abstract
Among the 20 cytoplasmic aminoacyl-tRNA synthetases (aaRSs), alanyl-tRNA synthetase (AlaRS) has unique features. AlaRS is the only aaRS that exclusively recognizes a single G3:U70 wobble base pair in the acceptor stem of tRNA, which serves as the identity element for both the synthetic and the proofreading activities of the synthetase. The recognition is relaxed during evolution and eukaryotic AlaRS can mis-aminoacylate noncognate tRNAs with a G4:U69 base pair seemingly as a deliberate gain of function for unknown reasons. Unlike other class II aaRSs, dimerization of AlaRS is not necessarily required for aminoacylation possibly due to functional compensations from the C-terminal domain (C-Ala). In contrast to other 19 cytoplasmic aaRSs that append additional domains or motifs to acquire new functions during evolution, the functional expansion of AlaRS is likely achieved through transformations of the existing C-Ala. Given both essential canonical and diverse non-canonical roles of AlaRS, dysfunction of AlaRS leads to neurodegenerative disorders in human and various pathological phenotypes in mouse models. In this review, the uniqueness of AlaRS in both physiological and pathological events is systematically discussed, with a particular focus on its novel functions gained in evolution.
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Affiliation(s)
- Han Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, Yunnan, China
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Litao Sun
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangdong, China
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10
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Kuo ME, Antonellis A, Shakkottai VG. Alanyl-tRNA Synthetase 2 (AARS2)-Related Ataxia Without Leukoencephalopathy. THE CEREBELLUM 2020; 19:154-160. [PMID: 31705293 DOI: 10.1007/s12311-019-01080-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mutations in the mitochondrial alanyl-tRNA synthetase gene, AARS2, have been reported to cause leukoencephalopathy associated with early ovarian failure, a clinical presentation described as "ovarioleukodystrophy." We present a sibling pair: one with cerebellar ataxia and one with vision loss and cognitive impairment in addition to ataxia. Neither shows evidence of leukoencephalopathy on MRI imaging. Exome sequencing revealed that both siblings are compound heterozygous for AARS2 variants (p.Phe131del and p.Ile328Met). Yeast complementation assays indicate that p.Phe131del AARS2 dramatically impairs gene function and that p.Ile328Met AARS2 is a hypomorphic allele. This work expands the phenotypic spectrum of AARS2-associated disease to include ataxia without leukoencephalopathy.
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Affiliation(s)
- Molly E Kuo
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.,Medical Scientist Training Program, University of Michigan, Ann Arbor, MI, USA
| | - Anthony Antonellis
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA. .,Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA. .,Department of Neurology, University of Michigan, Ann Arbor, MI, USA. .,Medical Science II, 3710A, 1241 E. Catherine St. SPC 5618, Ann Arbor, MI, 48109, USA.
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA. .,BSRB, 4009, 109 Zina Pitcher Place, Ann Arbor, MI, 48109, USA.
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11
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Kelly P, Kavoor A, Ibba M. Fine-Tuning of Alanyl-tRNA Synthetase Quality Control Alleviates Global Dysregulation of the Proteome. Genes (Basel) 2020; 11:genes11101222. [PMID: 33081015 PMCID: PMC7603204 DOI: 10.3390/genes11101222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/10/2020] [Accepted: 10/15/2020] [Indexed: 11/16/2022] Open
Abstract
One integral step in the transition from a nucleic acid encoded-genome to functional proteins is the aminoacylation of tRNA molecules. To perform this activity, aminoacyl-tRNA synthetases (aaRSs) activate free amino acids in the cell forming an aminoacyl-adenylate before transferring the amino acid on to its cognate tRNA. These newly formed aminoacyl-tRNA (aa-tRNA) can then be used by the ribosome during mRNA decoding. In Escherichia coli, there are twenty aaRSs encoded in the genome, each of which corresponds to one of the twenty proteinogenic amino acids used in translation. Given the shared chemicophysical properties of many amino acids, aaRSs have evolved mechanisms to prevent erroneous aa-tRNA formation with non-cognate amino acid substrates. Of particular interest is the post-transfer proofreading activity of alanyl-tRNA synthetase (AlaRS) which prevents the accumulation of Ser-tRNAAla and Gly-tRNAAla in the cell. We have previously shown that defects in AlaRS proofreading of Ser-tRNAAla lead to global dysregulation of the E. coli proteome, subsequently causing defects in growth, motility, and antibiotic sensitivity. Here we report second-site AlaRS suppressor mutations that alleviate the aforementioned phenotypes, revealing previously uncharacterized residues within the AlaRS proofreading domain that function in quality control.
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Affiliation(s)
- Paul Kelly
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA; (P.K.); (A.K.)
| | - Arundhati Kavoor
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA; (P.K.); (A.K.)
| | - Michael Ibba
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA; (P.K.); (A.K.)
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA
- Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
- Correspondence: ; Tel.: +1-714-516-5235
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12
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Kuzmishin Nagy AB, Bakhtina M, Musier-Forsyth K. Trans-editing by aminoacyl-tRNA synthetase-like editing domains. Enzymes 2020; 48:69-115. [PMID: 33837712 DOI: 10.1016/bs.enz.2020.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRS) are ubiquitous enzymes responsible for aminoacyl-tRNA (aa-tRNA) synthesis. Correctly formed aa-tRNAs are necessary for proper decoding of mRNA and accurate protein synthesis. tRNAs possess specific nucleobases that promote selective recognition by cognate aaRSs. Selecting the cognate amino acid can be more challenging because all amino acids share the same peptide backbone and several are isosteric or have similar side chains. Thus, aaRSs can misactivate non-cognate amino acids and produce mischarged aa-tRNAs. If left uncorrected, mischarged aa-tRNAs deliver their non-cognate amino acid to the ribosome resulting in misincorporation into the nascent polypeptide chain. This changes the primary protein sequence and potentially causes misfolding or formation of non-functional proteins that impair cell survival. A variety of proofreading or editing pathways exist to prevent and correct mistakes in aa-tRNA formation. Editing may occur before the amino acid transfer step of aminoacylation via hydrolysis of the aminoacyl-adenylate. Alternatively, post-transfer editing, which occurs after the mischarged aa-tRNA is formed, may be carried out via a distinct editing site on the aaRS where the mischarged aa-tRNA is deacylated. In recent years, it has become clear that most organisms also encode factors that lack aminoacylation activity but resemble aaRS editing domains and function to clear mischarged aa-tRNAs in trans. This review focuses on these trans-editing factors, which are encoded in all three domains of life and function together with editing domains present within aaRSs to ensure that the accuracy of protein synthesis is sufficient for cell survival.
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Affiliation(s)
- Alexandra B Kuzmishin Nagy
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH, United States.
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13
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Mutsuro-Aoki H, Hamachi K, Kurihara R, Tamura K. Aminoacylation of short hairpin RNAs through kissing-loop interactions indicates evolutionary trend of RNA molecules. Biosystems 2020; 197:104206. [PMID: 32640271 DOI: 10.1016/j.biosystems.2020.104206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 12/24/2022]
Abstract
The unique G3:U70 base pair in the acceptor stem of tRNAAla has been shown to be a critical recognition site by alanyl-tRNA synthetase (AlaRS). The base pair resides on one of the arms of the L-shaped structure of tRNA (minihelix) and the genetic code has likely evolved from a primordial tRNA-aaRS (aminoacyl-tRNA synthetase) system. In terms of the evolution of tRNA, incorporation of a G:U base pair in the structure would be important. Here, we found that two independent short hairpin RNAs change their conformation through kissing-loop interactions, finally forming a minihelix-like structure, in which the G3:U70 base pair is incorporated. The RNA system can be properly aminoacylated by the minimal Escherichia coli AlaRS variant with alanylation activity (AlaRS442N). Thus, characteristic structural features produced via kissing-loop interactions may provide important clues into the evolution of RNA.
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Affiliation(s)
- Hiromi Mutsuro-Aoki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kokoro Hamachi
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Ryodai Kurihara
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Koji Tamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
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14
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Chen M, Kuhle B, Diedrich J, Liu Z, Moresco JJ, Yates Iii JR, Pan T, Yang XL. Cross-editing by a tRNA synthetase allows vertebrates to abundantly express mischargeable tRNA without causing mistranslation. Nucleic Acids Res 2020; 48:6445-6457. [PMID: 32484512 PMCID: PMC7337962 DOI: 10.1093/nar/gkaa469] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/19/2020] [Accepted: 05/31/2020] [Indexed: 01/18/2023] Open
Abstract
The accuracy in pairing tRNAs with correct amino acids by aminoacyl-tRNA synthetases (aaRSs) dictates the fidelity of translation. To ensure fidelity, multiple aaRSs developed editing functions that remove a wrong amino acid from tRNA before it reaches the ribosome. However, no specific mechanism within an aaRS is known to handle the scenario where a cognate amino acid is mischarged onto a wrong tRNA, as exemplified by AlaRS mischarging alanine to G4:U69-containing tRNAThr. Here, we report that the mischargeable G4:U69-containing tRNAThr are strictly conserved in vertebrates and are ubiquitously and abundantly expressed in mammalian cells and tissues. Although these tRNAs are efficiently mischarged, no corresponding Thr-to-Ala mistranslation is detectable. Mistranslation is prevented by a robust proofreading activity of ThrRS towards Ala-tRNAThr. Therefore, while wrong amino acids are corrected within an aaRS, a wrong tRNA is handled in trans by an aaRS cognate to the mischarged tRNA species. Interestingly, although Ala-tRNAThr mischarging is not known to occur in bacteria, Escherichia coli ThrRS also possesses robust cross-editing ability. We propose that the cross-editing activity of ThrRS is evolutionarily conserved and that this intrinsic activity allows G4:U69-containing tRNAThr to emerge and be preserved in vertebrates to have alternative functions without compromising translational fidelity.
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Affiliation(s)
- Meirong Chen
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA.,College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Bernhard Kuhle
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jolene Diedrich
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ze Liu
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | - James J Moresco
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | - John R Yates Iii
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
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15
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Arutaki M, Kurihara R, Matsuoka T, Inami A, Tokunaga K, Ohno T, Takahashi H, Takano H, Ando T, Mutsuro-Aoki H, Umehara T, Tamura K. G:U-Independent RNA Minihelix Aminoacylation by Nanoarchaeum equitans Alanyl-tRNA Synthetase: An Insight into the Evolution of Aminoacyl-tRNA Synthetases. J Mol Evol 2020; 88:501-509. [DOI: 10.1007/s00239-020-09945-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 04/28/2020] [Indexed: 11/25/2022]
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16
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Kuhle B, Chihade J, Schimmel P. Relaxed sequence constraints favor mutational freedom in idiosyncratic metazoan mitochondrial tRNAs. Nat Commun 2020; 11:969. [PMID: 32080176 PMCID: PMC7033119 DOI: 10.1038/s41467-020-14725-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/30/2020] [Indexed: 01/05/2023] Open
Abstract
Metazoan complexity and life-style depend on the bioenergetic potential of mitochondria. However, higher aerobic activity and genetic drift impose strong mutation pressure and risk of irreversible fitness decline in mitochondrial (mt)DNA-encoded genes. Bilaterian mitochondria-encoded tRNA genes, key players in mitochondrial activity, have accumulated mutations at significantly higher rates than their cytoplasmic counterparts, resulting in foreshortened and fragile structures. Here we show that fragility of mt tRNAs coincided with the evolution of bilaterian animals. We demonstrate that bilaterians compensated for this reduced structural complexity in mt tRNAs by sequence-independent induced-fit adaption to the cognate mitochondrial aminoacyl-tRNA synthetase (aaRS). Structural readout by nuclear-encoded aaRS partners relaxed the sequence constraints on mt tRNAs and facilitated accommodation of functionally disruptive mutational insults by cis-acting epistatic compensations. Our results thus suggest that mutational freedom in mt tRNA genes is an adaptation to increased mutation pressure that was associated with the evolution of animal complexity. Bilaterian mitochondria-encoded tRNA genes accumulate mutations at higher rates than their cytoplasmic tRNA counterparts, resulting in idiosyncratic structures. Here the authors suggest an evolutionary basis for the observed mutational freedom of mitochondrial (mt) tRNAs and reveal the associated co-adaptive structural and functional changes in mt aminoacyl-tRNA synthetases.
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Affiliation(s)
- Bernhard Kuhle
- The Skaggs Institute for Chemical Biology, Scripps Research, La Jolla, CA, 92037, USA. .,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA.
| | - Joseph Chihade
- Department of Chemistry, Carleton College, 1 North College St., Northfield, MN, 55057, USA
| | - Paul Schimmel
- The Skaggs Institute for Chemical Biology, Scripps Research, La Jolla, CA, 92037, USA. .,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Department of Molecular Medicine, The Scripps Florida Research Institute, Jupiter, FL, 33458, USA.
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17
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Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes for protein synthesis with evolutionarily conserved enzymatic mechanisms. Despite their similarity across organisms, scientists have been able to generate effective anti-infective agents based on the structural differences in the catalytic clefts of ARSs from pathogens and humans. However, recent genomic, proteomic and functionomic advances have unveiled unexpected disease-associated mutations and altered expression, secretion and interactions in human ARSs, revealing hidden biological functions beyond their catalytic roles in protein synthesis. These studies have also brought to light their potential as a rich and unexplored source for new therapeutic targets and agents through multiple avenues, including direct targeting of the catalytic sites, controlling disease-associated protein-protein interactions and developing novel biologics from the secreted ARS proteins or their parts. This Review addresses the emerging biology and therapeutic applications of human ARSs in diseases including autoimmune and rare diseases, and cancer.
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18
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Sundal C, Carmona S, Yhr M, Almström O, Ljungberg M, Hardy J, Hedberg-Oldfors C, Fred Å, Brás J, Oldfors A, Andersen O, Guerreiro R. An AARS variant as the likely cause of Swedish type hereditary diffuse leukoencephalopathy with spheroids. Acta Neuropathol Commun 2019; 7:188. [PMID: 31775912 PMCID: PMC6880494 DOI: 10.1186/s40478-019-0843-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/12/2022] Open
Abstract
Swedish type Hereditary Diffuse Leukoencephalopathy with Spheroids (HDLS-S) is a severe adult-onset leukoencephalopathy with the histopathological hallmark of neuraxonal degeneration with spheroids, described in a large family with a dominant inheritance pattern. The initial stage of the disease is dominated by frontal lobe symptoms that develop into a rapidly advancing encephalopathy with pyramidal, deep sensory, extrapyramidal and optic tract symptoms. Median survival is less than 10 years. Recently, pathogenic mutations in CSF1R were reported in a clinically and histologically similar leukoencephalopathy segregating in several families. Still, the cause of HDLS-S remained elusive since its initial description in 1984, with no CSF1R mutations identified in the family. Here we update the original findings associated with HDLS-S after a systematic and recent assessment of several family members. We also report the results from exome sequencing analyses indicating the p.Cys152Phe variant in the alanyl tRNA synthetase (AARS) gene as the probable cause of this disease. The variant affects an amino acid located in the aminoacylation domain of the protein and does not cause differences in splicing or expression in the brain. Brain pathology in one case after 10 years of disease duration showed the end stage of the disease to be characterized by widespread liquefaction of the white matter leaving only some macrophages and glial cells behind the centrifugally progressing front. These results point to AARS as a candidate gene for rapidly progressing adult-onset CSF1R-negative leukoencephalopathies.
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Affiliation(s)
- Christina Sundal
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden
| | - Susana Carmona
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA
| | - Maria Yhr
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Odd Almström
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden
| | - Maria Ljungberg
- Department of Radiation Physics, Institute of Clinical Sciences, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - John Hardy
- Department of Neurodegenerative Disease, Reta Lila Weston Laboratories, Queen Square Genomics, UCL Dementia Research Institute, London, UK
| | - Carola Hedberg-Oldfors
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Åsa Fred
- Department of Pathology, Hospital of Halland, Halmstad, Sweden
| | - José Brás
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI, USA
| | - Anders Oldfors
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Oluf Andersen
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden.
| | - Rita Guerreiro
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA.
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI, USA.
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19
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Zeng QY, Peng GX, Li G, Zhou JB, Zheng WQ, Xue MQ, Wang ED, Zhou XL. The G3-U70-independent tRNA recognition by human mitochondrial alanyl-tRNA synthetase. Nucleic Acids Res 2019; 47:3072-3085. [PMID: 30952159 PMCID: PMC6451123 DOI: 10.1093/nar/gkz078] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/28/2019] [Accepted: 01/31/2019] [Indexed: 11/13/2022] Open
Abstract
Alanyl-tRNA synthetases (AlaRSs) from three domains of life predominantly rely on a single wobble base pair, G3-U70, of tRNAAla as a major determinant. However, this base pair is divergent in human mitochondrial tRNAAla, but instead with a translocated G5-U68. How human mitochondrial AlaRS (hmtAlaRS) recognizes tRNAAla, in particular, in the acceptor stem region, remains unknown. In the present study, we found that hmtAlaRS is a monomer and recognizes mitochondrial tRNAAla in a G3-U70-independent manner, requiring several elements in the acceptor stem. In addition, we found that hmtAlaRS misactivates noncognate Gly and catalyzes strong transfer RNA (tRNA)-independent pre-transfer editing for Gly. A completely conserved residue outside of the editing active site, Arg663, likely functions as a tRNA translocation determinant to facilitate tRNA entry into the editing domain during editing. Finally, we investigated the effects of the severe infantile-onset cardiomyopathy-associated R592W mutation of hmtAlaRS on the canonical enzymatic activities of hmtAlaRS. Overall, our results provide fundamental information about tRNA recognition and deepen our understanding of translational quality control mechanisms by hmtAlaRS.
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Affiliation(s)
- Qi-Yu Zeng
- 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 200031, China
| | - Gui-Xin Peng
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
| | - Guang Li
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
| | - Jing-Bo 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 200031, China
| | - Wen-Qiang Zheng
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, 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 200031, 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 200031, China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, 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 200031, China
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20
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Tang Y, Qin Q, Xing Y, Guo D, Di L, Jia J. AARS2 leukoencephalopathy: A new variant of mitochondrial encephalomyopathy. Mol Genet Genomic Med 2019; 7:e00582. [PMID: 30706699 PMCID: PMC6465728 DOI: 10.1002/mgg3.582] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/23/2018] [Accepted: 01/02/2019] [Indexed: 01/27/2023] Open
Abstract
Background Mutations in the mitochondrial alanyl‐transfer (t)RNA synthetase 2 (AARS2,OMIM:612035) have been linked to leukoencephalopathy recently. Till now, there have been 19 cases reported so far. However, the clinical and genetic characteristics of this disease are not fully understood. We reported an adult‐onset male leukoencephalopathy patient related to novel AARS2 gene mutations and reviewed all previous cases regarding the clinical and genetic features of AARS2 leukoencephalopathy. Methods The spectrum of clinical symptoms and the genetic analysis of the presented patient were identified and investigated. Besides this case, we assessed previously reported cases with AARS2 gene mutations. Results Here, we present a 30‐year‐old man with progressive motor deficits in the right lower limb and severe cerebellar ataxia for one year. MRI revealed extensive white matter lesions in periventricular regions and along the corticospinal tract. Genetic analysis revealed two new heterogeneous missense mutations in AARS2: c.179C>A and c.1703_1704del. We described the ragged red fiber (RRF) for the first time, suggesting that AARS2‐related leukoencephalopathy be a new variant of mitochondrial encephalomyopathy. Gradual improvement in motor function was observed with intravenous coenzyme complex treatment. We also summarized our case and all previously reported cases to provide an overview of AARS2‐related late‐onset leukoencephalopathy. Then, we compared clinical and neuroimaging features of AARS2‐related leukoencephalopathy with three other frequently diagnosed types of adult‐onset leukoencephalopathy to provide insight into diagnostic strategies. Conclusion The characteristic MRI abnormalities and clinical symptoms described here may help to distinguish AARS2‐related leukoencephalopathy from other adult‐onset leukoencephalopathies. The combination of encephalopathy and myopathy strongly suggest that AARS2‐related leukoencephalopathy is a new variant of mitochondrial encephalomyopathy. The response to coenzyme complex will shed light on future therapy investigation.
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Affiliation(s)
- Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Qi Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Yi Xing
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Dongmei Guo
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Li Di
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Jianping Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Geriatric Cognitive Disorders, Neurodegenerative Laboratory of Ministry of Education of the People's Republic of China, Beijing, China
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21
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Wei N, Zhang Q, Yang XL. Neurodegenerative Charcot-Marie-Tooth disease as a case study to decipher novel functions of aminoacyl-tRNA synthetases. J Biol Chem 2019; 294:5321-5339. [PMID: 30643024 DOI: 10.1074/jbc.rev118.002955] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that catalyze the first reaction in protein biosynthesis, namely the charging of transfer RNAs (tRNAs) with their cognate amino acids. aaRSs have been increasingly implicated in dominantly and recessively inherited human diseases. The most common aaRS-associated monogenic disorder is the incurable neurodegenerative disease Charcot-Marie-Tooth neuropathy (CMT), caused by dominant mono-allelic mutations in aaRSs. With six currently known members (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, and MetRS), aaRSs represent the largest protein family implicated in CMT etiology. After the initial discovery linking aaRSs to CMT, the field has progressed from understanding whether impaired tRNA charging is a critical component of this disease to elucidating the specific pathways affected by CMT-causing mutations in aaRSs. Although many aaRS CMT mutants result in loss of tRNA aminoacylation function, animal genetics studies demonstrated that dominant mutations in GlyRS cause CMT through toxic gain-of-function effects, which also may apply to other aaRS-linked CMT subtypes. The CMT-causing mechanism is likely to be multifactorial and involves multiple cellular compartments, including the nucleus and the extracellular space, where the normal WT enzymes also appear. Thus, the association of aaRSs with neuropathy is relevant to discoveries indicating that aaRSs also have nonenzymatic regulatory functions that coordinate protein synthesis with other biological processes. Through genetic, functional, and structural analyses, commonalities among different mutations and different aaRS-linked CMT subtypes have begun to emerge, providing insights into the nonenzymatic functions of aaRSs and the pathogenesis of aaRS-linked CMT to guide therapeutic development to treat this disease.
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Affiliation(s)
- Na Wei
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Qian Zhang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
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22
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Zhao X, Han J, Zhu L, Xiao Y, Wang C, Hong F, Jiang P, Guan MX. Overexpression of human mitochondrial alanyl-tRNA synthetase suppresses biochemical defects of the mt-tRNA Ala mutation in cybrids. Int J Biol Sci 2018; 14:1437-1444. [PMID: 30262995 PMCID: PMC6158735 DOI: 10.7150/ijbs.27043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Mutations of mitochondrial transfer RNAs (mt-tRNAs) play a major role in a wide range of mitochondrial diseases because of the vital role of these molecules in mitochondrial translation. It has previously been reported that the overexpression of mitochondrial aminoacyl tRNA synthetases is effective at partially suppressing the defects resulting from mutations in their cognate mt-tRNAs in cells. Here we report a detailed analysis of the suppressive activities of mitochondrial alanyl-tRNA synthetase (AARS2) on mt-tRNAAla 5655 A>G mutant. Mitochondrial defects in respiration, activity of oxidative phosphorylation complexes, ATP production, mitochondrial superoxide, and membrane potential were consistently rescued in m.5655A>G cybrids upon AARS2 expression. However, AARS2 overexpression did not result in a detectable increase in mutated mt-tRNAAla but caused an increase incharged mt-tRNAAla in mutant cybrids, leading to enhanced mitochondrial translation. This indicated that AARS2 improved the aminoacylation activity in the case of m.5655A>G, rather than having a stabilizing effect on the tRNA structure. The data presented in this paper deepen our understanding of the pathogenesis of mt-tRNA diseases.
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Affiliation(s)
- Xiaoxu Zhao
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiamin Han
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Ling Zhu
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yun Xiao
- Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Chenghui Wang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Fang Hong
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Pingping Jiang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
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23
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) establish the rules to express the universal genetic code. During aminoacylation, each of the 20 aaRSs associates 1 of 20 amino acids with a specific trinucleotide known as anticodon. Remarkably, for alanyl-tRNAs, the synthetase makes no contact with the anticodon. Instead, it uses a “second genetic code” by picking out a single G3:U70 base pair in the tRNA acceptor stem, which is close to the amino acid attachment site, but 76 Å away from the anticodon. Here, we show that, while in the three kingdoms of life, alanyl-tRNA synthetases use G3:U70 to identify alanyl-tRNAs, surprisingly, they use three different mechanisms to achieve this. We thus suggest that, in evolution, the genetic code had a powerful and persistent preference for associating G:U with alanine. Throughout three domains of life, alanyl-tRNA synthetases (AlaRSs) recognize a G3:U70 base pair in the acceptor stem of tRNAAla as the major identity determinant of tRNAAla. The crystal structure of the archaeon Archaeoglobus fulgidus AlaRS in complex with tRNAAla provided the basis for G3:U70 recognition with residues (Asp and Asn) that are conserved in the three domains [Naganuma M, et al. (2014) Nature 510:507–511]. The recognition mode is unprecedented, with specific accommodation of the dyad asymmetry of the G:U wobble pair and exclusion of the dyad symmetry of a Watson–Crick pair. With this conserved mode, specificity is based more on “fit” than on direct recognition of specific atomic groups. Here, we show that, in contrast to the archaeal complex, the Escherichia coli enzyme uses direct positive (energetically favorable) minor groove recognition of the unpaired 2-amino of G3 by Asp and repulsion of a competing base pair by Asn. Strikingly, mutations that disrupted positive recognition by the E. coli enzyme had little or no effect on G:U recognition by the human enzyme. Alternatively, Homo sapiens AlaRS selects G:U without positive recognition and uses Asp instead to repel a competitor. Thus, the widely conserved Asp-plus-Asn architecture of AlaRSs can select G:U in a straightforward (bacteria) or two different unconventional (eukarya/archaea) ways. The adoption of different modes for recognition of a widely conserved G:U pair in alanine tRNAs suggests an early and insistent role for G:U in the development of the genetic code.
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Structural Basis for the Bidirectional Activity of Bacillus nanoRNase NrnA. Sci Rep 2017; 7:11085. [PMID: 28894100 PMCID: PMC5593865 DOI: 10.1038/s41598-017-09403-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/24/2017] [Indexed: 12/21/2022] Open
Abstract
NanoRNAs are RNA fragments 2 to 5 nucleotides in length that are generated as byproducts of RNA degradation and abortive transcription initiation. Cells have specialized enzymes to degrade nanoRNAs, such as the DHH phosphoesterase family member NanoRNase A (NrnA). This enzyme was originally identified as a 3′ → 5′ exonuclease, but we show here that NrnA is bidirectional, degrading 2–5 nucleotide long RNA oligomers from the 3′ end, and longer RNA substrates from the 5′ end. The crystal structure of Bacillus subtilis NrnA reveals a dynamic bi-lobal architecture, with the catalytic N-terminal DHH domain linked to the substrate binding C-terminal DHHA1 domain via an extended linker. Whereas this arrangement is similar to the structure of RecJ, a 5′ → 3′ DHH family DNase and other DHH family nanoRNases, Bacillus NrnA has gained an extended substrate-binding patch that we posit is responsible for its 3′ → 5′ activity.
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Two crystal structures reveal design for repurposing the C-Ala domain of human AlaRS. Proc Natl Acad Sci U S A 2016; 113:14300-14305. [PMID: 27911835 DOI: 10.1073/pnas.1617316113] [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] [Indexed: 12/18/2022] Open
Abstract
The 20 aminoacyl tRNA synthetases (aaRSs) couple each amino acid to their cognate tRNAs. During evolution, 19 aaRSs expanded by acquiring novel noncatalytic appended domains, which are absent from bacteria and many lower eukaryotes but confer extracellular and nuclear functions in higher organisms. AlaRS is the single exception, with an appended C-terminal domain (C-Ala) that is conserved from prokaryotes to humans but with a wide sequence divergence. In human cells, C-Ala is also a splice variant of AlaRS. Crystal structures of two forms of human C-Ala, and small-angle X-ray scattering of AlaRS, showed that the large sequence divergence of human C-Ala reshaped C-Ala in a way that changed the global architecture of AlaRS. This reshaping removes the role of C-Ala in prokaryotes for docking tRNA and instead repurposes it to form a dimer interface presenting a DNA-binding groove. This groove cannot form with the bacterial ortholog. Direct DNA binding by human C-Ala, but not by bacterial C-Ala, was demonstrated. Thus, instead of acquiring a novel appended domain like other human aaRSs, which engendered novel functions, a new AlaRS architecture was created by diversifying a preexisting appended domain.
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) are modular enzymes globally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation. Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g., in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show huge structural plasticity related to function and limited idiosyncrasies that are kingdom or even species specific (e.g., the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS). Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably between distant groups such as Gram-positive and Gram-negative Bacteria. The review focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation, and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulated in last two decades is reviewed, showing how the field moved from essentially reductionist biology towards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRS paralogs (e.g., during cell wall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointed throughout the review and distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Mathias Springer
- Université Paris Diderot, Sorbonne Cité, UPR9073 CNRS, IBPC, 75005 Paris, France
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Urea Unfolding Study of E. coli Alanyl-tRNA Synthetase and Its Monomeric Variants Proves the Role of C-Terminal Domain in Stability. JOURNAL OF AMINO ACIDS 2015; 2015:805681. [PMID: 26617997 PMCID: PMC4649089 DOI: 10.1155/2015/805681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/20/2015] [Indexed: 11/17/2022]
Abstract
E. coli alanyl-tRNA exists as a dimer in its native form and the C-terminal coiled-coil part plays an important role in the dimerization process. The truncated N-terminal containing the first 700 amino acids (1–700) forms a monomeric variant possessing similar aminoacylation activity like wild type. A point mutation in the C-terminal domain (G674D) also produces a monomeric variant with a fivefold reduced aminoacylation activity compared to the wild type enzyme. Urea induced denaturation of these monomeric mutants along with another alaRS variant (N461 alaRS) was studied together with the full-length enzyme using various spectroscopic techniques such as intrinsic tryptophan fluorescence, 1-anilino-8-naphthalene-sulfonic acid binding, near- and far-UV circular dichroism, and analytical ultracentrifugation. Aminoacylation activity assay after refolding from denatured state revealed that the monomeric mutants studied here were unable to regain their activity, whereas the dimeric full-length alaRS gets back similar activity as the native enzyme. This study indicates that dimerization is one of the key regulatory factors that is important in the proper folding and stability of E. coli alaRS.
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Novoa EM, Vargas-Rodriguez O, Lange S, Goto Y, Suga H, Musier-Forsyth K, Ribas de Pouplana L. Ancestral AlaX editing enzymes for control of genetic code fidelity are not tRNA-specific. J Biol Chem 2015; 290:10495-503. [PMID: 25724653 DOI: 10.1074/jbc.m115.640060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Indexed: 01/15/2023] Open
Abstract
Accurate protein synthesis requires the hydrolytic editing of tRNAs incorrectly aminoacylated by aminoacyl-tRNA synthetases (ARSs). Recognition of cognate tRNAs by ARS is less error-prone than amino acid recognition, and, consequently, editing domains are generally believed to act only on the tRNAs cognate to their related ARSs. For example, the AlaX family of editing domains, including the editing domain of alanyl-tRNA synthetase and the related free-standing trans-editing AlaX enzymes, are thought to specifically act on tRNA(Ala), whereas the editing domains of threonyl-tRNA synthetases are specific for tRNA(Thr). Here we show that, contrary to this belief, AlaX-S, the smallest of the extant AlaX enzymes, deacylates Ser-tRNA(Thr) in addition to Ser-tRNA(Ala) and that a single residue is important to determine this behavior. Our data indicate that promiscuous forms of AlaX are ancestral to tRNA-specific AlaXs. We propose that former AlaX domains were used to maintain translational fidelity in earlier stages of genetic code evolution when mis-serylation of several tRNAs was possible.
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Affiliation(s)
- Eva Maria Novoa
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Oscar Vargas-Rodriguez
- the Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Stefanie Lange
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Yuki Goto
- the Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan, and
| | - Hiroaki Suga
- the Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan, and
| | - Karin Musier-Forsyth
- the Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Lluís Ribas de Pouplana
- From the Institute for Research in Biomedicine, c/ Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain, the Catalan Institution for Research and Advanced Studies, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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Euro L, Konovalova S, Asin-Cayuela J, Tulinius M, Griffin H, Horvath R, Taylor RW, Chinnery PF, Schara U, Thorburn DR, Suomalainen A, Chihade J, Tyynismaa H. Structural modeling of tissue-specific mitochondrial alanyl-tRNA synthetase (AARS2) defects predicts differential effects on aminoacylation. Front Genet 2015; 6:21. [PMID: 25705216 PMCID: PMC4319469 DOI: 10.3389/fgene.2015.00021] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/15/2015] [Indexed: 12/21/2022] Open
Abstract
The accuracy of mitochondrial protein synthesis is dependent on the coordinated action of nuclear-encoded mitochondrial aminoacyl-tRNA synthetases (mtARSs) and the mitochondrial DNA-encoded tRNAs. The recent advances in whole-exome sequencing have revealed the importance of the mtARS proteins for mitochondrial pathophysiology since nearly every nuclear gene for mtARS (out of 19) is now recognized as a disease gene for mitochondrial disease. Typically, defects in each mtARS have been identified in one tissue-specific disease, most commonly affecting the brain, or in one syndrome. However, mutations in the AARS2 gene for mitochondrial alanyl-tRNA synthetase (mtAlaRS) have been reported both in patients with infantile-onset cardiomyopathy and in patients with childhood to adulthood-onset leukoencephalopathy. We present here an investigation of the effects of the described mutations on the structure of the synthetase, in an effort to understand the tissue-specific outcomes of the different mutations. The mtAlaRS differs from the other mtARSs because in addition to the aminoacylation domain, it has a conserved editing domain for deacylating tRNAs that have been mischarged with incorrect amino acids. We show that the cardiomyopathy phenotype results from a single allele, causing an amino acid change R592W in the editing domain of AARS2, whereas the leukodystrophy mutations are located in other domains of the synthetase. Nevertheless, our structural analysis predicts that all mutations reduce the aminoacylation activity of the synthetase, because all mtAlaRS domains contribute to tRNA binding for aminoacylation. According to our model, the cardiomyopathy mutations severely compromise aminoacylation whereas partial activity is retained by the mutation combinations found in the leukodystrophy patients. These predictions provide a hypothesis for the molecular basis of the distinct tissue-specific phenotypic outcomes.
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Affiliation(s)
- Liliya Euro
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki Helsinki, Finland
| | - Svetlana Konovalova
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki Helsinki, Finland
| | - Jorge Asin-Cayuela
- Department of Clinical Chemistry, University of Gothenburg, Sahlgrenska University Hospital Gothenburg, Sweden
| | - Már Tulinius
- Department of Pediatrics, Queen Silvia Children's Hospital, University of Gothenburg Gothenburg, Sweden
| | - Helen Griffin
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University Newcastle upon Tyne, UK
| | - Rita Horvath
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University Newcastle upon Tyne, UK
| | - Robert W Taylor
- Institute of Neuroscience, Wellcome Trust Centre for Mitochondrial Research, Newcastle University Newcastle upon Tyne, UK
| | - Patrick F Chinnery
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University Newcastle upon Tyne, UK
| | - Ulrike Schara
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University of Essen Essen, Germany
| | - David R Thorburn
- Murdoch Childrens Research Institute, Royal Childrens Hospital and Department of Paediatrics, University of Melbourne Melbourne, VIC, Australia
| | - Anu Suomalainen
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki Helsinki, Finland ; Department of Neurology, Helsinki University Central Hospital Helsinki, Finland
| | - Joseph Chihade
- Department of Chemistry, Carleton College Northfield, MN, USA
| | - Henna Tyynismaa
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki Helsinki, Finland ; Department of Medical Genetics, Haartman Institute, University of Helsinki Helsinki, Finland
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Datt M, Sharma A. Novel and unique domains in aminoacyl-tRNA synthetases from human fungal pathogens Aspergillus niger, Candida albicans and Cryptococcus neoformans. BMC Genomics 2014; 15:1069. [PMID: 25479903 PMCID: PMC4301749 DOI: 10.1186/1471-2164-15-1069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 11/20/2014] [Indexed: 12/15/2022] Open
Abstract
Background Some species of fungi can cause serious human diseases, particularly to immuno-compromised individuals. Opportunistic fungal infections are a leading cause of mortality, and present an emerging challenge that requires development of new and effective therapeutics. Aminoacyl-tRNA synthetases (aaRSs) are indispensable components of cellular protein translation machinery and can be targeted for discovery of novel anti-fungal agents. Results Validation of aaRSs as potential drug targets in pathogenic microbes prompted us to investigate the genomic distribution of aaRSs within three fungi that infect humans – A. niger, C. albicans and C. neoformans. Hidden Markov Models were built for aaRSs and related proteins to search for homologues in these fungal genomes. Here, we provide a detailed and comprehensive annotation for 3 fungal genome aaRSs and their associated proteins. We delineate predicted localizations, subdomain architectures and prevalence of unusual motifs within these aaRSs. Several fungal aaRSs have unique domain appendages of unknown function e.g. A. niger AsxRS and C. neoformans TyrRS have additional domains that are absent from human homologs. Conclusions Detailed comparisons of fungal aaRSs with human homologs suggest key differences that could be exploited for specific drug targeting. Our cataloging and structural analyses provide a comprehensive foundation for experimentally dissecting fungal aaRSs that may enable development of new anti-fungal agents. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1069) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Amit Sharma
- Structural and Computational Biology group, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
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Smal C, Zanzoni S, D'Onofrio M, Molinari H, Cicero DO, Assfalg M. ¹H, ¹⁵N, and ¹³C chemical shift assignments of the C-Ala domain of the alanyl-tRNA synthetase of the psychrophilic bacterium Bizionia argentinensis sp. nov. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:415-418. [PMID: 24258519 DOI: 10.1007/s12104-013-9529-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/29/2013] [Indexed: 06/02/2023]
Abstract
A gene encoding a protein classified as alanyl-tRNA synthetase (AlaRS) was found in the genome of the psychrophilic bacteria Bizionia argentinensis. The enzyme is constituted by three domains with an evolutionarily conserved modular arrangement: the N-terminal aminoacylation domain, the editing domain and the C-terminal domain (C-Ala). Herein we report the near complete NMR resonance assignment of the 122 amino acid C-Ala domain from B. argentinensis. The chemical shift data, reported for the first time for a C-Ala domain, constitute the basis for NMR structural studies aimed at elucidating the cold-adaptation mechanism of AlaRS.
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Affiliation(s)
- Clara Smal
- Fundación Instituto Leloir, Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina
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Naganuma M, Sekine SI, Chong YE, Guo M, Yang XL, Gamper H, Hou YM, Schimmel P, Yokoyama S. The selective tRNA aminoacylation mechanism based on a single G•U pair. Nature 2014; 510:507-11. [PMID: 24919148 DOI: 10.1038/nature13440] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/06/2014] [Indexed: 11/09/2022]
Abstract
Ligation of tRNAs with their cognate amino acids, by aminoacyl-tRNA synthetases, establishes the genetic code. Throughout evolution, tRNA(Ala) selection by alanyl-tRNA synthetase (AlaRS) has depended predominantly on a single wobble base pair in the acceptor stem, G3•U70, mainly on the kcat level. Here we report the crystal structures of an archaeal AlaRS in complex with tRNA(Ala) with G3•U70 and its A3•U70 variant. AlaRS interacts with both the minor- and the major-groove sides of G3•U70, widening the major groove. The geometry difference between G3•U70 and A3•U70 is transmitted along the acceptor stem to the 3'-CCA region. Thus, the 3'-CCA region of tRNA(Ala) with G3•U70 is oriented to the reactive route that reaches the active site, whereas that of the A3•U70 variant is folded back into the non-reactive route. This novel mechanism enables the single wobble pair to dominantly determine the specificity of tRNA selection, by an approximate 100-fold difference in kcat.
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Affiliation(s)
- Masahiro Naganuma
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Shun-ichi Sekine
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yeeting Esther Chong
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] aTyr Pharma, 3545 John Hopkins Court, San Diego, California 92121, USA (Y.E.C.); Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, USA (M.G.)
| | - Min Guo
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] aTyr Pharma, 3545 John Hopkins Court, San Diego, California 92121, USA (Y.E.C.); Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, USA (M.G.)
| | - Xiang-Lei Yang
- The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Howard Gamper
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Paul Schimmel
- 1] The Skaggs Institute for Chemical Biology and the Department of Cell and Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2] The Scripps Florida Research Institute, 130 Scripps Way, 3B3 Jupiter, Florida 33458-5284, USA
| | - Shigeyuki Yokoyama
- 1] RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan [2] Department of Biophysics and Biochemistry and Laboratory of Structural Biology, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan [3] RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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Srivastav R, Kumar D, Grover A, Singh A, Manjasetty BA, Sharma R, Taneja B. Unique subunit packing in mycobacterial nanoRNase leads to alternate substrate recognitions in DHH phosphodiesterases. Nucleic Acids Res 2014; 42:7894-910. [PMID: 24878921 PMCID: PMC4081065 DOI: 10.1093/nar/gku425] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
DHH superfamily includes RecJ, nanoRNases (NrnA), cyclic nucleotide phosphodiesterases and pyrophosphatases. In this study, we have carried out in vitro and in vivo investigations on the bifunctional NrnA-homolog from Mycobacterium smegmatis, MSMEG_2630. The crystal structure of MSMEG_2630 was determined to 2.2-Å resolution and reveals a dimer consisting of two identical subunits with each subunit folding into an N-terminal DHH domain and a C-terminal DHHA1 domain. The overall structure and fold of the individual domains is similar to other members of DHH superfamily. However, MSMEG_2630 exhibits a distinct quaternary structure in contrast to other DHH phosphodiesterases. This novel mode of subunit packing and variations in the linker region that enlarge the domain interface are responsible for alternate recognitions of substrates in the bifunctional nanoRNases. MSMEG_2630 exhibits bifunctional 3′-5′ exonuclease [on both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) substrates] as well as CysQ-like phosphatase activity (on pAp) in vitro with a preference for nanoRNA substrates over single-stranded DNA of equivalent lengths. A transposon disruption of MSMEG_2630 in M. smegmatis causes growth impairment in the presence of various DNA-damaging agents. Further phylogenetic analysis and genome organization reveals clustering of bacterial nanoRNases into two distinct subfamilies with possible role in transcriptional and translational events during stress.
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Affiliation(s)
- Rajpal Srivastav
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
| | - Dilip Kumar
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
| | - Amit Grover
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
| | - Ajit Singh
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
| | - Babu A Manjasetty
- European Molecular Biology Laboratory, Grenoble Outstation, 6 rue Jules Horowitz, Grenoble 38042, France Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 6 rue Jules Horowitz, Grenoble 38042, France
| | - Rakesh Sharma
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
| | - Bhupesh Taneja
- CSIR-IGIB, Institute of Genomics and Integrative Biology, South Campus Mathura Road, New Delhi 110020, India
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Banerjee B, Banerjee R. Guanidine Hydrochloride Mediated Denaturation of E. coli Alanyl-tRNA Synthetase: Identification of an Inactive Dimeric Intermediate. Protein J 2014; 33:119-27. [DOI: 10.1007/s10930-014-9544-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Das M, Vargas-Rodriguez O, Goto Y, Suga H, Musier-Forsyth K. Distinct tRNA recognition strategies used by a homologous family of editing domains prevent mistranslation. Nucleic Acids Res 2013; 42:3943-53. [PMID: 24371276 PMCID: PMC3973320 DOI: 10.1093/nar/gkt1332] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Errors in protein synthesis due to mispairing of amino acids with tRNAs jeopardize cell viability. Several checkpoints to prevent formation of Ala- and Cys-tRNAPro have been described, including the Ala-specific editing domain (INS) of most bacterial prolyl-tRNA synthetases (ProRSs) and an autonomous single-domain INS homolog, YbaK, which clears Cys-tRNAPro in trans. In many species where ProRS lacks an INS domain, ProXp-ala, another single-domain INS-like protein, is responsible for editing Ala-tRNAPro. Although the amino acid specificity of these editing domains has been established, the role of tRNA sequence elements in substrate selection has not been investigated in detail. Critical recognition elements for aminoacylation by bacterial ProRS include acceptor stem elements G72/A73 and anticodon bases G35/G36. Here, we show that ProXp-ala and INS require these same acceptor stem and anticodon elements, respectively, whereas YbaK lacks inherent tRNA specificity. Thus, these three related domains use divergent approaches to recognize tRNAs and prevent mistranslation. Whereas some editing domains have borrowed aspects of tRNA recognition from the parent aminoacyl-tRNA synthetase, relaxed tRNA specificity leading to semi-promiscuous editing may offer advantages to cells.
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Affiliation(s)
- Mom Das
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA, Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA and Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
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Pham JS, Dawson KL, Jackson KE, Lim EE, Pasaje CFA, Turner KEC, Ralph SA. Aminoacyl-tRNA synthetases as drug targets in eukaryotic parasites. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 4:1-13. [PMID: 24596663 PMCID: PMC3940080 DOI: 10.1016/j.ijpddr.2013.10.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 01/02/2023]
Abstract
Aminoacyl-tRNA synthetases are essential and many aaRS inhibitors kill parasites. We examine compound inhibitors tested experimentally against parasite aaRSs. Successful inhibitors were discovered by both phenotype and target-based approaches. Selectivity and resistance are ongoing challenges for development of parasite drugs.
Aminoacyl-tRNA synthetases are central enzymes in protein translation, providing the charged tRNAs needed for appropriate construction of peptide chains. These enzymes have long been pursued as drug targets in bacteria and fungi, but the past decade has seen considerable research on aminoacyl-tRNA synthetases in eukaryotic parasites. Existing inhibitors of bacterial tRNA synthetases have been adapted for parasite use, novel inhibitors have been developed against parasite enzymes, and tRNA synthetases have been identified as the targets for compounds in use or development as antiparasitic drugs. Crystal structures have now been solved for many parasite tRNA synthetases, and opportunities for selective inhibition are becoming apparent. For different biological reasons, tRNA synthetases appear to be promising drug targets against parasites as diverse as Plasmodium (causative agent of malaria), Brugia (causative agent of lymphatic filariasis), and Trypanosoma (causative agents of Chagas disease and human African trypanosomiasis). Here we review recent developments in drug discovery and target characterisation for parasite aminoacyl-tRNA synthetases.
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Affiliation(s)
- James S Pham
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Karen L Dawson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Katherine E Jackson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Erin E Lim
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Charisse Flerida A Pasaje
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Kelsey E C Turner
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
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Zhou X, Wang E. Transfer RNA: a dancer between charging and mis-charging for protein biosynthesis. SCIENCE CHINA-LIFE SCIENCES 2013; 56:921-32. [PMID: 23982864 DOI: 10.1007/s11427-013-4542-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/13/2013] [Indexed: 01/17/2023]
Abstract
Transfer RNA plays a fundamental role in the protein biosynthesis as an adaptor molecule by functioning as a biological link between the genetic nucleotide sequence in the mRNA and the amino acid sequence in the protein. To perform its role in protein biosynthesis, it has to be accurately recognized by aminoacyl-tRNA synthetases (aaRSs) to generate aminoacyl-tRNAs (aa-tRNAs). The correct pairing between an amino acid with its cognate tRNA is crucial for translational quality control. Production and utilization of mis-charged tRNAs are usually detrimental for all the species, resulting in cellular dysfunctions. Correct aa-tRNAs formation is collectively controlled by aaRSs with distinct mechanisms and/or other trans-factors. However, in very limited instances, mis-charged tRNAs are intermediate for specific pathways or essential components for the translational machinery. Here, from the point of accuracy in tRNA charging, we review our understanding about the mechanism ensuring correct aa-tRNA generation. In addition, some unique mis-charged tRNA species necessary for the organism are also briefly described.
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Affiliation(s)
- Xiaolong Zhou
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
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Uemura Y, Nakagawa N, Wakamatsu T, Kim K, Montelione GT, Hunt JF, Kuramitsu S, Masui R. Crystal structure of the ligand-binding form of nanoRNase from Bacteroides fragilis, a member of the DHH/DHHA1 phosphoesterase family of proteins. FEBS Lett 2013; 587:2669-74. [PMID: 23851074 PMCID: PMC4113422 DOI: 10.1016/j.febslet.2013.06.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/25/2013] [Accepted: 07/01/2013] [Indexed: 01/07/2023]
Abstract
NanoRNase (Nrn) specifically degrades nucleoside 3',5'-bisphosphate and the very short RNA, nanoRNA, during the final step of mRNA degradation. The crystal structure of Nrn in complex with a reaction product GMP was determined. The overall structure consists of two domains that are interconnected by a flexible loop and form a cleft. Two Mn²⁺ ions are coordinated by conserved residues in the DHH motif of the N-terminal domain. GMP binds near the DHHA1 motif region in the C-terminal domain. Our structure enables us to predict the substrate-bound form of Nrn as well as other DHH/DHHA1 phosphoesterase family proteins.
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Affiliation(s)
- Yuri Uemura
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Noriko Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan
| | - Taisuke Wakamatsu
- Microbial Genetic Division, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Kwang Kim
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Gaetano T. Montelione
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - John F. Hunt
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Seiki Kuramitsu
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan,Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan
| | - Ryoji Masui
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan,Corresponding author: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1, Machikaneyama-cho, Toyonaka, Osaka 56-0043, Japan. Telephone: +81-6-6850-5434. Fax: +81-6-6850-5442. (R. Masui)
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Shepherd J, Ibba M. Lipid II-independent trans editing of mischarged tRNAs by the penicillin resistance factor MurM. J Biol Chem 2013; 288:25915-25923. [PMID: 23867453 DOI: 10.1074/jbc.m113.479824] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Streptococcus pneumoniae is a causative agent of nosocomial infections such as pneumonia, meningitis, and septicemia. Penicillin resistance in S. pneumoniae depends in part upon MurM, an aminoacyl-tRNA ligase that attaches L-serine or L-alanine to the stem peptide lysine of Lipid II in cell wall peptidoglycan. To investigate the exact substrates the translation machinery provides MurM, quality control by alanyl-tRNA synthetase (AlaRS) was investigated. AlaRS mischarged serine and glycine to tRNA(Ala), as observed in other bacteria, and also transferred alanine, serine, and glycine to tRNA(Phe). S. pneumoniae tRNA(Phe) has an unusual U4:C69 mismatch in its acceptor stem that prevents editing by phenylalanyl-tRNA synthetase (PheRS), leading to the accumulation of misaminoacylated tRNAs that could serve as substrates for translation or for MurM. Although the peptidoglycan layer of S. pneumoniae tolerates a combination of both branched and linear muropeptides, deletion of MurM results in a reversion to penicillin sensitivity in strains that were previously resistant. However, because MurM is not required for cell viability, the reason for its functional conservation across all strains of S. pneumoniae has remained elusive. We now show that MurM can directly function in translation quality control by acting as a broad specificity lipid-independent trans editing factor that deacylates tRNA. This activity of MurM does not require the presence of its second substrate, Lipid II, and can functionally substitute for the activity of widely conserved editing domain homologues of AlaRS, termed AlaXPs proteins, which are themselves absent from S. pneumoniae.
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Affiliation(s)
| | - Michael Ibba
- From the Department of Microbiology and; Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210.
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Khan S, Garg A, Sharma A, Camacho N, Picchioni D, Saint-Léger A, de Pouplana LR, Yogavel M, Sharma A. An appended domain results in an unusual architecture for malaria parasite tryptophanyl-tRNA synthetase. PLoS One 2013; 8:e66224. [PMID: 23776638 PMCID: PMC3680381 DOI: 10.1371/journal.pone.0066224] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/02/2013] [Indexed: 01/03/2023] Open
Abstract
Specific activation of amino acids by aminoacyl-tRNA synthetases (aaRSs) is essential for maintaining fidelity during protein translation. Here, we present crystal structure of malaria parasite Plasmodium falciparum tryptophanyl-tRNA synthetase (Pf-WRS) catalytic domain (AAD) at 2.6 Å resolution in complex with L-tryptophan. Confocal microscopy-based localization data suggest cytoplasmic residency of this protein. Pf-WRS has an unusual N-terminal extension of AlaX-like domain (AXD) along with linker regions which together seem vital for enzymatic activity and tRNA binding. Pf-WRS is not proteolytically processed in the parasites and therefore AXD likely provides tRNA binding capability rather than editing activity. The N-terminal domain containing AXD and linker region is monomeric and would result in an unusual overall architecture for Pf-WRS where the dimeric catalytic domains have monomeric AXDs on either side. Our PDB-wide comparative analyses of 47 WRS crystal structures also provide new mechanistic insights into this enzyme family in context conserved KMSKS loop conformations.
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Affiliation(s)
- Sameena Khan
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Ankur Garg
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Arvind Sharma
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Noelia Camacho
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Catalonia, Spain
| | - Daria Picchioni
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Catalonia, Spain
| | - Adélaïde Saint-Léger
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Catalonia, Spain
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Catalonia, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Catalonia, Spain
| | - Manickam Yogavel
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Amit Sharma
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
- * E-mail:
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Francis BR. Evolution of the genetic code by incorporation of amino acids that improved or changed protein function. J Mol Evol 2013; 77:134-58. [PMID: 23743924 DOI: 10.1007/s00239-013-9567-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 05/25/2013] [Indexed: 12/31/2022]
Abstract
Fifty years have passed since the genetic code was deciphered, but how the genetic code came into being has not been satisfactorily addressed. It is now widely accepted that the earliest genetic code did not encode all 20 amino acids found in the universal genetic code as some amino acids have complex biosynthetic pathways and likely were not available from the environment. Therefore, the genetic code evolved as pathways for synthesis of new amino acids became available. One hypothesis proposes that early in the evolution of the genetic code four amino acids-valine, alanine, aspartic acid, and glycine-were coded by GNC codons (N = any base) with the remaining codons being nonsense codons. The other sixteen amino acids were subsequently added to the genetic code by changing nonsense codons into sense codons for these amino acids. Improvement in protein function is presumed to be the driving force behind the evolution of the code, but how improved function was achieved by adding amino acids has not been examined. Based on an analysis of amino acid function in proteins, an evolutionary mechanism for expansion of the genetic code is described in which individual coded amino acids were replaced by new amino acids that used nonsense codons differing by one base change from the sense codons previously used. The improved or altered protein function afforded by the changes in amino acid function provided the selective advantage underlying the expansion of the genetic code. Analysis of amino acid properties and functions explains why amino acids are found in their respective positions in the genetic code.
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Affiliation(s)
- Brian R Francis
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071-3944, USA,
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Perona JJ, Gruic-Sovulj I. Synthetic and editing mechanisms of aminoacyl-tRNA synthetases. Top Curr Chem (Cham) 2013; 344:1-41. [PMID: 23852030 DOI: 10.1007/128_2013_456] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRS) ensure the faithful transmission of genetic information in all living cells. The 24 known aaRS families are divided into 2 structurally distinct classes (class I and class II), each featuring a catalytic domain with a common fold that binds ATP, amino acid, and the 3'-terminus of tRNA. In a common two-step reaction, each aaRS first uses the energy stored in ATP to synthesize an activated aminoacyl adenylate intermediate. In the second step, either the 2'- or 3'-hydroxyl oxygen atom of the 3'-A76 tRNA nucleotide functions as a nucleophile in synthesis of aminoacyl-tRNA. Ten of the 24 aaRS families are unable to distinguish cognate from noncognate amino acids in the synthetic reactions alone. These enzymes possess additional editing activities for hydrolysis of misactivated amino acids and misacylated tRNAs, with clearance of the latter species accomplished in spatially separate post-transfer editing domains. A distinct class of trans-acting proteins that are homologous to class II editing domains also perform hydrolytic editing of some misacylated tRNAs. Here we review essential themes in catalysis with a view toward integrating the kinetic, stereochemical, and structural mechanisms of the enzymes. Although the aaRS have now been the subject of investigation for many decades, it will be seen that a significant number of questions regarding fundamental catalytic functioning still remain unresolved.
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Affiliation(s)
- John J Perona
- Department of Chemistry, Portland State University, 751, Portland, OR, 97207, USA,
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Gowri VS, Ghosh I, Sharma A, Madhubala R. Unusual domain architecture of aminoacyl tRNA synthetases and their paralogs from Leishmania major. BMC Genomics 2012; 13:621. [PMID: 23151081 PMCID: PMC3532385 DOI: 10.1186/1471-2164-13-621] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 10/30/2012] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Leishmania major, a protozoan parasite, is the causative agent of cutaneous leishmaniasis. Due to the development of resistance against the currently available anti-leishmanial drugs, there is a growing need for specific inhibitors and novel drug targets. In this regards, aminoacyl tRNA synthetases, the linchpins of protein synthesis, have received recent attention among the kinetoplastid research community. This is the first comprehensive survey of the aminoacyl tRNA synthetases, their paralogs and other associated proteins from L. major. RESULTS A total of 26 aminoacyl tRNA synthetases were identified using various computational and bioinformatics tools. Phylogenetic analysis and domain architectures of the L. major aminoacyl tRNA synthetases suggest a probable archaeal/eukaryotic origin. Presence of additional domains or N- or C-terminal extensions in 11 aminoacyl tRNA synthetases from L. major suggests possibilities such as additional tRNA binding or oligomerization or editing activity. Five freestanding editing domains were identified in L. major. Domain assignment revealed a novel asparagine tRNA synthetase paralog, asparagine synthetase A which has been so far reported from prokaryotes and archaea. CONCLUSIONS A comprehensive bioinformatic analysis revealed 26 aminoacyl tRNA synthetases and five freestanding editing domains in L. major. Identification of two EMAP (endothelial monocyte-activating polypeptide) II-like proteins similar to human EMAP II-like proteins suggests their participation in multisynthetase complex formation. While the phylogeny of tRNA synthetases suggests a probable archaeal/eukaryotic origin, phylogeny of asparagine synthetase A strongly suggests a bacterial origin. The unique features identified in this work provide rationale for designing inhibitors against parasite aminoacyl tRNA synthetases and their paralogs.
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Affiliation(s)
- V S Gowri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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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.
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46
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Perona JJ, Hadd A. Structural diversity and protein engineering of the aminoacyl-tRNA synthetases. Biochemistry 2012; 51:8705-29. [PMID: 23075299 DOI: 10.1021/bi301180x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRS) are the enzymes that ensure faithful transmission of genetic information in all living cells, and are central to the developing technologies for expanding the capacity of the translation apparatus to incorporate nonstandard amino acids into proteins in vivo. The 24 known aaRS families are divided into two classes that exhibit functional evolutionary convergence. Each class features an active site domain with a common fold that binds ATP, the amino acid, and the 3'-terminus of tRNA, embellished by idiosyncratic further domains that bind distal portions of the tRNA and enhance specificity. Fidelity in the expression of the genetic code requires that the aaRS be selective for both amino acids and tRNAs, a substantial challenge given the presence of structurally very similar noncognate substrates of both types. Here we comprehensively review central themes concerning the architectures of the protein structures and the remarkable dual-substrate selectivities, with a view toward discerning the most important issues that still substantially limit our capacity for rational protein engineering. A suggested general approach to rational design is presented, which should yield insight into the identities of the protein-RNA motifs at the heart of the genetic code, while also offering a basis for improving the catalytic properties of engineered tRNA synthetases emerging from genetic selections.
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Affiliation(s)
- John J Perona
- Department of Chemistry, Portland State University, Portland, Oregon 97207, United States.
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47
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Huang Q, Yao P, Eriani G, Wang ED. In vivo identification of essential nucleotides in tRNALeu to its functions by using a constructed yeast tRNALeu knockout strain. Nucleic Acids Res 2012; 40:10463-77. [PMID: 22917587 PMCID: PMC3488233 DOI: 10.1093/nar/gks783] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The fidelity of protein biosynthesis requires the aminoacylation of tRNA with its cognate amino acid catalyzed by aminoacyl-tRNA synthetase with high levels of accuracy and efficiency. Crucial bases in tRNALeu to aminoacylation or editing functions of leucyl-tRNA synthetase have been extensively studied mainly by in vitro methods. In the present study, we constructed two Saccharomyces cerevisiae tRNALeu knockout strains carrying deletions of the genes for tRNALeu(GAG) and tRNALeu(UAG). Disrupting the single gene encoding tRNALeu(GAG) had no phenotypic consequence when compared to the wild-type strain. While disrupting the three genes for tRNALeu(UAG) had a lethal effect on the yeast strain, indicating that tRNALeu(UAG) decoding capacity could not be compensated by another tRNALeu isoacceptor. Using the triple tRNA knockout strain and a randomly mutated library of tRNALeu(UAG), a selection to identify critical tRNALeu elements was performed. In this way, mutations inducing in vivo decreases of tRNA levels or aminoacylation or editing ability by leucyl-tRNA synthetase were identified. Overall, the data showed that the triple tRNA knockout strain is a suitable tool for in vivo studies and identification of essential nucleotides of the tRNA.
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Affiliation(s)
- Qian Huang
- 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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Kawahara-Kobayashi A, Masuda A, Araiso Y, Sakai Y, Kohda A, Uchiyama M, Asami S, Matsuda T, Ishitani R, Dohmae N, Yokoyama S, Kigawa T, Nureki O, Kiga D. Simplification of the genetic code: restricted diversity of genetically encoded amino acids. Nucleic Acids Res 2012; 40:10576-84. [PMID: 22909996 PMCID: PMC3488234 DOI: 10.1093/nar/gks786] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
At earlier stages in the evolution of the universal genetic code, fewer than 20 amino acids were considered to be used. Although this notion is supported by a wide range of data, the actual existence and function of the genetic codes with a limited set of canonical amino acids have not been addressed experimentally, in contrast to the successful development of the expanded codes. Here, we constructed artificial genetic codes involving a reduced alphabet. In one of the codes, a tRNAAla variant with the Trp anticodon reassigns alanine to an unassigned UGG codon in the Escherichia coli S30 cell-free translation system lacking tryptophan. We confirmed that the efficiency and accuracy of protein synthesis by this Trp-lacking code were comparable to those by the universal genetic code, by an amino acid composition analysis, green fluorescent protein fluorescence measurements and the crystal structure determination. We also showed that another code, in which UGU/UGC codons are assigned to Ser, synthesizes an active enzyme. This method will provide not only new insights into primordial genetic codes, but also an essential protein engineering tool for the assessment of the early stages of protein evolution and for the improvement of pharmaceuticals.
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Affiliation(s)
- Akio Kawahara-Kobayashi
- Department of Computational Intelligence and Systems Science, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Midori-ku, Yokohama-shi, Kanagawa 226-8503, Japan
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Eletsky A, Acton TB, Xiao R, Everett JK, Montelione GT, Szyperski T. Solution NMR structures reveal a distinct architecture and provide first structures for protein domain family PF04536. JOURNAL OF STRUCTURAL AND FUNCTIONAL GENOMICS 2012; 13:9-14. [PMID: 22198206 PMCID: PMC3609422 DOI: 10.1007/s10969-011-9122-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 12/13/2011] [Indexed: 11/29/2022]
Abstract
The protein family (Pfam) PF04536 is a broadly conserved domain family of unknown function (DUF477), with more than 1,350 members in prokaryotic and eukaryotic proteins. High-quality NMR structures of the N-terminal domain comprising residues 41-180 of the 684-residue protein CG2496 from Corynebacterium glutamicum and the N-terminal domain comprising residues 35-182 of the 435-residue protein PG0361 from Porphyromonas gingivalis both exhibit an α/β fold comprised of a four-stranded β-sheet, three α-helices packed against one side of the sheet, and a fourth α-helix attached to the other side. In spite of low sequence similarity (18%) assessed by structure-based sequence alignment, the two structures are globally quite similar. However, moderate structural differences are observed for the relative orientation of two of the four helices. Comparison with known protein structures reveals that the α/β architecture of CG2496(41-180) and PG0361(35-182) has previously not been characterized. Moreover, calculation of surface charge potential and identification of surface clefts indicate that the two domains very likely have different functions.
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Affiliation(s)
- Alexander Eletsky
- Department of Chemistry, The State University of New York at Buffalo, Buffalo, NY 14260, USA
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50
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Makarova KS, Koonin EV, Kelman Z. The CMG (CDC45/RecJ, MCM, GINS) complex is a conserved component of the DNA replication system in all archaea and eukaryotes. Biol Direct 2012; 7:7. [PMID: 22329974 PMCID: PMC3307487 DOI: 10.1186/1745-6150-7-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 02/13/2012] [Indexed: 01/14/2023] Open
Abstract
Background In eukaryotes, the CMG (CDC45, MCM, GINS) complex containing the replicative helicase MCM is a key player in DNA replication. Archaeal homologs of the eukaryotic MCM and GINS proteins have been identified but until recently no homolog of the CDC45 protein was known. Two recent developments, namely the discovery of archaeal GINS-associated nuclease (GAN) that belongs to the RecJ family of the DHH hydrolase superfamily and the demonstration of homology between the DHH domains of CDC45 and RecJ, show that at least some Archaea possess a full complement of homologs of the CMG complex subunits. Here we present the results of in-depth phylogenomic analysis of RecJ homologs in archaea. Results We confirm and extend the recent hypothesis that CDC45 is the eukaryotic ortholog of the bacterial and archaeal RecJ family nucleases. At least one RecJ homolog was identified in all sequenced archaeal genomes, with the single exception of Caldivirga maquilingensis. These proteins include previously unnoticed remote RecJ homologs with inactivated DHH domain in Thermoproteales. Combined with phylogenetic tree reconstruction of diverse eukaryotic, archaeal and bacterial DHH subfamilies, this analysis yields a complex scenario of RecJ family evolution in Archaea which includes independent inactivation of the nuclease domain in Crenarchaeota and Halobacteria, and loss of this domain in Methanococcales. Conclusions The archaeal complex of a CDC45/RecJ homolog, MCM and GINS is homologous and most likely functionally analogous to the eukaryotic CMG complex, and appears to be a key component of the DNA replication machinery in all Archaea. It is inferred that the last common archaeo-eukaryotic ancestor encoded a CMG complex that contained an active nuclease of the RecJ family. The inactivated RecJ homologs in several archaeal lineages most likely are dedicated structural components of replication complexes. Reviewers This article was reviewed by Prof. Patrick Forterre, Dr. Stephen John Aves (nominated by Dr. Purificacion Lopez-Garcia) and Prof. Martijn Huynen. For the full reviews, see the Reviewers' Comments section.
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, Maryland 20894, USA.
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