title: Trans-kingdom rescue of Gln-tRNAGln synthesis in yeast cytoplasm and mitochondria.
abstract: Aminoacylation of transfer RNA(Gln) (tRNA(Gln)) is performed by distinct mechanisms in different kingdoms and represents the most diverged route of aminoacyl-tRNA synthesis found in nature. In Saccharomyces cerevisiae, cytosolic Gln-tRNA(Gln) is generated by direct glutaminylation of tRNA(Gln) by glutaminyl-tRNA synthetase (GlnRS), whereas mitochondrial Gln-tRNA(Gln) is formed by an indirect pathway involving charging by a non-discriminating glutamyl-tRNA synthetase and the subsequent transamidation by a specific Glu-tRNA(Gln) amidotransferase. Previous studies showed that fusion of a yeast non-specific tRNA-binding cofactor, Arc1p, to Escherichia coli GlnRS enables the bacterial enzyme to substitute for its yeast homologue in vivo. We report herein that the same fusion enzyme, upon being imported into mitochondria, substituted the indirect pathway for Gln-tRNA(Gln) synthesis as well, despite significant differences in the identity determinants of E. coli and yeast cytosolic and mitochondrial tRNA(Gln) isoacceptors. Fusion of Arc1p to the bacterial enzyme significantly enhanced its aminoacylation activity towards yeast tRNA(Gln) isoacceptors in vitro. Our study provides a mechanism by which trans-kingdom rescue of distinct pathways of Gln-tRNA(Gln) synthesis can be conferred by a single enzyme.
authors: Department of Life Sciences, National Central University, Jung-li 32001, Taiwan, Republic of China.
authors: Chih-Chi
authors: CC
authors: Liao
authors: Chen-Huan
authors: CH
authors: Lin
authors: Shun-Jia
authors: SJ
authors: Chen
authors: Chien-Chia
authors: CC
authors: Wang
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003593:Cytoplasm / Q000201:enzymology*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012351:RNA, Transfer, Gln / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics; D046249:Transfer RNA Aminoacylation
chemical_list: C102145:ARC1 protein, S cerevisiae; D012351:RNA, Transfer, Gln; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D000604:Amino Acyl-tRNA Synthetases; C020659:glutaminyl-tRNA synthetase