摘要： Aminoacylation of transfer RNA super(Gln) (tRNA super(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 super(Gln) is generated by direct glutaminylation of tRNA super(Gln) by glutaminyl-tRNA synthetase (GlnRS), whereas mitochondrial Gln-tRNA super(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 super(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 super(Gln) synthesis as well, despite significant differences in the identity determinants of E. coli and yeast cytosolic and mitochondrial tRNA super(Gln) isoacceptors. Fusion of Arc1p to the bacterial enzyme significantly enhanced its aminoacylation activity towards yeast tRNA super(Gln) isoacceptors in vitro. Our study provides a mechanism by which trans-kingdom rescue of distinct pathways of Gln-tRNA super(Gln) synthesis can be conferred by a single enzyme. 出版日期： 2012-10-01 出處： Nucleic acids research, 2012-10, Vol.40 (18), p.9171-9181 識別號： ISSN: 0305-1048 識別號： EISSN: 1362-4962 識別號： DOI: 10.1093/nar/gks689
