title: Sulfur Modifications of the Wobble U34in tRNAs and their Intracellular Localization in Eukaryotic Cells.
abstract: The wobble uridine (U34) of transfer RNAs (tRNAs) for two-box codon recognition, i.e., tRNALysUUU, tRNAGluUUC, and tRNAGlnUUG, harbor a sulfur- (thio-) and a methyl-derivative structure at the second and fifth positions of U34, respectively. Both modifications are necessary to construct the proper anticodon loop structure and to enable them to exert their functions in translation. Thio-modification of U34(s²U34) is found in both cytosolic tRNAs (cy-tRNAs) and mitochondrial tRNAs (mt-tRNAs). Although l-cysteine desulfurase is required in both cases, subsequent sulfur transfer pathways to cy-tRNAs and mt-tRNAs are different due to their distinct intracellular locations. The s²U34formation in cy-tRNAs involves a sulfur delivery system required for the biosynthesis of iron-sulfur (Fe/S) clusters and certain resultant Fe/S proteins. This review addresses presumed sulfur delivery pathways for the s²U34formation in distinct intracellular locations, especially that for cy-tRNAs in comparison with that for mt-tRNAs.
authors.affiliation: Departments of Biochemistry, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki Osaka 569-8686, Japan. med004@osaka-med.ac.jp.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Nakai
authors.affiliation: Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita Osaka 565-0871, Japan. nakai@protein.osaka-u.ac.jp.
authors.forename: Masato
authors.initials: M
authors.lastname: Nakai
authors.affiliation: Departments of Biochemistry, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki Osaka 569-8686, Japan. med013@osaka-med.ac.jp.
authors.forename: Takato
authors.initials: T
authors.lastname: Yano
mesh_terms: D000818:Animals; D000926:Anticodon / Q000737:chemistry; D013437:Carbon-Sulfur Lyases / Q000378:metabolism; D003600:Cytosol / Q000737:chemistry; D056890:Eukaryota / Q000235:genetics*; D006801:Humans; D008928:Mitochondria / Q000737:chemistry; D012343:RNA, Transfer / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D000926:Anticodon; D013455:Sulfur; D012343:RNA, Transfer; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase
keywords: cluster; cytosolic tRNA (cy-tRNA); iron-sulfur (Fe/S); mitochondrial tRNA (mt-tRNA); the wobble uridine (U34); thio-modification of U34 (s2U34)