title: The T-arm of tRNA is a substrate for tRNA (m5U54)-methyltransferase.
abstract: Fragments of Escherichia coli FUra-tRNA(1Val) as small as 15 nucleotides form covalent complexes with tRNA (m5U54)-methyltransferase (RUMT). The sequence essential for binding includes position 52 of the T-stem and the T-loop and extends toward the 3' acceptor end of FUra-tRNA. The in vitro synthesized 17mer T-arm of E. coli tRNA(1Val), composed of the seven-base T-loop and 5-base-pair stem, is a good substrate for RUMT. The Km is decreased 5-fold and kcat is decreased 2-fold compared to the entire tRNA. The T-arm structure could be further reduced to an 11mer containing the loop and two base pairs and still retain activity; the Km was similar to that of the 17mer T-arm, whereas kcat was decreased an additional 20-fold. The data indicate that the primary specificity determinants for the RUMT-tRNA interaction are contained within the primary and secondary structure of the T-arm of tRNA.
authors.affiliation: Department of Biochemistry, University of California, San Francisco 94143.
authors.forename: X R
authors.initials: XR
authors.lastname: Gu
authors.forename: D V
authors.initials: DV
authors.lastname: Santi
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008745:Methylation; D008969:Molecular Sequence Data; D012366:RNA, Transfer, Val / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D012359:tRNA Methyltransferases / Q000235:genetics* / Q000378:metabolism
chemical_list: D012366:RNA, Transfer, Val; D012359:tRNA Methyltransferases