title: Effects of modification of 4-thiouridine in E. coli tRNAfMet on methylation reaction with a thermostable Gm-methylase.
abstract: Gm-methylase isolated from an extreme thermophile, Thermus thermophilus HB 27 methylates the 2'-OH of the ribose of G18 in the consensus GG sequence in the D loop, by recognizing the D loop-and-stem structure as a minimal substrate. Modification of s4U8 of E. coli tRNAfMet with S-benzylthioisothiourea resulted in a considerable decrease in methylation activity of Gm-methylase. The effect was cancelled by reduction with beta-mercaptoethanol. However, aminoacylation activity and methylation activity of m1A-methylase were scarcely influenced by the modification. These results suggest the involvement of s4U8 residue of tRNA in the recognition of Gm-methylase.
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D008623:Mercaptoethanol / Q000494:pharmacology; D008745:Methylation; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012358:RNA, Transfer, Met; D013824:Thermus / Q000201:enzymology*; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology; D013891:Thiouridine; D012359:tRNA Methyltransferases / Q000378:metabolism*
chemical_list: D012346:RNA, Transfer, Amino Acyl; D012358:RNA, Transfer, Met; C024988:tRNA, formylmethionine-; D013891:Thiouridine; C000167:S-benzylthioisothiourea; D008623:Mercaptoethanol; D012359:tRNA Methyltransferases; C023196:tRNA (guanine(10)-N(2))-dimethyltransferase; D013890:Thiourea