Species-specific differences in the operational RNA code for aminoacylation of tRNA(Trp).
Identity elements play essential roles in the recognition of tRNAs by their cognate aminoacyl-tRNA synthetase. An operational RNA code relates amino acids to specific sequences and structural features of tRNA acceptor stems. In this study, a series of tRNA(Trp) variants was prepared by in vitro transcription and their efficiencies of aminoacylation by tryptophan (k(cat)/K(m)) were measured with the aid of Bacillus subtilis and human tryptophanyl-tRNA synthetases (TrpRS). The identity elements in the operational RNA code of human tRNA(Trp) were found to be: major element, discriminator base A73; minor elements, G1/C72 and U5/G68. From the cross-species aminoacylation assays, we conclude that the identity elements in tRNA(Trp) from B.subtilis and human all contribute to species-specific aminoacylation by TrpRS. Analyses of 22 TrpRS sequences covering three taxonomic domains (bacteria, eukarya and archaea) reveal that the sequences are divided into two evolutionarily distant groups. The same partition is also observed in the analyses of tRNA(Trp) acceptor stem sequences. Our data suggest that the two TrpRS groups may reflect co-adaptations needed to accommodate changes in the operational RNA code for tryptophan.
Xu
F
F
State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Life Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
Chen
X
X
Xin
L
L
Chen
L
L
Jin
Y
Y
Wang
D
D
D000215:Acylation; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012364:RNA, Transfer, Trp / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014364:Tryptophan / Q000378:metabolism; D014369:Tryptophan-tRNA Ligase / Q000235:genetics* / Q000378:metabolism
D012329:RNA, Bacterial; D012364:RNA, Transfer, Trp; D014364:Tryptophan; D014369:Tryptophan-tRNA Ligase