A single base substitution in the variable pocket of yeast tRNA(Arg) eliminates species-specific aminoacylation

• Published in: Biochimica et biophysica acta Vol. 1473; no. 2-3; p. 356
• Main Authors: Liu, W, Huang, Y, Eriani, G, Gangloff, J, Wang, E, Wang, Y
• Format: Journal Article
• Language: English
• Published: Netherlands 27.12.1999
• Subjects: Amino Acyl-tRNA Synthetases - metabolism; Escherichia coli - enzymology; Escherichia coli - genetics; Genes, Bacterial; Genes, Fungal; Kinetics; Point Mutation; RNA, Transfer, Amino Acyl - genetics; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Substrate Specificity - genetics; Templates, Genetic; Transcription, Genetic
• ISSN: 0006-3002
• DOI: 10.1016/S0304-4165(99)00143-9

Early biochemical data showed that aminoacyl-tRNA synthetases often displayed species-specific recognition of tRNA. We compared the ability of purified Saccharomyces cerevisiae and Escherichia coli arginyl-tRNA synthetases to aminoacylate native and transcribed yeast tRNA(Arg) as well as E. coli tRNA(Arg). The kinetic data revealed that yeast ArgRS could charge E. coli tRNA(Arg), but at a lower efficiency than it charged either the transcribed or native yeast tRNA(Arg). E. coli ArgRS can acylate only its cognate E. coli tRNA. Strikingly, a single base change from C to A at position 20 in yeast tRNA(3)(Arg) altered the species specificity. The transcript of yeast tRNA(3)(Arg)CA20 mutant was aminoacylated by E. coli ArgRS with a 10(6) increase in k(cat)/K(m) over that for aminoacylation of yeast tRNA(3)(Arg) transcript. This indicates that A20 is not only an important identity of E. coli tRNA(Arg), but is also the key to altering species-specific aminoacylation of yeast tRNA(Arg).