A single base substitution in the variable pocket of yeast tRNA(Arg) eliminates species-specific aminoacylation.
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).
Liu
W
W
State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, Academia Sinica, 320 Yue-yang Road, Shanghai, China.
Huang
Y
Y
Eriani
G
G
Gangloff
J
J
Wang
E
E
Wang
Y
Y
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D005800:Genes, Fungal; D007700:Kinetics; D017354:Point Mutation; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D013379:Substrate Specificity / Q000235:genetics*; D013698:Templates, Genetic; D014158:Transcription, Genetic
D012346:RNA, Transfer, Amino Acyl; D000604:Amino Acyl-tRNA Synthetases