Abstract
To study the evolution of the tRNA recognition mechanism, we constructed variants of baker's yeast tRNAThr transcripts using an in vitro transcription system and compared the recognition elements of yeast tRNAThr with those of Escherichia coli tRNAThr. In yeast tRNAThr, the second and third positions of the anticodon, G35U36, are major recognition sites, whereas the discriminator base A73 is not involved in aminoacylation. These are the same as in E. coli tRNAThr. These findings indicate the similarity of the recognition system by the cognate threonyl-tRNA synthetase functions in E. coli and yeast.
