AMINOACYLATION OF TRANSFER-RNAS WITH 2-THIOURIDINE DERIVATIVES IN THEWOBBLE POSITION OF THE ANTICODON

The first position or 'wobble base' in the anticodon of tRNAs is frequ ently the site of post-transcriptional modification. In Escherichia co li, glutamine, glutamate, and lysine tRNAs contain 2-thiouridine deriv atives in this position, and the significance of these modifications h as been under investigation since their discovery. Here we describe th e investigations to link 2-thiouridine derivatives to aminoacylation o f these tRNAs. The implications of these findings on the evolution of specificity of aminoacyl-tRNA synthetases and on translational regulat ion are also discussed.