Terminal oxidation-reduction of N-acetyl-phenylalanyl-tRNA blocks initiation complex formation with Escherichia coli 30S ribosomal subunits

Terminally oxidized-reduced tRNA^Phe of yeast, exclusively acylated at the 2′-hydroxyl of the 3′-terminal ribose of the tRNA, is a useful model for investigating the stereospecificity of AA-tRNA in protein synthesis. In this work, the ability of N-acetyl-Phe-tRNA^ox-red to form an initiation complex with Escherichiacoli 30S ribosomal subunits was investigated. Thirty per cent of added control N-acetyl-Phe-tRNA was bound in a reaction dependent on initiation factors, GTP, and poly U, but no binding of the oxidized-reduced analog could be detected. These results imply that initiation complex formation may be specific for the 3′-ester of initiator tRNA.