RELEASE OF TRANSFER RNA DURING PEPTIDE CHAIN ELONGATION

Abstract

In amino acid polymerization, the tRNA donating its peptidyl moiety to the neighboring aminoacyl-tRNA must be released from the ribosome for further growth of the polypeptide chain. It was not known at what stage of peptide elongation this tRNA is released. To study this question, we prepared ac-C(14)-Phe-H(3)-tRNA using H(3)-tRNA isolated from E. coli strain 15THU grown in the presence of H(3)-uracil, and followed the fate of the H(3)-tRNA during chain growth. Our results indicate that donor tRNA is released during the translocation step, mediated by the soluble factor G and GTP.