Induced Fit: A Common Strategy Used by the Ribosome in Decoding, Peptidyl Transfer and Termination

Presented by Venki Ramakrishnan, Laboratory of Molecular Biology, Structural Studies Division, Medical Research Council, Cambridge

Two critical functions of the ribosome are decoding of mRNA and synthesis of the peptide bond. Studies on the isolated 30S and 50S subunits have previously shown that both of these involve conformational changes induced by mimics of the incoming tRNA substrate. We show that these also occur in the context of the whole ribosome and full-length tRNAs. Interestingly, release factors which act at the end of translation by recognizing stop codons and cleaving the nascent polypeptide chain, also induce conformational changes in both the decoding and peptidyl transferase centers of the ribosome. The similarity and differences show how a common strategy is used in three critical functions of the ribosome, namely decoding, peptide bond formation and termination.