The mechanism of messenger RNA translocation through ribosomes.

The two recognized enzymatic steps involved in the extension of peptides on ribosomes of the 80S type have been studied in a highly purified transfer system derived from rabbit reticulocytes. Data presented are interpreted to reflect three ribosomal binding sites through which transfer RNA is moved in two independent enzymatic reactions each of which requires guanosine 5'-triphosphate hydrolysis. The binding enzyme facilitates translocation between the entry and acceptor ribosomal sites. Transferase II is involved in translocation between the acceptor and donor ribosomal sites. A model is proposed to account for movement of transfer RNA and messenger RNA between the ribosomal sites.