FIGURE 1.

Schematic illustrating the action of an RF during translation termination. A, a ribosome that has completed protein synthesis and translocated the stop codon to the A-site. The RF has two critical functional domains; one is required to recognize the stop triplet, and the other, which on correct positioning in the PTC, facilitates the hydrolysis of the ester bond between the terminal P-site tRNA and the nascent polypeptide. B, the correct insertion and spanning of these two RF functional domains that are ∼70 Å apart when in the ribosome. C, the completed protein has dissociated from the tRNA and is released from the ribosome, and in all probability, this is accompanied by specific chaperones to ensure correct folding and association with partner proteins (not depicted here).