Characterization of Three Proteins Involved in Polypeptide Chain Termination
This extract was created in the absence of an abstract.
Excerpt
At each stage of elongation, the growing polypeptide chain is bound to the ribosome-messenger RNA complex through the transfer RNA of the most recently incorporated amino acid residue (Gilbert, 1963; Bretscher, 1963). When the chain is complete, the last polypeptide-transfer RNA (tRNA) ester linkage is cleaved, releasing the chain from the tRNA and thus from the ribosomal complex. This hydrolysis occurs when the ribosome in the course of moving along the messenger RNA (mRNA) reaches a chain terminating signal.
The first step in elucidating the mechanism of polypeptide chain termination was to identify such signals. A purely genetic approach indicated that the codons UAA, UAG, and UGA could act as termination signals (Brenner, Stretton, and Kaplan, 1965; Weigert and Garen, 1965; Sambrook, Fan, and Brenner, 1967; Zipser, 1967). If by mutation such a codon appears, in phase, in the interior of a cistron, premature polypeptide chain termination occurs at the...
