InterPro domain: IPR000352

Peptide chain release factors (RFs) are required for the termination of protein biosynthesis [ 1 ]. At present two classes of RFs can be distinguished. Class I RFs bind to ribosomes that have encountered a stop codon at their decoding site and induce release of the nascent polypeptide. Class II RFs are GTP-binding proteins that interact with class I RFs and enhance class I RFactivity. In prokaryotes there are two class I RFs that act in a codon specific manner [ 2 ]: RF-1(gene prfA) mediates UAA and UAG-dependent termination while RF-2 (gene prfB) mediates UAA and UGA-dependent termination. RF-1 and RF-2 are structurally and evolutionary related proteins which have been shown to be part of a larger family [ 3 ].

1. Hidden infidelities of the translational stop signal. Prog. Nucleic Acid Res. Mol. Biol. 52, 293-335
2. Recent advances in peptide chain termination. Mol. Microbiol. 4, 861-5
3. Sequence comparison of new prokaryotic and mitochondrial members of the polypeptide chain release factor family predicts a five-domain model for release factor structure. Nucleic Acids Res. 20, 4423-8