Release Factor, Translation

Synonyms

eRF; RF; Termination factor

Definition

A release factor (RF) refers to a type of translation factor that triggers translation termination. Release factors fall into two classes; Class I release factors that bind the ribosome in response to the presence of a stop codon within the ribosomal A-site (acceptor site). This binding event triggers release of the nascent polypeptide by the ribosome, a so-called peptidyl release reaction. Eukaryote species utilize a single Class I RF, eRF1, that can recognize all three stop codons. Bacterial Class I RFs are of two types, those that recognize UAA and UAG triplets (RF1) and those that recognize UAA and UGA (RF2). Class II release factors are GTP-binding proteins that serve to enhance the efficiency of translation termination, either by promoting release of the Class I factor from the ribosome after peptidyl release (as in the case of bacterial release factors) or by forming a complex with the Class I RF prior to stop codon recognition (as...