InterPro domain: IPR004403

This entry represents the eRF1 and aRF1 proteins.

Terminating protein synthesis on the ribosome requires the presence of a class I polypeptide chain release factor (RF) to induce peptidyl-tRNA hydrolysis. Bacteria possess two class I RFs; RF1 which recognises UAG and UAA, and RF2 which recognises UGA and UAA. Mitochondrial RFs are related structurally and functionally to those of bacteria. Eukaryotes posses only a single class 1 factor, eRF1, which recognises all three termination codons. Similarly, in all archaeal species where the complete sequence of the genome is available, only a single class I factor, aRF1, has been identified so far. The aRF1 family is highly homologous to the eRF1 family, indicating a common origin and ancestor molecule. The bacterial and mitochondrial class I RFs show no significant sequence similarity with their eukaryotic and archaeal counterparts and are considered to form a separate family. For more information see [ 1 , 2 , 3 ].

1. Polypeptide chain release factors. Mol. Microbiol. 24, 449-56
2. Polypeptide release factor eRF1 from Tetrahymena thermophila: cDNA cloning, purification and complex formation with yeast eRF3. FEBS Lett. 457, 483-8
3. Translation termination factor aRF1 from the archaeon Methanococcus jannaschii is active with eukaryotic ribosomes. FEBS Lett. 472, 213-6