EEFSEC

Translation factor required for the incorporation of the rare amino acid selenocysteine encoded by UGA codons. Replaces the eRF1-eRF3-GTP ternary complex for the insertion of selenocysteine directed by the UGA codon. Insertion of selenocysteine at UGA codons is mediated by SECISBP2 and EEFSEC: SECISBP2 (1) specifically binds the SECIS sequence once the 80S ribosome encounters an in-frame UGA codon and (2) contacts the RPS27A/eS31 of the 40S ribosome before ribosome stalling. (3) GTP-bound EEFSEC then delivers selenocysteinyl-tRNA(Sec) to the 80S ribosome and adopts a preaccommodated state conformation. (4) After GTP hydrolysis, EEFSEC dissociates from the assembly, selenocysteinyl-tRNA(Sec) accommodates, and peptide bond synthesis and selenoprotein elongation occur..

Function from UniProtKB (P57772), read 2026-09-23. CC BY 4.0.