This entry represents the C-terminal RIFT beta barrel domain found in the Selenocysteine-specific elongation factor eEFSec [1]. Selenocysteine is the only proteinogenic amino acid encoded by a recoded in-frame UGA codon that does not operate as the canonical opal stop codon. A specialised translation elongation factor, eEFSec in eukaryotes and SelB in prokaryotes, promotes selenocysteine incorporation into selenoproteins [1].

1: Crystal structures of the human elongation factor eEFSec suggest a non-canonical mechanism for selenocysteine incorporation. Dobosz-Bartoszek M, Pinkerton MH, Otwinowski Z, Chakravarthy S, Soll D, Copeland PR, Simonovic M; Nat Commun. 2016;7:12941. PMID:27708257