This domain is found in Selenocysteine-specific elongation factor from humans (SelB) and similar sequences from eukaryotes. SelB is a translation factor necessary for the incorporation of selenocysteine into proteins. This protein adopts a chalice-like structure composed of four domains. This entry represents the third domain, which shows seven antiparallel beta-strands and a long alpha-helix [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