This domain is found twice in Selenocysteine-specific elongation factor from Escherichia coli (SelB) and in similar proteins mainly found in proteobacteria. SelB is a translation factor necessary for the incorporation of selenocysteine into proteins. SelB is composed of a N-terminal region, which contains Pfam:PF00009 and Pfam:PF03144, and a C-terminal extension that consists of four winged-helix (WH) domains arranged in tandem. This entry represents the first and third of these motifs, each containing three helices flanked by a three-stranded antiparallel beta-sheet [1].

1: Structural insight into a molecular switch in tandem winged-helix motifs from elongation factor SelB. Soler N, Fourmy D, Yoshizawa S; J Mol Biol. 2007;370:728-741. PMID:17537456