This domain is found in Selenocysteine-specific elongation factor from Escherichia coli (SelB) and similar bacterial sequences. SelB is a translation factor necessary for the incorporation of selenocysteine into proteins. The C-terminal region of this protein in bacteria shows four winged-helix (WH) domains arranged in tandem, which form two globular structures. This entry represents the second pair of WH domains (WH3 and 4). Each WH domain is an alpha-beta structure consisting of three alpha-helices and a twisted three- stranded antiparallel beta-sheet [1-3].

1: Crystal structure of an mRNA-binding fragment of Moorella thermoacetica elongation factor SelB. Selmer M, Su XD; EMBO J. 2002;21:4145-4153. PMID:12145214

2: Structural basis for mRNA recognition by elongation factor SelB. Yoshizawa S, Rasubala L, Ose T, Kohda D, Fourmy D, Maenaka K; Nat Struct Mol Biol. 2005;12:198-203. PMID:15665870

3: 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