Members of this family, which are required for the formation of the active site of the sex-determining protein Xol-1, adopt a secondary structure consisting of five alpha helices and six antiparallel beta sheets, in a beta-alpha-beta-beta-beta-alpha-beta-alpha-alpha-alpha-beta arrangement. The fold of this family is similar to that found in ribosomal protein S5 domain 2-like [1].

1: XOL-1, primary determinant of sexual fate in C. elegans, is a GHMP kinase family member and a structural prototype for a class of developmental regulators. Luz JG, Hassig CA, Pickle C, Godzik A, Meyer BJ, Wilson IA; Genes Dev. 2003;17:977-990. PMID:12672694