This domain is found in peptide chain release factors.

1: Crystal structure of a translation termination complex formed with release factor RF2. Korostelev A, Asahara H, Lancaster L, Laurberg M, Hirschi A, Zhu J, Trakhanov S, Scott WG, Noller HF; Proc Natl Acad Sci U S A. 2008;105:19684-19689. PMID:19064930