The C-terminal domain of the bacterial protein 'bypass of forespore C' contains a three-stranded beta-sheet and three alpha-helices. Its exact function is, as yet, unknown [1].

1: The structure of bypass of forespore C, an intercompartmental signaling factor during sporulation in Bacillus. Patterson HM, Brannigan JA, Cutting SM, Wilson KS, Wilkinson AJ, Ab E, Diercks T, de Jong RN, Truffault V, Folkers GE, Kaptein R; J Biol Chem. 2005;280:36214-36220. PMID:16049010