Members of this family pertain to a set of functionally uncharacterised hypothetical bacterial proteins. They adopt a ferredoxin-like fold, with a beta-alpha-beta-beta-alpha-beta arrangement [1].

1: Crystal structure of YIGZ, a conserved hypothetical protein from Escherichia coli k12 with a novel fold. Park F, Gajiwala K, Eroshkina G, Furlong E, He D, Batiyenko Y, Romero R, Christopher J, Badger J, Hendle J, Lin J, Peat T, Buchanan S; Proteins. 2004;55:775-777. PMID:15103642