Members of this family contain a four-stranded beta sheet and three alpha helices flanked by an additional beta strand. They are predominantly found in the bacterial GTP-binding protein Obg, and are still functionally uncharacterised [1].

1: Crystal structure of the GTP-binding protein Obg from Thermus thermophilus HB8. Kukimoto-Niino M, Murayama K, Inoue M, Terada T, Tame JR, Kuramitsu S, Shirouzu M, Yokoyama S; J Mol Biol. 2004;337:761-770. PMID:15019792