This protein family includes Swiss:A9W9V0 from Chloroflexus aurantiacus (Caur_1358), a 4-Oxalocrotonate tautomerase (4-OT). This protein adopts a beta-alpha-beta scaffold and forms part of a functional heterohexamer 4-OT (hh4-OT) that contains three heterodimer units, each composed of one alpha-subunit (Pfam:PF01361) and one beta-subunit (this entry) [1].

1: Kinetic and structural characterization of a heterohexamer 4-oxalocrotonate tautomerase from Chloroflexus aurantiacus J-10-fl: implications for functional and structural diversity in the tautomerase superfamily . Burks EA, Fleming CD, Mesecar AD, Whitman CP, Pegan SD; Biochemistry. 2010;49:5016-5027. PMID:20465238