This domain is found at the C-terminus of proteins that are members of MGTC/SAPB family. It adopts a ferredoxin-like fold and has a significant structural similarity to ACT-like domains. In contrast to the canonical ACT-like domains, this domain doesn't dimerize or bind to small molecules. It is probably involved in protein-protein interactions [1].

1: The C-terminal domain of the virulence factor MgtC is a divergent ACT domain. Yang Y, Labesse G, Carrere-Kremer S, Esteves K, Kremer L, Cohen-Gonsaud M, Blanc-Potard AB; J Bacteriol. 2012;194:6255-6263. PMID:22984256