This family contains an OB-fold found within MCM proteins. This domain contains an insertion at the zinc binding motif [2].

1: The structure and function of MCM from archaeal M. Thermoautotrophicum. Fletcher RJ, Bishop BE, Leon RP, Sclafani RA, Ogata CM, Chen XS; Nat Struct Biol. 2003;10:160-167. PMID:12548282

2: The 1.8-A crystal structure of the N-terminal domain of an archaeal MCM as a right-handed filament. Fu Y, Slaymaker IM, Wang J, Wang G, Chen XS; J Mol Biol. 2014;426:1512-1523. PMID:24378617