s of this group, including simian virus 40 large T-antigen (6), Escherichia coli DnaB (7) and Archaeal Mcm (4,8,9), are composed of a single subunit, the active eukaryotic Mcm helicases are composed of two trimeric Mcm4/6/7 proteins (10–14).
All the six Mcm 2–7 proteins contain highly conserved DNA-dependent ATPase motifs in their central regions (15,16). Among the several st