Probable component of the MCM2-7 complex (MCM complex) that may function as a DNA helicase and which is essential to undergo a single round of replication initiation and elongation per cell cycle in eukaryotic cells. Can complement the fission yeast mcm2 mutant. ATP + H2O = ADP + H(+) + phosphate Component of the minichromosome maintenance (MCM) complex, a heterotetramer composed of MCM2, MCM3, MCM4, MCM5, MCM6 and MCM7 (By similarity). Interacts with CSN5 (PubMed:18755073). Widely expressed, with higher expression in developing tissues. Belongs to the MCM family.