Minichromosome Maintenance Complex Binding Protein (MCMBP)

MCMBP bound to chromatin in a manner typical of MCM proteins, and that MCMBP was preferentially associated with a cellular origin in G1 but not S phase. In vivo tagging experiments, coimmunoprecipitation of endogenous MCM proteins in HeLa cells, and analysis of recombinant MCM complexes in insect cells revealed that MCMBP formed a hexamer with MCM3 through MCM7 that excluded MCM2; conversely, the hexamer of MCM2 through MCM7 excluded MCMBP. MCMBP also formed a complex with the MCM4 /MCM6/MCM7 core helicase in vitro, but, unlike MCM2, MCMBP did not inhibit helicase activity. The 640-amino acid MCMBP protein shares limited homology with members of the MCM family and is highly conserved in multicellular eukaryotes.