Involved in regulation of DNA replication. May play essential roles in origin recognition and cell cycle control of replication. Binds specifically to the oriC region, which alters the topological structure of the DNA and introduces localized melting of the DNA duplex. May recruit the MCM helicase onto the oriC region. Shows weak ATPase activity in the absence of DNA. Homodimer (Probable). Interacts with MCM. Belongs to the CDC6/cdc18 family.