An ORC/Cdc6/MCM2-7 Complex Is Formed in a Multistep Reaction to Serve as a Platform for MCM Double-Hexamer Assembly

► A Cdt1 interaction with MCM2-7 alleviates an autoinhibitory activity in Mcm6 ► OCM establishment occurs fast, while MCM2-7 double-hexamer formation is slow ► Both Orc1 and Cdc6 ATP-hydrolysis promote Cdt1 release and OCM formation ► The OCM represents a platform for double-hexamer assembly