. "The binding of the primer recognition complex involves the loading of proliferating cell nuclear antigen (PCNA). Replication Factor C transiently opens the PCNA toroid in an ATP-dependent reaction, and then allows PCNA to re-close around the double helix adjacent to the primer terminus. This leads to the formation of the \"sliding clamp\"."^^ . . . . . . . "Loading of PCNA - Sliding Clamp Formation"^^ . . . . . .