Figure 6.

Loop formation at the origin engineered by the E2 protein. (A) Small loop formation. The E2 protein binds to its binding sites at the origin in dimeric form, and this complex formation leads to a loop structure’s formation at the origin of DNA replication. A disk-shaped loop is formed when binding sites 1, 2, and 3 are bound to the E2 protein. (B) Large loop formation. When E2 is bound to all four binding sites, it attracts more E2 dimers to the complex and larger loop formation occurs.