Figure 7. A model for DNA translocation on the nucleosome.

Binding of the ATPase motor in an open state stabilizes a twist defect at SHL2, which pulls entry-side DNA toward the remodeler in a corkscrew-like motion. The closed state of the motor attained during ATP hydrolysis is incompatible with the twist defect at SHL2, forcing the extra DNA toward the dyad. Cycling of the ATPase motor therefore both creates twist defects and stimulates twist diffusion around the histone core.