Oligomeric XPD helicase exhibits enhanced unwinding activity by pushing in unstable regions of DNA

Helicases are a class of motor proteins that utilize ATP hydrolysis to translocate and unwind double-stranded DNA (dsDNA), and play key roles in genome maintenance processes. The mechanisms by which the unwinding activity of helicases is regulated remain poorly understood. XPD serves has a model for understanding a family of biomedically important helicases involved in genome repair. XPD as a monomer is an inefficient unwinder of dsDNA, able to unwind only short DNA duplexes due to difficulties melting stable (i.e.