Motion of a polyelectrolyte chain hooked around a post

The release kinetics of a single DNA molecule hooked around an obstacle in the presence of an electric field is investigated. A kinetic model which includes both electrical and stretching forces is introduced and used both in computer simulation and in the development of a simple analytic argument. These predict two regimes which depend on {Υ}=N/{β}, where N is the number of chain segments and 1/{β} is the dimensionless field strength. For short chains, {Υ}1, the characteristic unhooking time scales as N², whereas for long chains, {Υ}{}1, it scales as N. Without introducing post friction, the model is able to reproduce recent experimental observations.