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 =N/, where N is the number of chain segments and 1/ is the dimensionless field strength. For short chains, <1, the characteristic unhooking time scales as N2, whereas for long chains, 1, it scales as N. Without introducing post friction, the model is able to reproduce recent experimental observations. © 1994 The American Physical Society.