Dynamics of DNA in entangled polymer solutions: An anisotropic friction model

We studied the electrophoretic behavior of DNA chains in linear-polymer sol utions using Brownian dynamics with an anisotropic friction model in a thre e-dimensional space and projected on the x axis. For the three-dimensional model with a chain segment equal to 1/8 of the Kuhn length, a chain migrate s with U-shaped conformation with low anisotropy of friction. With high ani sotropy of friction, a chain always migrates with linear-shaped conformatio n with high segment-density regions, which remain at the same positions in space. This migration mode agrees with the observation of DNA in highly ent angled solutions [Ueda , Biophys. Chem. 71, 113 (1998)]. The projection mod el also reproduces the linear-shaped motion. We clarified that the essentia l conditions for linear shaped motion are the sufficient chain length of DN A, the small mesh size, and strong confinement by entanglement with solvent polymers. (C) 2001 American Institute of Physics.