Twisting DNA with variable intrinsic curvature

LPM2C, Université Joseph Fourier - France DRFMC/SI3M - CEA-CENG - 17 rue des Martyrs, 38054 Grenoble Cedex 9, France

Received: 19 July 1999
Accepted: 19 November 1999

Abstract

We study the effect of applying a twist to an elastic rod with intrinsic curvature distributed on segments spaced by elastic loops without intrinsic curvature. This model describes the elastic properties of DNA molecules with non-uniform roll-tilt distribution. A novel numerical technique is introduced to compute the equilibrium shape at fixed angle of torsion for a wide range of torque regimes. It is shown that the strain associated with torsion is preferably distributed on the segments with intrinsic curvature. An analytical solution is obtained for small torques. We discuss our results in the context of single-molecule experiments.