Dresden 2006 – scientific programme

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DY: Dynamik und Statistische Physik

DY 41: Dynamical Physics in Biological Systems

DY 41.1: Talk

Thursday, March 30, 2006, 10:00–10:15, SCH 251

DNA as a rigid-body chain — •Nils Becker and Ralf Everaers — MPI Physik Komplexer Systeme, Dresden

The functioning of the DNA molecule in many biological situations depends on its sequence-dependent elastic behavior on a scale of a few base pairs to a few helical turns. Examples include winding onto nucleosomes and transcription regulation.

We investigate the elastic properties of DNA at this scale. We study a chain model in which the monomers are the base pairs, considered as rigid bodies. We take into account the full detail of their sequence dependent nearest neighbor interaction, including coupling of rotational and translational degrees of freedom, within a harmonic approximation.

This model fits in as a natural step in a coarse-graining hierarchy of DNA models. On the microscopic side, it can be parametrized by existing inter-base pair harmonic potentials. This allows a calculation of the sequence-dependent elastic response to forces and moments that are applied to short stretches of DNA. Towards larger scales, by taking an appropriate continuum limit, we can relate it to classic chain models for semiflexible polymers.