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CPP: Chemische Physik und Polymerphysik

CPP 26: POSTER Dynamics and Diffusion

CPP 26.5: Poster

Donnerstag, 30. März 2006, 17:00–19:00, P2

Semiflexibility accelerates barrier crossing of hinged polymers — •Wolfram Möbius, Richard. A. Neher, and Ulrich Gerland — Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for Nanoscience (CeNS), LMU München

We study the planar rotational diffusion of a semiflexible polymer with one free and one hinged end. The hinged end is subject to a periodic potential that acts on the angle of the attachment. We find that the rate for the crossing of the potential barriers is considerably larger for a semiflexible polymer than for a stiff rod. This enhancement of the rate occurs even at persistence lengths which are much larger than the contour length, so that the average end-to-end distance of the polymer is close to its limiting value. To understand this behavior we consider a system where the polymer is replaced by two elastically jointed segments. This toy model is amenable to analytic treatment and we derive expressions for the diffusion and barrier crossing rates for large bending rigidities. Both models may help to understand the thermally activated wrapping and unwrapping of DNA in nucleosomes.