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AKB: Biologische Physik

AKB 100: Poster Session I

AKB 100.23: Poster

Samstag, 5. März 2005, 16:45–18:45, Poster TU D

Overcharging of a sphere by a rodlike polyelectrolyte — •Andrey Cherstvy and Roland G. Winkler — IFF, Forschungszentrum Jülich, D-52425 Jülich

We investigate the complexation of a polyelectrolyte bendable rod with an oppositely charged spherical macroion. We take into account the electrostatic bending of the rod and its asymmetric charge neutralization by sphere charges. The spontaneous curvature of the rod towards the sphere results in a substantial overcharging of such a polyelectrolyte complex. Assuming a discrete helical charge distribution on the rod surface, we calculate its electrostatic energy and the electrostatic contribution to its bending and twisting elasticity modules. We show that the helix is easier bend than the corresponding linear array of charges and also that its electrostatic twist rigidity modulus may change sign when the helical pitch is changed. We compare our results with results of existing theories and discuss their possible applications for the description of the structure of nucleosome core particles and twisting/bending of DNA duplexes.