Regensburg 2004 – wissenschaftliches Programm

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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology

SYLS 3: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"

SYLS 3.38: Poster

Mittwoch, 10. März 2004, 16:00–18:30, B

DNA-histone complexes: interaction and conformation — •Hoda Boroudjerdi and Roland Netz — Sektion Physik, Ludwig-Maximilians-Universitaet Muenchen, Theresienstr. 37, 80333 Muenchen

We investigate effective interaction between two complexes of semiflexible charged polymers with oppositely-charged spheres with parameters appropriate for the DNA-histone system. We determine the ground state of the system numerically by minimizing a free energy expression, which includes electrostatic effects on a linear level. We obtain the effective interaction potential between two complexes for various system parameters, namely, the charge valency of the spheres and the salt concentration. It is shown that within this model, complexes can attract each other at short distances depending on the system parameters, which arises from an interplay between electrostatic interactions, bending rigidity and conformational behavior of the charged polymers. We examine different phases of the system based on symmetry arguments, which include bridging and binding phases. Finally, we present the behavior of the second virial coefficient of this system in terms of the salt concentration, which exhibits a non-monotonic behavior with a minimum at moderate salt concentrations.