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BP: Fachverband Biologische Physik

BP 8: Charge Transfer

BP 8.3: Vortrag

Montag, 26. März 2007, 18:30–18:45, H44

Electrostatic screening and energy barriers for ion translocation across low-dielectric membranes — •Andrey Cherstvy — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzerstrasse 38, D-01187 Dresden, Germany

We present exact solutions of the linear Poisson-Boltzmann equation for several problems relevant for ion translocation across low-dielectric membranes [1]. Our results are obtained for a finite Debye screening length, and they generalize the classical results for pure Coulombic electrostatics [2]. We calculate the electrostatic self-energy of an ion in the middle of a low-dielectric slab, its energy inside a cylindrical high-dielectric pore, and its energy inside a high-dielectric spherical jacket. We consider also the influence of negative charges distributed on the walls of the cylindrical pore. We show that ion self-energy barriers are considerably reduced due to screening of electrolyte. We compare our results with some numerical results for screened electrostatic interactions in ion channels and wide biological pores [3].

[1] A. G. Cherstvy, J. Phys. Chem. B, 110, 14503 (2006). [2] A. V. Parsegian, Nature (London), 221, 844 (1969). [3] P. C. Jordan et al., Biophys. J. 55, 1041 (1989).