Application of the Poisson-Nernst-Planck theory with space-dependent diffusion coefficients to KcsA.

ABSTRACT: The Poisson-Nernst-Planck electrodiffusion theory serves to compute charge fluxes and is here applied to the ion current through a protein channel. KcsA was selected as an example because of the abundance of experimental and theoretical data. The potassium channels MthK and KvAP were used as templates to define two open channel models for KcsA. Channel boundary surfaces and protein charge distributions were defined according to atomic radii and partial atomic charges. To establish the sensitivity of the results to these parameters, two different sets were used. Assigning the potassium diffusion coefficients equal to the value for free-diffusion in water (1.96 x 10(-9) m(2)/s), the computed currents overestimated the experimental data. Ion distributions inside the channel suggest that the o

SUBMITTER: Furini S 

PROVIDER: S-EPMC1614472 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature