Multiscale study of counterion-induced attraction and bundle formation of F-actin using an Ising-like mean-field model.

ABSTRACT: An Ising-like counterion-binding model is developed and solved by a mean-field method. For G-actin, the calculated affinity constants of all the binding sites ranging from loose to tight binding match the experimental data. The model is used to calculate the interaction energy between two F-actin filaments. Within a certain counterion concentration range, a rapidly decaying attractive force between two parallel filaments is produced not only by the correlation of the counterion distributions on the two filaments, but also by the correlation of the configurations of the two filaments with fixed counterion positions, which has been ignored in previous calculations. The bundling energy depends strongly on the configuration of the filaments. Upon bundling, the tightly bound counterion site is

SUBMITTER: Yu X 

PROVIDER: S-EPMC1303660 | biostudies-literature | 2003 Dec

REPOSITORIES: biostudies-literature