Determination of the charge profile in the KcsA selectivity filter using ab initio calculations and molecular dynamics simulations

The charge profile of K+ and Na+ ions moving in a single file across the filter of the KcsA channel is determined using both molecular dynamics simulations and ab initio calculations. We show a strong correlation between the charge variation and the ion location resulting in a saw-tooth profile, which provides additional information on the influence of charge transfer on the permeation and selectivity of the channel.