Issue 16, 2008

Is the mobility of the pore walls and water molecules in the selectivity filter of KcsA channel functionally important?

Abstract

We performed in-depth analysis of the forces which act on the K+ ions in the selectivity filter of the KcsA channel in order to estimate the relative importance of static and dynamic influence of the filter wall and water molecules on ion permeation and selectivity. The forces were computed using the trajectories of all-atom molecular dynamics simulations. It is shown that the dynamics of the selectivity filter contributes about 3% to the net force acting on the ions and can be neglected in the studies focused on the macroscopic properties of the channel, such as the current. Among the filter atoms, only the pore-forming carbonyl groups can be considered as dynamic in the studies of microscopic events of conduction, while the dynamic effects from all other atoms are negligible. We also show that the dynamics of the water molecules in the filter can not be neglected. The fluctuating forces from the water molecules can be as strong as net forces from the pore walls and can effectively drive the ions through the local energy barriers in the filter.

Graphical abstract: Is the mobility of the pore walls and water molecules in the selectivity filter of KcsA channel functionally important?

Article information

Article type
Paper
Submitted
18 Dec 2007
Accepted
01 Feb 2008
First published
28 Feb 2008

Phys. Chem. Chem. Phys., 2008,10, 2249-2255

Is the mobility of the pore walls and water molecules in the selectivity filter of KcsA channel functionally important?

S. Kraszewski, S. O. Yesylevskyy, C. Boiteux, C. Ramseyer and V. N. Kharkyanen, Phys. Chem. Chem. Phys., 2008, 10, 2249 DOI: 10.1039/B719512E

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