Stochastic dynamics of remote knock-on permeation in biological ion channels

Tindjong, Rodrigue and Kaufman, Igor and Luchinsky, Dmitrii G. and McClintock, Peter V. E. and Khovanov, I. A. and Eisenberg, R. S. (2013) Stochastic dynamics of remote knock-on permeation in biological ion channels. In: Noise and Fluctuations (ICNF), 2013 22nd International Conference on. IEEE, Piscataway, N.J.. ISBN 9781479906680

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Brownian dynamics simulations provide evidence for a remote knock-on mechanism facilitating the permeation of a biological ion channel by an ion that is initially trapped at the selectivity filter (SF). Unlike the case of conventional direct knock-on, the second ion that instigates permeation does not need to enter the channel. Nor does it necessarily take the place of the permeating ion at the SF, and it can even be of a different ionic species. The study is based on the simultaneous, self-consistent, solution of the coupled Poisson and Langevin equations for a simple generic model, taking account of all the charges present. The new permeation mechanism involves electrostatic amplification attributable to the permittivity mismatch between water and protein: the arrival of the instigating ion at the channel entrance reduces the exit barrier for the ion trapped at the SF, facilitating escape.

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25 Nov 2013 11:16
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17 Sep 2023 03:52