Physics of selective conduction and point mutation in biological ion channels

W. A. T. Gibby; M. L. Barabash; C. Guardiani; D. G. Luchinsky; P. V. E. McClintock

doi:10.1103/physrevlett.126.218102

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arXiv · 2010.08450

Physics of selective conduction and point mutation in biological ion channels

W. A. T. Gibby·M. L. Barabash·C. Guardiani·D. G. Luchinsky·P. V. E. McClintock

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Abstract

We introduce a statistical and linear response theory of selective conduction in biological ion channels with multiple binding sites and possible point mutations. We derive an effective grand-canonical ensemble and generalised Einstein relations for the selectivity filter, assuming strongly coordinated ionic motion, and allowing for ionic Coulomb blockade. The theory agrees well with data from the KcsA K$^+$ channel and a mutant. We show that the Eisenman relations for thermodynamic selectivity follow from the condition for fast conduction and find that maximum conduction requires the binding sites to be nearly identical.

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W. A. T. Gibby, M. L. Barabash, C. Guardiani, D. G. Luchinsky, P. V. E. McClintock. 2020-10-16. Physics of selective conduction and point mutation in biological ion channels. https://doi.org/10.1103/physrevlett.126.218102

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