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Application of a Statistical and Linear Response Theory to Multi-Ion Na+ Conduction in NaChBac
William A T Gibby1, Olena A Fedorenko2,3, Carlo Guardiani1,4
1Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
Abstract:
Biological ion channels are fundamental to maintaining life. In this manuscript we apply our recently developed statistical and linear response theory to investigate Na+ conduction through the prokaryotic Na+ channel NaChBac. This work is extended theoretically by the derivation of ionic conductivity and current in an electrochemical gradient, thus enabling us to compare to a range of whole-cell data sets performed on this channel. Furthermore, we also compare the magnitudes of the currents and populations at each binding site to previously published single-channel recordings and molecular dynamics simulations respectively. In doing so, we find excellent agreement between theory and data, with predicted energy barriers at each of the four binding sites of ∼4,2.9,3.6, and 4kT.
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