2016/04/19 by D. G. Luchinsky, W. A. T. Gibby, Luchinsky, D. G. +7
Biochemistry, Genetics and Molecular Biology · Medicine · Neuroscience · #Biological Physics (physics.bio-ph) #Cardiac electrophysiology and arrhythmias #FOS: Physical sciences #Ion channel regulation and function #Neuroscience and Neural Engineering
paper · pdf · doi:10.48550/arxiv.1604.05758
openalex publication_date 2016/04/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present an equilibrium statistical-mechanical theory of selectivity in biological ion channels. In doing so, we introduce a grand canonical ensemble for ions in a channel's selectivity filter coupled to internal and external bath solutions for a mixture of ions at arbitrary concentrations, we use linear response theory to find the current through the filter for small gradients of electrochemical potential, and we show that the conductivity of the filter is given by the generalized Einstein relation. We apply the theory to the permeation of ions through the potassium selectivity filter, and are thereby able to resolve the long-standing paradox of why the high selectivity of the filter brings no associated delay in permeation. We show that the Eisenman selectivity relation follows directly from the condition of diffusion-limited conductivity through the filter. We also discuss the effect of wall fluctuations on the filter conductivity.