Physics of selective conduction and point mutation in biological ion channels

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.

References in corpus (2)

• Ionic Coulomb blockade as a fractional Wien effect
• Multi-ion conduction bands in a simple model of calcium ion channels