A simple model for multi-ion permeation. Single-vacancy conduction in a simple pore model. |
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Authors: | M F Schumaker and R MacKinnon |
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Affiliation: | Department of Chemistry, Brandeis University, Waltham, Massachusetts 02254. |
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Abstract: | Recent experimental evidence suggests that certain membrane channels operate in a nearly ion-saturated state. We therefore consider a "single-vacancy" model of ion permeation: if a channel has n conducting sites, it will contain either n or n-1 ions. Simple analytical expressions for the current, conductance, and reversal potential under bi-ionic conditions are derived. The results are compared with those of single ion models and recent experiments on Ca2(+)-activated K+ channels. |
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