A simple model for multi-ion permeation. Single-vacancy conduction in a simple pore model.
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.
Department of Chemistry, Brandeis University, Waltham, Massachusetts 02254.
M F
MF
Schumaker
R
R
MacKinnon
D055592:Biophysical Phenomena; D001703:Biophysics; D004553:Electric Conductivity; D004563:Electrochemistry; D004734:Energy Metabolism; D007473:Ion Channels / Q000378:metabolism*; D008564:Membrane Potentials; D008954:Models, Biological; D010539:Permeability
D007473:Ion Channels