Ion Channel Selectivity Using an Electric Stew

Abstract

Having the crystal structure of its pore solved, the K+ channel has been the target of most recent efforts to understand how ion channels decide which ions to pass. Nevertheless, the Ca2+ channel is essential for a complete picture of selectivity because, at first glance, its job and its mechanism appear so different from those of K+ channels. K+ channels choose a larger ion over a smaller (K+ over Na+) and do so with a pore structure that appears constrained from shrinking to fit Na+ (Doyle et al., 1998).