Chemical basis for alkali cation selectivity in potassium-channel proteins

The determination of the crystal structure of a K⁺-selective channel protein from Streptomyces lividans reveals how the rapid movement of K⁺ across membranes is catalyzed by a large family of pore-forming proteins. Many features of the structure mirror hypotheses, predictions and models of K⁺ channels developed over the past four decades of functional analysis.