Ion conduction pore is conserved among potassium channels

Potassium channels, a group of specialized membrane proteins, enable K + ions to flow selectively across cell membranes. Transmembrane K + currents underlie electrical signalling in neurons and other excitable cells. The atomic structure of a bacterial K + channel pore has been solved by means of X-ray crystallography. To the extent that the prokaryotic pore is representative of other K + channels, this landmark achievement has profound implications for our general understanding of K + channels. But serious doubts have been raised concerning whether the prokaryotic K + channel pore does actually represent those of eukaryotes. Here we have addressed this fundamental issue by substituting the prokaryotic pore into eukaryotic voltage-gated and inward-rectifier K + channels. The resulting chimaeras retain the respective functional hallmarks of the eukaryotic channels, which indicates that the ion conduction pore is indeed conserved among K + channels.