The Crystal Structure of a Potassium Channel — A New Era in the Chemistry of Biological Signaling

Abstract

The similarity to crown ethers is apparent when the arrangement of the oxygen atoms of the carbonyl groups of the protein backbone in the structure of the potassium channel (see schematic drawing of a section of the structure) found in the bacterium Streptomyces lividans is considered. This particular part of the channel pore acts as the selectivity filter, with the permeability of the channel for K+ being as much as 10 000 times greater than for the Na+ ion. In fact, in this area of the structure two K+ ions are located, a feature that enables high flux through the channel.

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