Engineering channels: atomic biology.

I on channels are protein valves that control an enormous range of biological function. Atomic-scale properties of channel proteins control macroscopic flows across otherwise insulating membranes of cells and subcellular compartments, and so the study of channels is a study in atomic biology. Ion channels are intrinsically multiscale devices that allow the amino acid side chains of a protein to control nerve signaling and coordinate muscle contraction—including the contraction that allows the heart to pump blood—and a host of other biological activities. A Google search for ‘‘ion channels’’ or ‘‘channelopathy’’ (1) shows the enormous importance of channels in biology and medicine.