This is a golden age for ion channels: a time when chemistry, molecular biology, and electrophysiology have come together with structural biology to provide glimpses into some truly amazing membrane proteins. And yet, as usual, the answers yield more questions. Is a new structure the structure of an open channel or of a closed one? How does the voltage sensor actually move? Though providing amazing insights, each crystal structure is just a still life portrait of the ion channel–it doesn't breathe or flicker; it has lost the “soul” that was deduced by electrophysiology. In a real sense, therefore, new structures serve as a starting point for more functional studies, rather than as an end point. Indeed, in this issue, Craven and Zagotta (2004) use functional studies to interpret structural information and enhance our understanding of the gating mechanisms of cyclic nucleotide-regulated channels.
Craven and Zagotta...
