Voltage-dependent K+ (Kv) channels conduct K+ ions across the cell membrane in response to changes in the membrane voltage. The channels contain voltage sensors that allow them to open and close their ion conduction pore over narrow voltage ranges. The structure of the voltage-dependent K+ channel Kv1.2 reveals that the voltage sensors are essentially independent domains inside the membrane and suggests how they perform mechanical work to open and close the pore.
This structure also represents a technical advance as it is one of the only crystal structures of a eukaryotic membrane protein for which the protein was produced using a heterologous expression system, rather than purified from a high-abundance natural source. The ability to produce a large quantity of recombinant channel protein suggests that other low-abundance eukaryotic membrane proteins will be able to be studied using x-ray crystallography. We are applying these techniques to understanding the structures and mechanisms of other ion channels. Of particular interest are ion channels that are selective for calcium or sodium ions.
Structure of the Kv1.2 channel viewed from the extracellular side
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