Forum 11/06/2003

“Three-dimensional structure of the human voltage gated potassium channel kv2.1”

Brian Adair, Research Associate – Department of Cell Biology, The Scripps Research Institute, La Jolla, CA

Voltage-gated potassium channels are important constituents in the generation of electrical signals in eukaryotic cells. We are conducting structural studies of an expressed clone of the human voltage-gated potassium channel, kv2.1. The protein has been extracted from CHO cells by solublization with the detergent DHPC and purified by ion-exchange chromatography. Electron micrographs of negatively stained, detergent-solublized protein have been used for single-particle image-reconstruction using the EMAN program suite. A three-dimensional model generated with enforced four-fold symmetry displays a roughly cylindrical object ~ 130 A long. Comparison with known atomic structures of the homologous potassium channels kvap and kcsa allows confident identification of the membrane-spanning sequence in the EM map. The homologous N-terminal tetramerization domain from shaker has also been located in the map by comparison with the known crystal structure.