STRUCTURAL STUDIES OF AUXILIARY SUBUNITS OF VOLTAGE DEP POTASSIUM CHANNELS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Potassium channels are important in many physiological processes such as excitability of a neuron, secretion of hormones, and contraction of a muscle cell. In a cell, all potassium channels are assembled with other cytosolic or transmembrane proteins, and channel functions modulated by these proteins. We study the molecular mechanism of channel modulation at the atomic level. Kvbeta is an oxidoreductase that attaches to a potassium channel. It converts between the oxidized and reduced forms and the conversion modulates channel function. We know the structure of the oxidized protein, but not the reduced one. In an effort to get the structure of the reduced Kvbeta, we have obtained crystals of Kvbeta subunit in the reduced form, and the crystals diffract to about 2.8 angstrom at a home source. The high intensity beam at Chess will enable us to collect higher resolution data sets, so that the conformational changes of the protein will be visualized clearly. We will screen frozen crystals, and collect data on ones that diffract to better than 2.5A.