W0239

Structural Studies of the T1 Domain of a Shaker Potassium Channel. Max Nanao, Paul Pfaffinger, Senyon Choe, Structural Biology, The Salk Institute, San Diego, CA 92186-5800 USA

Voltage-dependent, ion-selective potassium channels consist of four identical subunits. Subunit assembly occurs in a family-specific manner. As a result, the underlying structural framework must be general enough to accommodate oligomerization within each family, but specific enough to prevent heteromultimerization between subunits of different families.

We are investigating the structural determinants of subunit assembly and ion conductance by X-ray crystallographic methods. The structure of the Shaker T1 domain from Aplysia crystallizes in the I422 space group and has been solved by the molecular replacement method to a resolution of 2.3 Angstroms, using the model of a shorter T1 form (Kreusch et al.).

The structure reveals insights into the subunit specific homo-tetramerization, as well as the intriguing possibility that the tetramerization domain comprises part of the ion conducting pathway.

Kreusch, A., Pfaffinger, P., Stevens, C., Choe, S., Crystal Structure of The Tetramerization Domain of The Shaker Potassium Channel. Nature, in press.