Conformational Changes in Lipid Reconstituted Potassium Channel Voltage-Sensing Domains

Abstract

In the voltage-activated potassium channels, S1-S4 voltage-sensing domains control opening and closing of an associated pore domain. Electrophysiology experiments show that in the presence of lipids with positively charged head-groups, voltage sensors appear to be confined to the resting state (Schmidt, D., 2006). In order to define the structural changes in voltage sensing domains we purified the S1-S4 domain from KvAP and reconstituted it in either a POPC:POPG (1:1) lipid mixture or DOTAP, a positively charged lipid without a phosphate group.