Seminars Archive

Potential-induced confromational changes in voltage gated ion channels probed by electrochemical FTIR-ATR spectroscopy

Abstract
DEMOCRITOS - Theory@elettra seminar Voltage gated ion channels are among the most studied transmembrane proteins, their functional activity being at the basis of the generation and propagation of the action potential in excitable membranes. Particularly, bacterial K+ channels have been object of very intense structural and functional investigation during the last decade. In spite of this fact, a few key questions still remain open as to ion channel conformational changes in response to membrane potential variation. Indeed, the proposed mechanisms and developed models are essentially based on static structural (X-ray crystallography) data, or indirect functional (e.g. gating currents) and accessibility (e.g. Cys accessibility) evidences which fail to access the different conformational states of the channel (i.e. open vs closed). We have developed a novel spectroscopic approach (electrochemically controlled, polarized FTIR-ATR spectroscopy) to try to shed light on the conformational changes occurring to the channel upon gating. I will account for our recent results obtained on monolayers of KvAP by this technique, and I will discuss their impact on the mechanism describing the gating event.