The SFB 1078 kindly invites you to the following colloquium talk:

Dr. Keisuke Shibata hosted by Dr. Kenichi Ataka (FUB):

Title: Twisting and Protonation of the Retinal Chromophore Regulate Channel Gating of Channelrhodopsin C1C2

Channelrhodopsins (ChRs) are light-gated ion channels and have been attracted as central optogenetic tools. Although their optogenetics applications have progressed rapidly, the gating mechanism is unclear. Structural information is essential to reveal the gating mechanism. Therefore, we measured the structural changes in the retinal of C1C2, a representative ChR, by time-resolved Raman spectroscopy. The results revealed that the retinal is highly twisted in the open state. Taken together with the results of Raman, electrophysiology and transient absorption measurements, we revealed the following gating mechanism: twisting and twisting relaxation of the retinal regulate the channel opening and closing, respectively. The ion-conducting pathway includes the retinal Schiff base (RSB), and the RSB reprotonation rate-limits the channel closing.