Photochromism of Channelrhodopsin-1 of Volvox carteri (VCHR)

Channelrhodopsins (ChRs) are directly light-gated ion channels that regulate in nature photomovement responses in green algae. In neuroscience ChR is used for specific depolarization of selected cells in neuronal tissues or living animals (Optogenetics). This method opens great perspectives for addressing specific cell types in the brain and for understanding the molecular origin of mental diseases. Recombinant ChR1 of the colonial alga Volvox carteri shows an absorption spectrum 70 nm red-shifted (?max: 535 nm) compared to the spectrum of the usually used ChR2 from Chlamydomonas (?max: 465 nm). Based on theoretical considerations, quantum mechanical calculations, and spectroscopic data we will generate new ChRs with absorptions that cover the complete visible range between 400 and 600 nm. The function of the proteins will be analyzed by electrophysiology and time resolved spectroscopy. The new set of ChRs should allow to differentially depolarize different cell types in parallel in neuronal tissues by light of different color in neuroscience research.

The project is carried out in close collaboration with Prof. Marcus Elstner, TU Braunschweig.