EXC 2049/2: Improving Channelrhodopsins for Neuronal Application by Single Channel Recording, MD simulation, and Molecular Engineering

During the two previous Neurocure funding periods we have intensely characterized, engineered and modified a number of channelrhodopsins and have provided K-selective (WiCHR), Ca-selective (CapChR), and red-light sensitive channelrhodopsins (CsChrimson and raACR), as well as dual functional channelrhodopsin-tandems (BIPOLES) with a wide application range within the Neurocure community (AG Jentsch, Larkum, Mikhaylova, Owald, Plested, Schmitz). However, the single channel conductance and the on and off switching kinetics of the gates during the conducting state remained elusive. Recently, in a close collaboration with Klaus Benndorf (Jena), the single channel conductances and the on/off kinetics of the K-selective Channelrhodopsins HcKCR and WiChR (left) could be monitored and characterized. Both show two main conducting stated with variable intermediate states to a different extent depending on the membrane voltage.
Within the next Neurocure research program we will further analyze conductances, selectivities, and kinetics of various Cryptophyte Channelrhodopsins in order to understand the fundamental gating and selectivity properties.