Time-resolved spectroscopic and electrophysiological data reveal insights in the gating mechanism of anion channelrhodopsin

• DOI: 10.1038/s42003-021-02101-5
• Publication Date: 2021-05-14T10:03:17Z
• Authors: Max-Aylmer Dreier; Philipp Althoff; Mohamad Javad Nor...; Stefan Alexander ...; Samir F. El-Mashtoly; Mathias Lübben; Carsten Kötting; Till Rudack; Klaus Gerwert
• Keywords: Channelrhodopsin; Visual phototransduction; Halorhodopsin

Abstract Channelrhodopsins are widely used in optogenetic applications. High photocurrents and low current inactivation levels desirable. Two parallel photocycles evoked by different retinal conformations cause cation-conducting channelrhodopsin-2 ( Cr ChR2) inactivation: one with efficient conductivity; conductivity. Given the longer half-life of conducting photocycle intermediates, which accumulate under continuous illumination, resulting a largely reduced photocurrent. Here, we demonstrate that for channelrhodopsin-1 cryptophyte Guillardia theta Gt ACR1), highly C = N- anti -photocycle was sole operating cycle using time-resolved step-scan FTIR spectroscopy. The correlation between our spectroscopic measurements previously reported electrophysiological data provides insights into molecular gating mechanisms their role characteristic high photocurrents. mechanistic importance central constriction site amino acid Glu-68 is also shown. We propose canceling out poorly avoids observed ChR2, anticipate this discovery will advance development optimized tools.