Fig. 1.

(A) Visualization of dimeric ChR2 reconstituted into the lipid bilayer as used in this study [cartoon based on the crystal structure of the ChR1/2 chimera (data from ref. 9)]. Blue light illumination activates ChR2. (B) Single turnover (black arrows) and continuous illumination photocycle (blue arrows) (14, 40). (C) Schematic view of the experimental setup for generating and measuring different photointermediates. (D) The DNP enhancement is generated by magnetization transfer from the biradical AMUPOL to ChR2.