Opposite Charge Movements Within the Photoactive Site Modulate Two-Step Channel Closing in GtACR1.

ABSTRACT: Guillardia theta anion channelrhodopsin 1 is a light-gated anion channel widely used as an optogenetic inhibitory tool. Our recently published crystal structure of its dark (closed) state revealed that the photoactive retinylidene chromophore is located midmembrane in a full-length intramolecular tunnel through the protein, the radius of which is less than that of a chloride ion. Here we show that acidic (glutamate) substitutions for residues within the inner half-tunnel enhance the fast channel closing and, for residues within the outer half-tunnel, enhance the slow channel closing. The magnitude of these effects was proportional to the distance of the mutated residue from the photoactive site. These data indicate that the local electrical field across the photoactive site controls fast a

SUBMITTER: Sineshchekov OA 

PROVIDER: S-EPMC7018983 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature