Structural insights into light-gating of potassium-selective channelrhodopsin.

ABSTRACT: Structural information on channelrhodopsins' mechanism of light-gated ion conductance is scarce, limiting its engineering as optogenetic tools. Here, we use single-particle cryo-electron microscopy of peptidisc-incorporated protein samples to determine the structures of the slow-cycling mutant C110A of kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) in the dark and upon laser flash excitation. Upon photoisomerization of the retinal chromophore, the retinylidene Schiff base NH-bond reorients from the extracellular to the cytoplasmic side. This switch triggers a series of side chain reorientations and merges intramolecular cavities into a transmembrane K⁺ conduction pathway. Molecular dynamics simulations confirm K⁺ flux through the illuminated state bu

SUBMITTER: Morizumi T 

PROVIDER: S-EPMC11790859 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature