Structures of channelrhodopsin paralogs in peptidiscs explain their contrasting K⁺ and Na⁺ selectivities.

ABSTRACT: Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is a light-gated channel used for optogenetic silencing of mammalian neurons. It selects K⁺ over Na⁺ in the absence of the canonical tetrameric K⁺ selectivity filter found universally in voltage- and ligand-gated channels. The genome of H. catenoides also encodes a highly homologous cation channelrhodopsin (HcCCR), a Na⁺ channel with >100-fold larger Na⁺ to K⁺ permeability ratio. Here, we use cryo-electron microscopy to determine atomic structures of these two channels embedded in peptidiscs to elucidate structural foundations of their dramatically different cation selectivity. Together with structure-guided mutagenesis, we show that K⁺ versus Na

SUBMITTER: Morizumi T 

PROVIDER: S-EPMC10359266 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature