Molecular Biology Commons^™

Structures Of Channelrhodopsin Paralogs In Peptidiscs Explain Their Contrasting K+ And Na+ Selectivities, Takefumi Morizumi, Kyumhyuk Kim, Hai Li, Elena G Govorunova, Oleg A Sineshchekov, Yumei Wang, Lei Zheng, Éva Bertalan, Ana-Nicoleta Bondar, Azam Askari, Leonid S Brown, John L Spudich, Oliver P Ernst

Journal Articles

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+ …