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-Structure paper
タイトル | Structural basis for ion selectivity in potassium-selective channelrhodopsins. |
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ジャーナル・号・ページ | Cell, Vol. 186, Issue 20, Page 4325-4344.e26, Year 2023 |
掲載日 | 2023年9月28日 |
著者 | Seiya Tajima / Yoon Seok Kim / Masahiro Fukuda / YoungJu Jo / Peter Y Wang / Joseph M Paggi / Masatoshi Inoue / Eamon F X Byrne / Koichiro E Kishi / Seiwa Nakamura / Charu Ramakrishnan / Shunki Takaramoto / Takashi Nagata / Masae Konno / Masahiro Sugiura / Kota Katayama / Toshiki E Matsui / Keitaro Yamashita / Suhyang Kim / Hisako Ikeda / Jaeah Kim / Hideki Kandori / Ron O Dror / Keiichi Inoue / Karl Deisseroth / Hideaki E Kato / |
PubMed 要旨 | KCR channelrhodopsins (K-selective light-gated ion channels) have received attention as potential inhibitory optogenetic tools but more broadly pose a fundamental mystery regarding how their K ...KCR channelrhodopsins (K-selective light-gated ion channels) have received attention as potential inhibitory optogenetic tools but more broadly pose a fundamental mystery regarding how their K selectivity is achieved. Here, we present 2.5-2.7 Å cryo-electron microscopy structures of HcKCR1 and HcKCR2 and of a structure-guided mutant with enhanced K selectivity. Structural, electrophysiological, computational, spectroscopic, and biochemical analyses reveal a distinctive mechanism for K selectivity; rather than forming the symmetrical filter of canonical K channels achieving both selectivity and dehydration, instead, three extracellular-vestibule residues within each monomer form a flexible asymmetric selectivity gate, while a distinct dehydration pathway extends intracellularly. Structural comparisons reveal a retinal-binding pocket that induces retinal rotation (accounting for HcKCR1/HcKCR2 spectral differences), and design of corresponding KCR variants with increased K selectivity (KALI-1/KALI-2) provides key advantages for optogenetic inhibition in vitro and in vivo. Thus, discovery of a mechanism for ion-channel K selectivity also provides a framework for next-generation optogenetics. |
リンク | Cell / PubMed:37652010 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.53 - 2.66 Å |
構造データ | EMDB-34530: Membrane protein A EMDB-34531: Membrane protein B EMDB-35713, PDB-8iu0: |
化合物 | ChemComp-RET: ChemComp-PSC: ChemComp-PLM: ChemComp-HOH: |
由来 |
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キーワード | MEMBRANE PROTEIN / Cryo-EM |