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Structural basis for [Na.sup.+] transport mechanism by a light-driven [Na.sup.+] pump

Authors :
Kato, Hideaki E.
Inoue, Keiichi
Abe-Yoshizumi, Rei
Kato, Yoshitaka
Ono, Hikaru
Konno, Masae
Hososhima, Shoko
Ishizuka, Toru
Hoque, Mohammad Razuanul
Kunitomo, Hirofumi
Ito, Jumpei
Yoshizawa, Susumu
Yamashita, Keitaro
Takemoto, Mizuki
Nishizawa, Tomohiro
Taniguchi, Reiya
Kogure, Kazuhiro
Maturana, Andres D.
Iino, Yuichi
Yawo, Hiromu
Ishitani, Ryuichiro
Kandori, Hideki
Nureki, Osamu
Source :
Nature. May 7, 2015, p48, 18 p.
Publication Year :
2015

Abstract

Krokinobacter eikastus rhodopsin 2 (KR2) is the first light-driven [Na.sup.+] pump discovered, and is viewed as a potential next-generation optogenetics tool. Since the positively charged Schiff base proton, located within the ion-conducting pathway of all light-driven ion pumps, was thought to prohibit the transport of a non-proton cation, the discovery of KR2 raised the question of how it achieves [Na.sup.+] transport. Here we present crystal structures of KR2 under neutral and acidic conditions, which represent the resting and M-like intermediate states, respectively. Structural and spectroscopic analyses revealed the gating mechanism, whereby the flipping of Asp116 sequesters the Schiff base proton from the conducting pathway to facilitate [Na.sup.+] transport. Together with the structure-based engineering of the first light-driven [K.sup.+] pumps, electrophysiological assays in mammalian neurons and behavioural assays in a nematode, our studies reveal the molecular basis for light-driven non-proton cation pumps and thus provide a framework that may advance the development of next-generation optogenetics.<br />Many organisms capture light energy and information using the rhodopsin family of proteins, which comprise the heptahelical transmembrane (7-TM) proteins called opsins covalently linked to retinal. Based on their primary [...]

Details

Language :
English
ISSN :
00280836
Database :
Gale General OneFile
Journal :
Nature
Publication Type :
Academic Journal
Accession number :
edsgcl.412800503
Full Text :
https://doi.org/10.1038/nature14322