TY  - JOUR
AU  - Kovalev, Kirill
AU  - Astashkin, Roman
AU  - Gushchin, Ivan
AU  - Orekhov, Philipp
AU  - Volkov, Dmytro
AU  - Zinovev, Egor
AU  - Marin, Egor
AU  - Rulev, Maksim
AU  - Alekseev, Alexey
AU  - Royant, Antoine
AU  - Carpentier, Philippe
AU  - Vaganova, Svetlana
AU  - Zabelskii, Dmitrii
AU  - Baeken, Christian
AU  - Sergeev, Ilya
AU  - Balandin, Taras
AU  - Bourenkov, Gleb
AU  - Carpena, Xavier
AU  - Boer, Roeland
AU  - Maliar, Nina
AU  - Borshchevskiy, Valentin
AU  - Büldt, Georg
AU  - Bamberg, Ernst
AU  - Gordeliy, Valentin
TI  - Molecular mechanism of light-driven sodium pumping
JO  - Nature Communications
VL  - 11
IS  - 1
SN  - 2041-1723
CY  - [London]
PB  - Nature Publishing Group UK
M1  - FZJ-2020-01746
SP  - 2137
PY  - 2020
AB  - The light-driven sodium-pumping rhodopsin KR2 from Krokinobacter eikastus is the only non-proton cation active transporter with demonstrated potential for optogenetics. However, the existing structural data on KR2 correspond exclusively to its ground state, and show no sodium inside the protein, which hampers the understanding of sodium-pumping mechanism. Here we present crystal structure of the O-intermediate of the physiologically relevant pentameric form of KR2 at the resolution of 2.1 Å, revealing a sodium ion near the retinal Schiff base, coordinated by N112 and D116 of the characteristic NDQ triad. We also obtained crystal structures of D116N and H30A variants, conducted metadynamics simulations and measured pumping activities of putative pathway mutants to demonstrate that sodium release likely proceeds alongside Q78 towards the structural sodium ion bound between KR2 protomers. Our findings highlight the importance of pentameric assembly for sodium pump function, and may be used for rational engineering of enhanced optogenetic tools.
LB  - PUB:(DE-HGF)16
C6  - pmid:32358514
UR  - <Go to ISI:>//WOS:000531425700018
DO  - DOI:10.1038/s41467-020-16032-y
UR  - https://juser.fz-juelich.de/record/874981
ER  -