The voltage dependent sidedness of the reprotonation of the retinal schiff base determines the unique inward pumping of xenorhodopsin

  • The new class of microbial rhodopsins, called xenorhodopsins (XeRs),[1] extends the versatility of this family by inward H+ pumps.[2–4] These pumps are an alternative optogenetic tool to the light-gated ion channels (e.g. ChR1,2), because the activation of electrically excitable cells by XeRs is independent from the surrounding physiological conditions. In this work we functionally and spectroscopically characterized XeR from Nanosalina (NsXeR).[1] The photodynamic behavior of NsXeR was investigated on the ps to s time scale elucidating the formation of the J and K and a previously unknown long-lived intermediate. The pH dependent kinetics reveal that alkalization of the surrounding medium accelerates the photocycle and the pump turnover. In patch-clamp experiments the blue-light illumination of NsXeR in the M state shows a potential-dependent vectoriality of the photocurrent transients, suggesting a variable accessibility of reprotonation of the retinal Schiff base. Insights on the kinetically independent switching mechanism could furthermore be obtained by mutational studies on the putative intracellular H+ acceptor D220.

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Author:Juliane WeissbeckerGND, Chokri Boumrifak, Maximilian Breyer, Tristan Wießalla, Vitaly ShevchenkoORCiDGND, Thomas Mager, Chavdar SlavovORCiDGND, Alexey AlekseevORCiDGND, Kirill KovalevORCiDGND, Valentin GordeliyORCiDGND, Ernst BambergGND, Josef WachtveitlORCiDGND
Parent Title (German):Angewandte Chemie
Place of publication:Weinheim
Document Type:Article
Date of Publication (online):2021/08/02
Date of first Publication:2021/08/02
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/12/20
Tag:accessibility switch; inward proton pump; microbial rhodopsin; optogenetics
Page Number:9
Early View: Online Version before inclusion in an issue
We acknowledge the Collaborative Research Center, CRC 807 “Transport and Communication across Biological Membranes” for funding. Open access funding enabled and organized by Projekt DEAL.
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Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0