A novel subgroup of light-driven sodium pumps with an additional Schiff base counterion

  • Light-driven sodium pumps (NaRs) are unique ion-transporting microbial rhodopsins. The major group of NaRs is characterized by an NDQ motif and has two aspartic acid residues in the central region essential for sodium transport. Here we identified a new subgroup of the NDQ rhodopsins bearing an additional glutamic acid residue in the close vicinity to the retinal Schiff base. We thoroughly characterized a member of this subgroup, namely the protein ErNaR from Erythrobacter sp. HL-111 and showed that the additional glutamic acid results in almost complete loss of pH sensitivity for sodium-pumping activity, which is in contrast to previously studied NaRs. ErNaR is capable of transporting sodium efficiently even at acidic pH levels. X-ray crystallography and single particle cryo-electron microscopy reveal that the additional glutamic acid residue mediates the connection between the other two Schiff base counterions and strongly interacts with the aspartic acid of the characteristic NDQ motif. Hence, it reduces its pKa. Our findings shed light on a new subgroup of NaRs and might serve as a basis for their rational optimization for optogenetics.

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar
Metadaten
Author:Elizaveta PodoliakORCiD, Gerrit H. U. LammORCiD, Alexey AlekseevORCiDGND, Egor MarinORCiD, Anna V. Schellbach, Daniil A. FedotovORCiDGND, Artem StetsenkoORCiD, Nina MaliarORCiD, Gleb BourenkovORCiDGND, Taras BalandinORCiDGND, Christian Baeken, Roman AstashkinORCiD, Thomas R. SchneiderORCiD, Alex BatemanORCiD, Josef WachtveitlORCiDGND, Igor SchapiroORCiDGND, Volker BusskampORCiD, Albert GuskovORCiDGND, Valentin GordeliyORCiDGND, Kirill KovalevORCiDGND
URN:urn:nbn:de:hebis:30:3-794557
URL:https://www.biorxiv.org/content/10.1101/2023.10.11.561842v1
DOI:https://doi.org/10.1101/2023.10.11.561842
Parent Title (English):bioRxiv
Publisher:bioRxiv
Document Type:Preprint
Language:English
Date of Publication (online):2023/10/12
Date of first Publication:2023/10/12
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2024/04/15
Issue:2023.10.11.561842 Version 1
Edition:Version 1
Page Number:43
HeBIS-PPN:518161137
Institutes:Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International