Cryo-EM structure and dynamics of the green-light absorbing proteorhodopsin.

Hirschi, Stephan; Kalbermatter, David; Ucurum, Zöhre; Lemmin, Thomas; Fotiadis, Dimitrios (2021). Cryo-EM structure and dynamics of the green-light absorbing proteorhodopsin. Nature communications, 12(1), p. 4107. Nature Publishing Group 10.1038/s41467-021-24429-6

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The green-light absorbing proteorhodopsin (GPR) is the archetype of bacterial light-driven proton pumps. Here, we present the 2.9 Å cryo-EM structure of pentameric GPR, resolving important residues of the proton translocation pathway and the oligomerization interface. Superposition with the structure of a close GPR homolog and molecular dynamics simulations reveal conformational variations, which regulate the solvent access to the intra- and extracellular half channels harbouring the primary proton donor E109 and the proposed proton release group E143. We provide a mechanism for the structural rearrangements allowing hydration of the intracellular half channel, which are triggered by changing the protonation state of E109. Functional characterization of selected mutants demonstrates the importance of the molecular organization around E109 and E143 for GPR activity. Furthermore, we present evidence that helices involved in the stabilization of the protomer interfaces serve as scaffolds for facilitating the motion of the other helices. Combined with the more constrained dynamics of the pentamer compared to the monomer, these observations illustrate the previously demonstrated functional significance of GPR oligomerization. Overall, this work provides molecular insights into the structure, dynamics and function of the proteorhodopsin family that will benefit the large scientific community employing GPR as a model protein.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Faculty Institutions > NCCR TransCure
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Hirschi, Stephan; Kalbermatter, David; Ucurum Fotiadis, Zöhre and Fotiadis, Dimitrios José


500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health




Nature Publishing Group




Barbara Franziska Järmann-Bangerter

Date Deposited:

09 Sep 2021 10:07

Last Modified:

05 Dec 2022 15:52

Publisher DOI:


PubMed ID:





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