High-resolution cryo-electron microscopy structure of photosystem II from the mesophilic cyanobacterium, Synechocystis sp. PCC 6803

Authors

Christopher J. Gisriel, Yale University
Jimin Wang, Yale University
Jinchan Liu, Yale University
David A. Flesher, Yale University
Krystle M. Reiss, Yale University
Hao-Li Huang, Yale University
Ke R. Yang, Yale University
William H. Armstrong, Boston College
M. R. Gunner, CUNY City CollegeFollow
Victor S. Batista, Yale University
Richard J. Debus, University of California, Riverside
Gary W. Brudvig, Yale University

Document Type

Article

Publication Date

12-22-2021

Abstract

Photosystem II (PSII) enables global-scale, light-driven water oxidation. Genetic manipulation of PSII from the mesophilic cyanobacterium Synechocystis sp. PCC 6803 has provided insights into the mechanism of water oxidation; however, the lack of a highresolution structure of oxygen-evolving PSII from this organism has limited the interpretation of biophysical data to models based on structures of thermophilic cyanobacterial PSII. Here, we report the cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 at 1.93-Å resolution. A number of differences are observed relative to thermophilic PSII structures, including the following: the extrinsic subunit PsbQ is maintained, the C terminus of the D1 subunit is flexible, some waters near the active site are partially occupied, and differences in the PsbV subunit block the Large (O1) water channel. These features strongly influence the structural picture of PSII, especially as it pertains to the mechanism of water oxidation.

Comments

This work was originally published in PNAS, available at https://doi.org/10.1073/pnas.2116765118.

This open access article is distributed under Creative Commons Attribution- NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).