Journal Article

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

Debus, Richard J., Wang, Jimin, Brudvig, Gary W., Gisriel, Christopher J., Reiss, Krystle M., Batista, Victor S., Armstrong, William H., Flesher, David A., Gunner, M. R., Huang, Hao-Li, Yang, Ke R., Liu, Jinchan

2022

Overview

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.

• Publisher: National Academy of Sciences,Proceedings of the National Academy of Sciences
• Subject: Bacterial Proteins - metabolism / BASIC BIOLOGICAL SCIENCES / Biochemistry / Biological Sciences / C-Terminus / Chemistry / Cryoelectron Microscopy - methods / Cyanobacteria / Electron microscopy / High resolution / Microscopy / Oxidation / oxygen-evolving complex / photosynthesis / Photosystem II / Photosystem II Protein Complex - ultrastructure / Physical Sciences / Protein Conformation / PsbQ / PsbV / Scale (corrosion) / Synechocystis / Synechocystis - chemistry / Transmission electron microscopy / water channel / water oxidation