7PIW

Stacked stretched Dunaliella PSII

This is a non-PDB format compatible entry.

Summary for 7PIW

• Entry DOI: 10.2210/pdb7piw/pdb
• EMDB information: 13455
• Descriptor: Photosystem II protein D1, Photosystem II reaction center protein J, Photosystem II reaction center protein K, ... (57 entities in total)
• Functional Keywords: green algae, photosystem ii, thylakoid, oxygen evolving complex, cryo-em, stacking, photosynthesis
• Biological source: Dunaliella salina (Green alga, Protococcus salinus); More
• Total number of polymer chains: 99
• Total formula weight: 2170300.44

Authors

Caspy, I.,Fadeeva, M.,Mazor, Y.,Nelson, N. (deposition date: 2021-08-23, release date: 2022-08-17, Last modification date: 2024-10-16)

Primary citation

Caspy, I.,Fadeeva, M.,Mazor, Y.,Nelson, N.
Structure of Dunaliella Photosystem II reveals conformational flexibility of stacked and unstacked supercomplexes.
Elife, 12:-, 2023

PubMed Abstract: Photosystem II (PSII) generates an oxidant whose redox potential is high enough to enable water oxidation , a substrate so abundant that it assures a practically unlimited electron source for life on earth . Our knowledge on the mechanism of water photooxidation was greatly advanced by high-resolution structures of prokaryotic PSII . Here, we show high-resolution cryogenic electron microscopy (cryo-EM) structures of eukaryotic PSII from the green alga at two distinct conformations. The conformers are also present in stacked PSII, exhibiting flexibility that may be relevant to the grana formation in chloroplasts of the green lineage. CP29, one of PSII associated light-harvesting antennae, plays a major role in distinguishing the two conformations of the supercomplex. We also show that the stacked PSII dimer, a form suggested to support the organisation of thylakoid membranes , can appear in many different orientations providing a flexible stacking mechanism for the arrangement of grana stacks in thylakoids. Our findings provide a structural basis for the heterogenous nature of the eukaryotic PSII on multiple levels.

PubMed: 36799903
DOI: 10.7554/eLife.81150

Experimental method

ELECTRON MICROSCOPY (4 Å)