8R2I

Cryo-EM Structure of native Photosystem II assembly intermediate from Chlamydomonas reinhardtii

Summary for 8R2I

• Entry DOI: 10.2210/pdb8r2i/pdb
• EMDB information: 18848
• Descriptor: Photosystem II protein D1, Chain U, Predicted protein, Photosystem II reaction center protein Ycf12, ... (24 entities in total)
• Functional Keywords: photosystem ii, photosynthesis, biogenesis of psii, assembly intermediate, cryoem, assembly factor, chlamydomonas reinhardtii
• Biological source: Chlamydomonas reinhardtii; More
• Total number of polymer chains: 11
• Total formula weight: 261118.49

Authors

Fadeeva, M.,Klaiman, D.,Kandiah, E.,Nelson, N. (deposition date: 2023-11-06, release date: 2024-01-31, Last modification date: 2024-02-21)

Primary citation

Fadeeva, M.,Klaiman, D.,Kandiah, E.,Nelson, N.
Structure of native photosystem II assembly intermediate from Chlamydomonas reinhardtii .
Front Plant Sci, 14:1334608-1334608, 2023

PubMed Abstract: Photosystem II (PSII) is a dimer consisting of at least 13 nuclear-encoded and four chloroplast-encoded protein subunits that collectively function as a sunlight-driven oxidoreductase. In this study, we present the inaugural structure of a green alga PSII assembly intermediate (pre-PSII-int). This intermediate was isolated from chloroplast membranes of the temperature-sensitive mutant TSP4, cultivated for 14 hours at a non-permissive temperature. The assembly state comprises a monomer containing subunits A, B, C, D, E, F, H, I, K, and two novel assembly factors, Psb1 and Psb2. Psb1 is identified as a novel transmembrane helix located adjacent to PsbE and PsbF (cytochrome b559). The absence of PsbJ, typically found in mature PSII close to this position, indicates that Psb1 functions as an assembly factor. Psb2 is an eukaryotic homolog of the cyanobacterial assembly factor Psb27. The presence of iron, coupled with the absence of Q, Q, and the manganese cluster, implies a protective mechanism against photodamage and provides insights into the intricate assembly process.

PubMed: 38322422
DOI: 10.3389/fpls.2023.1334608

Experimental method

ELECTRON MICROSCOPY (2.9 Å)