8C29

Cryo-EM structure of photosystem II C2S2 supercomplex from Norway spruce (Picea abies) at 2.8 Angstrom resolution

Summary for 8C29

• Entry DOI: 10.2210/pdb8c29/pdb
• EMDB information: 16389
• Descriptor: Photosystem II protein D1, Photosystem II reaction center protein K, Photosystem II reaction center protein L, ... (43 entities in total)
• Functional Keywords: membrane protein complex, photosynthesis, photosystem, gymnosperm, membrane protein
• Biological source: Picea abies (Norway spruce); More
• Total number of polymer chains: 46
• Total formula weight: 1215556.42

Authors

Kopecny, D.,Semchonok, D.A.,Kouril, R. (deposition date: 2022-12-21, release date: 2023-07-26, Last modification date: 2024-11-13)

Primary citation

Opatikova, M.,Semchonok, D.A.,Kopecny, D.,Ilik, P.,Pospisil, P.,Ilikova, I.,Roudnicky, P.,Zeljkovic, S.C.,Tarkowski, P.,Kyrilis, F.L.,Hamdi, F.,Kastritis, P.L.,Kouril, R.
Cryo-EM structure of a plant photosystem II supercomplex with light-harvesting protein Lhcb8 and alpha-tocopherol.
Nat.Plants, 9:1359-1369, 2023

PubMed Abstract: The heart of oxygenic photosynthesis is the water-splitting photosystem II (PSII), which forms supercomplexes with a variable amount of peripheral trimeric light-harvesting complexes (LHCII). Our knowledge of the structure of green plant PSII supercomplex is based on findings obtained from several representatives of green algae and flowering plants; however, data from a non-flowering plant are currently missing. Here we report a cryo-electron microscopy structure of PSII supercomplex from spruce, a representative of non-flowering land plants, at 2.8 Å resolution. Compared with flowering plants, PSII supercomplex in spruce contains an additional Ycf12 subunit, Lhcb4 protein is replaced by Lhcb8, and trimeric LHCII is present as a homotrimer of Lhcb1. Unexpectedly, we have found α-tocopherol (α-Toc)/α-tocopherolquinone (α-TQ) at the boundary between the LHCII trimer and the inner antenna CP43. The molecule of α-Toc/α-TQ is located close to chlorophyll a614 of one of the Lhcb1 proteins and its chromanol/quinone head is exposed to the thylakoid lumen. The position of α-Toc in PSII supercomplex makes it an ideal candidate for the sensor of excessive light, as α-Toc can be oxidized to α-TQ by high-light-induced singlet oxygen at low lumenal pH. The molecule of α-TQ appears to shift slightly into the PSII supercomplex, which could trigger important structure-functional modifications in PSII supercomplex. Inspection of the previously reported cryo-electron microscopy maps of PSII supercomplexes indicates that α-Toc/α-TQ can be present at the same site also in PSII supercomplexes from flowering plants, but its identification in the previous studies has been hindered by insufficient resolution.

PubMed: 37550369
DOI: 10.1038/s41477-023-01483-0

Experimental method

ELECTRON MICROSCOPY (2.785 Å)