6LY5

Organization and energy transfer in a huge diatom PSI-FCPI supercomplex

Summary for 6LY5

• Entry DOI: 10.2210/pdb6ly5/pdb
• EMDB information: 30012
• Descriptor: FCPI-7, FCPI-9, FCPI-13, ... (46 entities in total)
• Functional Keywords: diatom, psi-fcpi, photosysyem, photosynthesis
• Biological source: Chaetoceros gracilis; More
• Total number of polymer chains: 36
• Total formula weight: 1277922.82

Authors

Xiong, P.,Caizhe, X. (deposition date: 2020-02-13, release date: 2020-10-21, Last modification date: 2025-04-09)

Primary citation

Xu, C.,Pi, X.,Huang, Y.,Han, G.,Chen, X.,Qin, X.,Huang, G.,Zhao, S.,Yang, Y.,Kuang, T.,Wang, W.,Sui, S.F.,Shen, J.R.
Structural basis for energy transfer in a huge diatom PSI-FCPI supercomplex.
Nat Commun, 11:5081-5081, 2020

PubMed Abstract: Diatom is an important group of marine algae and contributes to around 20% of the global photosynthetic carbon fixation. Photosystem I (PSI) of diatoms is associated with a large number of fucoxanthin-chlorophyll a/c proteins (FCPIs). We report the structure of PSI-FCPI from a diatom Chaetoceros gracilis at 2.38 Å resolution by single-particle cryo-electron microscopy. PSI-FCPI is a monomeric supercomplex consisting of 12 core and 24 antenna subunits (FCPIs), and 326 chlorophylls a, 34 chlorophylls c, 102 fucoxanthins, 35 diadinoxanthins, 18 β-carotenes and some electron transfer cofactors. Two subunits designated PsaR and PsaS were found in the core, whereas several subunits were lost. The large number of pigments constitute a unique and huge network ensuring efficient energy harvesting, transfer and dissipation. These results provide a firm structural basis for unraveling the mechanisms of light-energy harvesting, transfer and quenching in the diatom PSI-FCPI, and also important clues to evolutionary changes of PSI-LHCI.

PubMed: 33033236
DOI: 10.1038/s41467-020-18867-x

Experimental method

ELECTRON MICROSCOPY (2.38 Å)