8XLS

PSI-FCPI of the diatom Thalassiosira pseudonana CCMP1335

Summary for 8XLS

• Entry DOI: 10.2210/pdb8xls/pdb
• EMDB information: 38457
• Descriptor: Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I reaction center subunit XII, Photosystem I reaction center subunit Psa29, ... (32 entities in total)
• Functional Keywords: photosystem i, electron transport, photosynthesis
• Biological source: Thalassiosira pseudonana CCMP1335; More
• Total number of polymer chains: 17
• Total formula weight: 546618.07

Authors

Kato, K.,Nakajima, Y.,Shen, J.R.,Nagao, R. (deposition date: 2023-12-26, release date: 2024-10-30, Last modification date: 2024-11-27)

Primary citation

Kato, K.,Nakajima, Y.,Xing, J.,Kumazawa, M.,Ogawa, H.,Shen, J.R.,Ifuku, K.,Nagao, R.
Structural basis for molecular assembly of fucoxanthin chlorophyll a / c -binding proteins in a diatom photosystem I supercomplex.
Elife, 13:-, 2024

PubMed Abstract: Photosynthetic organisms exhibit remarkable diversity in their light-harvesting complexes (LHCs). LHCs are associated with photosystem I (PSI), forming a PSI-LHCI supercomplex. The number of LHCI subunits, along with their protein sequences and pigment compositions, has been found to differ greatly among the PSI-LHCI structures. However, the mechanisms by which LHCIs recognize their specific binding sites within the PSI core remain unclear. In this study, we determined the cryo-electron microscopy structure of a PSI supercomplex incorporating fucoxanthin chlorophyll /-binding proteins (FCPs), designated as PSI-FCPI, isolated from the diatom CCMP1335. Structural analysis of PSI-FCPI revealed five FCPI subunits associated with a PSI monomer; these subunits were identified as RedCAP, Lhcr3, Lhcq10, Lhcf10, and Lhcq8. Through structural and sequence analyses, we identified specific protein-protein interactions at the interfaces between FCPI and PSI subunits, as well as among FCPI subunits themselves. Comparative structural analyses of PSI-FCPI supercomplexes, combined with phylogenetic analysis of FCPs from and the diatom , underscore the evolutionary conservation of protein motifs crucial for the selective binding of individual FCPI subunits. These findings provide significant insights into the molecular mechanisms underlying the assembly and selective binding of FCPIs in diatoms.

PubMed: 39480899
DOI: 10.7554/eLife.99858

Experimental method

ELECTRON MICROSCOPY (2.3 Å)