8JP3

FCP trimer in diatom Thalassiosira pseudonana

Summary for 8JP3

• Entry DOI: 10.2210/pdb8jp3/pdb
• EMDB information: 36466
• Descriptor: Fucoxanthin chlorophyll a/c protein 8, (3S,3'S,5R,5'R,6S,6'R,8'R)-3,5'-dihydroxy-8-oxo-6',7'-didehydro-5,5',6,6',7,8-hexahydro-5,6-epoxy-beta,beta-caroten-3'- yl acetate, CHLOROPHYLL A, ... (6 entities in total)
• Functional Keywords: fcp trimer, photosynthesis
• Biological source: Thalassiosira pseudonana CCMP1335
• Total number of polymer chains: 3
• Total formula weight: 102085.31

Authors

Feng, Y.,Li, Z.,Zhou, C.C.,Liu, C.,Shen, J.R.,Wang, W. (deposition date: 2023-06-10, release date: 2024-06-12, Last modification date: 2024-11-27)

Primary citation

Zhou, C.,Feng, Y.,Li, Z.,Shen, L.,Li, X.,Wang, Y.,Han, G.,Kuang, T.,Liu, C.,Shen, J.R.,Wang, W.
Structural and spectroscopic insights into fucoxanthin chlorophyll a/c-binding proteins of diatoms in diverse oligomeric states.
Plant Commun., 5:101041-101041, 2024

PubMed Abstract: Diatoms, a group of prevalent marine algae, significantly contribute to global primary productivity. Their substantial biomass is linked to enhanced absorption of blue-green light underwater, facilitated by fucoxanthin chlorophyll a/c-binding proteins (FCPs), exhibiting oligomeric diversity across diatom species. Utilizing mild CN-PAGE analysis on solubilized thylakoid membranes, we displayed monomeric, dimeric, trimeric, tetrameric and pentameric FCPs in diatoms. Mass spectrometry analysis revealed each oligomeric FCP has specific protein compositions, constituting a large Lhcf family of FCP antennas. In addition, we resolved the structures of Thalassiosira pseudonana FCP (Tp-FCP) homotrimer and Chaetoceros gracilis FCP (Cg-FCP) pentamer by cryo-electron microscopy at 2.73 Å and 2.65 Å resolutions, respectively. The distinct pigment composition and organization in various oligomeric FCPs change their blue-green light-harvesting, excitation energy transfer pathways. In comparison to dimeric and trimeric FCPs, Cg-FCP tetramer and Cg-FCP pentamer exhibit stronger absorption by Chls c, red-shifted and broader Chl a fluorescence emission, as well as more robust circular dichroism signals originating from Chl a-carotenoid dimers. These spectroscopic characteristics indicate that Chl a molecules in Cg-FCP tetramer and Cg-FCP pentamer are more heterogeneous than in both dimers and Tp-FCP trimer. The structural and spectroscopic insights provided by this study contribute to a better understanding of the mechanisms that empower diatoms to adapt to fluctuating light environments.

PubMed: 39030906
DOI: 10.1016/j.xplc.2024.101041

Experimental method

ELECTRON MICROSCOPY (2.73 Å)