View source for 9unu


==PSI-1 FCPI supercomplex from haptophyte Chrysotila roscoffensis==
<StructureSection load='9unu' size='340' side='right'caption='[[9unu]], [[Resolution|resolution]] 2.18&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9unu]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Chrysotila_roscoffensis Chrysotila roscoffensis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9UNU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9UNU FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.18&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=A86:(3S,3S,5R,5R,6S,6R,8R)-3,5-dihydroxy-8-oxo-6,7-didehydro-5,5,6,6,7,8-hexahydro-5,6-epoxy-beta,beta-caroten-3-yl+acetate'>A86</scene>, <scene name='pdbligand=BCR:BETA-CAROTENE'>BCR</scene>, <scene name='pdbligand=CLA:CHLOROPHYLL+A'>CLA</scene>, <scene name='pdbligand=DD6:(1~{R},3~{S},6~{S})-1,5,5-trimethyl-6-[(1~{Z},3~{E},5~{E},7~{E},9~{E},11~{E},13~{E},15~{E})-3,7,12,16-tetramethyl-18-[(4~{R})-2,6,6-trimethyl-4-oxidanyl-cyclohexen-1-yl]octadeca-1,3,5,7,9,11,13,15-octaen-17-ynyl]-7-oxabicyclo[4.1.0]heptan-3-ol'>DD6</scene>, <scene name='pdbligand=DGD:DIGALACTOSYL+DIACYL+GLYCEROL+(DGDG)'>DGD</scene>, <scene name='pdbligand=KC1:(2E)-3-[(21R)-9-ethenyl-14-ethyl-21-(methoxycarbonyl)-4,8,13,18-tetramethyl-20-oxo-3,4-didehydrophorbin-3-yl-kappa~2~N~23~,N~25~]prop-2-enoato(2-)magnesium'>KC1</scene>, <scene name='pdbligand=LHG:1,2-DIPALMITOYL-PHOSPHATIDYL-GLYCEROLE'>LHG</scene>, <scene name='pdbligand=LMG:1,2-DISTEAROYL-MONOGALACTOSYL-DIGLYCERIDE'>LMG</scene>, <scene name='pdbligand=PQN:PHYLLOQUINONE'>PQN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9unu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9unu OCA], [https://pdbe.org/9unu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9unu RCSB], [https://www.ebi.ac.uk/pdbsum/9unu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9unu ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Photosystem I (PSI) converts light energy into chemical energy in photosynthesis, and forms supercomplexes with light-harvesting complexes (LHCI) in eukaryotes to enhance energy capture and transfer. Various numbers and organizations of both PSI core and LHCI subunits are observed in various organisms. A subgroup of haptophytes named coccolithophores play a major role in marine carbon cycle and CaCO(3) production, and the light-harvesting antennas of them are named FCPs (fucoxanthin-chlorophyll a/c binding protein) because they bind chlorophyll c and fucoxanthin in addition to chlorophyll a. A structure of a large PSI-FCPI supercomplex containing 38 FCPI subunits has been reported from a coccolithophore Emiliania huxleyi recently (L. Shen et al., Science 389, eadv2132, 2025). Here we solved five cryo-electron microscopy (cryo-EM) structures of PSI-FCPI supercomplexes isolated from another coccolithophore Chrysotila roscoffensis with different detergents at resolutions ranging from 2.3 to 1.7 A. These structures represent discrete PSI-FCPIs containing 1, 4, 6, 8 and 9 FCPI subunits, with FCPIs arranged in a modular fashion. Association of each FCPI module to the PSI core, as well as the arrangement of protein subunits and pigments, are revealed. Contributions of individual antenna modules to excitation energy transfer were calculated and compared with PSI-FCPI supercomplexes from other species of coccolithophores and haptophytes. These results pinpoint the assembly of stable PSI-FCPI supercomplexes in C. roscoffensis and provide insights into how antenna modules contribute to energy transfer in coccolithophores.

Multiple structures of photosystem I-FCPI supercomplexes from a coccolithophore alga reveal a modular antenna organization.,La Rocca R, Tsai PC, Kato K, Nakajima Y, Akita F, Shen JR Biochim Biophys Acta Bioenerg. 2026 Mar 19;1867(3):149588. doi: , 10.1016/j.bbabio.2026.149588. PMID:41864554<ref>PMID:41864554</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9unu" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Chrysotila roscoffensis]]
[[Category: Large Structures]]
[[Category: Akita F]]
[[Category: Kato K]]
[[Category: La Rocca R]]
[[Category: Nakajima Y]]
[[Category: Shen J-R]]
[[Category: Tsai P-C]]