View source for 8to2


==Bottom cylinder of high-resolution phycobilisome quenched by OCP (local refinement)==
<StructureSection load='8to2' size='340' side='right'caption='[[8to2]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8to2]] is a 29 chain structure with sequence from [https://en.wikipedia.org/wiki/Synechocystis_sp._PCC_6803 Synechocystis sp. PCC 6803]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8TO2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8TO2 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&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=45D:BETA,BETA-CAROTENE-4,4-DIONE'>45D</scene>, <scene name='pdbligand=CYC:PHYCOCYANOBILIN'>CYC</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=8to2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8to2 OCA], [https://pdbe.org/8to2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8to2 RCSB], [https://www.ebi.ac.uk/pdbsum/8to2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8to2 ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cyanobacteria use large antenna complexes called phycobilisomes (PBSs) for light harvesting. However, intense light triggers non-photochemical quenching, where the orange carotenoid protein (OCP) binds to PBS, dissipating excess energy as heat. The mechanism of efficiently transferring energy from phycocyanobilins in PBS to canthaxanthin in OCP remains insufficiently understood. Using cryo-electron microscopy, we unveiled the OCP-PBS complex structure at 1.6- to 2.1-angstrom resolution, showcasing its inherent flexibility. Using multiscale quantum chemistry, we disclosed the quenching mechanism. Identifying key protein residues, we clarified how canthaxanthin's transition dipole moment in its lowest-energy dark state becomes large enough for efficient energy transfer from phycocyanobilins. Our energy transfer model offers a detailed understanding of the atomic determinants of light harvesting regulation and antenna architecture in cyanobacteria.

Structural and quantum chemical basis for OCP-mediated quenching of phycobilisomes.,Sauer PV, Cupellini L, Sutter M, Bondanza M, Dominguez Martin MA, Kirst H, Bina D, Koh AF, Kotecha A, Greber BJ, Nogales E, Polivka T, Mennucci B, Kerfeld CA Sci Adv. 2024 Apr 5;10(14):eadk7535. doi: 10.1126/sciadv.adk7535. Epub 2024 Apr , 5. PMID:38578996<ref>PMID:38578996</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8to2" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synechocystis sp. PCC 6803]]
[[Category: Cupellini L]]
[[Category: Sauer PV]]
[[Category: Sutter M]]