View source for 7zsi


==Structure of Orange Carotenoid Protein with canthaxanthin bound after 5 minutes of illumination==
<StructureSection load='7zsi' size='340' side='right'caption='[[7zsi]], [[Resolution|resolution]] 1.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7zsi]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Synechocystis Synechocystis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7ZSI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7ZSI FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.399&#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=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=7zsi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7zsi OCA], [https://pdbe.org/7zsi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7zsi RCSB], [https://www.ebi.ac.uk/pdbsum/7zsi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7zsi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/OCP_SYNY3 OCP_SYNY3] Acts as a photo-protectant. Essential for inhibiting white and blue-green light non-photochemical quenching (NPQ). Binding carotenoids improves OCP's intrinsic photoprotectant activity by broadening its absorption spectrum and facilitating the dissipation of absorbed energy.<ref>PMID:16531492</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Orange Carotenoid protein (OCP) is the only known photoreceptor which uses carotenoid for its activation. It is found exclusively in cyanobacteria, where it functions to control light-harvesting of the photosynthetic machinery. However, the photochemical reactions and structural dynamics of this unique photosensing process are not yet resolved. We present time-resolved crystal structures at second-to-minute delays under bright illumination, capturing the early photoproduct and structures of the subsequent reaction intermediates. The first stable photoproduct shows concerted isomerization of C9'-C8' and C7'-C6' single bonds in the bicycle-pedal (s-BP) manner and structural changes in the N-terminal domain with minute timescale kinetics. These are followed by a thermally-driven recovery of the s-BP isomer to the dark state carotenoid configuration. Structural changes propagate to the C-terminal domain, resulting, at later time, in the H-bond rupture of the carotenoid keto group with protein residues. Solution FTIR and UV/Vis spectroscopy support the single bond isomerization of the carotenoid in the s-BP manner and subsequent thermal structural reactions as the basis of OCP photoreception.

Light activation of Orange Carotenoid Protein reveals bicycle-pedal single-bond isomerization.,Chukhutsina VU, Baxter JM, Fadini A, Morgan RM, Pope MA, Maghlaoui K, Orr CM, Wagner A, van Thor JJ Nat Commun. 2022 Oct 28;13(1):6420. doi: 10.1038/s41467-022-34137-4. PMID:36307413<ref>PMID:36307413</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7zsi" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synechocystis]]
[[Category: Baxter JM]]
[[Category: Chukhutsina VU]]
[[Category: Fadini A]]
[[Category: Maghlaoui K]]
[[Category: Morgan RM]]
[[Category: Orr C]]
[[Category: Pope MA]]
[[Category: Wagner A]]
[[Category: Van Thor JJ]]