View source for 7sa3


==Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light==
<StructureSection load='7sa3' size='340' side='right'caption='[[7sa3]], [[Resolution|resolution]] 2.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7sa3]] is a 9 chain structure with sequence from [https://en.wikipedia.org/wiki/Synechococcus_sp._PCC_7335 Synechococcus sp. PCC 7335]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SA3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SA3 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]] 2.25&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BCR:BETA-CAROTENE'>BCR</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=CL7:CHLOROPHYLL+D'>CL7</scene>, <scene name='pdbligand=CLA:CHLOROPHYLL+A'>CLA</scene>, <scene name='pdbligand=DGD:DIGALACTOSYL+DIACYL+GLYCEROL+(DGDG)'>DGD</scene>, <scene name='pdbligand=F6C:Chlorophyll+F'>F6C</scene>, <scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</scene>, <scene name='pdbligand=PHO:PHEOPHYTIN+A'>PHO</scene>, <scene name='pdbligand=PL9:2,3-DIMETHYL-5-(3,7,11,15,19,23,27,31,35-NONAMETHYL-2,6,10,14,18,22,26,30,34-HEXATRIACONTANONAENYL-2,5-CYCLOHEXADIENE-1,4-DIONE-2,3-DIMETHYL-5-SOLANESYL-1,4-BENZOQUINONE'>PL9</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=7sa3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7sa3 OCA], [https://pdbe.org/7sa3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7sa3 RCSB], [https://www.ebi.ac.uk/pdbsum/7sa3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7sa3 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/B4WKH9_SYNS7 B4WKH9_SYNS7] Photosystem II (PSII) is a light-driven water:plastoquinone oxidoreductase that uses light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation. It consists of a core antenna complex that captures photons, and an electron transfer chain that converts photonic excitation into a charge separation. The D1/D2 (PsbA/PsbD) reaction center heterodimer binds P680, the primary electron donor of PSII as well as several subsequent electron acceptors.[ARBA:ARBA00037683]
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== Publication Abstract from PubMed ==
Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 A resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the Chl(D1) position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth.

Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f.,Gisriel CJ, Shen G, Ho MY, Kurashov V, Flesher DA, Wang J, Armstrong WH, Golbeck JH, Gunner MR, Vinyard DJ, Debus RJ, Brudvig GW, Bryant DA J Biol Chem. 2022 Jan;298(1):101424. doi: 10.1016/j.jbc.2021.101424. Epub 2021 , Nov 19. PMID:34801554<ref>PMID:34801554</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Photosystem II 3D structures|Photosystem II 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Synechococcus sp. PCC 7335]]
[[Category: Brudvig GW]]
[[Category: Bryant DA]]
[[Category: Gisriel CJ]]