9eh5
From Proteopedia
(Difference between revisions)
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| - | '''Unreleased structure''' | ||
| - | + | ==Structure of a mutated photosystem II complex reveals changes to the hydrogen-bonding network that affect proton egress during O-O bond formation== | |
| + | <StructureSection load='9eh5' size='340' side='right'caption='[[9eh5]], [[Resolution|resolution]] 1.97Å' scene=''> | ||
| + | == Structural highlights == | ||
| + | <table><tr><td colspan='2'>[[9eh5]] is a 20 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=9EH5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9EH5 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]] 1.97Å</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=BCT:BICARBONATE+ION'>BCT</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=CLA:CHLOROPHYLL+A'>CLA</scene>, <scene name='pdbligand=DGD:DIGALACTOSYL+DIACYL+GLYCEROL+(DGDG)'>DGD</scene>, <scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene>, <scene name='pdbligand=FME:N-FORMYLMETHIONINE'>FME</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>, <scene name='pdbligand=RRX:(3R)-BETA,BETA-CAROTEN-3-OL'>RRX</scene>, <scene name='pdbligand=SQD:1,2-DI-O-ACYL-3-O-[6-DEOXY-6-SULFO-ALPHA-D-GLUCOPYRANOSYL]-SN-GLYCEROL'>SQD</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=9eh5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9eh5 OCA], [https://pdbe.org/9eh5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9eh5 RCSB], [https://www.ebi.ac.uk/pdbsum/9eh5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9eh5 ProSAT]</span></td></tr> | ||
| + | </table> | ||
| + | == Function == | ||
| + | [https://www.uniprot.org/uniprot/PSBA2_SYNY3 PSBA2_SYNY3] | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
| + | Photosystem II (PSII) is the water-splitting enzyme of oxygenic photosynthesis. Using light energy, PSII catalytically oxidizes two water molecules to fuel downstream metabolism, forming an O-O bond and releasing O(2) as a byproduct. The reaction mechanism requires the strategic removal of four protons via conserved hydrogen-bonding networks, but these pathways remain poorly understood. Site-directed mutagenesis has been used to study these pathways and the role of specific side chains, such as Lys317 of the D2 subunit. Previous studies showed that the D2-Lys317Ala substitution, which abolishes the flexible hydrogen-bonding -NH(3)(+) group, resulted in delayed O(2) release kinetics and diminished catalytic turnover, suggesting Lys317 has a crucial role in facilitating proton egress. Here, we investigated this proton egress pathway by determining the cryo-EM structure of PSII containing the D2-Lys317Ala substitution at a resolution of 1.97 A. We observed that four new water molecules fill the space previously occupied by Lys317, but these waters lack specific water-protein interactions, leading to heterogeneity and suboptimal hydrogen bonding. We hypothesize that these waters negatively contribute to the existing hydrogen-bonding network and increase the entropic barrier for proton transfer. Additionally, we observed that a conserved chloride ion (Cl1), which is associated with Lys317, is unexpectedly maintained in D2-Lys317Ala PSII. However, unlike in wild-type, Cl1 has no measured effect on oxygen-evolution rates in D2-Lys317Ala PSII. This suggests that the role of Cl1 is dependent on the Lys317 amino group. These findings provide new insight into proton egress through the Cl1 hydrogen-bonding channel. | ||
| - | + | Structure of a mutated photosystem II complex reveals changes to the hydrogen-bonding network that affect proton egress during O-O bond formation.,Flesher DA, Shin J, Debus RJ, Brudvig GW J Biol Chem. 2025 Feb 6:108272. doi: 10.1016/j.jbc.2025.108272. PMID:39922494<ref>PMID:39922494</ref> | |
| - | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |
| - | [[Category: | + | </div> |
| + | <div class="pdbe-citations 9eh5" style="background-color:#fffaf0;"></div> | ||
| + | == References == | ||
| + | <references/> | ||
| + | __TOC__ | ||
| + | </StructureSection> | ||
| + | [[Category: Large Structures]] | ||
| + | [[Category: Synechocystis sp. PCC 6803]] | ||
| + | [[Category: Brudvig GW]] | ||
| + | [[Category: Debus RJ]] | ||
| + | [[Category: Flesher DA]] | ||
| + | [[Category: Shin J]] | ||
Current revision
Structure of a mutated photosystem II complex reveals changes to the hydrogen-bonding network that affect proton egress during O-O bond formation
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