View source for 2prc


==PHOTOSYNTHETIC REACTION CENTER FROM RHODOPSEUDOMONAS VIRIDIS (UBIQUINONE-2 COMPLEX)==
<StructureSection load='2prc' size='340' side='right'caption='[[2prc]], [[Resolution|resolution]] 2.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2prc]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Blastochloris_viridis Blastochloris viridis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PRC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2PRC 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]] 2.45&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BPB:BACTERIOPHEOPHYTIN+B'>BPB</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=LDA:LAURYL+DIMETHYLAMINE-N-OXIDE'>LDA</scene>, <scene name='pdbligand=MQ7:MENAQUINONE-7'>MQ7</scene>, <scene name='pdbligand=NS5:15-CIS-1,2-DIHYDRONEUROSPORENE'>NS5</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=UQ2:UBIQUINONE-2'>UQ2</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=2prc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2prc OCA], [https://pdbe.org/2prc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2prc RCSB], [https://www.ebi.ac.uk/pdbsum/2prc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2prc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CYCR_BLAVI CYCR_BLAVI] The reaction center of purple bacteria contains a tightly bound cytochrome molecule which re-reduces the photo oxidized primary electron donor.<ref>PMID:10736158</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/pr/2prc_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2prc ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
BACKGROUND: In a reaction of central importance to the energetics of photosynthetic bacteria, light-induced electron transfer in the reaction centre (RC) is coupled to the uptake of protons from the cytoplasm at the binding site of the secondary quinone (QB). In the original structure of the RC from Rhodopseudomonas viridis (PDB entry code 1PRC), the QB site was poorly defined because in the standard RC crystals it was only approximately 30% occupied with ubiquinone-9 (UQ9). We report here the structural characterization of the QB site by crystallographic refinement of UQ9-depleted RCs and of complexes of the RC either with ubiquinone-2 (UQ2) or the electron-transfer inhibitor stigmatellin in the QB site. RESULTS: The structure of the RC complex with UQ2, refined at 2.45 A resolution, constitutes the first crystallographically reliably defined binding site for quinones from the bioenergetically important quinone pool of biological, energy-transducing membranes. In the UQ9-depleted QB site of the RC structure, refined at 2.4 A resolution, apparently five (and possibly six) water molecules are bound instead of the ubiquinone head group, and a detergent molecule binds in the region of the isoprenoid tail. All of the protein-cofactor interactions implicated in the binding of the ubiquinone head group are also implicated in the binding of the stigmatellin head group. In the structure of the stigmatellin-RC complex, refined at 2.4 A resolution, additional hydrogen bonds stabilize the binding of stigmatellin over that of ubiquinone. The tentative position of UQ9 in the QB site in the original data set (1PRC) was re-examined using the structure of the UQ9-depleted RC as a reference. A modified QB site model, which exhibits greater similarity to the distal ubiquinone-10 (UQ10) positioning in the structure of the RC from Rhodobacter sphaeroides (PDB entry code 1PCR), is suggested as the dominant binding site for native UQ9. CONCLUSIONS: The structures reported here can provide models of quinone reduction cycle intermediates. The binding pattern observed for the stigmatellin complex, where the ligand donates a hydrogen bond to Ser L223 (where 'L' represents the L subunit of the RC), can be viewed as a model for the stabilization of a monoprotonated reduced intermediate (QBH or QBH-). The presence of Ser L223 in the QB site indicates that the QB site is not optimized for QB binding, but for QB reduction to the quinol.

The coupling of light-induced electron transfer and proton uptake as derived from crystal structures of reaction centres from Rhodopseudomonas viridis modified at the binding site of the secondary quinone, QB.,Lancaster CR, Michel H Structure. 1997 Oct 15;5(10):1339-59. PMID:9351808<ref>PMID:9351808</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 2prc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Blastochloris viridis]]
[[Category: Large Structures]]
[[Category: Lancaster CRD]]
[[Category: Michel H]]