View source for 3hyw


==3-D X-Ray structure of the sulfide:quinone oxidoreductase of the hyperthermophilic bacterium Aquifex aeolicus in complex with decylubiquinone==
<StructureSection load='3hyw' size='340' side='right'caption='[[3hyw]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3hyw]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Aquifex_aeolicus Aquifex aeolicus]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=3h28 3h28]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3HYW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3HYW 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&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CSS:S-MERCAPTOCYSTEINE'>CSS</scene>, <scene name='pdbligand=DCQ:2-DECYL-5,6-DIMETHOXY-3-METHYLCYCLOHEXA-2,5-DIENE-1,4-DIONE'>DCQ</scene>, <scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=H2S:HYDROSULFURIC+ACID'>H2S</scene>, <scene name='pdbligand=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</scene>, <scene name='pdbligand=PS9:OCTATHIOCANE'>PS9</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=3hyw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3hyw OCA], [https://pdbe.org/3hyw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3hyw RCSB], [https://www.ebi.ac.uk/pdbsum/3hyw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3hyw ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SQRD_AQUAE SQRD_AQUAE] Catalyzes the oxidation of hydrogen sulfide, with the help of a quinone. Consecutive reaction cycles lead to the accumulation of a polysulfide product on the active site Cys residues; these products are released when they exceed a critical length, typically as cyclooctasulfur.<ref>PMID:10816041</ref> <ref>PMID:19487671</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/hy/3hyw_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=3hyw ConSurf].
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== Publication Abstract from PubMed ==
Sulfide:quinone oxidoreductase (SQR) is a flavoprotein with homologues in all domains of life except plants. It plays a physiological role both in sulfide detoxification and in energy transduction. We isolated the protein from native membranes of the hyperthermophilic bacterium Aquifex aeolicus, and we determined its X-ray structure in the "as-purified," substrate-bound, and inhibitor-bound forms at resolutions of 2.3, 2.0, and 2.9 A, respectively. The structure is composed of 2 Rossmann domains and 1 attachment domain, with an overall monomeric architecture typical of disulfide oxidoreductase flavoproteins. A. aeolicus SQR is a surprisingly trimeric, periplasmic integral monotopic membrane protein that inserts about 12 A into the lipidic bilayer through an amphipathic helix-turn-helix tripodal motif. The quinone is located in a channel that extends from the si side of the FAD to the membrane. The quinone ring is sandwiched between the conserved amino acids Phe-385 and Ile-346, and it is possibly protonated upon reduction via Glu-318 and/or neighboring water molecules. Sulfide polymerization occurs on the re side of FAD, where the invariant Cys-156 and Cys-347 appear to be covalently bound to polysulfur fragments. The structure suggests that FAD is covalently linked to the polypeptide in an unusual way, via a disulfide bridge between the 8-methyl group and Cys-124. The applicability of this disulfide bridge for transferring electrons from sulfide to FAD, 2 mechanisms for sulfide polymerization and channeling of the substrate, S(2-), and of the product, S(n), in and out of the active site are discussed.

The structure of Aquifex aeolicus sulfide:quinone oxidoreductase, a basis to understand sulfide detoxification and respiration.,Marcia M, Ermler U, Peng G, Michel H Proc Natl Acad Sci U S A. 2009 Jun 1. PMID:19487671<ref>PMID:19487671</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3hyw" style="background-color:#fffaf0;"></div>

==See Also==
*[[Quinone reductase 3D structures|Quinone reductase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Aquifex aeolicus]]
[[Category: Large Structures]]
[[Category: Ermler U]]
[[Category: Marcia M]]
[[Category: Michel H]]
[[Category: Peng GH]]