View source for 3mm5


==Dissimilatory sulfite reductase in complex with the substrate sulfite==
<StructureSection load='3mm5' size='340' side='right'caption='[[3mm5]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3mm5]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Archaeoglobus_fulgidus Archaeoglobus fulgidus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3MM5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3MM5 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO3:SULFITE+ION'>SO3</scene>, <scene name='pdbligand=SRM:SIROHEME'>SRM</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=3mm5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3mm5 OCA], [https://pdbe.org/3mm5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3mm5 RCSB], [https://www.ebi.ac.uk/pdbsum/3mm5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3mm5 ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/DSRA_ARCFU DSRA_ARCFU] Catalyzes the reduction of sulfite to sulfide. This is the terminal oxidation reaction in sulfate respiration.
== 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/mm/3mm5_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=3mm5 ConSurf].
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== Publication Abstract from PubMed ==
A vital process in the biogeochemical sulfur cycle is the dissimilatory sulfate reduction pathway in which sulfate (SO(2)) is converted to hydrogen sulfide (HS). Dissimilatory sulfite reductase (dSir), its key enzyme, hosts a unique siroheme-[4Fe-4S] cofactor and catalyzes the six-electron reduction of sulfite (SO(2)) to HS. To explore this reaction, we determined the X-ray structures of dSir from the archaeon Archaeoglobus fulgidus in complex with sulfite, sulfide (S(2)) carbon monoxide (CO), cyanide (CN), nitrite (NO), nitrate (NO), and phosphate (PO(3)). Activity measurements indicated that dSir of A. fulgidus reduces, besides sulfite and nitrite, thiosulfate (SO(2)) and trithionate (SO(2)) and produces the latter two compounds besides sulfide. On this basis, a three-step mechanism was proposed, each step consisting of a two-electron transfer, a two-proton uptake, and a dehydration event. In comparison, the related active site structures of the assimilatory sulfite reductase (aSir)- and dSir-SO(2)complexes reveal different conformations of Argalpha170 and Lysalpha211 both interacting with the sulfite oxygens (its sulfur atom coordinates the siroheme iron), a sulfite rotation of ~60 degrees relative to each other, and different access of solvent molecules to the sulfite oxygens from the active site cleft. Therefore, solely in dSir a further sulfite molecule can be placed in van der Waals contact with the siroheme-ligated sulfite or sulfur-oxygen intermediates necessary for forming thiosulfate and trithionate. Although reported for dSir from several sulfate-reducing bacteria, the in vivo relevance of their formation is questionable.

Reaction cycle of the dissimilatory sulfite reductase from Archaeoglobus fulgidus.,Parey K, Warkentin E, Kroneck PM, Ermler U Biochemistry. 2010 Oct 19;49(41):8912-21. PMID:20822098<ref>PMID:20822098</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Archaeoglobus fulgidus]]
[[Category: Large Structures]]
[[Category: Ermler U]]
[[Category: Kroneck PMH]]
[[Category: Parey K]]
[[Category: Warkentin E]]