View source for 3l66


==Xenobiotic Reductase A - C25A Variant with Coumarin==
<StructureSection load='3l66' size='340' side='right'caption='[[3l66]], [[Resolution|resolution]] 1.28&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3l66]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3L66 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3L66 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]] 1.28&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BU3:(R,R)-2,3-BUTANEDIOL'>BU3</scene>, <scene name='pdbligand=COU:COUMARIN'>COU</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</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=3l66 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3l66 OCA], [https://pdbe.org/3l66 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3l66 RCSB], [https://www.ebi.ac.uk/pdbsum/3l66 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3l66 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q3ZDM6_PSEPU Q3ZDM6_PSEPU] 
== 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/l6/3l66_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=3l66 ConSurf].
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== Publication Abstract from PubMed ==
Xenobiotic reductase A (XenA) from Pseudomonas putida 86 catalyzes the NADH/NADPH-dependent reduction of various substrates, including 2-cyclohexenone and 8-hydroxycoumarin. XenA is a member of the old yellow enzyme (OYE) family of flavoproteins and is structurally and functionally similar to other bacterial members of this enzyme class. A characteristic feature of XenA is the presence of a cysteine residue (Cys25) in the active site, where in most members of the OYE family a threonine residue is found that modulates the reduction potential of the FMN/FMNH(-) couple. We investigated the role of Cys25 by studying two variants in which the residue has been exchanged for a serine and an alanine residue. While the exchange against alanine has a remarkably small effect on the reduction potential, the reactivity and the structure of XenA, the exchange against serine increases the reduction potential by +82 mV, increases the rate constant of the reductive half-reaction and decreases the rate constant in the oxidative half-reaction. We determined six crystal structures at high to true atomic resolution (d(min) 1.03-1.80 A) of the three XenA variants with and without the substrate coumarin bound in the active site. The atomic resolution structure of XenA in complex with coumarin reveals a compressed active site geometry in which the isoalloxazine ring is sandwiched between coumarin and the protein backbone. The structures further reveal that the conformation of the active site and substrate interactions are preserved in the two variants, indicating that the observed changes are due to local effects only. We propose that Cys25 and the residues in its place determine which of the two half-reactions is rate limiting, depending on the substrate couple. This might help to explain why the genome of Pseudomonas putida encodes multiple xenobiotic reductases containing either cysteine, threonine or alanine in the active site.

Cysteine as a modulator residue in the active site of xenobiotic reductase A: a structural, thermodynamic and kinetic study.,Spiegelhauer O, Mende S, Dickert F, Knauer SH, Ullmann GM, Dobbek H J Mol Biol. 2010 Apr 23;398(1):66-82. Epub 2010 Mar 3. PMID:20206186<ref>PMID:20206186</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: Large Structures]]
[[Category: Pseudomonas putida]]
[[Category: Dobbek H]]
[[Category: Spiegelhauer O]]