View source for 5kqk


==Crystal structure of the Q233E/N240D variant of the catalase-peroxidase from B. pseudomallei==
<StructureSection load='5kqk' size='340' side='right'caption='[[5kqk]], [[Resolution|resolution]] 1.75&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5kqk]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Burkholderia_pseudomallei_1710b Burkholderia pseudomallei 1710b]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5KQK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5KQK 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]] 1.75&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=OXY:OXYGEN+MOLECULE'>OXY</scene>, <scene name='pdbligand=TOX:1-HYDROPEROXY-L-TRYPTOPHAN'>TOX</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=5kqk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5kqk OCA], [https://pdbe.org/5kqk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5kqk RCSB], [https://www.ebi.ac.uk/pdbsum/5kqk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5kqk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KATG_BURP1 KATG_BURP1] Bifunctional enzyme with both catalase and broad-spectrum peroxidase activity.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The unusual Met-Tyr-Trp adduct composed of cross-linked side chains along with an associated mobile Arg is essential for catalase activity in catalase-peroxidases. In addition, acidic residues in the entrance channel, in particular an Asp and a Glu approximately 7 and approximately 15 A, respectively, from the heme, significantly enhance catalase activity. The mechanism by which these channel carboxylates influence catalase activity is the focus of this work. Seventeen new variants with fewer and additional acidic residues have been constructed and characterized structurally and for enzymatic activity, revealing that their effect on activity is roughly inversely proportional to their distance from the heme and adduct, suggesting that the electrostatic potential of the heme cavity may be affected. A discrete group of protonable residues are contained within a 15 A sphere surrounding the heme iron, and a computational analysis reveals that the pKa of the distal His112, alone, is modulated within the pH range of catalase activity by the remote acidic residues in a pattern consistent with its protonated form having a key role in the catalase reaction cycle. The electrostatic potential also impacts the catalatic reaction through its influence on the charged status of the Met-Tyr-Trp adduct.

The Catalase Activity of Catalase-Peroxidases Is Modulated by Changes in the pKa of the Distal Histidine.,Machuqueiro M, Victor B, Switala J, Villanueva J, Rovira C, Fita I, Loewen PC Biochemistry. 2017 Apr 20. doi: 10.1021/acs.biochem.6b01276. PMID:28409923<ref>PMID:28409923</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5kqk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Catalase 3D structures|Catalase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Burkholderia pseudomallei 1710b]]
[[Category: Large Structures]]
[[Category: Loewen PC]]