View source for 28wu


==Crystal Structure of Catalase HPII (KatE) from Escherichia coli==
<StructureSection load='28wu' size='340' side='right'caption='[[28wu]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[28wu]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_BL21(DE3) Escherichia coli BL21(DE3)]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=28WU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=28WU 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=28wu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=28wu OCA], [https://pdbe.org/28wu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=28wu RCSB], [https://www.ebi.ac.uk/pdbsum/28wu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=28wu ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CATE_ECOLI CATE_ECOLI] Decomposes hydrogen peroxide into water and oxygen; serves to protect cells from the toxic effects of hydrogen peroxide.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Recombinant protein expression in E. coli is a key methodology for modern biomedical research. Typically, a polyhistidine-tagged ("His-tagged") protein is purified using immobilized metal affinity chromatography (IMAC), achieving close to apparently homogenous target protein preparations. However, contaminant host proteins may nonetheless be co-purified at trace amounts. This includes bacterial catalase, which can even be found crystallized instead of an intended target protein. Here, we found that less than 0.03% of the original endogenous bacterial catalase remaining in a final recombinant protein product can easily be detected in an enzymatic H(2)O(2) (hydrogen peroxide) scavenging assay, because of the high inherent turnover of catalase and its lack of need for additional cofactors. If present in a recombinant protein preparation, this activity may give unintended effects, especially if the target protein is a redox active enzyme, such as glutathione peroxidase, glutaredoxin, ribonucleotide reductase, thioredoxin, or peroxiredoxin. Here, we found that genetic deletion of the two katG and katE genes in a bacterial expression host could fully eliminate catalase from the recombinant protein product without any appreciable loss of final yield. We suggest that this genetic approach is to be preferred for the removal of catalase instead of using more extensive purification schemes. KEY POINTS: * Catalase contaminates recombinant His-tagged proteins purified from E. coli. * A small amount of catalase yields substantial activity due to its high turnover. * Genetic knockout eliminates catalase contamination without compromising yields.

A katE katG double-knockout E. coli strain eliminates the risk of catalase contamination in recombinant proteins.,Scholz AT, Coppo L, Nolan E, Hernandez M, Wang X, Mishra P, Schnell R, Pato ZA, Chen Y, Dagnell M, Andor A, Cheng Q, Arner ESJ Appl Microbiol Biotechnol. 2026 Apr 22;110(1):136. doi: , 10.1007/s00253-026-13820-2. PMID:42020871<ref>PMID:42020871</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 28wu" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Schnell R]]