View source for 5gyb


==Crystal structure of ENZbleach xylanase V5N+V6N+K7R+K223R+K227R and T28C+T60C mutant==
<StructureSection load='5gyb' size='340' side='right'caption='[[5gyb]], [[Resolution|resolution]] 1.65&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5gyb]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Termite_gut_metagenome Termite gut metagenome]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5GYB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5GYB 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]] 1.65&#8491;</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=5gyb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5gyb OCA], [https://pdbe.org/5gyb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5gyb RCSB], [https://www.ebi.ac.uk/pdbsum/5gyb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5gyb ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In the pulp bleaching industry, enzymes with robust activity at high pH and temperatures are desirable for facilitating the pre-bleaching process with simplified processing and minimal use of chlorinated compounds. To engineer an enzyme for this purpose, we determined the crystal structure of the Xyn12.2 xylanase, a xylan-hydrolyzing enzyme derived from the termite gut symbiont metagenome, as the basis for structure-based protein engineering to improve Xyn12.2 stability in high heat and alkaline conditions. Engineered cysteine pairs that generated exterior disulfide bonds increased the kcat of Xyn12.2 variants and melting temperature at all tested conditions. These improvements led to up to 4.2-fold increases in catalytic efficiency at pH 9.0, 50 degrees C for 1h and up to 3-fold increases at 60 degrees C. The most effective variants, XynTT and XynTTTE, exhibited 2-3-fold increases in bagasse hydrolysis at pH 9.0 and 60 degrees C compared to the wild-type enzyme. Overall, engineering arginines and phenylalanines for increased pKa and hydrogen bonding improved enzyme catalytic efficiency at high stringency conditions. These modifications were the keys to enhancing thermostability and alkaliphilicity in our enzyme variants, with XynTT and XynTTTE being especially promising for their application to the pulp and paper industry.

Structure-based protein engineering for thermostable and alkaliphilic enhancement of endo-beta-1,4-xylanase for applications in pulp bleaching.,Boonyapakron K, Jaruwat A, Liwnaree B, Nimchua T, Champreda V, Chitnumsub P J Biotechnol. 2017 Jul 31. pii: S0168-1656(17)31572-9. doi:, 10.1016/j.jbiotec.2017.07.035. PMID:28774672<ref>PMID:28774672</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5gyb" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Termite gut metagenome]]
[[Category: Boonyapakorn K]]
[[Category: Chitnumsub P]]
[[Category: Jaruwat A]]