View source for 1bk1


==ENDO-1,4-BETA-XYLANASE C==
<StructureSection load='1bk1' size='340' side='right'caption='[[1bk1]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1bk1]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Aspergillus_luchuensis Aspergillus luchuensis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BK1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1BK1 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&#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=1bk1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1bk1 OCA], [https://pdbe.org/1bk1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1bk1 RCSB], [https://www.ebi.ac.uk/pdbsum/1bk1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1bk1 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/XYN3_ASPKW XYN3_ASPKW] 
== 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/bk/1bk1_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=1bk1 ConSurf].
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== Publication Abstract from PubMed ==
Xylanase C from Aspergillus kawachii has an optimum pH of 2.0 and is stable at pH 1.0. The crystal structure of xylanase C was determined at 2.0 A resolution (R-factor = 19.4%). The overall structure was similar to those of other family 11 xylanases. Asp37 and an acid-base catalyst, Glu170, are located at a hydrogen-bonding distance (2.8 A), as in other xylanases with low pH optima. Asp37 of xylanase C was replaced with asparagine and other residues by site-directed mutagenesis. Analyses of the wild-type and mutant enzymes showed that Asp37 is important for high enzyme activity at low pH. In the case of the asparagine mutant, the optimum pH shifted to 5.0 and the maximum specific activity decreased to about 15% of that of the wild-type enzyme. On structural comparison with xylanases with higher pH optima, another striking feature of the xylanase C structure was found; the enzyme has numerous acidic residues concentrated on the surface (so-called 'Ser/Thr surface' in most family 11 xylanases). The relationship of the stability against extreme pH conditions and high salt concentrations with the spatially biased distribution of charged residues on the proteins is discussed.

Crystallographic and mutational analyses of an extremely acidophilic and acid-stable xylanase: biased distribution of acidic residues and importance of Asp37 for catalysis at low pH.,Fushinobu S, Ito K, Konno M, Wakagi T, Matsuzawa H Protein Eng. 1998 Dec;11(12):1121-8. PMID:9930661<ref>PMID:9930661</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1bk1" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Aspergillus luchuensis]]
[[Category: Large Structures]]
[[Category: Fushinobu S]]
[[Category: Ito K]]
[[Category: Konno M]]
[[Category: Matsuzawa H]]
[[Category: Wakagi T]]