View source for 2qxt


==Crystal Structure Analysis of the Bacillus subtilis lipase crystallized at pH 4.5==
<StructureSection load='2qxt' size='340' side='right'caption='[[2qxt]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2qxt]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_globigii"_migula_1900 "bacillus globigii" migula 1900]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2QXT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2QXT FirstGlance]. <br>
</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[2qxu|2qxu]]</div></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">lipA ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1423 "Bacillus globigii" Migula 1900])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Triacylglycerol_lipase Triacylglycerol lipase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.3 3.1.1.3] </span></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=2qxt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qxt OCA], [https://pdbe.org/2qxt PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2qxt RCSB], [https://www.ebi.ac.uk/pdbsum/2qxt PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2qxt ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/ESTA_BACSU ESTA_BACSU]] Active toward p-nitrophenyl esters and triacylglycerides with a marked preference for esters with C8 acyl groups.<ref>PMID:8396026</ref>  
== 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/qx/2qxt_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=2qxt ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Understanding the structural basis of altered properties of proteins due to changes in temperature or pH provides useful insights in designing proteins with improved stability. Here we report the basis for the pH-dependent thermostability of the Bacillus subtilis lipase (Lip A) using spectroscopic and X-ray crystallographic studies. At pH values above 7, lipase denatures and aggregates when heated at temperatures above 45 degrees C. However, at pH below 6 lipase denatures upon heating but the activity and its native structure is completely recovered upon cooling. In order to obtain the structural basis of this unusual stability of lipase, we determined high-resolution crystal structures of the lipase in two different crystal forms at pH 4.5 and 5. These structures show linear oligomerization of lipase using only two types of dimeric associations and these inter-molecular interactions are completely absent in several crystal forms of wild-type and mutant proteins obtained at basic pH. In accordance with the crystallographic studies, spectroscopic investigations reveal an invariant secondary structure in the pH range of 4-10. Quaternary organization of lipase at low pH resulted in changes in the tryptophan environment and binding of 1-anilino-8-naphthalene sulfate (ANS) at low pH. Low pH stability of the lipase is not observed in the presence of sodium chloride (&gt;0.2 M) indicating the importance of ionic interactions at low pH. Inter- and intra-molecular ionic interactions that occur at pH below 6.0 are proposed to trap the molecule in a conformation that allows its complete refolding upon cooling.

Structural basis for the remarkable stability of Bacillus subtilis lipase (Lip A) at low pH.,Rajakumara E, Acharya P, Ahmad S, Sankaranaryanan R, Rao NM Biochim Biophys Acta. 2008 Feb;1784(2):302-11. Epub 2007 Nov 12. PMID:18053819<ref>PMID:18053819</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 2qxt" style="background-color:#fffaf0;"></div>

==See Also==
*[[Lipase 3D Structures|Lipase 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacillus globigii migula 1900]]
[[Category: Large Structures]]
[[Category: Triacylglycerol lipase]]
[[Category: Rajakumara, E]]
[[Category: Sankaranarayanan, R]]
[[Category: Alpha/beta hydrolase fold]]
[[Category: Hydrolase]]
[[Category: Lipid degradation]]
[[Category: Secreted]]