View source for 2q39


==Beta-lactoglobulin (low humidity)==
<StructureSection load='2q39' size='340' side='right'caption='[[2q39]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2q39]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2Q39 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2Q39 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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2q39 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2q39 OCA], [https://pdbe.org/2q39 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2q39 RCSB], [https://www.ebi.ac.uk/pdbsum/2q39 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2q39 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LACB_BOVIN LACB_BOVIN] Primary component of whey, it binds retinol and is probably involved in the transport of that molecule.
== 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/q3/2q39_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=2q39 ConSurf].
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== Publication Abstract from PubMed ==
Dimeric lactoglobulin molecules exist in the open conformation at basic pH, whereas they exist in the closed conformation at acidic pH, after undergoing the Tanford transition around neutral pH. Orthorhombic crystals consisting of molecules in the open conformation, grown close to neutral pH, undergo a water-mediated transformation when the relative humidity around the crystals is reduced. The two subunits in the dimer are related by a crystallographic twofold axis in the native crystals while the dimer is asymmetric in the low humidity form. Interestingly, one of the subunits in the dimer in the low humidity form is in an open conformation while the other is in a closed conformation. This is the first observation of such an asymmetric dimer. A hydrogen bond between the side chains of Gln35 and Tyr42 exists and the side chain of Glu89 is substantially buried in the closed subunit of the asymmetric unit, as in other structures with molecules in the closed conformation. However, the closure of the EF loop is not complete; its conformation can be described as half-closed. A comparison of different crystal structures of beta-lactoglobulin indicates that the conformation of the loops in the molecule is substantially influenced by other factors such as crystal packing, the pH, and the composition of the medium, while the change in the conformation of the EF loop follows the Tanford transition. The mutual disposition of the two subunits in the low humidity form is halfway between those in the open and closed structures. The present work further demonstrates that structural changes that occur during partial dehydration could mimic those that occur during the action of proteins. Proteins 2008. (c) 2007 Wiley-Liss, Inc.

An asymmetric dimer of beta-lactoglobulin in a low humidity crystal form-Structural changes that accompany partial dehydration and protein action.,Vijayalakshmi L, Krishna R, Sankaranarayanan R, Vijayan M Proteins. 2007 Oct 11;71(1):241-249. PMID:17932936<ref>PMID:17932936</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 2q39" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-lactoglobulin 3D structures|Beta-lactoglobulin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Krishna R]]
[[Category: Sankaranarayanan R]]
[[Category: Vijayalakshmi L]]
[[Category: Vijayan M]]