View source for 1pzy


==W314A-BETA1,4-GALACTOSYLTRANSFERASE-I COMPLEXED WITH ALPHA-LACTALBUMIN IN THE PRESENCE OF N-ACETYLGLUCOSAMINE, UDP AND MANGANESE==
<StructureSection load='1pzy' size='340' side='right'caption='[[1pzy]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1pzy]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus] and [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PZY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PZY 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=UDP:URIDINE-5-DIPHOSPHATE'>UDP</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=1pzy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1pzy OCA], [https://pdbe.org/1pzy PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1pzy RCSB], [https://www.ebi.ac.uk/pdbsum/1pzy PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1pzy ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LALBA_MOUSE LALBA_MOUSE] Regulatory subunit of lactose synthase, changes the substrate specificity of galactosyltransferase in the mammary gland making glucose a good acceptor substrate for this enzyme. This enables LS to synthesize lactose, the major carbohydrate component of milk. In other tissues, galactosyltransferase transfers galactose onto the N-acetylglucosamine of the oligosaccharide chains in glycoproteins.
== 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/pz/1pzy_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=1pzy ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
beta1,4-Galactosyltransferase-I (beta4Gal-T1) undergoes critical conformational changes upon substrate binding from an open conformation (conf-I) to the closed conformation (conf-II). This change involves two flexible loops: the small (residues 313-316) and the long loop (residues 345-365). Upon substrate binding, Trp314 in the small flexible loop moves towards the catalytic pocket and interacts with the donor and the acceptor substrates. For a better understanding of the role played by Trp314 in the conformational changes of beta4Gal-T1, we mutated it to Ala and carried out substrate-binding, proteolytic and crystallographic studies. The W314A mutation reduces the enzymatic activity, binding to substrates and to the modifier protein, alpha-lactalbumin (LA), by over 99%. The limited proteolysis with Glu-C or Lys-C proteases shows differences in the rate of cleavage of the long loop of the wild-type and mutant W314A, indicating conformational differences in the region between the two proteins. Without substrate, the mutant crystallizes in a conformation (conf-I') (1.9A resolution crystal structure), that is not identical with, but close to an open conformation (conf-I), whereas its complex with the substrates and alpha-lactalbumin, crystallizes in a conformation (2.3A resolution crystal structure) that is identical with the closed conformation (conf-II). This study shows the crucial role Trp314 plays in the conformational state of the long loop, in the binding of substrates and in the catalytic mechanism of the enzyme.

The role of tryptophan 314 in the conformational changes of beta1,4-galactosyltransferase-I.,Ramasamy V, Ramakrishnan B, Boeggeman E, Qasba PK J Mol Biol. 2003 Aug 29;331(5):1065-76. PMID:12927542<ref>PMID:12927542</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 1pzy" style="background-color:#fffaf0;"></div>

==See Also==
*[[Alpha-lactalbumin 3D structures|Alpha-lactalbumin 3D structures]]
*[[Glycosyltransferase 3D structures|Glycosyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Boeggeman E]]
[[Category: Qasba PK]]
[[Category: Ramakrishnan B]]
[[Category: Ramasamy V]]