View source for 1tw1


==beta-1,4-galactosyltransferase mutant Met344His (m344H-Gal-T1) complex with UDP-galactose and magnesium==
<StructureSection load='1tw1' size='340' side='right'caption='[[1tw1]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1tw1]] 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=1TW1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1TW1 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=DIO:1,4-DIETHYLENE+DIOXIDE'>DIO</scene>, <scene name='pdbligand=GDU:GALACTOSE-URIDINE-5-DIPHOSPHATE'>GDU</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1tw1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1tw1 OCA], [https://pdbe.org/1tw1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1tw1 RCSB], [https://www.ebi.ac.uk/pdbsum/1tw1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1tw1 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/B4GT1_BOVIN B4GT1_BOVIN] The Golgi complex form catalyzes the production of lactose in the lactating mammary gland and could also be responsible for the synthesis of complex-type N-linked oligosaccharides in many glycoproteins as well as the carbohydrate moieties of glycolipids.  The cell surface form functions as a recognition molecule during a variety of cell to cell and cell to matrix interactions, as those occurring during development and egg fertilization, by binding to specific oligosaccharide ligands on opposing cells or in the extracellular matrix.
== 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/tw/1tw1_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=1tw1 ConSurf].
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== Publication Abstract from PubMed ==
Beta-1,4-galactosyltransferase (beta4Gal-T1) in the presence of manganese ion transfers galactose from UDP-galactose (UDP-Gal) to N-acetylglucosamine (GlcNAc) that is either free or linked to an oligosaccharide. Crystallographic studies on bovine beta4Gal-T1 have shown that the primary metal binding site is located in the hinge region of a long flexible loop, which upon Mn(2+) and UDP-Gal binding changes from an open to a closed conformation. This conformational change creates an oligosaccharide binding site in the enzyme. Neither UDP nor UDP analogues efficiently induce these conformational changes in the wild-type enzyme, thereby restricting the structural analysis of the acceptor binding site. The binding of Mn(2+) involves an uncommon coordination to the Sdelta atom of Met344; when it is mutated to His, the mutant M344H, in the presence of Mn(2+) and UDP-hexanolamine, readily changes to a closed conformation, facilitating the structural analysis of the enzyme bound with an oligosaccharide acceptor. Although the mutant M344H loses 98% of its Mn(2+)-dependent activity, it exhibits 25% of its activity in the presence of Mg(2+). The crystal structures of M344H-Gal-T1 in complex with either UDP-Gal.Mn(2+) or UDP-Gal.Mg(2+), determined at 2.3 A resolution, show that the mutant enzyme in these complexes is in a closed conformation, and the coordination stereochemistry of Mg(2+) is quite similar to that of Mn(2+). Although either Mn(2+) or Mg(2+), together with UDP-Gal, binds and changes the conformation of the M344H mutant to the closed one, it is the Mg(2+) complex that engages efficiently in catalyses. Thus, this property enabled us to crystallize the M344H mutant for the first time with the acceptor substrate chitobiose in the presence of UDP-hexanolamine and Mn(2+). The crystal structure determined at 2.3 A resolution reveals that the GlcNAc residue at the nonreducing end of chitobiose makes extensive hydrophobic interactions with the highly conserved Tyr286 residue.

Effect of the Met344His mutation on the conformational dynamics of bovine beta-1,4-galactosyltransferase: crystal structure of the Met344His mutant in complex with chitobiose.,Ramakrishnan B, Boeggeman E, Qasba PK Biochemistry. 2004 Oct 5;43(39):12513-22. PMID:15449940<ref>PMID:15449940</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 1tw1" style="background-color:#fffaf0;"></div>

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