1nhe: Difference between revisions

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-[[Image:1nhe.gif|left|200px]]<br /><applet load="1nhe" size="450" color="white" frame="true" align="right" spinBox="true"
-caption="1nhe, resolution 2.50&Aring;" />
-'''Crystal structure of Lactose synthase complex with UDP'''<br />
-==Overview==
+==Crystal structure of Lactose synthase complex with UDP==
-The lactose synthase (LS) enzyme is a 1:1 complex of a catalytic, component, beta1,4-galactosyltransferse (beta4Gal-T1) and a regulatory, component, alpha-lactalbumin (LA), a mammary gland-specific protein. LA, promotes the binding of glucose (Glc) to beta4Gal-T1, thereby altering its, sugar acceptor specificity from N-acetylglucosamine (GlcNAc) to glucose, which enables LS to synthesize lactose, the major carbohydrate component, of milk. The crystal structures of LS bound with various substrates were, solved at 2 A resolution. These structures reveal that upon substrate, binding to beta4Gal-T1, a large conformational change occurs in the region, comprising residues 345 to 365. This repositions His347 in such a way that, it can participate in the coordination of a metal ion, and creates a sugar, and LA-binding site. At the sugar-acceptor binding site, a hydrophobic, N-acetyl group-binding pocket is found, formed by residues Arg359, Phe360, and Ile363. In the Glc-bound structure, this hydrophobic pocket is absent., For the binding of Glc to LS, a reorientation of the Arg359 side-chain, occurs, which blocks the hydrophobic pocket and maximizes the interactions, with the Glc molecule. Thus, the role of LA is to hold Glc by hydrogen, bonding with the O-1 hydroxyl group in the acceptor-binding site on, beta4Gal-T1, while the N-acetyl group-binding pocket in beta4Gal-T1, adjusts to maximize the interactions with the Glc molecule. This study, provides details of a structural basis for the partially ordered kinetic, mechanism proposed for lactose synthase.
+<StructureSection load='1nhe' size='340' side='right'caption='[[1nhe]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>[[1nhe]] 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]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1j94 1j94]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NHE OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NHE 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='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=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=PG4:TETRAETHYLENE+GLYCOL'>PG4</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=1nhe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nhe OCA], [https://pdbe.org/1nhe PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nhe RCSB], [https://www.ebi.ac.uk/pdbsum/1nhe PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nhe 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/nh/1nhe_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=1nhe ConSurf].
+<div style="clear:both"></div>
-==About this Structure==
+==See Also==
-NHE is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] and [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with CA, UDP and PG4 as [http://en.wikipedia.org/wiki/ligands ligands]. This structure superseeds the now removed PDB entry 1J94. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NHE OCA].
+*[[Alpha-lactalbumin 3D structures|Alpha-lactalbumin 3D structures]]
+*[[Glycosyltransferase 3D structures|Glycosyltransferase 3D structures]]
-==Reference==
+__TOC__
-Crystal structure of lactose synthase reveals a large conformational change in its catalytic component, the beta1,4-galactosyltransferase-I., Ramakrishnan B, Qasba PK, J Mol Biol. 2001 Jun 29;310(1):205-18. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11419947 11419947]
+</StructureSection>
 [[Category: Bos taurus]]
+[[Category: Large Structures]]
 [[Category: Mus musculus]]
-[[Category: Protein complex]]
+[[Category: Qasba PK]]
-[[Category: Qasba, P.K.]]
+[[Category: Ramakrishnan B]]
-[[Category: Ramakrishnan, B.]]
-[[Category: CA]]
-[[Category: PG4]]
-[[Category: UDP]]
-[[Category: crystal structure]]
-[[Category: lactose synthase]]
-[[Category: mad methods]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 22:15:25 2007''