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New page: left|200px<br /><applet load="1nkh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nkh, resolution 2.00Å" /> '''Crystal structure of...
 
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[[Image:1nkh.gif|left|200px]]<br /><applet load="1nkh" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1nkh, resolution 2.00&Aring;" />
'''Crystal structure of Lactose synthase complex with UDP and Manganese'''<br />


==Overview==
==Crystal structure of Lactose synthase complex with UDP and Manganese==
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='1nkh' size='340' side='right'caption='[[1nkh]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1nkh]] 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=1j8x 1j8x]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NKH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NKH 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&#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=PG4:TETRAETHYLENE+GLYCOL'>PG4</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1nkh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nkh OCA], [https://pdbe.org/1nkh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nkh RCSB], [https://www.ebi.ac.uk/pdbsum/1nkh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nkh 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/nk/1nkh_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=1nkh ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1NKH 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, MN, SO4, UDP and PG4 as [http://en.wikipedia.org/wiki/ligands ligands]. This structure superseeds the now removed PDB entry 1J8X. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NKH 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: Bos taurus]]
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Mus musculus]]
[[Category: Protein complex]]
[[Category: Qasba PK]]
[[Category: Qasba, P.K.]]
[[Category: Ramakrishnan B]]
[[Category: Ramakrishnan, B.]]
[[Category: CA]]
[[Category: MN]]
[[Category: PG4]]
[[Category: SO4]]
[[Category: UDP]]
[[Category: lactose synthease]]
[[Category: udp and mn binding]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 22:20:03 2007''

Latest revision as of 11:50, 10 April 2024

Crystal structure of Lactose synthase complex with UDP and ManganeseCrystal structure of Lactose synthase complex with UDP and Manganese

Structural highlights

1nkh is a 4 chain structure with sequence from Bos taurus and Mus musculus. This structure supersedes the now removed PDB entry 1j8x. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2Å
Ligands:, , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

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

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1nkh, resolution 2.00Å

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