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1g13

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(New page: 200px<br /> <applet load="1g13" size="450" color="white" frame="true" align="right" spinBox="true" caption="1g13, resolution 2.0&Aring;" /> '''HUMAN GM2 ACTIVATOR ...)
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[[Image:1g13.gif|left|200px]]<br />
 
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<applet load="1g13" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1g13, resolution 2.0&Aring;" />
 
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'''HUMAN GM2 ACTIVATOR STRUCTURE'''<br />
 
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==Overview==
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==HUMAN GM2 ACTIVATOR STRUCTURE==
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GM2 activator protein (GM2-AP) belongs to a small group of non- enzymatic, lysosomal proteins that act as cofactors in the sequential degradation of, gangliosides. It has been postulated that GM2-AP extracts single GM2, molecules from membranes and presents them in soluble form to, beta-hexosaminidase A for cleavage of N-acetyl-d-galactosamine and, conversion to GM3. The high affinity of GM2-AP for GM2 is based on specfic, recognition of the oligosaccharide moiety as well as the ceramide lipid, tail. Genetic defects in GM2-AP result in an atypical form of Tay-Sachs, disease known as variant AB GM2 gangliosidosis. The 2.0 A resolution, crystal structure of GM2-AP reported here reveals a previously unobserved, fold whose main feature is an eight-stranded cup-shaped anti-parallel, beta-pleated sheet. The striking feature of the GM2-AP structure is that, it possesses an accessible central hydrophobic cavity rather than a buried, hydrophobic core. The dimensions of this cavity (12 Ax14 Ax22 A) are, suitable for binding 18-carbon lipid acyl chains. Flexible surface loops, and a short alpha-helix decorate the mouth of the beta-cup and may control, lipid entry to the cavity.
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<StructureSection load='1g13' size='340' side='right'caption='[[1g13]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
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== Structural highlights ==
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==Disease==
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<table><tr><td colspan='2'>[[1g13]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G13 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1G13 FirstGlance]. <br>
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Known disease associated with this structure: GM2-gangliosidosis, AB variant OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=272750 272750]]
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</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>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr>
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==About this Structure==
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1g13 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1g13 OCA], [https://pdbe.org/1g13 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1g13 RCSB], [https://www.ebi.ac.uk/pdbsum/1g13 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1g13 ProSAT]</span></td></tr>
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1G13 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with EPE as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1G13 OCA].
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</table>
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== Disease ==
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==Reference==
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[https://www.uniprot.org/uniprot/SAP3_HUMAN SAP3_HUMAN] Defects in GM2A are the cause of GM2-gangliosidosis type AB (GM2GAB) [MIM:[https://omim.org/entry/272750 272750]; also known as Tay-Sachs disease AB variant. GM2-gangliosidosis is an autosomal recessive lysosomal storage disease marked by the accumulation of GM2 gangliosides in the neuronal cells. GM2GAB is characterized by GM2 gangliosides accumulation in the presence of both hexosaminidase A and B.<ref>PMID:1915858</ref> <ref>PMID:8244332</ref> <ref>PMID:8900233</ref>
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Crystal structure of human GM2-activator protein with a novel beta-cup topology., Wright CS, Li SC, Rastinejad F, J Mol Biol. 2000 Dec 1;304(3):411-22. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11090283 11090283]
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== Function ==
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[https://www.uniprot.org/uniprot/SAP3_HUMAN SAP3_HUMAN] The large binding pocket can accommodate several single chain phospholipids and fatty acids, GM2A also exhibits some calcium-independent phospholipase activity (By similarity). Binds gangliosides and stimulates ganglioside GM2 degradation. It stimulates only the breakdown of ganglioside GM2 and glycolipid GA2 by beta-hexosaminidase A. It extracts single GM2 molecules from membranes and presents them in soluble form to beta-hexosaminidase A for cleavage of N-acetyl-D-galactosamine and conversion to GM3.
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/g1/1g13_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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=1g13 ConSurf].
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<div style="clear:both"></div>
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== References ==
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<references/>
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__TOC__
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
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[[Category: Single protein]]
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[[Category: Large Structures]]
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[[Category: Li, S.C.]]
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[[Category: Li SC]]
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[[Category: Rastinejad, F.]]
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[[Category: Rastinejad F]]
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[[Category: Wright, C.S.]]
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[[Category: Wright CS]]
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[[Category: EPE]]
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[[Category: beta cup]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 16:59:14 2007''
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Current revision

HUMAN GM2 ACTIVATOR STRUCTURE

PDB ID 1g13

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