View source for 1py4


==Beta2 microglobulin mutant H31Y displays hints for amyloid formations==
<StructureSection load='1py4' size='340' side='right'caption='[[1py4]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1py4]] is a 4 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=1PY4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PY4 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]] 2.9&#8491;</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=1py4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1py4 OCA], [https://pdbe.org/1py4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1py4 RCSB], [https://www.ebi.ac.uk/pdbsum/1py4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1py4 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN] Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:[https://omim.org/entry/241600 241600]. Affected individuals show marked reduction in serum concentrations of immunoglobulin and albumin, probably due to rapid degradation.<ref>PMID:16549777</ref>   Note=Beta-2-microglobulin may adopt the fibrillar configuration of amyloid in certain pathologic states. The capacity to assemble into amyloid fibrils is concentration dependent. Persistently high beta(2)-microglobulin serum levels lead to amyloidosis in patients on long-term hemodialysis.<ref>PMID:3532124</ref> <ref>PMID:1336137</ref> <ref>PMID:7554280</ref> <ref>PMID:4586824</ref> <ref>PMID:8084451</ref> <ref>PMID:12119416</ref> <ref>PMID:12796775</ref> <ref>PMID:16901902</ref> <ref>PMID:16491088</ref> <ref>PMID:17646174</ref> <ref>PMID:18835253</ref> <ref>PMID:18395224</ref> <ref>PMID:19284997</ref> 
== Function ==
[https://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system.
== 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/py/1py4_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=1py4 ConSurf].
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== Publication Abstract from PubMed ==
beta2-Microglobulin (beta2m) is the non-covalently bound light chain of the human class I major histocompatibility complex (MHC-I). The natural turnover of MHC-I gives rise to the release of beta2m into plasmatic fluids and to its catabolism in the kidney. beta2m dissociation from the heavy chain of the complex is a severe complication in patients receiving prolonged hemodialysis. As a consequence of renal failure, the increasing beta2m concentrations can lead to deposition of the protein as amyloid fibrils. Here we characterize the His31--&gt;Tyr human beta2m mutant, a non-natural form of beta2m that is more stable than the wild-type protein, displaying a ten-fold acceleration of the slow phase of folding. We report the 2.9A resolution crystal structure and the NMR characterization of the mutant beta2m, focussing on selected structural features and on the molecular packing observed in the crystals. Juxtaposition of the four mutant beta2m molecules contained in the crystal asymmetric unit, and specific hydrogen bonds, stabilize a compact protein assembly. Conformational heterogeneity of the four independent molecules, some of their mutual interactions and partial unpairing of the N-terminal beta-strand in one protomer are in keeping with the amyloidogenic properties displayed by the mutant beta2m.

beta2-microglobulin H31Y variant 3D structure highlights the protein natural propensity towards intermolecular aggregation.,Rosano C, Zuccotti S, Mangione P, Giorgetti S, Bellotti V, Pettirossi F, Corazza A, Viglino P, Esposito G, Bolognesi M J Mol Biol. 2004 Jan 23;335(4):1051-64. PMID:14698299<ref>PMID:14698299</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 1py4" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Bellotti V]]
[[Category: Bolognesi M]]
[[Category: Corazza A]]
[[Category: Esposito G]]
[[Category: Giorgetti S]]
[[Category: Mangione P]]
[[Category: Pettirossi F]]
[[Category: Rosano C]]
[[Category: Viglino P]]
[[Category: Zuccotti S]]