3d25: Difference between revisions
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==Crystal structure of HA-1 minor histocompatibility antigen bound to human class I MHC HLA-A2== | |||
=== | <StructureSection load='3d25' size='340' side='right' caption='[[3d25]], [[Resolution|resolution]] 1.30Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3d25]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3D25 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3D25 FirstGlance]. <br> | |||
</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">HLA-A, HLAA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]), B2M, CDABP0092, HDCMA22P ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3d25 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3d25 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3d25 RCSB], [http://www.ebi.ac.uk/pdbsum/3d25 PDBsum]</span></td></tr> | |||
</table> | |||
== Disease == | |||
[[http://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN]] Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:[http://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 == | |||
[[http://www.uniprot.org/uniprot/1A02_HUMAN 1A02_HUMAN]] Involved in the presentation of foreign antigens to the immune system. [[http://www.uniprot.org/uniprot/HMHA1_HUMAN HMHA1_HUMAN]] GTPase activator for the Rho-type GTPases (Potential).<ref>PMID:8260714</ref> <ref>PMID:8532022</ref> <ref>PMID:9798702</ref> <ref>PMID:12601144</ref> Precursor of the histocompatibility antigen HA-1. More generally, minor histocompatibility antigens (mHags) refer to immunogenic peptide which, when complexed with MHC, can generate an immune response after recognition by specific T-cells. The peptides are derived from polymorphic intracellular proteins, which are cleaved by normal pathways of antigen processing. The binding of these peptides to MHC class I or class II molecules and its expression on the cell surface can stimulate T-cell responses and thereby trigger graft rejection or graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation from HLA-identical sibling donor. GVHD is a frequent complication after bone marrow transplantation (BMT), due to mismatch of minor histocompatibility antigen in HLA-matched sibling marrow transplants. Specifically, mismatching for mHag HA-1 which is recognized as immunodominant, is shown to be associated with the development of severe GVHD after HLA-identical BMT. HA-1 is presented to the cell surface by MHC class I HLA-A*0201, but also by other HLA-A alleles. This complex specifically elicits donor-cytotoxic T-lymphocyte (CTL) reactivity against hematologic malignancies after treatment by HLA-identical allogenic BMT. It induces cell recognition and lysis by CTL.<ref>PMID:8260714</ref> <ref>PMID:8532022</ref> <ref>PMID:9798702</ref> <ref>PMID:12601144</ref> [[http://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/d2/3d25_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/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
T cell recognition of minor histocompatibility antigens (mHags) underlies allogeneic immune responses that mediate graft-versus-host disease and the graft-versus-leukemia effect following stem cell transplantation. Many mHags derive from single amino acid polymorphisms in MHC-restricted epitopes, but our understanding of the molecular mechanisms governing mHag immunogenicity and recognition is incomplete. Here we examined antigenic presentation and T-cell recognition of HA-1, a prototypic autosomal mHag derived from single nucleotide dimorphism (HA-1(H) versus HA-1(R)) in the HMHA1 gene. The HA-1(H) peptide is restricted by HLA-A2 and is immunogenic in HA-1(R/R) into HA-1(H) transplants, while HA-1(R) has been suggested to be a "null allele" in terms of T cell reactivity. We found that proteasomal cleavage and TAP transport of the 2 peptides is similar and that both variants can bind to MHC. However, the His>Arg change substantially decreases the stability and affinity of HLA-A2 association, consistent with the reduced immunogenicity of the HA-1(R) variant. To understand these findings, we determined the structure of an HLA-A2-HA-1(H) complex to 1.3A resolution. Whereas His-3 is accommodated comfortably in the D pocket, incorporation of the lengthy Arg-3 is predicted to require local conformational changes. Moreover, a soluble TCR generated from HA-1(H)-specific T-cells bound HA-1(H) peptide with moderate affinity but failed to bind HA-1(R), indicating complete discrimination of HA-1 variants at the level of TCR/MHC interaction. Our results define the molecular mechanisms governing immunogenicity of HA-1, and highlight how single amino acid polymorphisms in mHags can critically affect both MHC association and TCR recognition. | |||
Secondary anchor polymorphism in the HA-1 minor histocompatibility antigen critically affects MHC stability and TCR recognition.,Nicholls S, Piper KP, Mohammed F, Dafforn TR, Tenzer S, Salim M, Mahendra P, Craddock C, van Endert P, Schild H, Cobbold M, Engelhard VH, Moss PA, Willcox BE Proc Natl Acad Sci U S A. 2009 Mar 10;106(10):3889-94. Epub 2009 Feb 20. PMID:19234124<ref>PMID:19234124</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Beta-2 microglobulin|Beta-2 microglobulin]] | *[[Beta-2 microglobulin|Beta-2 microglobulin]] | ||
*[[Major histocompatibility complex|Major histocompatibility complex]] | *[[Major histocompatibility complex|Major histocompatibility complex]] | ||
== References == | |||
== | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Cobbold, M | [[Category: Cobbold, M]] | ||
[[Category: Craddock, C | [[Category: Craddock, C]] | ||
[[Category: Dafforn, T R | [[Category: Dafforn, T R]] | ||
[[Category: Endert, P van | [[Category: Endert, P van]] | ||
[[Category: Engelhard, V H | [[Category: Engelhard, V H]] | ||
[[Category: Mahendra, P | [[Category: Mahendra, P]] | ||
[[Category: Mohammed, F | [[Category: Mohammed, F]] | ||
[[Category: Moss, P A.H | [[Category: Moss, P A.H]] | ||
[[Category: Nicholls, S | [[Category: Nicholls, S]] | ||
[[Category: Piper, K P | [[Category: Piper, K P]] | ||
[[Category: Salim, M | [[Category: Salim, M]] | ||
[[Category: Schild, H | [[Category: Schild, H]] | ||
[[Category: Tenzer, S | [[Category: Tenzer, S]] | ||
[[Category: Willcox, B E | [[Category: Willcox, B E]] | ||
[[Category: Glycoprotein]] | [[Category: Glycoprotein]] | ||
[[Category: Hla-a2]] | [[Category: Hla-a2]] | ||