View source for 1hhk

==THE ANTIGENIC IDENTITY OF PEPTIDE(SLASH)MHC COMPLEXES: A COMPARISON OF THE CONFORMATION OF FIVE PEPTIDES PRESENTED BY HLA-A2==
<StructureSection load='1hhk' size='340' side='right' caption='[[1hhk]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1hhk]] is a 6 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Human_t-lymphotropic_virus_1 Human t-lymphotropic virus 1]. The February 2005 RCSB PDB [http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Major Histocompatibility Complex''  by David S. Goodsell is [http://dx.doi.org/10.2210/rcsb_pdb/mom_2005_2 10.2210/rcsb_pdb/mom_2005_2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HHK OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1HHK FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">BETA-2-MICROGLOBULIN ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])</td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1hhk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hhk OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1hhk RCSB], [http://www.ebi.ac.uk/pdbsum/1hhk PDBsum]</span></td></tr>
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== 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/TAX_HTL1C TAX_HTL1C]] Transcriptional activator that activates both the viral long terminal repeat (LTR) and cellular promoters via activation of CREB, NF-kappa-B, SRF and AP-1 pathways. Binds to three 21 bp repeat elements located within the LTRs, referred to as Tax-responsive elements (TRE). Binding to TRE requires the interaction with CREB1 and CREBBP. Also induces chromatin remodeling of proviral LTR-mediated gene expression by recruiting the histone acetyl transferases CREBBP and EP300 to the chromatin, which results in histone acetylation. Via its interaction with IKK regulatory subunit IKBKG, Tax-1 persistently stimulates I-kappa-B kinase (IKK), resulting in constitutive activation of the transcription factor NF-kappa-B. Induction of the nuclear expression of members of the NFkB family of transcription factors, which leads to up-regulated expression of many gene promoters containing NFkB motifs. These genes include those encoding IL2, IL15, IL2RA and IL15RA, leading to autocrine IL2/IL2RA and IL15/IL15RA loops. The resulting T-cell proliferation leads to malignant transformation and to the development of adult T-cell leukemia (ATL). IL13, known to be linked to leukemogenesis, is also up-regulated by Tax-1. Interaction with PDZ domain-containing proteins induce IL2-independent growth, which may be a factor in multi-step leukemogenesis. Inhibits the action of at least three cellular tumor suppressors p53/TP53, RB1 and DLG1, and suppresses their abilities to dictate apoptosis in primary cells. Required for viral replication (By similarity). [[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/hh/1hhk_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].
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== Publication Abstract from PubMed ==
Complexes of five peptides (from HIV-1, influenza A virus, HTLV-1, and hepatitis B virus proteins) bound to the human class I MHC molecule HLA-A2 have been studied by X-ray crystallography. While the peptide termini and their second and C-terminal anchor side chains are bound similarly in all five cases, the main chain and side chain conformations of each peptide are strikingly different in the center of the binding site, and these differences are accessible to direct TCR recognition. Each of the central peptide residues is seen to point up for some bound peptides, but down or sideways for others. Thus, although fixed at its ends, the structure of an MHC-bound peptide appears to be a highly complex function of its entire sequence, potentially sensitive to even small sequence differences. In contrast, MHC structural variation is relatively limited. These results offer a structural framework for understanding the role of nonanchor peptide side chains in both peptide-MHC binding affinity and TCR recognition.

The antigenic identity of peptide-MHC complexes: a comparison of the conformations of five viral peptides presented by HLA-A2.,Madden DR, Garboczi DN, Wiley DC Cell. 1993 Nov 19;75(4):693-708. PMID:7694806<ref>PMID:7694806</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Beta-2 microglobulin|Beta-2 microglobulin]]
*[[Major histocompatibility complex|Major histocompatibility complex]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Human t-lymphotropic virus 1]]
[[Category: Major Histocompatibility Complex]]
[[Category: RCSB PDB Molecule of the Month]]
[[Category: Garboczi, D N.]]
[[Category: Madden, D R.]]
[[Category: Wiley, D C.]]
[[Category: Histocompatibility antigen]]