View source for 1wiq


==STRUCTURE OF T-CELL SURFACE GLYCOPROTEIN CD4, TRIGONAL CRYSTAL FORM==
<StructureSection load='1wiq' size='340' side='right'caption='[[1wiq]], [[Resolution|resolution]] 5.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1wiq]] is a 2 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=1WIQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1WIQ 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]] 5&#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=1wiq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1wiq OCA], [https://pdbe.org/1wiq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1wiq RCSB], [https://www.ebi.ac.uk/pdbsum/1wiq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1wiq ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.
== 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/wi/1wiq_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=1wiq ConSurf].
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== Publication Abstract from PubMed ==
CD4 is a co-receptor in the cellular immune response. It increases the avidity of association between a T cell and an antigen-presenting cell by interacting with non-polymorphic portions of the complex between class II major histocompatibility complex (MHC) and T-cell receptor (TCR) molecules, and it contributes directly to signal transduction through its cytoplasmic association with the lymphocyte kinase Lck. CD4 also serves as the high-affinity receptor for cellular attachment and entry of the human immunodeficiency virus (HIV). The extracellular portion of CD4 comprises four immunoglobulin-like domains (D1-D4). This part of human CD4 (residues 1-369) has been characterized as a recombinant soluble protein (sCD4), and crystal structures have been described for the human D1D2 fragment and for the rat D3D4 fragment. We have now determined the structures of intact sCD4 in three crystal lattices. These structures have a hinge-like variability at the D1D2 to D3D4 junction that might be important in immune recognition and HIV fusion, and a common dimeric association through D4 domains. Dynamic light scattering measurements and chemical crosslinking of sCD4 corroborate dimerization at high protein concentration. We suggest that such dimers mayhave relevance as mediators of signal transduction in T cells.

Dimeric association and segmental variability in the structure of human CD4.,Wu H, Kwong PD, Hendrickson WA Nature. 1997 May 29;387(6632):527-30. PMID:9168119<ref>PMID:9168119</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[CD4 3D structures|CD4 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Hendrickson WA]]
[[Category: Kwong PD]]
[[Category: Wu H]]