View source for 1xar


==Crystal Structure of a fragment of DC-SIGNR (containing the carbohydrate recognition domain and two repeats of the neck).==
<StructureSection load='1xar' size='340' side='right'caption='[[1xar]], [[Resolution|resolution]] 2.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xar]] 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=1XAR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XAR 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]] 2.25&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</scene></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=1xar FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xar OCA], [https://pdbe.org/1xar PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xar RCSB], [https://www.ebi.ac.uk/pdbsum/1xar PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xar ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CLC4M_HUMAN CLC4M_HUMAN] Probable pathogen-recognition receptor involved in peripheral immune surveillance in liver. May mediate the endocytosis of pathogens which are subsequently degraded in lysosomal compartments. Probably recognizes in a calcium-dependent manner high mannose N-linked oligosaccharides in a variety of pathogen antigens, including HIV-1 gp120, HIV-2 gp120, SIV gp120, ebolavirus glycoproteins, HCV E2, and human SARS coronavirus protein S. Is a receptor for ICAM3, probably by binding to mannose-like carbohydrates. Is presumably a coreceptor for the SARS coronavirus.<ref>PMID:11257134</ref> <ref>PMID:11226297</ref> 
== 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/xa/1xar_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=1xar ConSurf].
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== Publication Abstract from PubMed ==
The human cell surface receptors DC-SIGN (dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin) and DC-SIGNR (DC-SIGN-related) bind to oligosaccharide ligands found on human tissues as well as on pathogens including viruses, bacteria, and parasites. The extracellular portion of each receptor contains a membrane-distal carbohydrate-recognition domain (CRD) and forms tetramers stabilized by an extended neck region consisting of 23 amino acid repeats. Cross-linking analysis of full-length receptors expressed in fibroblasts confirms the tetrameric state of the intact receptors. Hydrodynamic studies on truncated receptors demonstrate that the portion of the neck of each protein adjacent to the CRD is sufficient to mediate the formation of dimers, whereas regions near the N terminus are needed to stabilize the tetramers. Some of the intervening repeats are missing from polymorphic forms of DC-SIGNR. Two different crystal forms of truncated DC-SIGNR comprising two neck repeats and the CRD reveal that the CRDs are flexibly linked to the neck, which contains alpha-helical segments interspersed with non-helical regions. Differential scanning calorimetry measurements indicate that the neck and CRDs are independently folded domains. Based on the crystal structures and hydrodynamic data, models for the full extracellular domains of the receptors have been generated. The observed flexibility of the CRDs in the tetramer, combined with previous data on the specificity of these receptors, suggests an important role for oligomerization in the recognition of endogenous glycans, in particular those present on the surfaces of enveloped viruses recognized by these proteins.

Extended neck regions stabilize tetramers of the receptors DC-SIGN and DC-SIGNR.,Feinberg H, Guo Y, Mitchell DA, Drickamer K, Weis WI J Biol Chem. 2005 Jan 14;280(2):1327-35. Epub 2004 Oct 26. PMID:15509576<ref>PMID:15509576</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 1xar" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Drickamer K]]
[[Category: Feinberg H]]
[[Category: Guo Y]]
[[Category: Mitchell DA]]
[[Category: Weis WI]]