View source for 1ok2


==Decay accelerating factor (CD55): the structure of an intact human complement regulator.==
<StructureSection load='1ok2' size='340' side='right'caption='[[1ok2]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ok2]] 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=1OK2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OK2 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1ok2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ok2 OCA], [https://pdbe.org/1ok2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ok2 RCSB], [https://www.ebi.ac.uk/pdbsum/1ok2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ok2 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/DAF_HUMAN DAF_HUMAN] This protein recognizes C4b and C3b fragments that condense with cell-surface hydroxyl or amino groups when nascent C4b and C3b are locally generated during C4 and c3 activation. Interaction of daf with cell-associated C4b and C3b polypeptides interferes with their ability to catalyze the conversion of C2 and factor B to enzymatically active C2a and Bb and thereby prevents the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade.<ref>PMID:7525274</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/ok/1ok2_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/main_output.php?pdb_ID=1ok2 ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The human complement regulator CD55 is a key molecule protecting self-cells from complement-mediated lysis. X-ray diffraction and analytical ultracentrifugation data reveal a rod-like arrangement of four short consensus repeat (SCR) domains in both the crystal and solution. The stalk linking the four SCR domains to the glycosylphosphatidylinositol anchor is extended by the addition of 11 highly charged O-glycans and positions the domains an estimated 177 A above the membrane. Mutation mapping and hydrophobic potential analysis suggest that the interaction with the convertase, and thus complement regulation, depends on the burial of a hydrophobic patch centered on the linker between SCR domains 2 and 3.

Complement regulation at the molecular level: the structure of decay-accelerating factor.,Lukacik P, Roversi P, White J, Esser D, Smith GP, Billington J, Williams PA, Rudd PM, Wormald MR, Harvey DJ, Crispin MD, Radcliffe CM, Dwek RA, Evans DJ, Morgan BP, Smith RA, Lea SM Proc Natl Acad Sci U S A. 2004 Feb 3;101(5):1279-84. Epub 2004 Jan 20. PMID:14734808<ref>PMID:14734808</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1ok2" style="background-color:#fffaf0;"></div>

==See Also==
*[[CD55|CD55]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Billington J]]
[[Category: Crispin MDM]]
[[Category: Dwek RA]]
[[Category: Esser D]]
[[Category: Evans DJ]]
[[Category: Lea SM]]
[[Category: Lukacik P]]
[[Category: Morgan BP]]
[[Category: Radcliffe CM]]
[[Category: Roversi P]]
[[Category: Rudd PM]]
[[Category: Smith GP]]
[[Category: Smith RAG]]
[[Category: White J]]
[[Category: Williams PA]]
[[Category: Wormald MR]]