View source for 2xwb


==Crystal Structure of Complement C3b in complex with Factors B and D==
<StructureSection load='2xwb' size='340' side='right'caption='[[2xwb]], [[Resolution|resolution]] 3.49&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2xwb]] is a 8 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=2XWB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2XWB 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]] 3.49&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=2xwb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2xwb OCA], [https://pdbe.org/2xwb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2xwb RCSB], [https://www.ebi.ac.uk/pdbsum/2xwb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2xwb ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/CFAD_HUMAN CFAD_HUMAN] Defects in CFD are the cause of complement factor D deficiency (CFDD) [MIM:[https://omim.org/entry/613912 613912]. CFDD is an immunologic disorder characterized by increased susceptibility to bacterial infections, particularly Neisseria infections, due to a defect in the alternative complement pathway.
== Function ==
[https://www.uniprot.org/uniprot/CFAD_HUMAN CFAD_HUMAN] Factor D cleaves factor B when the latter is complexed with factor C3b, activating the C3bbb complex, which then becomes the C3 convertase of the alternate pathway. Its function is homologous to that of C1s in the classical pathway.
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== Publication Abstract from PubMed ==
Activation of the complement cascade induces inflammatory responses and marks cells for immune clearance. In the central complement-amplification step, a complex consisting of surface-bound C3b and factor B is cleaved by factor D to generate active convertases on targeted surfaces. We present crystal structures of the pro-convertase C3bB at 4 angstrom resolution and its complex with factor D at 3.5 angstrom resolution. Our data show how factor B binding to C3b forms an open "activation" state of C3bB. Factor D specifically binds the open conformation of factor B through a site distant from the catalytic center and is activated by the substrate, which displaces factor D's self-inhibitory loop. This concerted proteolytic mechanism, which is cofactor-dependent and substrate-induced, restricts complement amplification to C3b-tagged target cells.

Structures of C3b in complex with factors B and D give insight into complement convertase formation.,Forneris F, Ricklin D, Wu J, Tzekou A, Wallace RS, Lambris JD, Gros P Science. 2010 Dec 24;330(6012):1816-20. PMID:21205667<ref>PMID:21205667</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 2xwb" style="background-color:#fffaf0;"></div>

==See Also==
*[[Complement C3 3D structures|Complement C3 3D structures]]
*[[Complement factor 3D structures|Complement factor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Forneris F]]
[[Category: Gros P]]
[[Category: Lambris JD]]
[[Category: Ricklin D]]
[[Category: Tzekou A]]
[[Category: Wallace RS]]
[[Category: Wu J]]