View source for 4p39


==Crystal structure of the human C5aR antagonist C5a-A8==
<StructureSection load='4p39' size='340' side='right'caption='[[4p39]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4p39]] is a 4 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=4P39 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4P39 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]] 2.401&#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=4p39 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4p39 OCA], [https://pdbe.org/4p39 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4p39 RCSB], [https://www.ebi.ac.uk/pdbsum/4p39 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4p39 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/CO5_HUMAN CO5_HUMAN] Defects in C5 are the cause of complement component 5 deficiency (C5D) [MIM:[https://omim.org/entry/609536 609536]. A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis.  Note=An association study of C5 haplotypes and genotypes in individuals with chronic hepatitis C virus infection shows that individuals homozygous for the C5_1 haplotype have a significantly higher stage of liver fibrosis than individuals carrying at least 1 other allele (PubMed:15995705).
== Function ==
[https://www.uniprot.org/uniprot/CO5_HUMAN CO5_HUMAN] Activation of C5 by a C5 convertase initiates the spontaneous assembly of the late complement components, C5-C9, into the membrane attack complex. C5b has a transient binding site for C6. The C5b-C6 complex is the foundation upon which the lytic complex is assembled.  Derived from proteolytic degradation of complement C5, C5 anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes. C5a also stimulates the locomotion of polymorphonuclear leukocytes (chemokinesis) and direct their migration toward sites of inflammation (chemotaxis).
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== Publication Abstract from PubMed ==
Complement is an ancient part of the innate immune system that plays a pivotal role in protection against invading pathogens and helps to clear apoptotic and necrotic cells. Upon complement activation, a cascade of proteolytic events generates the complement effectors, including the anaphylatoxins C3a and C5a. Signalling through their cognate G-protein coupled receptors, C3aR and C5aR, leads to a wide range of biological events promoting inflammation at the site of complement activation. The function of anaphylatoxins is regulated by circulating carboxypeptidases that remove their C-terminal arginine residue, yielding C3a-desArg and C5a-desArg. Whereas human C3a and C3a-desArg adopt a canonical four-helix bundle fold, the conformation of human C5a-desArg has recently been described as a three-helix bundle. Here, the crystal structures of an antagonist version of human C5a, A8(Delta71-73), and of murine C5a and C5a-desArg are reported. Whereas A8(Delta71-73) adopts a three-helix bundle conformation similar to human C5a-desArg, the two murine proteins form a four-helix bundle. A cell-based functional assay reveals that murine C5a-desArg, in contrast to its human counterpart, exerts the same level of activition as murine C5a on its cognate receptor. The role of the different C5a conformations is discussed in relation to the differential activation of C5a receptors across species.

Structural and functional characterization of human and murine C5a anaphylatoxins.,Schatz-Jakobsen JA, Yatime L, Larsen C, Petersen SV, Klos A, Andersen GR Acta Crystallogr D Biol Crystallogr. 2014 Jun;70(Pt 6):1704-17. doi:, 10.1107/S139900471400844X. Epub 2014 May 30. PMID:24914981<ref>PMID:24914981</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 4p39" style="background-color:#fffaf0;"></div>

==See Also==
*[[Complement C5 3D structures|Complement C5 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Andersen GR]]
[[Category: Larsen C]]
[[Category: Schatz-Jakobsen JA]]
[[Category: Yatime L]]