3cu7

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Template:STRUCTURE 3cu7

Contents 1 Human Complement Component 5 2 Disease 3 Function 4 About this Structure 5 Reference

Human Complement Component 5

Template:ABSTRACT PUBMED 18536718

Disease

[CO5_HUMAN] Defects in C5 are the cause of complement component 5 deficiency (C5D) [MIM: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

[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).

About this Structure

3cu7 is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

• Fredslund F, Laursen NS, Roversi P, Jenner L, Oliveira CL, Pedersen JS, Nunn MA, Lea SM, Discipio R, Sottrup-Jensen L, Andersen GR. Structure of and influence of a tick complement inhibitor on human complement component 5. Nat Immunol. 2008 Jul;9(7):753-60. Epub 2008 Jun 8. PMID:18536718 doi:10.1038/ni.1625