Structural highlights
Function
[C4BPA_HUMAN] Controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. Alpha chain binds C4b. It interacts also with anticoagulant protein S and with serum amyloid P component.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Human C4b-binding protein (C4BP) protects host tissue, and those pathogens able to hijack this plasma glycoprotein, from complement-mediated destruction. We now show that the first two complement control protein (CCP) modules of the C4BP alpha-chain, plus the four residues connecting them, are necessary and sufficient for binding a bacterial virulence factor, the Streptococcus pyogenes M4 (Arp4) protein. Structure determination by NMR reveals two tightly coupled CCP modules in an elongated arrangement within this region of C4BP. Chemical shift perturbation studies demonstrate that the N-terminal, hypervariable region of M4 binds to a site including strand 1 of CCP module 2. This interaction is accompanied by an intermodular reorientation within C4BP. We thus provide a detailed picture of an interaction whereby a pathogen evades complement.
Human C4b-binding protein, structural basis for interaction with streptococcal M protein, a major bacterial virulence factor.,Jenkins HT, Mark L, Ball G, Persson J, Lindahl G, Uhrin D, Blom AM, Barlow PN J Biol Chem. 2006 Feb 10;281(6):3690-7. Epub 2005 Dec 5. PMID:16330538[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jenkins HT, Mark L, Ball G, Persson J, Lindahl G, Uhrin D, Blom AM, Barlow PN. Human C4b-binding protein, structural basis for interaction with streptococcal M protein, a major bacterial virulence factor. J Biol Chem. 2006 Feb 10;281(6):3690-7. Epub 2005 Dec 5. PMID:16330538 doi:10.1074/jbc.M511563200
