3hs0

From Proteopedia

Revision as of 06:28, 25 March 2013

Template:STRUCTURE 3hs0

Cobra Venom Factor (CVF) in complex with human factor B

Template:ABSTRACT PUBMED 19574954

Disease

[CFAB_HUMAN] Defects in CFB are a cause of susceptibility to hemolytic uremic syndrome atypical type 4 (AHUS4) [MIM:612924]. An atypical form of hemolytic uremic syndrome. It is a complex genetic disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal failure and absence of episodes of enterocolitis and diarrhea. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease. Note=Susceptibility to the development of atypical hemolytic uremic syndrome can be conferred by mutations in various components of or regulatory factors in the complement cascade system. Other genes may play a role in modifying the phenotype.^[1][2]

Function

[CFAB_HUMAN] Factor B which is part of the alternate pathway of the complement system is cleaved by factor D into 2 fragments: Ba and Bb. Bb, a serine protease, then combines with complement factor 3b to generate the C3 or C5 convertase. It has also been implicated in proliferation and differentiation of preactivated B-lymphocytes, rapid spreading of peripheral blood monocytes, stimulation of lymphocyte blastogenesis and lysis of erythrocytes. Ba inhibits the proliferation of preactivated B-lymphocytes. [CO3_NAJKA] Complement-activating protein in cobra venom. It is a structural and functional analog of complement component C3b, the activated form of C3. It binds factor B (CFB), which is subsequently cleaved by factor D (CFD) to form the bimolecular complex CVF/Bb. CVF/Bb is a C3/C5 convertase that cleaves both complement components C3 and C5. Structurally, it resembles the C3b degradation product C3c, which is not able to form a C3/C5 convertase. Unlike C3b/Bb, CVF/Bb is a stable complex and completely resistant to the actions of complement regulatory factors H (CFH) and I (CFI). Therefore, CVF continuously activates complement resulting in the depletion of complement activity.

About this Structure

3hs0 is a 8 chain structure with sequence from Homo sapiens and Naja kaouthia. Full crystallographic information is available from OCA.

See Also

• Cobra venom factor

Reference

• Janssen BJ, Gomes L, Koning RI, Svergun DI, Koster AJ, Fritzinger DC, Vogel CW, Gros P. Insights into complement convertase formation based on the structure of the factor B-cobra venom factor complex. EMBO J. 2009 Aug 19;28(16):2469-78. Epub 2009 Jul 2. PMID:19574954 doi:10.1038/emboj.2009.184

1. ↑ Goicoechea de Jorge E, Harris CL, Esparza-Gordillo J, Carreras L, Arranz EA, Garrido CA, Lopez-Trascasa M, Sanchez-Corral P, Morgan BP, Rodriguez de Cordoba S. Gain-of-function mutations in complement factor B are associated with atypical hemolytic uremic syndrome. Proc Natl Acad Sci U S A. 2007 Jan 2;104(1):240-5. Epub 2006 Dec 20. PMID:17182750 doi:10.1073/pnas.0603420103
2. ↑ Maga TK, Nishimura CJ, Weaver AE, Frees KL, Smith RJ. Mutations in alternative pathway complement proteins in American patients with atypical hemolytic uremic syndrome. Hum Mutat. 2010 Jun;31(6):E1445-60. doi: 10.1002/humu.21256. PMID:20513133 doi:10.1002/humu.21256