1Q0P

A domain of Factor B

Summary for 1Q0P

• Entry DOI: 10.2210/pdb1q0p/pdb
• Descriptor: Complement factor B, MANGANESE (II) ION (3 entities in total)
• Functional Keywords: factor b, von willebrand factor, mac-1, i domain, a domain, hydrolase
• Biological source: Homo sapiens (human)
• Cellular location: Secreted: P00751
• Total number of polymer chains: 1
• Total formula weight: 25233.40

Authors

Bhattacharya, A.A.,Liddington, R.C. (deposition date: 2003-07-17, release date: 2004-03-30, Last modification date: 2024-02-14)

Primary citation

Bhattacharya, A.A.,Lupher Jr., M.L.,Staunton, D.E.,Liddington, R.C.
Crystal Structure of the A Domain from Complement Factor B Reveals an Integrin-like Open Conformation.
STRUCTURE, 12:371-378, 2004

PubMed Abstract: Complement factor B is a 90 kDa protein consisting of three domains: a three-module complement control protein, a von Willebrand factor A domain, and a C-terminal serine protease (SP) domain that adopts a default inactive (zymogen) conformation. The interaction between factor B and pathogen-bound C3b is mediated by its A domain, triggering a conformational change in factor B that ultimately creates the "C3 convertase" of the alternative complement pathway. We report the crystal structure of the A domain from factor B and show that it contains an integrin-like MIDAS motif that adopts the "open" conformation typical of integrin-ligand complexes, with an acidic residue (provided by a fortuitous crystal contact) completing the coordination of the metal ion. Modeling studies indicate that the factor B A domain can also adopt the closed conformation, supporting the hypothesis that an "integrin-like switch" is conserved in complement proteins and perhaps in 60 other A domains found within the human proteome.

PubMed: 15016353
DOI: 10.1016/j.str.2004.02.012

Experimental method

X-RAY DIFFRACTION (1.8 Å)