Crystal structure of the A domain from complement factor B reveals an integrin-like open conformation.
Structure
; 12(3): 371-8, 2004 Mar.
Article
em En
| MEDLINE
| ID: mdl-15016353
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator B do Complemento
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article