Structural basis of type 2A von Willebrand disease investigated by molecular dynamics simulations and experiments.
PLoS One
; 7(10): e45207, 2012.
Article
em En
| MEDLINE
| ID: mdl-23110044
ABSTRACT
The hemostatic function of von Willebrand factor is downregulated by the metalloprotease ADAMTS13, which cleaves at a unique site normally buried in the A2 domain. Exposure of the proteolytic site is induced in the wild-type by shear stress as von Willebrand factor circulates in blood. Mutations in the A2 domain, which increase its susceptibility to cleavage, cause type 2A von Willebrand disease. In this study, molecular dynamics simulations suggest that the A2 domain unfolds under tensile force progressively through a series of steps. The simulation results also indicated that three type 2A mutations in the C-terminal half of the A2 domain, L1657I, I1628T and E1638K, destabilize the native state fold of the protein. Furthermore, all three type 2A mutations lowered in silico the tensile force necessary to undock the C-terminal helix α6 from the rest of the A2 domain, the first event in the unfolding pathway. The mutations F1520A, I1651A and A1661G were also predicted by simulations to destabilize the A2 domain and facilitate exposure of the cleavage site. Recombinant A2 domain proteins were expressed and cleavage assays were performed with the wild-type and single-point mutants. All three type 2A and two of the three predicted mutations exhibited increased rate of cleavage by ADAMTS13. These results confirm that destabilization of the helix α6 in the A2 domain facilitates exposure of the cleavage site and increases the rate of cleavage by ADAMTS13.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator de von Willebrand
/
Doença de von Willebrand Tipo 2
/
Simulação de Dinâmica Molecular
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article