Conformational changes in IgE contribute to its uniquely slow dissociation rate from receptor FcÉRI.
Nat Struct Mol Biol
; 18(5): 571-6, 2011 May.
Article
em En
| MEDLINE
| ID: mdl-21516097
ABSTRACT
Among antibody classes, IgE has a uniquely slow dissociation rate from, and high affinity for, its cell surface receptor FcÉRI. We show the structural basis for these key determinants of the ability of IgE to mediate allergic hypersensitivity through the 3.4-Å-resolution crystal structure of human IgE-Fc (consisting of the CÉ2, CÉ3 and CÉ4 domains) bound to the extracellular domains of the FcÉRI α chain. Comparison with the structure of free IgE-Fc (reported here at a resolution of 1.9 Å) shows that the antibody, which has a compact, bent structure before receptor engagement, becomes even more acutely bent in the complex. Thermodynamic analysis indicates that the interaction is entropically driven, which explains how the noncontacting CÉ2 domains, in place of the flexible hinge region of IgG antibodies, contribute together with the conformational changes to the unique binding properties of IgE.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Imunoglobulina E
/
Receptores de IgE
Limite:
Humans
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article