Bending: the rule for IgE

Immunoglobulin E (IgE) has important roles in the mechanisms of allergic disease, but the impact of the structure and shape of IgE on the development of allergic response has been unclear. In 17 June Advanced Online Nature Immunology, Tommy Wan and colleagues from King's College London, UK, shows that IgE Fc has an asymmetrically bent conformation which may explain its unique binding kinetics and its ability to cause persistent allergic sensitization of mast cells (Nat Immunol 2002, DOI: 10.1038/ni811).

Wan et al. analyzed human IgE Fc at a 2.6-Å resolution and observed that the molecule have a distinctive, disulfide-linked Cε2 domain pair. The Cε2 pair is folded back asymmetrically onto the Cε3 and Cε4 domains, which causes an acute bend in the IgE molecule. This structural detail implies that a substantial conformational change involving Cε2 must accompany the binding of IgE to the mast cell receptor FcεRi.

"This identifies a ...