Figure 3. Orthogonal views depicting conformational changes in IgE-Fc upon binding a single molecule of derCD23 (not shown).
A substantial rigid body movement of the IgE-Fc Cε2 domains upon derCD23 binding is observed when compared to free IgE-Fc (yellow and green). In addition, the Cε3 domain in the derCD23-bound chain (red) adopts an extreme closed conformation, in contrast to the Cε3 domain in the free chain (blue), which adopts an extreme open conformation. The structures were superposed on their (Cε4)2 domains.