Figure 2.

Schematic indicating positions of mutations on generic Fc structure. Positions mutated relative to parental subtype are depicted as red spheres on a structure of IgG1 Fc having an idealized hinge (wheat and blue, cartoon) for IgG1σ (A), IgG2σ (B), and IgG4σ1/2 (C). For clarity, the sites of mutation are labeled on only one of two equivalent Fc chains. IgG4σ2 differs from IgG4σ1 by the deletion of G236 (position indicated with a small, grey sphere and labeled with an asterisk).