The RF61 Fab–IgG1 Fc contact region. The six CDRs of RF61, all of which make contact except L2, and the strands and loop regions that constitute the epitope on the Cγ3 domains of IgG Fc, are indicated in this stereo image. The VH and VL domains of RF61 are shown in green and purple, respectively, and the IgG Fc A and B chains are in light and dark-blue, respectively.