Structure of the RF61 Fab–IgG1 Fc complex. The two chains of the Fc fragment, with the N-linked carbohydrate (ball-and-stick representation), are shown in dark and light-blue (chains A and B, respectively). For the two Fabs, bound symmetrically to the Cγ3 domains of the Fc, heavy chains are shown in red and green and light chains in orange and purple. Two cations and the cacodylate moiety are shown in yellow. (Figure produced by MolScript39).