Figure 1.

Crystal structure of the ibalizumab-CD4 complex (PDB id: 3O2D) (A) and a fragment of CD4 with selected interacting residues of the antibody (B). CD4 is shown as a cyan ribbon or as a solvent-accessible surface colored by interpolated charge (blue–positive, gray–neutral, red–negative). The antibody is shown as a green or orange ribbon for the light and heavy chains, respectively. Interacting residues are shown in stick representation, with carbon atoms colored the same as the parent chain. Intermolecular interactions are shown as dashed lines: green–hydrogen bonds, orange–charge-assisted hydrogen bonds, pink–hydrophobic interactions, and white–hydrogen bond donor/π interactions.