Figure 3.

Schematic diagrams depicting the CH3 interfaces of the BEAT (B) homodimer, the BEAT heterodimer containing the additional Q3A substitution in BEAT (A), the BEAT Q3A-D84.4Q heterodimer, and the original BEAT heterodimer. Interdomain interactions were calculated from the homology models for the first two and from the crystal structures for the latter two (PDB codes 6G1E and 5M3V, respectively). Homology models were generated based on the crystal structure of the original BEAT Fc. The IMGT numbering is used. Charged residues are colored in red (negative) or blue (positive). Hydrophobic interactions are in gray lines, and electrostatic interactions are in dashed red lines. The symmetric electrostatic interactions between Asp^84.4 and Arg⁹⁰ in the BEAT (B) homodimer as well as the asymmetric interactions between Asp^84.4, Asp^84.2, and Arg⁹⁰ in the BEAT Q3A heterodimer are boxed in dashed black lines, and the residues are colored in yellow.