The FVIII C2 domain/3E6 F_ABinterface. (A) Direct molecular contacts between the 3E6 light chain and C2 domain residues Lys2183/Asp2187; pink: fVIII C2 domain, cyan: 3E6 light chain. (B) Direct molecular contacts between the 3E6 heavy chain and the C2 domain 2211-2215 loop; pink: fVIII C2 domain, blue: 3E6 heavy chain. (C,D) Electrostatic surface potentials for the 3E6 epitope on the fVIII C2 domain (C) and the variable region of the 3E6 F_AB (D); blue: positive charge, red: negative charge. The surface potentials were calculated with APBS at surface potential values of ±5 kT/e, and the surfaces were displayed in PyMol.