Map of overlapping mAb epitopes onto the A2 surface. (A) X-ray structure of BDD fVIII (PDB 2R7E) showing regions recognized by group A mAbs (Asp403-His444 and Arg484-Ile508) and group E mAbs (Glu604-Cys711). A2 residues Asp712-Arg740 were not identified in the structure. (B) Regions with the A2 polypeptide chain identified by homolog-scanning mutagenesis were used to anchor the Venn diagram onto the A2 surface.