Ribbon diagram of the α_IIb/β₃ head region indicating possible binding footprints of 5 mAb pairs. Structural coordinates were from Protein Data Bank (3FCS)¹⁹  viewed with WebLab viewer Pro 3.7 (Molecular Simulations Inc). Amino acid residues 606-959 of α_IIb and 561-690 of β₃ were omitted for the sake of clarity. Alpha helical structures are red, and β sheets are turquoise. Solid ovals represent likely footprints of mAbs 10E5, 7E3, AP3, and RGD peptide based on prior crystallographic¹⁷  or mutagenic^31,32  studies. Dashed ovals represent likely binding footprints of 7 other mAbs inferred from their reactions with chimeric α_IIb/β₃ constructs and from blocking studies summarized in Table 3.