Schematic of the three-dimensional structure of humanized murine GPIIIa. (A) The hybrid, PSI, and EGF1 domains of human GPIIIa. (B) Humanized murine GPIIIa. The positions of the murine amino acids that have been humanized (T₃₀→A, S₃₂→P, Q₃₃→L, N₃₉→D and M₄₇₀→Q) are indicated in panel B, as are the amino acids required for the binding of the HPA-1a–specific human mAb 26.4. Ser₄₆₉ is conserved in mouse and human GPIIIa.