FIGURE 10.

Putative accessibility of epitopes of function-blocking mAbs in a model of the headpiece of α5β1 bound to 3FN9,10. A–E, molecular model is the same as that shown in Fig. 9. In respective panels, residue Leu-212 (P1D6 epitope) is shown in yellow; residues Glu-126, Leu-128, and Trp-157 (mAb 16 epitope) are shown in orange; residue Ser-85 (JBS5 and SNAKA52 epitopes) is shown in red within the α5 subunit (blue ribbon); residue Val-211 (AIIB2 epitope) is shown in brown, and residue Lys-218 (4B4 epitope) is shown in cyan within the β1 subunit (green ribbon). The α2 helix in the βI domain is shown in magenta. 3FN9,10 is shown as a semi-transparent light gray surface, and the surface of accessible 3FN9,10 residues within 20 Å of indicated mAb epitope residues is rendered in semi-transparent pink. Residue Arg-1468 (from the Pro-Pro-Ser-Arg-Asn synergy sequence of murine fibronectin) is shown in dark pink and indicated by the pink text in A. Anti-α5 mAbs would be sterically hindered from binding to indicated epitope residues by fibronectin, whereas anti-β1 mAbs would not. Scale bars, 20 Å.