Fig. 1.
Integrin conformational states and preparation of αxβ2–Fab complexes. (A–C) Schematic of three conformational states of integrin. (D) Schematic of the αxβ2 ectodomain construct used in this study. (E and F) Ribbon diagrams of the αxβ2 ectodomain in extended-closed headpiece (E) and extended-open headpiece (F) conformations. Spheres show Cα atoms of residues to which epitopes are mapped. Epitopes are labeled in the headpiece conformation for which mAb are found to be specific in this study. Models are based on the bent αxβ2 crystal structure (4) and open αIIbβ3 headpiece (13). (G and H) Superdex 200 size exclusion chromatography profiles of αxβ2 in the absence and presence of the indicated Fabs.