The αV subunit is in cyan. The β3 hybrid domain is in green, and other β3 domains are in magenta. The β3 tail domain CD loop (residues Asp-672–Lys-676) is in blue. Residues mutated to cysteine are shown with spheres at the positions of αV G307 Cα (cyan) and β3 R563 Cα (magenta). The position of the N-glycan wedge introduced by the β3 NIN305T mutation is shown with a yellow sphere at Asn-303 Cα. A, this view emphasizes the β-I domain β6-strand and α7-helix, the only elements shown as a ribbon, and their proximity to the β-tail domain CD loop. B, this view is rotated relative to A and emphasizes the glycan wedge introduced into a crevice between the hybrid and β-I domain that widens in the open headpiece conformation.