Fig. 3: Overall structure of the IR/S597 complex.
From: Activation of the insulin receptor by an insulin mimetic peptide
a 3D reconstruction of the IR dimer with two S597 peptides bound. b The ribbon representation of the IR dimer with two S597 peptides bound fitted into the cryo-EM map at 5.4 Å resolution. c Close-up view of the binding of S597 at the L1 domain of one protomer (blue) and FnIII-1 domain of another (green). The component-1 binding helix of S597 is shown in yellow, the component-2 binding helix in pink, and the linker region in gray. d Superposition between S597-bound IR protomer (blue) and apo-IR protomer (gray). e Working model for S597-induced IR activation. The simultaneous binding of S597 to both the L1 domain of one protomer and the FnIII-1 domain of another would trigger the structural transition of IR directly from Λ-shaped apo-form to extended T-shaped IR dimer and stabilize the active form. A cartoon representation of the IR/insulin complex in a compact T-shape is shown for comparison.
