Extended Data Fig. 5: Structure and position of the α-helical domain (AHD).
From: Cryo-EM structure of an activated GPCR–G protein complex in lipid nanodiscs
a, Density maps and models showing the interaction between Gβ1 (purple) and Gαi1 AHD (gold) in the canonical state. Zoom-in view of the Gαi1 AHD is shown. b, Density maps and models showing the interaction between Gβ1 (purple) and Gαi1 AHD (dark green) in the noncanonical state. Zoom-in view of the Gαi1 AHD is shown. The models in (a) and (b) are superposed on the Gβ1 subunits and are shown in the same view. AHD in both states interacts with the second and third blades of Gβ1. c-f, Comparison of the AHD of the canonical state NTS-NTSR1-Gi-cND (gold) with c, A crystal structure of GDP-Gi (blue; PDB 1GP2), d, A crystal structure of β2AR-Gs with nanobody Nb35 (AHD is dark red and Nb35 is green; PDB 3SN6), e, A cryo-EM structure of Rhodopsin–Gi with Fab G50 (AHD is pink and Fab G50 is green; PDB 6CMO), and f, A cryo-EM structure of Smoothened-Gi with Fab G50 (AHD is light blue and Fab G50 is green; PDB 6OT0). The models are superposed on the Gα Ras-like domain.
