Extended Data Fig. 8: Comparison of the G-protein Signaling of MOR and NTSR1.

a) Major structures observed in the GTP-induced activation of MOR-Gi and NTSR1-Gi in the presence of full/super agonist. b) Structure of the G-ACT-3 intermediate state of the MOR-GI-GTP complex with a stable, inactive-like receptor (PDB:9ODL). c) Comparison of ICL2 interactions with the β2-β3 loop and α1 helix comparing MOR-Gi-nucleotide free and MOR-Gi-GTP in an AHD domain open state (left) and comparing NTSR-Gi with MOR-Gi in the nucleotide free state (right). d) Comparison of the ICL2 region of MOR-Gi and NTSR1-Gi in their canonical nucleotide free states. e) Traces of ICL2-β2-β3 loop distances from MD simulations of the NTSR-Gi C-Closed-GTP state (top) and the same complex with MOR substituted (bottom); lines represent distances in the cryoEM structures of the C-Closed-GTP and NC-Closed-GTP complexes. f) Kinetic BRET traces for the MOR constructs tested in this work signaling through Gq. Experiments were performed with 4 independent experiments with 4 technical replicates each. g) Amino acid frequency plots for Family A GPCR ICL2 regions grouped on primary G-protein.