Extended Data Fig. 5. Cryo-EM map quality of the β₁AR_6P–βarr1–F_ab30 complex and model validation.

Unless otherwise stated, density maps were visualized using Chimera³⁸ (contour level 0.017) and encompass a radius of 2 Å around the region of interest. a, Transmembrane helices of β₁AR_6P with density shown as a mesh. b, ICL2 of β₁AR_6P. For clarity, the neighbouring βarr1 side chains are depicted without density. c, ECL3 of β₁AR_6P and the adjacent helical turns of H6 and H7. d, The phosphorylated V₂R_6P C terminus. Inset, interaction between the V₂R_6P phospho-threonine dyad and the βarr1 lariat loop. Density in the inset is depicted with contour level 0.01 (carve radius 2 Å). e, The finger loop of βarr1. f, Formoterol and the neighbouring side chains in the orthosteric binding site. g, FSC of the refined model versus the map (green curve), and FSC_work and FSC_free validation curves (blue and red curves, respectively). h, Amino acid sequence of the β₁AR_6P construct used for the cryo-EM structure determination. The residues are numbered according to the wild-type sequence of β₁AR. Residues are coloured according to how they have been modelled (key). Regions highlighted in grey represent the transmembrane α-helices, amphipathic helix 8 is highlighted in yellow, and phosphorylated residues are highlighted in green. The dashes represent amino acid residues that were deleted.