a, PAR2 receptor is shown with the location of the StaR mutations (in orange stick representation) and the glycosylation site mutation N222Q (in red stick representation). The location of the sodium ion (in purple sphere) is indicated. b, b562RIL is inserted between residue Leu2695.65 and Glu276ICL3 of ICL3 of PAR2. c, The N-terminal lobe of T4L is not involved in crystal contacts and is less well ordered compared to the C-terminal lobe. d, Electron density for AZ8838; view from extracellular space looking down the receptor TMD bundle. For all panels, density shown (blue mesh) is from a composite omit map calculated using the final model of PAR2 double fusion complexed with AZ8838 and contoured at 1.0σ.