Fig. 2: Characterizing the coupling of tβ1AR coupling to engineered Gα subunits.
a, MS spectra of purified tβ1AR complexed with mini-Gs in the presence of the agonists isoprenaline (1), norepinephrine (8), carmoterol (9) and dobutamine (10) at a concentration of 25 μM. The peaks assigned to the receptor–mini-Gs complex and the receptor monomer are denoted in orange and blue, respectively. b, Schematic illustration of the stimulation propensity of agonists towards Gs and Gi proteins and the potential biased effect of agonists. c, Mass spectra of tβ1AR–mini-Gi/s complexes formed in response to agonists 1 and 8–10 at 25 μM. The signals of the tβ1AR–mini-Gi/s complex, receptor monomer and mini-Gs are shown in magenta, blue and grey, respectively. d, Different deuterium uptake upon tβ1AR activation in the absence of G proteins is induced by norepinephrine and isoprenaline and mapped onto the structure of tβ1AR (PDB: 2Y03). Increased uptake in comparison with the receptor without treatment is denoted in red, and decreased uptake is coloured blue. The ICL3 motif is uniquely modulated by isoprenaline, highlighted by the green circle. Representative spectra from three independent experiments are shown in a and c.
