Extended Data Figure 6: Observed NMR effects of the reverse mutations of TS-β1AR towards the native β1AR sequence.
From: Backbone NMR reveals allosteric signal transduction networks in the β1-adrenergic receptor
a, 1H–15N TROSY spectra of TS-β1AR and several reverse single and double mutants in complex with either atenolol (cyan) or isoprenaline (dark blue). Resonances are marked with assignment information (black, definite; cyan, tentative). b, Enlarged regions of the 1H–15N correlation spectra showing only the resonance positions of V226(5.57) and V280(6.25) for all mutants in both ligand-receptor complexes. The black bar represents 0.1 p.p.m. in 1H and 1 p.p.m. in 15N. For all mutants, the resonances for V226(5.57) show efficacy-related chemical shift changes between atenolol (diamonds) and isoprenaline (circles). For the A227Y mutants TS-β1AR(A227Y) (green), TS-β1AR(V129I/A227Y) (orange) and TS-β1AR(A227Y/L343Y) (cyan), the 1H–15N resonances of V226(5.57) also exhibit an overall shift due to a ring current effect from the introduced Y227(5.58) side chain, which has no structural significance. However, the V129I mutants TS-β1AR(V129I) (red) and TS-β1AR(V129I/A227Y) (orange) exhibit further 1H–15N shifts towards a more active (that is, bent) state of TM5 relative to the mutants that carry the V129(3.40) residue. For all mutants, the V280(6.25) resonances fall basically in identical positions and show no changes between atenolol and isoprenaline.
