Figure 2. Distribution of effects of Gα_i1 alanine mutants on the nucleotide-bound and receptor-bound states.

a, b, Changes in stability (∆T_m) of Gα_i1(Ala)-GDP (w/ 1mM GDP) (a) and ∆T_m of Gα_i1(Ala)-GTPγS (w/ 0.1mM GTPγS) (b). Gray: -2°C < ∆T_m < 2°C; blue: ∆T_m < -2°C; red: 2°C < ∆T_m. The ∆T_m of Gα_i1(WT)-GDP or -GTPγS was shown as the black dot. c, Distribution of ∆ complex formation efficiency of Rho*-G_i(Ala). Blue: ∆ complex formation efficiency is less than -10%; gray: between -10% and 10%; red: more than 10%. d, Distribution of ∆complex stability of Rho*-G_i(Ala). Blue: ∆complex stability is less than -10%; gray: between -10% and 10%; red: more than 10%. The definition of ∆T_m, ∆complex formation efficiency, and ∆complex stability are described in the methods section. All data are presented in Supplementary Table 1. As for ∆T_m of Gα_i1 (WT)-GDP and Gα_i1(Ala)-GTPγS, data points represent mean ± s.d. from 25 and 24 individual experiments, respectively. As for ∆complex formation efficiency and ∆complex stability of Rho*-G_i(WT), data points represent mean ± s.d. of 33 and 38 individual experiments, respectively.