Fig. 8. Calculation of free energy changes (ΔG^calc) upon dissociation of RBD/REGN10987-Fab complexes.

a ΔG^calc values calculated for the different RBD variants using different initial conformations (n = 99, in total) positively correlate with the structural characteristics of these conformations (Supplementary Data 1-11 and 1-12). b Same as (a), but averaged for each RBD variant (arithmetic mean ± S.E.M., n = 17 for Wuhan, Omicron, N440K RBD variants, and n = 12 for other RBD variants). c Calculated ΔG^calc values vs RBD variant/MD replica (Run1 to Run3). Bars are the averages (arithmetic mean ± S.E.M., the n numbers are the same as in (b)) for the RBD variants, and dashed lines are means for the replicas. *(p < 0.05) and **(p < 0.01) indicate significant differences between the RBD variants according to one-way ANOVA/Tukey test. #(p < 0.05), ##(p < 0.01), and ####(p < 0.0001) indicate significant differences between the four groups of MD replicas according to two-way ANOVA/Tukey test. Groups: Weak+L-Runs (Omic-1, 440-1, and 446-1), Weak+H-Runs (Omic-2, Omic-3, 440-2, 440-3, 446-2, and 446-3), Strong+L-Runs (WT-3, 498-1, 501-3, and Oth-1), Strong+H-Runs (WT-1, WT-2, 498-2, 498-3, 501-1, 501-2, Oth-2, and Oth-3). &(p = 1.7 × 10⁻⁶, n = 99 independent ΔG calculations, two-tailed t-test) indicates significant difference between ‘Weak’’ and ‘Strong’’ binders. d Boltzmann-weighted averaged ΔGcalc values (abscissa, Boltzmann-weighted mean ± Boltzmann-weighted SD, N = 12–17, Supplementary Data 1-13) for different RBD variants show a strong positive correlation with the averaged experimental ΔGexp values (ordinate, arithmetic mean ± SD, N = 6, Supplementary Data 1-14). ΔG^exp values recalculated from the MST data (Fig. 5) are shown as diamonds. ΔG^exp values recalculated from EC₅₀ and K_d values reported in the literature^{8,35,38,39,57} are shown as circles. Datapoints for the N440K, G446S, and Omicron BA.1 variants corresponding to lower estimates of EC₅₀ or K_d values^{8,35,38,39,57} are shown by horizontally crosse_d circles and diamond. ΔG^exp value for the Omicron BA.1 variant recalculated from the measured EC₅₀ value⁵² is shown as a star. Only one experimental data point is present for the ‘Others’’ RBD variant. The different ΔG^exp data sets were aligned assuming that the dissociation free energy for WT RBD is 15 kcal/mol. Therefore, only one data point is shown for the WT variant. Blue and red dashed lines represent regressions to linear models with unitary and variable slope, respectively.