Figure 4.

The dynamic proxy of methyl groups is an excellent reporter of both methyl and total side-chain rotameric entropy. (o) The normalized methyl rotameric entropy for each protein is calculated as the summation of S_b for individual methyl-bearing amino acids divided by the number of associated rotamer angles (Nχ). () The total rotameric entropy for each protein is calculated as the summation of S_b for all residues and is normalized by the respective total number of rotamer angles (Nχ). The average methyl O²_axis parameter for all methyl-bearing residues including Ala is that obtained from MD simulations. A very high linear correlation is observed for both methyl-side chain rotamer entropy [slope = −1.16 ± 0.17, R² = 0.90] and total rotamer entropy [slope = −0.74 ± 0.10, R² = 0.91 ]. The inset shows the correlation of the uncorrected entropy with the entropy corrected for correlated motions using () second–order and () third-order MIST estimates of inter-residue correlations. Both correlations are highly linear with a slope of −0.89 (R² = 0.99) and slope = −0.83 (R² = 0.96) for second-order and third-order MIST calculations, respectively.