FIG. 10.

Distribution of X₀, ${\mathbf{X}}_0^{\prime }$ for a blocked serine and MDP. (a) and(b) illustrate the superposition of the structures; one X₀ is shown in licorice and colored based on element, the rest X₀ shown in gray lines; ${\mathbf{X}}_0^{\prime }$ structures are shown in a different color in line form. [(c) and (d)] Φ − Ψ free energy surfaces of a blocked serine in solution with (c) CHARMM36 and (d) DFTB3-Mulliken charges, the latter better resembles the DFTB3/3OB/CHARMM result (see, e.g., Ref. 53). [(e) and (f)] Free energy map projected onto the first two principal components for a MDP in solution using (e) CHARMM36 and (f) DFTB3/3OB/CHARMM. The dots indicate the locations of X₀, ${\mathbf{X}}_0^{\prime }$, and the labels correspond to those used in Table III.