The RMSDs of the zwitterionic tripeptide EPs, evaluated on a molecular surface defined by twice the vdW atomic radii, are presented in Figure . The average RMSD of the CP 3 -based EPs is 13.5 kJ/mol. Most of the individual RMSDs are close to the average, thus showing that the accuracy is rather consistent. However, there are a few notable outliers, namely CYS, CYX, and HIS, with a significantly higher error for CYS and HIS, and a significantly lower error in the case of the dimeric CYX tripeptide. We were unfortunately not able to identify any convincing explanations for this behavior.