For the eleven molecules shown in Figure , experimental NOE data in chloroform were available. To assess the statistical convergence of our simulations, we split each trajectory into five segments of equal length and performed the analysis on each segment, using the standard deviation of the five splits as an error bar. As an example for the expected range of violations, we show the detailed results for BC1 and NLeu5S in chloroform using OpenFF 2 in Figure . While the BC1 ensemble matches the experimental data very well, we find large violations for NLeu5S. The results for the other compounds are given in Figures S6-S8 in the Supporting Information. Figure shows high NOE violations for NLeu5S. To investigate where the deviations originate (given that the ensemble of NLeu5R, that differs only in the stereoconfiguration of one methyl group, agrees well with experiment as seen in Figure ), we performed clustering as described in the Methods section to extract five clusters. In Figure , the representative structures of the clusters are shown with the distances corresponding to the NOE bounds with the highest violations highlighted in yellow (note that there is a simplification for the purpose of clarity: while the NOE distances are averaged with r -6 weights for the quantitative analysis, we show the distance between centers of mass of the respective hydrogen atoms). The structure of the most populated cluster (97.3 %) is similar to the one observed by Comeau et al. in simulations with the GROMOS force field , exhibiting a single intramolecular hydrogen bond between the nitrogen atom of the linker and the carboxylate of the alanine. To fulfill the experimental constraints, a significant rearrangement would be required, where the phenylalanine side chain folds towards the other side of the ring.