The final backbone torsional parameters and associated errors in the recreation of the QM energy scans are given in Section S3.2 of the Supporting Information. For the alanine and glycine scans, the error for the QUBE force field evaluated using eq 5 is 1.25 kcal/mol compared to 0.93 kcal/mol for OPLS-AA/M, which is a reasonable level of agreement. For proline and serine, the errors remain comparable to OPLS-AA/M.