Alanine, glycine, serine, and proline torsional parameters are fit to available QM potential energy surfaces and are therefore residue-specific. Threonine uses torsional parameters fit to the serine torsional scan, and all other amino acid use torsional parameters fit to joint alanine/glycine energy scans. These backbone parameters are combined with the dipeptide sidechain torsional parameters to give the full QUBE protein force field parameter set. Blue is used for non-bonded terms, yellow is used for bonded terms.