A direct comparison to experimental spectra is not possible for DKP and NAGMA, but we can compare to the spectra calculated by Hanson-Heine et al. using a vibrational exciton model based on harmonic localized-mode frequencies and coupling constants. Overall, the calculated 2D IR spectra show a very good agreement. This is not surprising, since the parameters of the vibrational exciton models corresponding to our calculations (see Table Here, we do not rely on an empirical parameter, but are able to calculate this localmode anharmonic shift directly. From our calculations, we obtain ∆ = 4 cm -1 and ∆ = 7 cm -1 for DKP and NAGMA, respectively. These local-mode anharmonic shifts, which is significantly lower than the commonly used empirical value, and also indicate that this anharmonic shift might show significant variations. This is in line with earlier computational studies of the anharmonicity of amide I modes in small peptides, which have been shown to vary substantially depending on the considered conformation.