In particular, the strong negative π → π * band at about 200 nm shows a good agreement with the experimental CD spectrum. The largest deviation is a predicted positive band around 210 nm, which is absent in the experiment. This may arise from the neglect of side-chain transitions (e.g. histidine residues or the amide bonds of asparagine and glutamine), or to the underestimation of n → π * /π → π * mixing within each peptide bond. Finally, we note that the broadening of the negative band is underestimated in the simulations, possibly due to the neglect of vibronic structure in the π → π * band. A greater broadening may hide the positive contributions at around 210 nm.