Comparison of proton chemical shifts for all protons in the structures with PDB IDs 1c44, 2mc5, 1ail, and 1d3z predicted using the AF-QM/MM model, shifts classical model, and SHIFTX2 semi-empirical/classical model. The chart on top shows the correlation coefficient, R, between the predicted and observed chemical shifts. The chart on bottom shows the average signed chemical shift deviation compared to experiment with the error bars indicating the standard deviation of the computed errors. The HA protons are those attached to the Cα of each amino acid. The rest are shown in their local chemical environment.