Performance of various predictors for the 15N shifts in ubiquitin, using the first model from pdb ID 1d3z as the input structure. Comparisons are made to the observed shifts from BMRB entry bmr17769. R is the Pearson correlation coefficient, slope is the slope of the best fit line (shown as dashed line in Fig. 4), and RMSE is the root-mean-square difference between calculated and observed shifts.