Observed vs. Predicted Chemical Shift Differences by Residues

The two main plots show the difference between the actual and predicted chemical shift values, by residue, for the atom types selected by the cursors on the left. The atom type for each main plot can be selected independently, so you can compare the values for any two atom types. The red horizontal line shows the average difference for the selected atom type, for residues with helix and sheet secondary structures.

The averages for CA and CB include values from all residues; the averages for all of the other atoms include only values from residues belonging to helices or beta strands.

All GLY HA2 and HA3 assignments are excluded from the plots and calculations. All shifts from residues with large backbone B-factors (1.6 larger than the average) in the corresponding X-ray structure are excluded from the plots and calculations.

The N predicted shifts of SER, THR and GLY are excluded from all calculations.

All chemical shift referencing correction calculations exclude large outliers, i.e.

The chemical shift referencing correction method uses chemical shift values simulated by the DC program included in the NMRPipe package ( http://spin.niddk.nih.gov/NMRPipe/dynamo/).