Empirical analysis of backbone chemical shifts in proteins

Chemical shift data from the BMRB were correlated with PDB structures for 590 proteins and corrected for unexplained systematic offset and non-IUPAC recommended referencing.  Shifts were sorted according to secondary structure type, determined with DSSP for the corresponding structures.  The dataset was filtered by discarding points lying in disallowable regions of Ramachandran plots.  Typically these data points localize to residues at the N or C terminus of the protein, or the ends of helices and strands.

I. Average chemical shift values for helix and beta strand classes and subclasses
II. Analysis of random coil backbone chemical shifts
III. Modification of the conventional chemical shift to highlight differences between alpha and 3,10 helices
IV. References

Analysis performed by Amanda Mayo and Kyoko Yap of the Ikura laboratory, Department of Medical Biophysics, University of Toronto; Division of Molecular and Structural Biology, Ontario Cancer Institute, May 2001.

Please note these are preliminary results with an update to follow soon.

contact: Kyoko L. Yap