Abstract: A simple technique for identifying protein secondary structures through the analysis of backbone ¹³C chemical shifts is described. It is based on the Chemical-Shift Index [Wishart et al. (1992) Biochemistry, 31, 1647-1651] which was originally developed for the analysis of ¹H^a chemical shifts. By extending the Chemical-Shift Index to include ¹³C^a, ¹³C^b and carbonyl ¹³C chemical shifts, it is now possible to use four independent chemical-shift measurements to identify and locate protein secondary structures. It is shown that by combining both ¹H and ¹³C chemical-shift indices to produce a 'consensus' estimate of secondary structure, it is possible to achieve a predictive accuracy in excess of 92%. This suggests that the secondary structure of peptides and proteins can be accurately obtained from ¹H and ¹³C chemical shifts, without recourse to NOE measurements.

J Biomol NMR 1994 Mar;4(2):171-80

  Below is the updated table of proteins from the BMRB database that comprise the ¹³C  Chemical Shift Index