The 13C Chemical-Shift Index: A simple method for the identification of protein secondary structure using 13C chemical-shift data

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 1Hα chemical shifts. By extending the Chemical-Shift Index to include 13Cα, 13Cβ 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. © 1994 ESCOM Science Publishers B.V.