The X-Pro peptide bond as an nmr probe for conformational studies of flexible linear peptides
Article first published online: 1 FEB 2004
Copyright © 1976 John Wiley & Sons, Inc.
Volume 15, Issue 10, pages 2025–2041, October 1976
How to Cite
Grathwohl, C. and Wüthrich, K. (1976), The X-Pro peptide bond as an nmr probe for conformational studies of flexible linear peptides. Biopolymers, 15: 2025–2041. doi: 10.1002/bip.1976.360151012
- Issue published online: 1 FEB 2004
- Article first published online: 1 FEB 2004
- Manuscript Accepted: 8 APR 1976
- Manuscript Received: 23 JAN 1976
The equilibrium between the cis and trans forms of X-Pro peptide bonds can readily be measured in the 13C nmr spectra. In the present paper we investigate how observation of this equilibrium could be used as an nmr probe for conformational studies of flexible polypeptide chains. The experiments include studies by 13C nmr of a series of linear oligopeptides containing different X-L-Pro peptide bonds, with X = Gly, L-Ala, L-Leu, L-Phe, D-Ala, D-Leu, and D-Phe. Overall the study confirms that X-Pro peptide bonds can generally be useful as 13C nmr probes reporting the formation of nonrandom conformation in flexible polypeptide chains. It was found that the cis–trans equilibrium of X-Pro is greatly affected by the side chain of X and the configuration of the α-carbon atom of X. On the basis of these observations some general rules are suggested for a practical applications of the X-Pro nmr probes in conformational studies of polypeptide chains.