The X-Pro peptide bond as an nmr probe for conformational studies of flexible linear peptides

✍ Scribed by Christoph Grathwohl; Kurt Wüthrich

• Publisher: Wiley (John Wiley & Sons)
• Year: 1976
• Tongue: English
• Weight: 950 KB
• Volume: 15
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1976.360151012

✦ Synopsis

Abstract

The equilibrium between the cis and trans forms of X‐Pro peptide bonds can readily be measured in the ^13^C 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 ^13^C 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 ^13^C 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.