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Published January 1, 1979 | public
Journal Article

Conformational Analysis by Nuclear Magnetic Resonance Spectroscopy: ^(15)N NMR of a Cyclic Pentapeptide

Abstract

The cyclic pentapeptide cyclo-(Gly(I)-Pro-Gly(2)-D-Ala-Prow), which has been shown by ^1H and ^(13)C NMR to incorporate both β and γ turns, has been used as a model system to explore the use of ^(15)N NMR to analyze the conformations of peptides. Assignments of ^(15)N resonances to specific amino acids have been made by analogy with similar peptides and confirmed by ^(15)N labeling. Nitrogen chemical shifts of the peptide, which is soluble in a wide variety of solvents, are sensitive to solvent changes. In water, two conformations corresponding to different cis-trans configurations of the peptide bonds are present. By means of ^(15)N labeling and an analysis of ^(15)N chemical shifts the involvement of Gly(1) in this cis-trans isomerism has been established. These results indicate substantial utility for ^(15)N NMR in the conformational analysis of peptides.

Additional Information

© 1979 American Chemical Society. Received November 21, 1977. We are very much indebted to Drs. Donald D. Giannini, Glenn R. Sullivan, and Mrs. Keiko Kanamori for the ^(15)N spectra and Dr. B. Bartmann for a sample of cyclo-(Pro-Gly)3. Acknowledgment is made to the donors of the Petroleum Research Fund, administered by the American Chemical Society, for support of this work. In addition we acknowledge the support of the Public Health Service, Grants GM 10224-13 and GM 11072-15, as well as the National Science Foundation.

Additional details

Created:
August 19, 2023
Modified:
October 24, 2023