Conformational comparison of cyclic peptide and pseudopeptide structures with intramolecular hydrogen bonding
✍ Scribed by Arno F. Spatola; Lila M. Gierasch; Arlene L. Rockwell
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1983
- Tongue
- English
- Weight
- 263 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0006-3525
No coin nor oath required. For personal study only.
✦ Synopsis
An nmr spectral comparison of a model cyclic pentapeptide cyclo(G1y-Pro-Gly-D-Phe-Pro) with an analogous pseudopeptide has been made. The pseudopeptide contains a $[CH2S] amide bond replacement a t the only amide linkage that, in the model, is not involved in an intramolecular hydrogen bond. Both proton and carbon-13 nmr spectral evidence confirms the retention of pand y-turns in the pseudopeptide in chloroform. Characteristic chemical shifts, temperature dependence, and glycine a-resonances support this interpretation. However, evidence of a more flexible conformation involving cis-trans proline isomerism is seen on addition of dimethylsulfoxide.