skip to main content
Show Results with:

Structure of cyclic peptides: the crystal and solution conformation of cyclo(Phe-Phe-Aib-Leu-Pro)

Zanotti, G. et al.

The journal of peptide research. VOL 51; NUMBER 6, ; 1998, 460-466 (pages 460-466) -- 1998

Check library holdings

  • Title:
    Structure of cyclic peptides: the crystal and solution conformation of cyclo(Phe-Phe-Aib-Leu-Pro)
  • Author: Zanotti, G.;
    Saviano, M.;
    Saviano, G.;
    Tancredi, T.;
    Rossi, F.;
    Pedone, C.;
    Benedetti, E.
  • Found In: The journal of peptide research. VOL 51; NUMBER 6, ; 1998, 460-466
  • Journal Title: The journal of peptide research.
  • Subjects: Medicine; Biotechnology; Pharmaceutical Chemistry; LCC: K16; Dewey: 612
  • Language: English
  • Abstract: A solid-state and solution conformation analyses of the cyclopentapeptide cyclo(Phe-Phe-Aib-Leu-Pro) has been carried out by X-ray diffraction and nuclear magnetic resonance techniques. The structure of the hexagonal crystals, grown from a methanol solution [a = b = 16.530(4) ?, c = 21.356(9) ?, space group P6~5, Z = 6], shows the presence of one intramolecular N-HùùùO=C hydrogen bond with the formation of a ç-turn (C~7). The Aib^3 residue, at the center of the ç-turn, presents unexpected values of the torsion angles [cursive phi = 70.5ø and cap pi = -73.8ø], which have been observed only once before for this helicogenic residue. A cis peptide bond occurs between Leu^4 and Pro^5; all other peptide bonds are trans. The overall conformation for the cyclopentapeptide with one cis-peptide bond on one side and an intramolecular ç-turn on the opposite side results in an equatorial topology of the side-chains of the Phe^1, Phe^2 and Leu^4 residues. Indeed, the C^à-C^á and C^áC^ç bonds of these residues lie approximately in the mean plane of the cyclic ring system, The structure is compared with data in the literature on cyclic pentapeptides. In addition the Pro-Phe-Phe moiety shows a conformation similar to that observed in other larger cyclic bioactive peptides, which indicates a reduced number of conformations for this sequence. The solution study was carried out in three different solvent systems: chloroform, acetonitrile and methanol in the temperature interval 220-300 K. In all three solvents the room temperature spectra show that the peptide is conformationally nonhomogeneous. In acetonitrile at low temperatures it is possible to reduce the conformational equilibrium to two predominant conformers which differ for the cis-trans isomerism of the Leu^4-Pro^3 peptide bond.
  • Identifier: Journal ISSN: 1397-002X
  • Publication Date: 1998
  • Physical Description: Physical
  • Shelfmark(s): 5030.528000
  • UIN: ETOCRN052911059

Searching Remote Databases, Please Wait