title: NMR studies of a series of dehydrodermorphins.
abstract: The third and fifth aromatic residues of dermorphin, a potent mu-opioid peptide, and of its N-terminal fragments, from the pentapeptide to the parent heptapeptide amide, have been systematically substituted with Z-dehydrophenylalanine (delta-Phe) and/or Phe to investigate the conformation-activity relationship. The characterization in DMSO-d6 at 500 MHz indicates that, in this solvent, all peptides adopt essentially random, extended conformations, as a consequence of the strong solvation. The chemical shift of the methyl group of D-Ala is influenced by the precise orientation of the side chain of the third residue in a fashion that can be correlated to the mu potency, consistently with our model of mu-receptor. However, the complexes of the pentapeptides with 18-crown-6-ether, when dissolved in chloroform, adopt ordered, folded conformations, a behavior that closely parallels the CD observations in methanol.
authors.forename: M A
authors.initials: MA
authors.lastname: Castiglione-Morelli
authors.forename: G
authors.initials: G
authors.lastname: Saviano
authors.forename: P A
authors.initials: PA
authors.lastname: Temussi
authors.forename: G
authors.initials: G
authors.lastname: Balboni
authors.forename: S
authors.initials: S
authors.lastname: Salvadori
authors.forename: R
authors.initials: R
authors.lastname: Tomatis
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides; D018847:Opioid Peptides; D011487:Protein Conformation
chemical_list: D009842:Oligopeptides; D018847:Opioid Peptides; C030058:dermorphin