title: Combined use of NMR, distance geometry and MD calculations for the conformational analysis of opioid peptides of the type [D(L)-Cys2, D(L)-Cys5]enkephalin.
abstract: The solution structures of a series of conformationally restricted pentapeptides with a sequence H-Tyr1-Cys2-Gly3-Phe4-Cys5-OH cyclic (2-5) disulfide, where the cysteines possess either the D or L configuration, were examined by a combined approach including NMR measurements as well as MD calculations. It turned out that at least one low energy conformer of H-Tyr1-D-Cys2-Gly3-Phe4-D-Cys5-OH cyclic (2-5) disulfide (DCDCE), as well as one conformer out of the group of calculated conformers for H-Tyr1-D-Cys2-Gly3-Phe4-Cys5-OH cyclic (2-5) disulfide (DCLCE), satisfies the NMR data obtained in this study, whereas for the derivative H-Tyr1-Cys2-Gly3-Phe4-Cys5-OH cyclic (2-5) disulfide, which contains solely L-Cys (LCLCE), there is no single structure compatible with the NMR data.
authors.affiliation: Institute of Organic Chemistry, Karl Franzens University, Graz, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Kolp
authors.forename: F
authors.initials: F
authors.lastname: Andreae
authors.forename: W M
authors.initials: WM
authors.lastname: Fabian
authors.forename: H
authors.initials: H
authors.lastname: Sterk
mesh_terms: D003198:Computer Simulation; D004745:Enkephalins / Q000737:chemistry*; D006860:Hydrogen Bonding; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: D004745:Enkephalins; D010456:Peptides, Cyclic; C031935:enkephalin, Cys(2)-CysNH2(5)-