title: Conformational analysis of two cyclic disulfide peptides.
abstract: Complete nmr and CD studies of two cyclic tetrapeptides with disulfide bonds, Ac-L-Pen-L-Pro-D-Val-L-Cys-NH2 (1) and Ac-L-Cys-L-Pro-D-Val-L-Cys-NH2 (2) bonds have been carried out in different solvents to investigate the formation and stabilization of beta-turn structures and to determine the stereochemistry of the disulfide linkage. Both peptides have three-dimensional structures with a type II beta-turn, as derived from quantitative nuclear Overhauser effect data. The combined use of CD and nmr indicates that the dihedral angle of the disulfide bridge is different in the two peptides, although the chirality is maintained.
authors.affiliation: Department of Organic Chemistry, University of Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: García-Echeverría
authors.forename: G
authors.initials: G
authors.lastname: Siligardi
authors.forename: P
authors.initials: P
authors.lastname: Mascagni
authors.forename: W
authors.initials: W
authors.lastname: Gibbons
authors.forename: E
authors.initials: E
authors.lastname: Giralt
authors.forename: M
authors.initials: M
authors.lastname: Pons
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D004220:Disulfides; D010456:Peptides, Cyclic