title: Conformational perturbations in retro-analogs of the tBuCO-Ala-Gly-NHiPr dipeptide. Crystal structure of the retro-dipeptide with a reversed Ala-Gly amide bond.
abstract: The three retro-analogs of the tBuCO-Ala-Gly-NHiPr dipeptide, in which each amide bond had been successively reversed, were studied in solution by 1H-n.m.r. and i.r. spectroscopy with reference to the conformational properties of their parent dipeptide. Reversal of the Ala-Gly amide bond proved to perturb the folding tendency of the backbone less than the inversion of either of the terminal amide bonds. The crystal structure of the retro-peptide containing a reversed Ala-Gly amide bond was also solved by X-ray diffraction and constitutes the first available data for this retro-peptide series. In contrast to the beta II-folded structure of the parent dipeptide, the retro-peptide molecule adopts an open conformation in the crystal.
authors.affiliation: UA-CNRS-494, ENSIC-INPL, Nancy, France.
authors.forename: E J
authors.initials: EJ
authors.lastname: Gomez
authors.forename: B
authors.initials: B
authors.lastname: Vitoux
authors.forename: M
authors.initials: M
authors.lastname: Marraud
authors.forename: C
authors.initials: C
authors.lastname: Sakarellos
authors.forename: L
authors.initials: L
authors.lastname: el Masdouri
authors.forename: A
authors.initials: A
authors.lastname: Aubry
mesh_terms: D004151:Dipeptides; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010456:Peptides, Cyclic; D011487:Protein Conformation; D012996:Solutions; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D004151:Dipeptides; D010456:Peptides, Cyclic; D012996:Solutions; C063947:tert-butoxycarbonyl-alanyl-glycyl-isopropylamide