title: First observation of a beta-turn conformation fused with the oxy-analogue of an alpha-turn: the molecular structure of a model peptide of the C-terminal part of gramicidin A.
abstract: The molecular structure of N-tert-butyloxycarbonyl-D-leucyl-L-phenylalanyl ethanolamide (t-Boc-D-Leu-L-Phe-EA), a protected analogue of the C-terminal dipeptide of the membrane-active linear antibiotic gramicidin A, has been determined by X-ray diffraction. One of the two independent molecules in the asymmetric unit is characterized by a chain reversal stabilized by an intramolecular, three-centre, double hydrogen bonding. It represents the first experimental evidence for a beta-turn conformation fused with the oxy-analogue of an alpha-turn.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D004151:Dipeptides; D006096:Gramicidin; D008958:Models, Molecular; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D004151:Dipeptides; D006096:Gramicidin; C037792:N-tertiary-butyloxycarbonyl-leucyl-phenylalanine-ethanolamide