title: Three protected tetrapeptides.
abstract: The structures of three protected tetrapeptides, containing the Boc-Gly-Gly-Phe-X-OMe chain, tert-butoxycarbonyl-glycy-glycl-phenylalanine-leucine methyl ester dihydrate, Boc-Gly-Gly-L-Phe-D-Leu-OMe, C25H38N4O7.2H2O, tert-butoxycarbonyl-glycy-glycl-phenylalanine-methionine methyl ester dihydrate, Boc-Gly-Gly-L-Phe-D-Met-OMe, C24H36N4O7S.2H2O and tert-butoxycarbonyl-glycy-glycl-phenylalanine-norleucine methyl ester dihydrate, Boc-Gly-Gly-D-Phe-L-Nle-OMe, C25H38N4O7.2H2O, are described. The three molecules have the same conformation on the tetrapeptide chain and display the same packing, consisting of couples of molecules linked head-to-tail by two hydrogen (N--H...O) bonds; other hydrogen bonds, also involving two water molecules of crystallization, link these couples together and give rise to a planar structure.
authors.affiliation: Istituto per l'Applicazione delle Tecniche Chimiche Avanzate ai Problemi Agrobiologici, CNR, Sassari, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Fenude
authors.forename: G
authors.initials: G
authors.lastname: Casalone
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D009842:Oligopeptides