title: Conformation of diastereomeric peptide sequences: structural analysis of Z-D-Val-Ac6c-Gly-L-Phe-OMe.
abstract: We have recently undertaken a systematic structural analysis of fully protected tetrapeptides containing at the N- and C-terminus either homo- or heterochiral amino acids, spaced by an achiral dipeptide segment. The interest for this class of peptides derives from the observation that, on reverse-phase (HPLC), the homo- and heterochiral sequences have a markedly different retention times. The diastereomeric sequences, namely Z-(L/D)-Val-X-Y-L-Phe-OMe (X = Sar, Gly, Ac3c, Aib, Ac5c, Ac6c, Deg, Dpg, Dbu, Dip, Dph; Y = Sar, Gly, Ac3c, Aib, Ac5c, Ac6c) show different overall hydrophobicity attributed to a different three-dimensional structure that also depends on the X-Y segment. Therefore, following preliminary studies in solution, we report here the detailed x-ray analysis of the tetrapeptide Z-D-Val-Ac6c-Gly-L-Phe-OMe in order to understand the structural features governing the overall hydrophobicity of linear fully protected tetrapeptides.
authors.affiliation: Department of Chemistry, University Federico II, Napoli, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Di Blasio
authors.forename: A
authors.initials: A
authors.lastname: Lombardi
authors.forename: F
authors.initials: F
authors.lastname: Nastri
authors.forename: M
authors.initials: M
authors.lastname: Saviano
authors.forename: C
authors.initials: C
authors.lastname: Pedone
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Nakao
authors.forename: S
authors.initials: S
authors.lastname: Kuwata
authors.forename: V
authors.initials: V
authors.lastname: Pavone
mesh_terms: D000595:Amino Acid Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D009842:Oligopeptides