Conformation of diastereomeric peptide sequences: structural analysis of Z-D-Val-Ac6c-Gly-L-Phe-OMe.
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.
Di Blasio
B
B
Department of Chemistry, University Federico II, Napoli, Italy.
Lombardi
A
A
Nastri
F
F
Saviano
M
M
Pedone
C
C
Yamada
T
T
Nakao
M
M
Kuwata
S
S
Pavone
V
V
D000595:Amino Acid Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D014961:X-Ray Diffraction
D009842:Oligopeptides