The synthesis and biological activity of a novel cyclic beta-sheet-type antimicrobial dehydropeptide based on gramicidinS (GS) is described. The GS analogue, containing two (Z)-(beta-3-pyridyl)-alpha,beta-dehydroalanine (DeltaZ3Pal) residues at the 4 and 4' positions (2), was synthesized by solution-phase methodologies using Boc-Leu-DeltaZ3Pal azlactone. Analogue 2 exhibited high antimicrobial activity
of α, β -dehydrophenylalanine on activity and conformation. The analog peptide shows high biological activity in stimulating superoxide production by rabbit neutrophils. An NMR analysis of the solution conformation of the ΔZ-Phe analog, using nuclear Overhauser effects and comparisons with the corresponding saturated peptides, favours a significant population of extended backbone conformations.
New synthesis of the cyclic tetrapeptide tentoxin employing an azlactone as key intermediate
作者:Florine Cavelier、Jean Verducci
DOI:10.1016/0040-4039(95)00762-2
日期:1995.6
An improved preparation of the cyclictetrapeptideTentoxin is reported employing an azlactone as key intermediate. This new synthetic route offers the advantage over existing methodologies that the dehydro amino acid would easily be varied, thus allowing the simple preparation of analogues.
Here we report the synthesis and biological properties of peptide-based molecules bearing constrained analogues of phenylalanine at the C-terminal. Compounds were tested as proteasome subunits' inhibitors. Dehydro-peptides showed good inhibition, in particular against trypsin-like (T-L) proteasome activity while some C-terminal Tic-derivatives inhibit only caspase-like activity in enzymatic beta 1 subunits with a certain degree of efficacy. The best analogues of the series demonstrated good resistance to proteolysis and a capacity to permeate the cell membrane. (c) 2007 Elsevier Masson SAS. All rights reserved.