Water induced β-turn modification in a chemotactic tetrapeptide. Synthesis, crystal conformation, and activity of HCO-Met-Leu-ΔZPhe-Phe-OMe
摘要:
In order to study the influence of the conformation on the activity and bioselectivity, the new tetrapeptide ligand of the chemotactic formylpeptide receptors HCO-Met-Leu-DELTA(z)Phe-Phe-OMe (2) has been studied. Compound 2 has been designed so as to induce a preferential beta-turn conformation with the N-formyl group located outside the backbone loop, The crystallographic analysis reveals that 2 adopts only in part the expected conformation due to the presence of a water molecule inside the turn. Details on the H-bonding network stabilizing the ''open-turn'' are given. The tetrapeptide 2 is active towards human neutrophils, stimulating directed migration, superoxide anion generation and lysozyme release. The influence of the backbone conformation on the bioselectivity is discussed.