CONFORMATIONAL STUDIES OF TACHYKININ PEPTIDES USING NMR SPECTROSCOPY

Abstract

Conformational analysis of two tachykinin family peptides: Scyliorhinin I (Seyl) and Scyliorhinin II (Scyll) was carried out by 1D- and 2D NMR (DQF-COSY, TOCSY, HMQC, HMBC, NOESY and ROESY) and molecular dynamics calculation methods in water and DMSO. Scyliorhinin I is a equipment agonist ofNK-1 and NK-2 taehykinin receptors and Scyliorhinin II is a selective agonist of NK-3 tachykinin receptor. In DMSO, two groups of conformations (major and minor) were obtained for both peptides based on the experimental data. The conformations proposed for Scyl represent a folded structure, which show certain similarities to the structures reported for other NK.-1 and NK-2 taehykinin agonists. In water Scyl I displays a flexible, extended structure, whereas in DMSO the structure is more compact and in the fragment from centre to the C-terminus several [3-tums may be present.