δ-Toxin and analogues as peptide models for protein ion channels

Abstract

δ-Toxin, six analogues and their acetylated derivatives, have been synthesised. The model peptides, based on the parent compound δ-toxin, incorporate components of the proposed pore-forming segments of the protein ion channels. The backbone conformations of the peptides have been elucidated by a combination of two-dimensional NMR experiments and distance geometry and molecular mechanics calculations. In several of the compounds a relatively stable helix is formed but in peptides incorporating a proline in the centre of the molecule a bend-helix motif is present.