Replacing proline at the apex of heptapeptide-based chloride ion transporters alters their properties and their ionophoretic efficacy

Abstract

A membrane anchored heptapeptide, (C₁₈H₃₇)₂NHCOCH₂OCH₂CO–NH–Gly–Gly–Gly–Pro–Gly–Gly–Gly–OCH₂Ph, has proved to be a selective chloride anion transporter that functions in phospholipid bilayer membranes. When Pro was replaced by the natural amino acid Leu, the activity decreased dramatically. In the present study, Pro is replaced by pipecolic acid (homoproline, Pip); the resulting anchored heptapeptide is a membrane active, chloride selective transporter.