Synthetic ion transporters in bilayer membranes

Abstract

A variety of synthetic compounds mediate ion transport across bilayer membranes. The majority of reported cases involve transport across vesicle membranes, with mechanism inferred by comparison with known transporters. Single channel conductance techniques provide more direct mechanistic information. Two examples are discussed. In the first, an active unimolecular transporter (G8TrgP)₄Tet is shown to induce erratic formation of transient high conductivity pores. In the second, a linear pore-former A8TrgPA8TrgA is shown produce regular multi-level channels in diphytanoylPC membranes. The pore formed shows ion selectivity in the sequence Cs⁺ > K⁺ > Na⁺. A model consisting of an aggregate of a few A8TrgPA8TrgA molecules in the bilayer would be qualitatively consistent with the data.