Anion-selective transport activities of tetrameric sterol-spermine conjugates.

Three tetrameric sterol-spermine conjugates were shown to be capable of mediating chloride transport across 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC)-based liposomal membranes via an anion-exchange mechanism. Of the three conjugates, the one that was derived from deoxycholic acid showed the highest activity. Such anion transporting properties may provide molecular basis for the antibacterial activities of these sterol-spermine tetramers. In other words, they function as antibiotics, most probably via the formation of anion-selective pores or channels.