Using small molecules to facilitate exchange of bicarbonate and chloride anions across liposomal membranes.

Bicarbonate is involved in a wide range of biological processes, which include respiration, regulation of intracellular pH and fertilization. In this study we use a combination of NMR spectroscopy and ion-selective electrode techniques to show that the natural product prodigiosin, a tripyrrolic molecule produced by microorganisms such as Streptomyces and Serratia, facilitates chloride/bicarbonate exchange (antiport) across liposomal membranes. Higher concentrations of simple synthetic molecules based on a 4,6-dihydroxyisophthalamide core are also shown to facilitate this antiport process.

A transmembrane anion transporter selective for nitrate over chloride.

The C3-symmetric triamide selectively transports NO3- anions across lipid vesicles: this H+-NO3- co-transporter alters the pH inside of liposomes experiencing a NO3-/Cl- gradient.