A Bilious Ionophore

See allHide authors and affiliations

Science  22 Dec 2000:
Vol. 290, Issue 5500, pp. 2213
DOI: 10.1126/science.290.5500.2213c

One of the fundamental characteristics of cells is the control of the permeability barrier between them and the outside world. Constituents that are meant to stay inside, such as macromolecules and phosphorylated metabolites, are insoluble in and retained by the membrane bilayer of hydrophobic lipids, whilst nutrient and waste products are transported by carriers or channels inserted into the membrane. The process of transport remains an outstanding problem, and simpler systems may be a productive route of study.

Bandyopadhyay et al. describe the one-step synthesis, from spermine and cholic acid, of a sodium ionophore. The activity of this adduct is highly sensitive to the length of the lipid acyl chains, and they interpret its sodium-carrying capacity as due to a dimeric structure in which the amphiphilic sterol moieties align perpendicularly to the plane of the membrane with their hydroxyl groups offering a hydrophilic interior channel for the passage of sodium ions. — GJC

J. Am. Chem. Soc., in press.

Navigate This Article