Arginine-rich peptides use anions to cross membranes in biological systems, say Swiss researchers.

Arginine-rich peptides use anions to cross membranes in biological systems, say Swiss researchers.

Bilayer membranes, which separate aqueous compartments in living organisms, are generally seen as impermeable barriers. But peptides rich in the amino acid arginine can cross these membranes easily. This is one of several phenomena known collectively as ’arginine magic’.

Stefan Matile and co-workers at the University of Geneva have shown that these peptides form complexes with anions to help them cross the membranes. Changing the anions’ structure then allowed Matile’s group to shed light on the mechanism of arginine’s ’magic trick’.

They found the movement of such peptides across bilayer membranes is possible because of repeated complexation/decomplexation of the anions. The resulting changes in solubility of the complexes allow them to adapt to different environments within the membranes.

Membrane-penetrating peptides could be used as cellular targets, and some anions could be potential biochemical probes, says Matile.

David Barden