Molecular dynamics study of perturbation on protocell membrane induced by magnesium ion

Abstract

Among research of origin of life, vesicles are often studied as protocells. Fatty acids are synthesized abiotically, and their properties have been investigated as one of the most promising candidates for protocell membranes. Magnesium ions Mg²⁺ in particular are thought to have played an important role for ribozymes. However, it has been found that in the presence of magnesium ions, protocells of pure fatty acids cannot exist or retain its contents. In this study, we analyzed the response of fatty acid bilayers to Mg²⁺ using molecular dynamics simulations to elucidate the mechanism of vesicle destabilization. In the results, tighter packing of fatty acid molecules was shown. It was also found that adding Mg²⁺ causes attraction between ionized fatty acid molecules. These results suggest that the destabilization of fatty acid vesicles by Mg²⁺ may be due to pore formation by shrinkage of the outer leaflet of the vesicles.