Surfactant structure around DNA in aqueous solution

Abstract

Two different possible structures for decanetrimethylammonium surfactants around a DNA strand in aqueous solution were investigated using molecular dynamics. The first structure had surfactant going out radially from the DNA in a ‘hairy ’ structure and in the other the surfactants were in a micelle structure. Both systems were simulated for 1 ns. Results for the radius of gyration, the density and various radial distribution functions are given. By comparison with these results neutron diffraction experiments could definitively distinguish between these structures. The ‘hairy ’ structure showed some evidence of clumping. Although this can be interpreted as incipient micelle formation, it was also found that head groups did move into the groove, a change which is not consistent with micelle formation. In comparison the micelle structure remained stable, although the shape elongated.