DNA Complexed with Oppositely Charged Amphiphile in Low-Polar Organic Solvents

Abstract

The stoichiometric complexes of the DNA samples of rather different molecular masses: 300−500 b.p. (DNA1) and 5000−10000 b.p. (DNA2) with dodecyldimethylammonium (DODA) chloride as a cationic amphiphile were prepared. DNA1−DODA and DNA2−DODA complexes are soluble in low polar organic solvents, in particular, in chloroform, as well as the complexes of ordinary linear polyelectrolytes with micelle-forming ionic surfactants. The solution behavior of the DNA−DODA complexes was studied by ultracentrifugation, viscometry, isothermal diffusion, and electrical birefringence techniques. It has been found that the DNA−DODA complex species in their dilute solutions in chloroform and a chloroform−acetone mixture (2:1) are represented by individual complex macromolecules retaining a double spirality, but strongly compacted. The latter is contrasting with other polyelectrolyte−surfactant complexes, which behave in chloroform as in a good solvent, taking expanded random coil conformations. The possible reason of such a...