[Effect of water on DNA structure in a model microemulsion system].

The physical state of water in a system of reversed micelles at different molar rations of H2O and a nonionic surfactant (tetraethylene glycol monododecyl ether, Brij 30) was studied by NMR spectroscopy. In addition, the effect of water on the structure of the intramicellar DNA was investigated using the intercalator ethidium bromide. It was shown by NMR diffusometry that the state of water inside micelles can be considered as supercooled. It was found that the condensation of DNA inside micelles takes place only at definite ratios of water and Brij 30 (from 1.26 to 5). If free water is absent and if the percentage of free water inside in reversed micelles is more than 50%, the process of DNA condensation is disturbed. It is assumed that the molecular memory inherent in the supercooled state of water affects the formation and stabilization of the condensed state of DNA.