DNA conformational dynamics in the presence of catanionic mixtures

• Published in: FEBS letters 1999-06, Vol.453 (1), p.113-118
• Main Authors: Mel’nikov, Sergey M., Dias, Rita, Mel’nikova, Yuliya S., Marques, Eduardo F., Miguel, Maria G., Lindman, Björn
• Format: Article
• Language: English
• Subjects: Anions - pharmacology; Catanionic mixture; Cations - pharmacology; Cetrimonium; Cetrimonium Compounds - pharmacology; Coil-globule transition; Cryogenic transmission electron microscopy; DNA; DNA, Viral - chemistry; DNA, Viral - drug effects; DNA, Viral - ultrastructure; Fluorescence microscopy; Microscopy, Electron; Microscopy, Fluorescence; Nucleic Acid Conformation - drug effects; Octanes - pharmacology; Surface-Active Agents - pharmacology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(99)00699-7

DNA conformational behavior in the presence of non-stoichiometric mixtures of two oppositely charged surfactants, cetyltrimethylammonium bromide and sodium octyl sulfate, was directly visualized in an aqueous solution with the use of a fluorescence microscopy technique. It was found that in the presence of cationic-rich catanionic mixtures, DNA molecules exhibit a conformational transition from elongated coil to compact globule states. Moreover, if the catanionic mixtures form positively charged vesicles, DNA is adsorbed onto the surface of the vesicles in a collapsed globular form. When anionic-rich catanionic mixtures are present in the solution, no change in the DNA conformational behavior was detected. Cryogenic transmission electron microscopy, as well as measurements of translational diffusion coefficients of individual DNA chains, supported our optical microscopy observations.