Preliminary morphological and X-ray diffraction studies of the crystals of the DNA cetyltrimethylammonium salt

Abstract

Double-stranded DNA molecules (molecular weight 2.5 X 10(5) - 5 X 10(5) daltons) have been crystallized from water-salt solutions as cetyltrimethylammonium salts (CTA-DNA). Variation of crystallization conditions results in a production of different types of CTA-DNA crystals: spherulits, dendrites, needle-shaped and faceted rhombic crystals, the latter beeing up to 0.3 mm on a side. X-ray diffraction data indicate that DNA molecules in the crystals form a hexagonal lattice which parameters vary slightly with the morphological type of the crystal. Comparison of the melting curves of the DNA preparation before and after crystallization suggests that DNA molecules are partially fractionated in the course of crystallization. Crystals of the CTA-DNA-proflavine complex have also been obtained.

An Investigation on Interaction between 14mer DNA Oligonucleotide and CTAB by Fluorescence and Fluorescence Resonance Energy Transfer Studies

“…In addition to this the hydrophobic moieties of the surfactant molecules stabilize the complex through the hydrophobic interactions with the DNA. [15][16][17] Based on the studies carried out on the compaction of doublestranded DNA (ds-DNA) by cationic surfactants, using fluorescence microscopy, three distinguishable regimes of the DNA compaction process are highlighted, depending on the concentration of the cationic surfactant. 1,[18][19][20][21][22][23][24] In the absence of surfactant, DNA molecules in solution exist in extended (coil) conformation with relatively slow wormlike motion.…”

“…A number of researchers have shown that in the DNA−surfactant complexes the cationic surfactant molecules bind to the DNA chains through electrostatic interactions. In addition to this the hydrophobic moieties of the surfactant molecules stabilize the complex through the hydrophobic interactions with the DNA. − …”

Self-Assembled Supramolecular Films Derived from Marine Deoxyribonucleic Acid (DNA)−Cationic Surfactant Complexes: Large-Scale Preparation and Optical and Thermal Properties

“…It has been shown that the 1:1 stoichiometric combination of an anionic polyelectrolyte with a cationic surfactant leads to spontaneous formation of highly organized assemblies. − The self-assembled bulk materials exhibit interesting properties such as thermotropic liquid-crystalline behavior, which results from long-range organization on a mesoscopic length scale. Also, DNA, which is an anionic polyelectrolyte, could be quantitatively precipitated with cationic surfactants in water. − The method of precipitating various types of DNA by cationic surfactants has been applied to DNA extraction, concentration, and counting. − It was suggested that DNA could be recovered in a native state to form DNA−cationic surfactant complexes with 12-, 14-, and 16-carbon alkyltrimethylammonium bromides − No doubt, these studies are very important for understanding the mechanisms of cell transfection and gene therapy.…”

A New Cubic Phase Containing DNA and a Surfactant

“…So far, the only resulting complex structures that have been characterised are a hexagonal structure (which consists of a network of cylindrical surfactant micelles with the DNA rods intercalated in between) and a lamellar structure (when the surfactant has special hydrotope counterions). [7,8] In this Communication, we describe the formation and characterisation of a new cubic phase that contains short DNA chains (i.e., 150 base pairs and a length that is at least equal to the persistence length); this phase is formed using a short-tailed surfactant: decyltrimethylammonium (C 10 TAB).…”