How Does Alcohol Dissolve the Complex of DNA with a Cationic Surfactant?

Abstract

The single-chain observation of isolated giant DNAs complexed with a cationic surfactant, CTAB, was performed using fluorescence microscopy. The DNA−CTAB complex exhibits a re-entrant transition, collapsed globule → elongated coil → collapsed globule, with an increase in the alcohol concentration. The existence of DNA in its coil state at an intermediate concentration of alcohol implies that this environment is a good solvent for the DNA chains. On the other hand, the presence of the globule state at both low and high alcohol concentrations indicates that this is a poor solvent for the complex. Regardless of this fact, the globule generated at a high alcohol concentration is unexpectedly soluble; i.e., this is a good solvent for the complex with respect to the solvability, but it is a bad solvent with respect to the polymer conformation. This unique property of the complex is attributable to the effect of micelle formation, where surfactant molecules cover the entire globule and lower the surface energy of the collapsed state. This conclusion is supported by additional experiments on the conformational change in DNA with alcohol in the absence of CTAB and on observations with CD and UV spectroscopy for the complex with different alcohol concentrations.

Morphology and properties of globular polymeric materials in the solid state: A composite material of DNA with a cationic surfactant

“…21,22 Sergeyev et al have found that double stranded DNA molecules, when combined with the cationic surfactant molecule, cetyltrimethylammonium bromide (CTAB), displayed entrant and reentrant coil-globule transitions in aqueous ethanol solution as a function of the concentration of ethanol. 20 This finding confirmed that the DNA-surfactant complex, DNA-CTA, in pure ethanol was in the globular state even in a condensed solution. DNA-CTA globules are considered stable in ethanol solution because of the encapsulated structure of DNA by surfactant CTA 1 molecules.…”

“…DNA-CTA globules are considered stable in ethanol solution because of the encapsulated structure of DNA by surfactant CTA 1 molecules. 20,23 This stable globular complex suggests the possibility of making a globular solid without constructing chain entanglements among molecules.…”

“…[13][14][15][16][17] Yoshikawa and his collaborators, as well as other groups, examined coil-globule transition using this method. [18][19][20] In conjunction with the optical tweezers technique, Perkins et al, observed a reptation-like motion of DNA molecules. 21,22 Sergeyev et al have found that double stranded DNA molecules, when combined with the cationic surfactant molecule, cetyltrimethylammonium bromide (CTAB), displayed entrant and reentrant coil-globule transitions in aqueous ethanol solution as a function of the concentration of ethanol.…”

Effects of Acid and Base on the Inductive Efficiency of Oligonucleotide on the Vesicle Formation from Single‐Chained Cationic Surfactant

“…[24][25][26][27] Therefore, the vesicles in Figures 4D and 4G are much bigger than those in Figures 2C and 2D.…”

Fractionation of protein, RNA, and plasmid DNA in centrifugal precipitation chromatography using cationic surfactant CTAB containing inorganic salts NaCl and NH4Cl

“…This interaction leads to the neutralization of charge on the phosphate group and induces a high degree of hydrophobicity that in turn brings down the solubility of the DNA -CTAB complex (Kunjappu and Nair, 1992). Since DNA-surfactant complexes are generally insoluble in water (Sergeyev et al, 1999), the difficulty in solubilizing the DNA pellets after CTAB precipitation is one of the drawbacks observed in the process exploiting DNA-CTAB complex formation for isolation of plasmid DNA from lysate of bacterial culture (Ishaqu et al, 1990;Lander et al, 2002).…”