Effect of organic solvents on the properties of the complexes of DNA with proflavine and similar compounds

Abstract

SynopsisIn order to obtain information on the binding forces involved in the formation of the complex proflavine-DNA by the stronger process I, the stability of the complexes was investigated in the presence of various organic solvents, methanol, ethanol, n-propanol, isopropanol, formamide, dimethyl sulfoxide, p-dioxane, glycerol, and ethylene glycol. Quantitative data on binding in terms of K l n and r were obtained by means of absorption and fluorescence spectra, as well as by a thermal denaturation technique.The effectiveness of the solvents increases with their hydrocarbon content, but can hardly be related to their dielectric constant. The complex formation is effectively suppressed by organic solvent concentrations, in which DNA still preserves its double-helical conformation. These results demonstrate the importance of hydrophobic forces in the formation of the complex proflavine-DNA in aqueous solution.The similarity in spectroscopic properties of proflavine bound to DNA by process I and the same dye dissolved in an organic solvent make it possible to interpret the observed red shift of the long-wavelength absorption peak as being due to the interaction of the dye molecules with the less polar environment.The same behavior was found for other dyes capable of intercalation like purified trypaflavine, phenosafranine and ethidium bromide. However, intercalation is not a necessary condition, as it was shown in the case of pinacyanol, which binds only a t the surface of DNA.All organic solvents used decrease the binding ability of the dye.

Interaction of BSA with proflavin: A spectroscopic approach

“…The roles of proflavin as a mutagen and as an enzyme inhibitor have been extensively studied [1,2]. Although the interaction of proflavin with DNA [3,4] has been widely studied but its interaction with protein has not yet been explored.…”

Label‐Free Detection of DNA Hybridization in Presence of Intercalators Using Electrochemical Impedance Spectroscopy

“…They bind to dsDNA, preferably at a GC basepair, via intercalation of their planar chromophore [20,21]. The structures of ActD/DNA and proflavine/DNA complexes have been elucidated using NMR spectroscopy [22], structural modeling [23,24], fluorescence spectroscopy [25,26], and circular dichroism [27]. Additionally, electrochemical methods such as cyclic voltammetry were applied to characterize the interactions of intercalators with DNA [28 -31].…”

Selected Topics in Photochemistry of Nucleic Acids, Recent Results and Perspectives

“…A promising approach to explain this fact comes from solvent dependent measurements of absorption and fluorescence spectra of dyes. Spectral changes, when dye molecules pass from their free hydrated state to the nucleic acid bound state where dye molecules become surrounded by purine, pyrimidine and sugar moieties, are often similar to those accompanying the change from water to organic solvents (Lober et al, 1972;. Fluorescence intensity of dissolved dyes as a rule is enhanced with the amount of organic solvent in an organic solvent-water mixture.…”