Binding Interaction of Cationic Phenazinium Dyes with Calf Thymus DNA: A Comparative Study

Abstract

Absorption, steady-state fluorescence, steady-state fluorescence anisotropy, and intrinsic and induced circular dichroism (CD) have been exploited to explore the binding of calf thymus DNA (ctDNA) with three cationic phenazinium dyes, viz., phenosafranin (PSF), safranin-T (ST), and safranin-O (SO). The absorption and fluorescence spectra of all the three dyes reflect significant modifications upon interaction with the DNA. A comparative study of the dyes with respect to modification of fluorescence and fluorescence anisotropy upon binding, effect of urea, iodide-induced fluorescence quenching, and CD measurements reveal that the dyes bind to the ctDNA principally in an intercalative fashion. The effect of ionic strength indicates that electrostatic attraction between the cationic dyes and ctDNA is also an important component of the dye-DNA interaction. Intrinsic and induced CD studies help to assess the structural effects of dyes binding to DNA and confirm the intercalative mode of binding as suggested by fluorescence and other studies. Finally it is proposed that dyes with bulkier substitutions are intercalated into the DNA to a lesser extent.

Enhancement in fluorescence response by a quencher for amiloride upon binding to thymine opposite an abasic site in a DNA duplex

“…S2), giving the K SV values for amiloride in the presence and absence of a DNA duplex are 8.8 ± 0.1 M −1 and 0.76 ± 0.04 M −1 , respectively (n = 3). The large difference in the K SV values confirms the intercalative binding of amiloride within an AP site-containing DNA duplex, since K SV is indicative of the accessibility of the quencher, I − , to the fluorophore, amiloride [18,19]. The binding affinity of amiloride to thymine was then examined quantitatively by fluorescence titration experiments in a 500 mM NaI or NaCl solution, and the results are shown in Fig.…”

Interaction of Two Flavonoids With Calf Thymus Dna: A Multi - Spectroscopic, Electrochemical and Molecular Modelling Approach

“…The phenomenon indicated an interaction between DNA and the flavonoid and it is typical of intercalate mode. 30 The hypochromic shift observed in the spectra of flavonoids indicates helical ordering of flavonoids in the DNA helix. Flavonoids binding to DNA through intercalation is characterized by change in the absorbance hypochromic and a red shift in wavelength, due to the intercalative binding mode involving a stacking interaction between the DNA base pairs.…”

“…In this paper DNA interaction of two compounds with DNA is reported. [24][25] The interaction is carried out with Calf Thymus DNA and studied via spectroscopic and cyclic voltammetric analysis. 26 Furthermore, molecular modeling methods can be applied to study of interaction drugs and biomacromolecules for saving time and money, especially since the reactivity of newly designed drugs with their targeted biomolecules can be predicted prior to chemical synthesis.…”

Perimidine based selective colorimetric and fluorescent turn-off chemosensor of aqueous Cu2+: studies on its antioxidant property along with its interaction with calf thymus-DNA

“…Fluorescence spectroscopic titration of 1 with CT-DNA 29 2 mL of the 1 (5 mM) was diluted to 2 mL citrate-phosphate buffer of pH 7, and 2 mL of the CT-DNA (1 mM) solution was added each time to the diluted solution of 1. Aer mixing homogeneously, uorescence spectra were recorded at room temperature by exciting 1 at 346 nm.…”

“…3.11. Interaction of 1 with CT-DNA 28,29 Upon the addition of aqueous CT-DNA to the solution of 1 in citrate-phosphate buffer medium of pH 7, there occurs a slight absorption changes with an isosbestic point at 292 nm (Fig. 9a).…”