Quest for Mode of Binding of 2-(4-(Dimethylamino)styryl)-1-methylpyridinium Iodide with Calf Thymus DNA

Abstract

The mode of binding of 2-(4-(dimethylamino)styryl)-1-methylpyridinium iodide (DASPMI) with calf thymus DNA as revealed from different steady state and time-resolved emission spectroscopic measurements has been reported in this paper. Fluorescence enhancement of DASPMI and its quenching by potassium iodide (KI) points to groove binding of dye with ct-DNA, rather than intercalation in the ct-DNA helix. An increase in steady state anisotropy and fluorescence lifetime hints at binding with ct-DNA. The value of binding constant from emission and association constant from circular dichroic spectrum also indicates weak binding. The strong dependence on ionic strength or salt in controlling the binding of DASPMI with ct-DNA by electrostatic interaction confirms groove binding. The high semicone angle of DASPMI in ct-DNA certainly rules out the possibility of intercalated bonding. A theoretical modeling shows that the probe is bound to ct-DNA as a crescent with a curvature of 11.35 A, which is the previously known curvature of probe in the minor groove.

Report of Interaction Between Calf Thymus DNA and Pyrimidine-Annulated Spiro-Dihydrofuran

“…It is reported that, in case of minor groove binding and electrostatic binding, the CD spectra show insignificant change whereas, intercalating binding causes a remarkable change in the positive and negative bands [37]. As illustrated in Figure 5, after addition of PSDF to the DNA solution does not produced any significant change in the intrinsic CD spectrum of the DNA indicating that binding of PSDF with CTDNA does not disturb the stacking of bases.…”

Exploration of binding of bisphenol A and its analogues with calf thymus DNA by optical spectroscopic and molecular docking methods

“…Molecular modeling studies can gain some important insight into the binding interactions between ligands and DNA [50].…”

Synthesis and multi-spectroscopic DNA binding study of 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives of fatty acid

“…The interaction of small molecules with DNA is gaining interest in the area of medicinal chemistry for exploring the structural and functional features of macromolecules to design new and effective drugs against various diseases [1]. Synthetic indol alkaloids such as β-carboline alkaloid possessing large pharmaceutical activities, particularly as a potential antitumoral agent by way of intercalation into DNA and inhibition of topoisomerase I and II [2].…”