Manna A, Chakravorti S. Supramolecular effect of curcurbit[7]uril on the binding mode of 2-(4-(dimethylamino) styryl)-1-methylpyridinium iodide with Calf Thymus DNA: From minor groove to intercalative.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015;
150:120-126. [PMID:
26037496 DOI:
10.1016/j.saa.2015.05.035]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/08/2015] [Accepted: 05/12/2015] [Indexed: 06/04/2023]
Abstract
The effect of curcurbit[7]uril (CB[7]) in the binding mode of 2-(4-(dimethylamino) styryl)-1-methylpyridinium (DASPMI) with Calf Thymus DNA has been discussed in this paper. Red shift, intensity change in absorption and emission spectra and presence of isosbestic point with increasing concentration of CB[7] in groove bound DASPMI-DNA complex indicates a change in binding pattern. Appearance of a third slower component in lifetime decay in presence of CB[7] which gets more slow in high CB[7] concentration is indicative of a new type of binding. Major changes in ct-DNA bands in circular dichroism spectra with addition of CB[7] make a strong case for intercalative binding. Increased computed values of binding constant associated with diminishing quenching constant in presence of potassium iodide make a positive candidate for intercalative binding. Formation of big spherical condensate in DASPMI-DNA complex in presence of CB[7] which grows bigger in higher CB[7] concentration shows a morphological change. Molecular docking nicely portrays the intercalative nature of binding corroborating the experimental evidences.
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