Spectrophotometric Study on the Binding of Two Water Soluble Schiff Base Complexes of Mn (III) with ct-DNA

Abstract

In this work, binding of two water soluble Schiff base complexes: Bis sodium (5-sulfosalicylaldehyde) o-phenylendiiminato) Manganese (III) acetate (Salophen complex) and Bis sodium (5-sulfosalicylaldehyde) 1, 2 ethylendiiminato) Manganese (III) acetate (Salen complex) with calf thymus (ct) DNA were investigated by using different spectroscopic and electrometric techniques including UV-vis, Circular dichroism (CD) and fluorescence spectroscopy, viscommetry and cyclic voltammetry (CV). Both complexes have shown a hyperchromic and a small bathochromic shift in the visible region spectra. A competitive binding study showed that the enhanced emission intensity of ethidium bromide (EB) in the presence of DNA was quenched by the addition of the two Schiff base complexes indicating that they displace EB from its binding site in DNA. Moreover structural changes in the CD spectra and an increase in the CV spectra with addition of DNA were observed. The results show that both complexes bind to DNA. The binding constants have been calculated using fluorescence data for two complexes also K(b) was calculated with fluorescence Scatchard plot for Salophen. Ultimately, the experimental results show that the dominant interactions are electrostatic while binding mode is surface binding then followed by hydrophobic interactions in grooves in high concentration of complexes.

Some new Ag(I), VO(II) and Pd(II) chelates incorporating tridentate imine ligand: Design, synthesis, structure elucidation, density functional theory calculations for DNA interaction, antimicrobial and anticancer activities and molecular docking studies

“…Metal chelates interact with DNA probably through a mode that includes hydrophobic or electrostatic interaction. As expressed previously, the HNAPd metal chelate has a replaceable water ligand in solution, which might be substituted with DNA molecules in solution . Likewise because of the expulsion of water ligand from the metal chelate in solution, the explored metal chelates would have a flat part in the middle.…”

Combined Systems Approaches Reveal a Multistage Mode of Action of a Marine Antimicrobial Peptide against Pathogenic Escherichia coli and Its Protective Effect against Bacterial Peritonitis and Endotoxemia

“…2b, the B-DNA structure was observed in the absence of N4, which was characterized by a positive long-wavelength band at 270 nm and a negative band at approximately 240 nm. At a low N4-to-DNA ratio of 1.25, the DNA spectrum was characterized by a dominant negative band at 245 nm, due to the right-handed helicity B form of DNA and a positive band at 270 nm, due to the base stacking between N4 and DNA bases; there was a slight additional reduction in the CD amplitude, which indicated that N4 has an effect on the helicity structure of the DNA (26). The DNA CD spectra changed at a higher N4-to-DNA ratio of 5.0, which contained a negative band at approximately 250 nm and a positive band at approximately 270 nm, and there was a greater decrease in the CD amplitude.…”

Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies

“…These spectral characteristics indicate that the complex interacts with DNA most likely through a mode that involves electrostatic or hydrophobic interaction. As stated before, CuL complexes have a replaceable acetate ligand in solution, which may be replaced with H 2 O molecules in solution . So the complex contains a positive charge on the copper atom in the middle.…”