Interactions of DNA bases with selected metal ions
Several authors have investigated the interactions between DNA and metal ions to understand how metal ions affect the structure of DNA leading to the some types of cancers and neurodegenerative diseases. But these studies on interaction between DNA and metal ions have led to conflicting results, probably because DNA is studied as a macromolecule. The study of the larger bio-molecules, such as DNA and proteins, could be accounted by examining the smaller fragments of which they are composed. Our study was designed to examine the interactions of two DNA bases (thymine and cytosine) with various metal ions (Al, Ca, Ce, Cu, Fe, Hg, Mg, and Tl) using UV visible, infrared and Raman techniques. The study was carried out in aqueous solutions at different pH values and metal ion/ligand concentrations. UV visible spectra of thymine/cytosine and their metal complexes have shown that all metal ions cited above interact with thymine/cytosine, but the extent of the interaction depends on the nature of the metal ion, molar ratio, and pH value. The stronger interaction was observed between trivalent metal ions (Al, Ce, and Tl) and thymine/cytosine. Infrared and Raman spectra have shown some marker bands useful to identify the sites involved in metal chelation to the thymine and cytosine. Particularly, preferred binding sites on thymine and cytosine are N and O atoms for the all metal ions. For thymine, the preferred binding sites are N and O atoms for the divalent and trivalent metal ions, and only N atom for the monovalent metal ions. For cytosine, the preferred binding sites are N and O atoms for the divalent and trivalent metal ions, and N atom for the monovalent metal ions. Infrared and Raman spectroscopes are powerful tools for investigating the preferred binding sites of the metal ions on a molecule.
Analytical chemistry|Inorganic chemistry|Pharmacy sciences
Mahesh Kumar Aitha,
"Interactions of DNA bases with selected metal ions"
ETD Collection for Tennessee State University.