Chromium has been extensively used in dyes, chrome plating and leather industries. Contamination of chromium is ubiquitous in environment. The cellular reductants such as cysteine, glutathione and ascorbate reduces Cr(VI) to Cr(III). Chromium in +3 oxidation state is susceptible to form different DNA adducts including DNA interstrand crosslinks (ICLs), DNA-protein crosslinks (DPCs) as well as with DNA phosphates. These Cr (III) adducts have been shown to exhibit different mutagenic potencies. Though numerous studies have been reported on Cr(III) mutagenesis, the influence of Cr(III)-aminoacid-DNA ternary adducts (DPC) in thermodynamics of DNA and its biological consequences are yet to be ascertain. In the present study, we have carried out systematic study on the Cr(III)-aminoacid-DNA adducts in a sequence dependent manner by varying flanking bases near the adducted site. The modification of oligonucleotides by DPC was characterized using MALDI-TOF. Structural perturbations induced by Cr(III) adduct to the duplex DNA were studied using circular dichroism and thermodynamic parameters were calculated using UV-visible spectroscopy. The results from this study will be helpful in understanding the structural perspectives of Cr(III)-aminoacids-DNA ternary adducts in mutagenesis.

Detailed investigation on thermodynamics of chromium(III)-aminoacid-DNA ternary adducts and its role in mutagenesis

246th National Meeting (2013)

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