Book of Abstracts: Albany 2007
June 19-23 2007
Thermodynamic Stability of a DNA Duplex Containing a Spiroiminodihydantoin Lesion
Chromium(VI) is well established as a potent carcinogen. Inside the cell Cr(VI) is reduced to Cr(III) generating high valent Cr(V) and Cr(IV) compounds as well as carbon- and oxygen-based radicals. These species can oxidatively damage DNA producing base lesions and strand breaks. Hexavalent Cr produces both 7,8-dihydro-8-oxoguanine (8-oxoG) and spiroiminodihydantoin (Sp) lesions, with Sp adducts being present in amounts at least 10-20 times greater than 8-oxoG (1, 2). In this study, the thermodynamic stability of a 15-mer DNA duplex containing an Sp lesion is examined using spectroscopic techniques and differential scanning calorimetry. The enthalpies, entropies and free energies of duplex formation for the 15-mer containing guanine, 8-oxoG and Sp are compared and discussed in relation to how the presence of this lesion could affect cellular processes.
References and Footnotes
Fadzai Chinyengetere and
Department of Chemistry, Smith College, Northampton, MA 01063