Role of copper (II) ions in OH and SO-4 induced damage in poly(dG-dC): a fluorimetric study

Double stranded poly(dG-dC) has been irradiated with 60Co γ-rays under different conditions. The structural damage in poly(dG-dC) due to attack of OH and SO-4 radicals in the absence and presence of copper (II) ions has been investigated. Ethidium bromide (EB) which intercalates with double stranded nucleic acid, has been used as a fluorescent probe. No change in the fluorescence emission spectral shape of EB bound to poly(dG-dC) due to irradiation under the conditions studied was observed. SO-4 radical is found to be more efficient than OH in structural damage of poly(dG-dC). It is observed that Cu(II) ions sensitise the OH induced structural damage whereas they protect against the SO-4 radical induced damage. (author)