A study of the interaction of 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraaza-cyclotetradeca-4,11-dienatocopper with DNA by ethidium fluorescence spectroscopy

摘要

The interaction of copper(II) and its 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclo-tetradeca-4,11-diene (HTDE) complex with calf thymus DNA has been investigated by ethidium fluorescence spectroscopy. The experimental data shows that Cu(II), Cu(II) HTDE and Cu(II) HTDE-thiol-hydrogen peroxide cause ethidium to dissociate from its host molecule and decrease the relative emission intensity of DNA-ethidium. Two different interaction modes could be deduced from the Cu(II) characteristics, the structure, and steric constraint of Cu(II) HTDE, and the composition of the system. The evidence accumulated suggests that Cu(II) HTDE intercalates predomimantly into the double-helical DNA in the absence of a reducing agent and hydrogen peroxide, and that it binds within the minor groove of DNA in the presence of RSH and H{sub}2O{sub}2.