[Effect of copper ions on the photochemical activity of quinacrine and its interaction with DNA]

The influence of cuprum ions on the interaction between the antimalarial drug quinacrine (QA) and DNA is studied by polarized laser luminescence spectroscopy and fluorescence microscopy at molecular and cellular levels. An alteration of quinacrine luminescence intensity in complex with DNA caused by cuprum ions is explained in terms of redistribution of QA molecules from quenching GC- to fluorescent AT-DNA binding sites due to the competition of Cu2+ with the dye. Mechanisms of component interactions in the triplex "DNA-QA-Cu2+" in model and cellular systems are shown to be in qualitative agreement. QA photodynamic activity change caused by Cu2+ action is explained on the basis of the ideas being developed.