DNA cleavage by homo- and heterotetranuclear Cu(II) and Mn(II) complexes with tetrathioether-tetrathiol moiety

Novel homotetranuclear Cu(II) and heteronuclear Cu(II)-Mn(II) complexes wit h tetrathioether-tetrathiol moiety have been prepared and their DNA relaxat ion activities with plasmid pCYTEXP (5kb) were electrophoretically establis hed. The cleavage products analyzed by neutral agarose gel electrophoresis indicated that the interaction of the metal complexes with supercoiled plas mid DNA yielded linear, nicked or degraded DNA. The relaxation activities o f both homo- and heterotetranuclear (SK4) complexes are time- and concentra tion-dependent. The findings suggest that SK4 with potent nucleolytic activ ity is a good nuclease substitute in the presence of cooxidant. Furthermore , the observation of induction of DNA into smaller fragments by SK4 is also significant.