Superior hydrolytic DNA cleavage by a dinuclear copper(II) N4S4-donor complex compared with a mononuclear N2S2-donor close analogue

The cleavage of plasmid DNA by a dinuclear copper(II) complex of 1,2,4,5-te trakis(1'-amino-3'-thiabutyl) benzene is promoted significantly (rate const ruct of 3.3 x 10(-5) s(-1) at pH 7.8 and 37 degrees C) compared with the es sentially inactive mononuclear copper(II) complex of the analogue 1,2-bis(1 '-amino-3'-thiabutyl) benzene (rate constant < 10(-10) s(-1)). This implies that the two copper ions in close proximity and acting synergetically are important in accelerating cleavage, and separate roles for the two coppers in the dimer are proposed. (C) 2000 Elsevier Science S.A. All rights reserv ed.