Zinc complexes for hydrolytic cleavage of DNA

Artificial metallonucleases [Zn II (CysGly)(HisAla)] (1) and [Zn(CysGly)(HisLeu)] (2) have been prepared, characterized and their DNA cleavage abilities probed. UV, viscosity and fluorescence investigations show that the 1:1:1 complexes bind to CT-DNA through an intercalation. Gel electrophoresis studies reveal that these complexes cleave the plasmid pBR 322 DNA (form I) through nicked (form II) to linear (form III) forms under physiological conditions (37°C, H 2 O, pH 7.5). DNA hydrolytic cleavage rate constants for complexes 1 and 2 at 37°C have been determined to be 0.55 h -1 and 0.49 h -1 , respectively. Since redox-active metals can also account for the DNA cleavage, the cleavage by non-redox metal like zinc assumes importance.