DNA degradation by the copper(II) complex with tripodal-ligands containing peptide group

Copper-based transition metal complexes which perform single-strand scission of DNA in a site-specific manner have been designed. The complexes Cu(dpg)(+) and Cu(dpgt)Cl+ (H(dpg) and (dpgt) represent bis(2-pyridylmethyl) derivatives of glycylglycine and glycylglycylglycine, respectively), were prepared in this study and its crystal structures were determined. We have found that Cu(dpgt)Cl+ and Cu(dpg)(+) complexes convert supercoiled plasmid DNA into a mixture of nicked and linear forms in the presence of hydrogen peroxide, whereas related Cu(II) complexes, which lack a peptide group, produce complete degradation of DNA under the same experimental conditions. (C) 1998 Elsevier Science Ltd. All rights reserved.