INTERACTION OF DOUBLE-HELICAL POLYNUCLEAR COPPER(I) COMPLEXES WITH DOUBLE-STRANDED DNA

Double-helical metal complexes, the helicates H-2-H-5, were found to bind to double-helical DNA by spectroscopic, DNA-melting, and electrophoretic-mobility measurements. The helicates also inhibited the cleavage of DNA by two restriction enzymes, SspI and EcoRV, a property which agrees with the binding occurring in the major groove of the double helix. Visible-light irradiation of solutions containing a helicate and the pBR322 plasmid led to single-strand cleavage, indicating that these complexes could be of interest as potential probes for nucleic-acid structure.