DNA interaction of CuII, NiII and ZnII functionalized salphen complexes: studies by linear dichroism, gel electrophoresis and PCR

Abstract

The interaction of salphen-type Ni^II, Cu^II and Zn^II complexes with native DNA was investigated by exploiting linear dichroism experiments. The Ni^II complex behaves as a typical intercalator, binding strongly and stiffening and unwinding the DNA. The strength of the DNA interaction is slightly weaker for the copper complex and much weaker for the zinc complex. Plasmid-DNA gel electrophoresis experiments indicated that while Cu^II and Zn^II complexes do not induce the unwinding of supercoiled DNA, the Ni^II complex has a nuclease activity without the addition of external agents. On the other hand, as shown in the PCR assays, we demonstrate that, at the used concentrations, only the Cu^II complex is able to inhibit the DNA amplification mediated by Taq DNA polymerase. In this paper we have also reported a detailed characterization of the three compounds including 2D-NMR and ESI-mass experiments and X-ray single crystal structure of the copper and nickel compounds.