Inhibition of endonuclease cleavage and DNA replication of E. coli plasmid by the antitumor rhodium(II) complex

Binding effect of the antitumor complex rhodium(II) acetate [Rh2(O2CCH3)4] (Rh1) to the plasmid pUC19 DNA has been studied under different molar ratio of Rh1 compound to base pair of pUC19 DNA (Rf) and reaction time. The Rh1 binding inhibited the activity of restriction enzyme. The binding effect was monitored using gel electrophoresis. The results indicate that at least one Rh1 binds with the recognition sequence and the binding has no preference between A–T and G–C pairs. At high value of Rf = 100, ICP-MS (Inductively Coupled Plasma Mass Spectrometry) measurement confirmed that 46% of Rh1 binds to DNA. PCR amplification of the DNA was also inhibited by the Rh1 binding. The transformation experiment using Escherichia coli suggested that the cell growth was inhibited after binding the Rh1 to the plasmid. These results indicated that DNA synthesis could be inhibited both in vitro and in vivo by the Rh2(O2CCH3)4 binding.