DNA interaction with zinc(II) ions

We focused on interactions of Zn(II) with DNA in this study. These interactions were monitored using UV/vis spectrophotometry and gel electrophoresis. Firstly, we isolated and amplified 498bp fragment of DNA. Samples were obtained by incubation of DNA fragment with Zn(II) for 60min at 25°C. After incubation, the samples were dialyzed and analyzed immediately. In this way, DNA was converted into a metal bound DNA (Zn–DNA). Interaction of Zn(II) with DNA caused change in the absorption spectrum (190–350nm) and decrease in the melting temperature (Tm) of Zn–DNA. Spectrophotometric (UV/vis) analysis showed that increasing concentrations of zinc(II) ions led to the increase in the absorbance at 200nm and decrease in absorbance at 251nm. Application of zinc(II) ions at 5.5μM concentration caused decrease in Tm for app. 7.5°C in average in comparison with control (75.5±3°C). The lowest melting temperature (60.5±2.5°C) was observed after application of zinc(II) ions at 33μM concentration. Gel electrophoresis proved significance of Zn(II) in the renaturation of DNA. Samples of Zn–DNA (15μM DNA+5.5–55μM Zn(II)) caused significant changes in the renaturation of DNA in comparison with the control, untreated DNA (15μM DNA).