Abstract:
A systematic study on the interaction between 2-(3,5-dimethyl-pyrazol-1-yl)-6,8-dimethyl-4b,9-dihydro-1,5,8 a,9-Tetraaza-Fluorene(PTF) or its metal complexes and salmon sperm DNA was investigated using ultraviolet(UV), fluorescence, circular dichroism(CD) spectrum and viscometric method under simulated physiological conditions. Our results showed that the PTF can form a complex with Cu(Ⅱ) and Zn(Ⅱ) at a coordination ratio of 2∶1. A significant hypochromic effect on the UV spectrum of DNA was appeared after the action of PTF,PTF-Cu(Ⅱ) and PTF-Zn(Ⅱ), accompanied by the equal absorption points, closed to the 2∶1 molar ratio of combination. After a series of interactions of three PTF or its metal complexes, the fluorescence spectrum of the DNA was quenched and their binding site n is close to 1. The amplitude of positive and negative peaks of CD spectrum decreased significantly, especially in the trend of action of PTF-Cu(Ⅱ) and PTF-Zn(Ⅱ). The relative viscosity and denaturation temperature of DNA increased in turn after the action of PTF, PTF-Cu(Ⅱ) and PTF-Zn(Ⅱ). Moreover,the PTF, PTF-Cu(Ⅱ) and PTF-Zn(Ⅱ) all had good antibacterial activities on Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Cruciferous black rot. As a whole, our comprehensive analysis showed that the interaction modes of PTF, PTF-Cu(Ⅱ), PTF-Zn(Ⅱ) and DNA were all intercalation, and the binding ability trend was PTF-Zn(Ⅱ)>PTF-Cu(Ⅱ)>PTF.