Interaction of Complex of Europium and Hbbimp with DNA

The complex of Eu(Ⅲ) and Hbbimp (2,6-bis [bis (2-benzimidazolylmethyl)] aminomethyl-4-methylphenoxo ) was synthesized and characterized. The interaction of the complex with calf thymus (CT) DNA was investigated with UV and fluorescence spectra. The result shows that the absorbance of CT DNA is reduced and its wavelength at the maximum peak is red-shifted, and the intensity of fluorescent spectra of ethidium bromide (EB)-DNA is weakened gradually when the concentration of the complex [C(complex)] is increased. UV melting curves of CT DNA prove the existence of the denaturation and degradation together when the complex exists. The complex is capable of promoting cleavage of pBR322 DNA at 50 ℃ and transforming most of the supercoiled DNA into nicked DNA. However, the supercoiled DNA can be absolutely transformed into the nicked DNA by the mixture of the complex and H2O2 when the C(H2O2) is less than 1×10-3 mol·L-1 and the ratio of C(complex) and C(H2O2) is equal to 1:20 at 37 ℃.