Multispectroscopic studies of interaction between herbicide linuron and calf thymus DNA

The interaction between linuron and calf thymus DNA(DNA) was investigated in physiological buffer(pH 7.4) by UV-vis absorption,fluorescence,circular dichroism(CD) and FT-IR spectroscopies coupled with viscosity measurement and DNA melting technique.The result showed that the fluorescence intensity of MB-DNA complex was greatly enhanced by linuron,suggesting that there existed a strong competition for DNA binding between linuron and MB.Moreover,the relative viscosity and melting temperature of DNA increased in the presence of linuron.These results provided evidences that linuron intercalated into the base pairs of DNA.The constringency of CD spectral indicated the conformation conversion from B-DNA to C-DNA and the guanine and adenine were mainly influenced from the analysis of FT-IR spectra.