S-异丙甲草胺与小牛胸腺DNA的相互作用

应用紫外光谱、荧光光谱、DNA热变性法以及黏度法研究了S-异丙甲草胺与小牛胸腺DNA(ctDNA)的相互作用. 结果表明, S-异丙甲草胺使ctDNA在200 nm处的吸收峰发生明显改变, 表现出红移和减色效应, 而对260 nm处的吸收峰产生影响较小, 排除了嵌插作用的可能; ctDNA对S-异丙甲草胺内源性荧光表现出很强的猝灭作用, 且随温度的升高, 其猝灭程度有所下降, 表明S-异丙甲草胺是以形成加合物的方式与ctDNA结合的, 并求得了它们在不同温度下的结合常数; 将不同离子强度条件下S-异丙甲草胺与ctDNA作用以及不同S-异丙甲草胺浓度下ctDNA的热变性温度和黏度变化的研究结果与紫外光谱和荧光光谱相结合, 可以判断S-异丙甲草胺是以沟槽作用的方式与ctDNA结合的.

Interaction of S-Metolachlor with Calf Thymus DNA

The interaction of S-metolachlor with calf thymus DNA(ctDNA) was investigated using UV absorption spectra, fluorescence spectra, thermal denaturation and viscometry of DNA. The experimental results from UV absorption spectra show that when S-metolachlor was added, the red shift and hypochromic effect were observed in the absorption peak of ctDNA at 200 nm, while its effect on the absorption peak at 260 nm was very little, which indicate that the intercalation binding could be excluded. Moreover, the experimental results of the thermal denaturation and viscometry of ctDNA also excluded the possibility of the intercalation binding between the S-metolachlor and ctDNA. The fluorescence spectra indicate the intrinsic fluorescence of S-metolachlor could be strongly quenched by ctDNA, and with the temperature increasing, its quenching effect decreased, which suggest that the adducts of S-metolachlor and ctDNA were formed, and the binding constants were calculated. In addition, it was suggested from the results of the effect of the ion strength on the fluorescence system of the S-metolachlor-ctDNA that the electrostatic binding was also excluded. So, the possible binding mode between S-metolachlor and ctDNA was the groove binding according to the above experimental results.