沙丁胺醇与小牛胸腺DNA相互作用研究

Study on the interaction between salbutamol and calf thymus DNA

在生理酸度条件下(pH7.4),运用紫外–可见吸收光谱、荧光光谱、圆二色谱(CD)和傅立叶红外光谱(FT–IR)并结合分子模拟、DNA熔点及粘度测定,研究了沙丁胺醇(Sal)与小牛胸腺DNA(ctDNA)的相互作用。结果表明,ctDNA以静态方法猝灭Sal的内源荧光,25℃时ctDNA与Sal的结合常数为1.26×104L·mol,氢键和范德华力是两者结合的主要驱动力。Sal存在下,ctDNA的熔点无明显变化,KI荧光猝灭效应和盐效应不明显,证实Sal与ctDNA主要通过沟槽模式结合。FT-IR与分子模拟结果显示,Sal倾向于与ctDNA的胸腺嘧啶(T碱基)结合。CD和凝胶电泳分析表明,Sal与ctDNA结合没有对DNA产生明显损伤,DNA仍维持B型构象。

The interaction between salbutamol （Sal） and calf thymus DNA in pH 7.4 Tris-HC1 buffer was investigated by UV-vis absorption, fluorescence, circular dichroism （CD） and Fourier transform infrared （ FF - IR） spectroscopy, coupled with molecular simulation technique, viscosity measurements and DNA melting studies. The results showed that ctDNA could quench the intrinsic fluorescence of Sal by static quenching. The binding constant between Sal and ctDNA was calculated to be 1.26 × 104 L/mol at 25℃, and the binding of Sal to ctDNA was driven mainly by hydrogen bonding and van der Waals interaction. It was found that Sal bound to ctDNA with groove binding as evidenced by no significant change in denaturation temperature of ctDNA as well as in iodide quenching effect and salt effect. The results from FF-IR and molecular docking analysis manifested that Sal preferential bound to the thymine bases of ctDNA. The analysis of CD and agarose gel electrophoresis indicated Sal didn＇t induce DNA damage, and remained B-DNA conformation.