荧光光谱法与分子模拟研究氨苄西林钠与牛血清蛋白相互作用及构象变化

Study on the Interaction and Conformational Changes between Ampicillin Sodium and Bovine Serum Albumin by Fluorescence Spectrometry and Molecular Simulation

目的研究氨苄西林钠(APS)与牛血清蛋白(BSA)的相互作用机制与构象变化。方法通过同步荧光光谱、三维荧光光谱、圆二色谱和分子模拟等方法,在近生理条件下,研究了APS与BSA的相互作用机制及其构象变化。结果随着APS浓度的增加,BSA的二级结构各含量均发生了相应的改变,同时BSA荧光强度明显降低,BSA氨基酸残基的峰位发生了一定的位移,等高条纹线在疏密程度及形状上也出现了一定的变化,Stokes位移也随之增大。APS主要结合在BSA的SiteⅠ位点,且APS通过氢键与BSA的残基相结合。结论APS与BSA的相互作用力主要为氢键,结合位点为Site I位点,BSA的构象也发生改变。

Objective To investigate The interacdtion and conformational changes between ampicillin sodium(APS)and bovine serum albumin.Methods The mechanism of interaction and conformational changes between APS and BSA were investigated by simultaneous fluorescence spectroscopy,three-dimensional fluorescence spectroscopy,circular dichroism and molecular simulation under near-physiological conditions.Results With the increasing of APS concentration,the contents of secondary structures of BSA were changed accordingly,and the fluorescence intensity of BSA was decreased significantly.Meantime,the peak position of amino acid residues in BSA was shifted to a certain extent.The density and shape of isometric fringe lines were also changed at the same time,and the Stokes shift was also increased accordingly.Conclusion The interaction force between APS and BSA is mainly hydrogen bond and the binding site is Site I.The conformation of BSA has also been changed.