电喷雾质谱法研究全氟辛酸和全氟辛磺酸与载脂蛋白CⅢ的相互作用

摘要

This work has studied the interactions between perfluorooctanoic acid(PFOA),perfluorooctane sulfonic acid(PFOS)with apolipoprotein C Ⅲ by electrospray ionization mass spectrometry (ESI-MS ). ESI-MS and competitive binding experiment results showed that the Apo C Ⅲ protein could form stable protein complexes with PFOA and PFOS,respectively. PFOS has showed the higher binding affinity with Apo C Ⅲ than PFOA. Apo CⅢcould bind with PFOA with stoichiometric ratio of 1 : 1,but could bind more PFOS to form three types of protein complexes with the stoichiometric ratios of 1 : 1,1 : 2,1 : 3. The binding constants of PFOS-Apo CⅢ,and PFOA-Apo CⅢhave been determined by ESI-MS measurement as 8. 33×104 M-1,7. 79×104 M-1,respective-ly. Molecular docking(MD)simulation supported the observation obtained from ESI-MS and further explored the specific binding bites.%本文采用电喷雾质谱法(ESI-MS)研究了全氟辛酸(PFOA)和全氟辛磺酸(PFOS)与载脂蛋白CⅢ(Apo CⅢ)的相互作用.ESI-MS检测和竞争性实验结果表明Apo CⅢ分别能够和PFOA及PFOS形成稳定的蛋白复合物,PFOS的结合能力强于PFOA.当样品溶液中蛋白质与配体小分子的摩尔浓度比为1:4时,Apo CⅢ蛋白能够与PFOA形成化学计量比为1:1的复合物;与PFOS可形成1:1、1:2、1:3的复合物.由ESI-MS图谱计算出PFOS-Apo CⅢ,PFOA-Apo CⅢ结合常数Ka1分别为8.33×104 M-1,7.79×104 M-1.分子对接模拟辅助质谱实验方法进一步探究了这些PFCs与Apo CⅢ的结合位点.