杂环胺与牛血清白蛋白的相互作用研究

Study on Interaction between Heterocyclic Aromatic Amines and Bovine Serum Albumin

杂环胺是食物热加工生成的一类具有致癌性的化学危害物,考察其与转运蛋白的相互作用,对了解它的体内毒性有重要意义。通过多光谱方法研究了两种常见杂环胺2-氨基-3-甲基咪唑[4,5-f]-喹啉(IQ)和9H-吡啶并[3,4-b]吲哚(Norharman)分别与牛血清白蛋白(BSA)之间的相互作用。结果表明,两种杂环胺均能自发地与BSA结合产生荧光淬灭,且结合位点n均约为1个。IQ对BSA的荧光淬灭机理为动态和静态的联合淬灭,且以动态淬灭机理为主,两者的分子间相互作用主要是疏水作用力;Norharman对BSA的淬灭属于静态淬灭,结合力类型主要是氢键和范德华力。两种杂环胺与BSA之间的结合均能导致BSA构象的改变,且IQ引起的构象改变程度要高于Norharman。此外,依据能量最低原则,通过分子对接模拟了杂环胺与BSA的结合位点。

Heterocyclic aromatic amines(HAAs),as a kind of carcinogenic substance,is mainly generated in the thermal process of foods.The study of its interaction with transport proteins is important for revealing its toxicity in human bodies.The interaction between two common heterocyclic aromatic amines as 2-amino-3-methylimidazole[4,5-f]-quinoline(IQ),9H-pyrido[3,4-b]indole(Norharman)and bovine serum albumin(BSA)was studied with multi-spectroscopic methods.It shows that both heterocyclic aromatic amines can be spontaneously combined with BSA to quench the endogenous fluorescence,and the binding site is about one for both heterocyclic aromatic amines.The quenching mechanism of IQ to BSA is a combination of dynamic and static quenching,in most cases dynamic quenching is dorminant.The molecular interaction between IQ and BSA is mainly driven by a hydrophobic force.The quenching mechanism between Norharman and BSA is the static quenching of ground state complex formation,and the binding is driven by hydrogen bonding and van der Waals force.Both IQ and Norharman can cause the changes of BSA conformation,and the degree of conformational change caused by IQ is higher than that of Norharman.In addition,according to the principle of minimum energy,the binding site of HAAs and BSA was simulated by molecular docking.