转基因抗虫蛋白Cry1Ac与表面活性剂作用的芘探针光谱分析

摘要

以芘作为外源荧光探针,采用牛血清蛋白作为参照,考察了转基因抗虫蛋白Cry1Ac与4种表面活性剂相互作用的荧光光谱特征.结果表明,鼠李糖脂和Tween 80体系的芘荧光行为有相似的变化规律,可与蛋白质发生稳定的缔合过程.Cry1Ac蛋白的亲水性和分子极性较强,在表面活性剂浓度低时,可导致芘的I1/I3值较高.在阴离子、非离子表面活性剂胶团形成后,2种蛋白质的存在均不改变芘与表面活性剂的结合位点.十六烷基三甲基溴化铵对芘的荧光有一定猝灭作用,且在Cry1Ac蛋白介入下不能形成稳定的胶束.%The characteristics of interactions between the transgenic insect-resistant protein(Cry1Ac)and four different surfactants were investigated by fluorescence of pyrene,an extrinsic fluorescent probe. While the bo-vine serum albumin(BSA)was used as a reference protein. The results show that the fluorescence behavior of pyrene in RL and Tween 80 systems has a similar change pattern, and the two surfactants can be associated with proteins stably. The hydrophily and molecular polarity of Cry1Ac protein are of high values,which lead to higher I1/I3values of pyrene when the surfactant concentration is low. After the surfactant micelles formed, neither of the proteins will change the binding sites of pyrene with the nonionic or anionic surfactants. However,CTAB has a quenching effect on fluorescence of pyrene, and it cannot form stable micelles in the presence of Cry1Ac protein.