异黄酮与β-伴大豆球蛋白的相互作用及其对蛋白结构和潜在致敏性的影响

Interaction of Isoflavones withβ-Conglycinin and Its Effect on the Structure and Potential Allergenicity of Their Complex

探究异黄酮和β-伴大豆球蛋白(β-conglycinin,BCG)的相互作用机理及其对复合物结构和潜在致敏性的影响。利用荧光光谱、圆二色光谱分析2种大豆异黄酮(染料木素(genistein,Gen)、大豆苷元(daidzein,Dai))与BCG相互作用的猝灭类型、结合位点数、作用力类型和蛋白二级结构含量的变化,表征不同条件下制备的异黄酮-BCG复合物的结构,并利用酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)与消化产物免疫印迹检测其潜在致敏性。结果表明:活性异黄酮(Gen/Dai)对BCG的猝灭为静态猝灭,且相互作用力以疏水相互作用为主,结合位点数均接近1;并且与异黄酮相互作用诱导了BCG氨基酸微环境的极性增加,使蛋白肽链伸展,结构更为松散;ELISA与消化产物免疫印迹结果显示,与异黄酮结合后蛋白的潜在致敏性增强。本研究有助于科学认识异黄酮在食品复杂基质体系中对过敏蛋白致敏性影响机制,对其抗过敏的深度开发利用具有重要意义。

In this study,the interaction mechanism of isoflavones withβ-conglycinin(BGG)and its effect on the structure and potential allergenicity of their complex were investigated.Fluorescence spectroscopy and circular dichroism spectroscopy were used to analyze the types of quenching,the number of binding sites,the types of forces and the secondary structure content of BGG complexes with one of the two soy isoflavones genistein(Gen)and daidzein(Dai).The structure of isoflavone-BGG complexes prepared under different conditions was characterized,and the potential allergenicity of the complexes were detected by enzyme linked immunosorbent assay(ELISA)and Western blotting.The result showed that isoflavones caused a static quench of the fluorescence of BGG,and the interaction was dominated by hydrophobic interactions,with one binding site.Furthermore,the interaction with isoflavones induced an increase in the polarity of the amino acid microenvironment of BGG,which led to unfolding of the peptide chain and a looser structure.ELISA and immunoblotting of digestion products showed that the potential allergenicity of the protein was enhanced by the binding of isoflavones.The results of this study would be helpful to understand how isoflavones affect the allergenicity of allergenic proteins in complex food matrices,and be significant for its further development and utilization for allergenicity reduction.