摘要
以大豆分离蛋白(SPI)与芹菜素(API)为研究对象,通过采用荧光光谱法、紫外-可见吸收光谱法和圆二色光谱法并结合分子模拟技术研究芹菜素与大豆分离蛋白之间的相互作用。荧光滴定结果表明,芹菜素对大豆分离蛋白的荧光有较强的猝灭作用,为静态猝灭机制。获得的热力学参数熵变与焓变均为负值,表明芹菜素与大豆分离蛋白间的相互作用力主要为氢键和范德华力。同步荧光实验表明,芹菜素与大豆分离蛋白结合导致酪氨酸残基周围微环境疏水性增加和色氨酸残基周围微环境极性增加。三维荧光光谱和圆二色光谱实验表明,芹菜素与大豆分离蛋白作用使得蛋白质多肽链部分伸展,蛋白质表面疏水性下降,巯基含量增加,进一步的分子模拟显示芹菜素分子分别插入到大豆分离蛋白的SPI-7s和SPI-11s的疏水空腔中,与LEU226,GLN77,THR75,HIS76,ASN74以及THR353,THR328,MET329,LEU354,ASP342,LYS113,THR358,LYS330等氨基酸残基发生相互作用,并与HIS76,ANS74以及ARG340,LYS330,THR358,THR328和SER339氨基酸残基形成氢键。
The interaction between soybean protein isolate(SPI)and apigenin(API)was studied by fluorescence spectroscopy,UV-vis absorption spectroscopy and circular dichroism spectroscopy combined with molecular simulation.The fluorescence titration results showed that API had a strong quenching effect on the fluorescence of SPI,which was a static quenching mechanism.The thermodynamic parameters of entropy change and enthalpy change were negative,indicating that the interaction forces between API and SPI were hydrogen bond and van der Waals force.Synchronous fluorescence experiments showed that the binding of API and SPI resulted in the increase of hydrophobicity of microenvironment around tyrosine residues and polarity of microenvironment around tryptophan residues.The results of three-dimensional fluorescence spectra and circular dichroism spectra showed that the interaction between API and SPI lead to a partial extension of polypeptide chain of protein,a decrease in hydrophobicity of the protein surface and an increase in sulfhydryl content.Further molecular simulation showed that API molecules were inserted into the hydrophobic cavity of SPI,interacted with the amino acid residues LEU226,GLN77,THR75,HIS76 and ASN74 in SPI-7s,and interacted with HIS76,ANS74,ARG340,Arg 340 in SPI-11s.Meantime,the hydrogen bonds were formed between API and the amino acid residues such as HIS76,ANS74,ARG340,LYS330,THR358,THR328 and SER339.
作者
鄢雨中
陈蕾
张国文
YAN Yuzhong;CHEN Lei;ZHANG Guowen(State Key Laboratory of Food Science and Technology,Nanchang University,Nanchang 330047,China)
出处
《南昌大学学报（理科版）》
CAS
北大核心
2021年第5期477-484,共8页
Journal of Nanchang University(Natural Science)
基金
国家自然科学基金资助项目(22078143)
江西省自然科学基金资助项目(20202BAB205005,20212ACB205010)
食品科学与技术国家重点实验室课题(SKLF-ZZA-201912)。
关键词
芹菜素
大豆分离蛋白
光谱学
相互作用
apigenin
soybean protein isolate
spectroscopy
molecular simulation
