摘要
在模拟人体血液p H 7.4的条件下,用分子对接及其荧光光谱、3D荧光、圆二色谱等方法研究黄曲霉毒素G1(aflatoxin G_1,AFG_1)与人血清白蛋白(human serum albumin,HSA)的相互作用。结果发现,根据双对数方程得出AFG1与HSA结合反应猝灭机制为静态猝灭,4个温度条件下结合常数数量级均为104,结合位点数近似为1。通过分子对接和热力学参数计算,AFG1结合在HSA的ⅠB疏水腔中,二者结合力主要为疏水作用和氢键。通过研究体内金属离子对AFG1-HSA反应的影响,Fe^(3+)、Mg^(^(2+))能增大AFG1对HSA的亲和力,而Zn^(2+)、Cu^(2+)、Mn^(2+)离子则能大大降低AFG1与HSA的亲和力。基于F?rster’s能量转移,二者反应距离为3.26 nm。3D荧光结果显示,二者的结合反应使HSA生色团氨基酸残基疏水性增加,二级结构发生改变;圆二色谱结果表明,加入AFG1使得HSA的α-螺旋含量增加。
The interaction between the mycotoxin aflatoxin G1(AFG1)and human serum albumin(HSA)was investigated by molecular docking,fluorescence spectroscopy,3D fluorescence spectrum,and circular dichroism(CD)under simulated physiological conditions(pH7.4).According to the double logarithmic equation,the major binding mechanism between AFG1and HSA was a static quenching process.At four different temperatures,the magnitude of binding constants was104and the number of binding sites was approximate to1.Through the molecular docking and the calculation of thermodynamic parameters,the binding site of AFG1was in theⅠB hydrophobic cavity,and hydrophobic interaction and hydrogen bonding were the major forces in the binding process.By studying the effect of metal ions on AFG1-HSA reaction,the affinity ofAFG1to HSA could be increased by Mg2+and Fe3+but greatly reduced by Zn2+,Mn2+and Cu2+.The binding distance betweenAFG1and HSA was calculated to be3.26nm based on F?rster’s non-radiation energy transfer theory.The3D florescence spectra revealed that the microenvironment of amino acid residues became more hydrophobic after the binding reaction.CD spectra revealed that the conformation of HSA was changed during the binding reaction as shown by an increase inα-helix.
作者
钟红
王佳曼
马良
江涛
ZHONG Hong;WANG Jiaman;MA Liang;JIANG Tao(College of Food Science, Southwest University, Chongqing 400715, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2017年第5期86-91,共6页
Food Science
基金
国家重点基础研究发展计划(973计划)项目(2013CB127803)
国家自然科学基金青年科学基金项目(31301476)
关键词
黄曲霉毒素G1
人血清白蛋白
光谱
分子对接
结合反应
aflatoxin G1 (AFG1)
human serum albumin (HSA)
spectrum
molecular docking
binding interaction
