光谱法和分子对接技术研究胡桃醌与人血清白蛋白的相互作用  

Spectroscopy and Molecular Docking Technique for Investigation of Interaction between Juglone and Human Serum Albumin

作　　者：申炳俊[1] 柳婷婷 SHEN Bing-Jun;LIU Ting-Ting(School of Life Science and Technology,Changchun University of Science and Technology,Changchun 130022,China)

机构地区：[1]长春理工大学生命科学技术学院,长春130022

出　　处：《分析化学》2020年第10期1383-1391,共9页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.11704044);吉林省科技厅发展计划项目(No.20191102011YY);长春理工大学科技创新基金(No.JJLG-2018-14)资助。

摘　　要：胡桃醌(Jug)是民间抗癌验方青龙衣的主要活性物质之一,其与蛋白质的相互作用及作用机理研究鲜见报道。本研究在模拟人体生理条件下,利用内源荧光光谱、紫外吸收光谱、同步荧光光谱、三维荧光光谱以及分子对接技术,研究了Jug与人血清白蛋白(HSA)之间的作用机理。荧光光谱结果表明,Jug能有效猝灭HSA内源荧光,猝灭机制属静态猝灭,通过Lineweaver-Burk方程求得两者间结合常数(KA)为3.72×102 L/mol (310 K),结合位点数(n)约为1。根据Van′t Hoff定律计算得到的热力学参数(ΔH=-142.07 kJ/mol和ΔS=-409.08 J/(mol·K))表明,Jug与HSA之间的主要作用力为氢键和范德华力。根据Forster′s能量转移定律,确定Jug与HSA结合距离为2.61 nm。紫外吸收光谱、同步荧光光谱和三维荧光光谱研究发现,Jug对HSA二级结构有轻微影响,使酪氨酸(Tyr)残基周围微环境疏水性增加。分子对接结果进一步表明,Jug通过范德华力、氢键和疏水作用力与HSA的亚域ⅢA中氨基酸残基进行作用。本研究有助于从分子水平上了解Jug在人体内的储藏运输过程以及对蛋白质功能的影响机制。Juglone(Jug) is one of the main active substances in the folk anti-cancer prescription walnut green husk and there are few reports on its interaction with protein and its mechanism of action. Here, the interaction mechanism between Jug and human serum albumin(HSA) was investigated by endogenous fluorescence spectrum, ultraviolet absorption spectrum, synchronous fluorescence spectrum, 3 D fluorescence spectrum and molecular docking methods under the simulative physiological conditions. Fluorescence spectra results revealed that Jug could quench(static quenching) the intrinsic fluorescence of HSA. According to the Mineweaver-Burk equation, the binding constant(K_A) was calculated to be 3.72×10~2 L/mol(310 K) and the number of binding sites(n) were approximately equal to 1. The thermodynamic parameters obtained by van′t Hoff′s law(ΔH=-142.07 kJ/mol, ΔS=-409.08 J/(mol·K)) revealed that the main forces between Jug and HSA were hydrogen bond and van der Waals. The binding distance(2.61 nm) between Jug and HSA was determined based on Forster′s energy transformation law. The results of ultraviolet absorption spectroscopy, simultaneous fluorescence spectroscopy and 3 D fluorescence spectroscopy indicated that Jug slightly affected the secondary structure of HSA and increased the hydrophobicity of the microenvironment around the tryosine residue. Molecular docking results further illustrated that Jug interacted with amino acid residues on subdomain Ⅲ A of HSA through van der Waals forces, hydrogen bonding and hydrophobic forces. This study was helpful to understand the storage and transportation process of Jug in human body and its effect on protein function at molecular level.

关 键 词：胡桃醌 人血清白蛋白 荧光光谱 紫外吸收光谱 同步荧光 分子对接技术 

分 类 号：R285[医药卫生—中药学] O657.3[医药卫生—中医学]