白藜芦醇二聚体与眼镜蛇神经毒素的作用机制

Mechanism of Interaction of Resveratrol Dimer with Cobra Neurotoxin

通过Discovery Studio软件模拟白藜芦醇不同结构二聚体与眼镜蛇神经毒素(NT)的相互作用,采用波长365nm的光诱导白藜芦醇二聚体的形成,通过紫外-可见光谱分析和荧光光谱分析得到不同白藜芦醇浓度和不同光照时间下NT的紫外-可见光谱和荧光光谱,并对结合能及作用参数进行了运算.结果表明:相比于单体,白藜芦醇二聚物对NT的结合能更大、作用更强;波长365nm的光照射白藜芦醇后,NT光谱发生了变化,紫外光吸收增强,吸收峰红移,荧光猝灭,有新发射峰生成;荧光猝灭速率常数为5.62×1012L/(mol·s),猝灭机制属于静态猝灭;白藜芦醇二聚物和NT的结合常数为5.12×105L/mol,结合位点数为1,结合距离为3.40nm,易发生非辐射能量转移;同步荧光光谱显示白藜芦醇二聚体可与NT的酪氨酸和色氨酸残基作用,羟基氢键导致其亲水性提高;白藜芦醇二聚体与NT的主要作用位点在色氨酸残基.

The interaction of various resveratrol dimers with cobra neurotoxin （NT）was simulated with Discovery Studio software.Then,the dimer was photo-induced by light with a wavelength of 365 nm,and the UV-Vis and fluo-rescence spectra of NT mixed with resveratrol were analyzed at different resveratrol concentrations and illumina-tion durations.Finally,the binding energy and some other parameters of the interaction were calculated.The re-sults show that （1 ）resveratrol dimer is of higher binding energy and stronger interaction than the monomer;（2 ） some changes occur in the spectra after the illumination,such as enhanced ultra-violet absorption,red-shifted ab-sorption peak,fluorescence quenching and new emission peak;（3）the fluorescence quenching is a static quench-ing with a rate constant of 5.62 ＆#215;1012 L/（mol ·s）;（4）the binding constant of resveratrol and NT is 5.12 ×10^5 L/mol,the number of binding sites is 1,and the binding distance is 3.40 nm,which may easily result in non-radiation energy transfer;（5 ）as illustrated by synchronous fluorescence spectra,the dimer can interact with tyrosin and tryptophan residues of NT and hydroxyl hydrogen bonds may contribute to the improvement of hydrophi-licity;and （6）the main interaction site of NT with resveratrol dimer is the tryptophan residue.