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贝加因黄酮具有广泛的生理和药理活性,它与蛋白质相互作用机制的研究对于深入了解其药理药效具有重要的意义.采用紫外和荧光光谱等手段对贝加因黄酮与不同异构体的人血清白蛋白复合物的结构进行了表征.在弱碱性条件下,贝加因的紫外吸收光谱发生了明显的变化,说明其A环上的羟基发生了解离,而在pH值4.5～2.0范围内,贝加因的结构基本保持不变.贝加因与不同异构体的人血清白蛋白作用后,其紫外光谱吸收I带发生显著的红移,显示出药物与蛋白质发生了特异性的结合.贝加因对不同异构体的荧光猝灭机制主要为静态猝灭过程,通过药物对蛋白质的荧光猝灭实验,计算了它们之间的结合常数.研究结果表明,药物与蛋白质的结合常数随pH值的降低而减小,这可能与蛋白质的结构变化有关.研究还发现,与不同异构体蛋白质作用后,药物的荧光发射峰有显著的增强效应.上述实验结果充分证明贝加因与不同异构体的蛋白质之间形成了复合物,药物分子结合在蛋白质IIA亚域邻近色氨酸残基的SiteI结合位点.结合计算机分子模拟,对药物与蛋白质的结合模式进行了讨论.
Bergain flavone has a wide range of physiological and pharmacological activities. The study of its interaction with proteins has important implications for understanding its pharmacological efficacy. Ultraviolet and fluorescence spectroscopy were used to measure the flavonoids and different isomers of beigain. The structure of the human serum albumin complex was characterized. Under weak alkaline conditions, the ultraviolet absorption spectrum of bekacin changed significantly, indicating that the hydroxyl group on the A ring undergoes derivatization, and the pH is 4.5 to 2.0. In the range, the structure of bekacin remained basically unchanged. After the interaction between bevacicin and human isomer albumin of different isomers, a significant red shift was observed in the ultraviolet absorption band I of the benzine, indicating specificity of the drug and protein. The combination of bekacin and the fluorescence quenching mechanism of different isomers is mainly a static quenching process. Through the fluorescence quenching experiments of drugs on proteins, the binding constant between them was calculated. The results showed that the drug and protein The binding constant decreases with the decrease of the pH value, which may be related to the structural changes of the protein. The study also found that the fluorescence emission peak of the drug has a significant enhancement effect after interacting with different isoform proteins. The above experimental results fully demonstrate that bekasin forms complexes with proteins of different isoforms, and the drug molecules bind to the Site I binding site of tryptophan residues near the protein IIA subdomain. Combining with computer molecular simulation, Drug-protein binding patterns were discussed.