比较研究山姜素和豆蔻明与人-γ球蛋白的相互作用

将互为同分异构体的两种植物药活性组分山姜素和豆蔻明作为研究对象,应用荧光光谱法、紫外光谱法以及红外光谱法并结合分子对接技术首次对这两种黄酮类化合物与人-γ球蛋白(Human gammagobulin,HG)的相互作用进行了详细研究.荧光光谱法的研究结果表明,这两种药物均与HG有较强的相互作用(结合常数均在104～105之间);山姜素对HG表现为静态猝灭机理,而豆蔻明对HG表现出非常少见的动态猝灭机理.比较不同温度(298,308和318K)下两种药物与蛋白相互作用的结合参数都有所差别,维持药物-HG体系的作用力也不同.山姜素和豆蔻明分子与HG色氨酸残基间的结合距离r值(分别为3.88和4.52nm)都小于7nm,说明发生了能量转移.同步荧光与红外光谱法定性及定量地研究了药物对HG二级结构的不同影响程度.两种分子对接结果表明了这两种药物与HG的结合区域.

Comparison of the Interaction of Alpinetin and Cardamonin with Human Gammaglobulin

Both active components of plant herbs with an analogical isomeride structure (alpinetin and cardamonin) were chosen as research targets.A combination of intrinsic fluorescence,UV-Vis,FTIR and the molecular modeling techniques has been used to characterize the binding between both flavones and human gammaglobulin (HG).The results from fluorescence spectroscopy indicated that the two drugs could interact with the protein strongly (binding constants between 104～105).The two drugs indicated different quenching mechanisms (static quenching mechanism for alpinetin and dynamic quenching mechanism for cardamonin rarely).The binding parameters for the different dug-HG systems are different at different temperatures (298,308,and 318 K),and the binding modes were also different.The values of r are lower than 7 nm after interaction between the protein tryptophan residue and the bound alpinetin or cardamonin molecules (3.88 and 4.52 nm,respectively),which indicated the efficiency of energy transfer.The secondary structure compositions of the complexes of the globulin with the drugs were estimated by qualitative and quantitative analyses from synchronous fluorescence spectra and FT-IR experimental data.The two results of molecular model studies revealed the different binding locations for the drug-HG systems.