胡椒碱分子键合人血清白蛋白位点的表征

利用荧光光谱法、紫外光谱法并结合计算机模拟技术在分子水平上研究了胡椒碱与人血清白蛋白(human serum albumin HSA)的键合作用.同步荧光及紫外光谱图表明,胡椒碱对HSA微环境有影响.位点竞争试验证明,胡椒碱分子键合在HSA的位点Ⅱ区.通过荧光光谱滴定数据求得不同温度下(300K 310K和318 K)药物与蛋白相互作用的结合常数及结合位点数.分子模拟的结果显示了胡椒碱与HSA的键合区域和键合模式,表明药物与蛋白有较强的键合作用;维持药物与蛋白质的相互作用力主要是疏水用,兼有氢键(位于氨基酸残基Arg 257,Arg 222及Arg218位).通过实验数据计算得到的热力学参数(ΔH0与ΔS0的值分别为原33.11 kJ·mol-1和原18.90 J·mol原1·K-1)确定了胡椒碱与HSA分子的相互作用力类型主要为氢键兼范德华力.

Characterization of Piperine Binding Site on Human Serum Albumin

Intrinsic fluorescence, absorption spectroscopy and the molecular modeling techniques were used to characterize piperine to human serum albumin (HSA). The synchronous fluorescence and absorption spectroscopes indicated that piperine participated in the microenvironment surrounding HSA in aqueous solution. Fluorescent displacement measurements confirmed that piperine bind HSA on site II. The binding constants and the number of binding sites between piperine and HSA at different temperatures(300 K，310 K and 318 K) were calculated according to the data obtained from fluorescence titration. The molecular docking to reveal the possible binding mode suggested that the binding of piperine to HSA has appeared to be strong by a hydrophobic interaction and there are three hydrogen bonds interactions between the drug and the residues Arg 257, Arg222 and Arg218. The values of different thermodynamic parameters obtained from experimental data (the enthalpy change and the entropy change were calculated to be 33.11 kJ•mol-1 and 18.90 J•mol-1•K-1) suggested that hydrogen bonds and van’der Waals force interaction are the predominant intermolecular forces stabilizing the complex.