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采用多种光谱技术对喜树碱和牛血清白蛋白的相互作用进行了研究。结果表明喜树碱和牛血清白蛋白可形成基态复合物,引起牛血清白蛋白内源荧光猝灭。通过计算获得了二者在不同温度下的结合常数及结合位点数。根据喜树碱和牛血清白蛋白结合的热力学参数,确定了二者之间主要为疏水作用力。根据Frster非辐射能量转移理论确定了喜树碱和牛血清白蛋白的作用距离。同步荧光光谱显示喜树碱主要与蛋白中色氨酸残基发生相互作用,改变其周围的局部构象。红外光谱提示喜树碱可引起蛋白的构象发生改变,α-螺旋二级结构减少。
The interaction of camptothecin and bovine serum albumin has been studied using a variety of spectroscopic techniques. The results show that camptothecin and bovine serum albumin can form ground state complexes, causing endogenous fluorescence quenching of bovine serum albumin. The binding constants and binding sites of the two at different temperatures were obtained by calculation. According to the thermodynamic parameters of the combination of camptothecin and bovine serum albumin, it is confirmed that the interaction between camptothecin and bovine serum albumin is mainly hydrophobic. The distance between camptothecin and bovine serum albumin was determined according to Förster’s non-radiative energy transfer theory. Synchronous fluorescence spectroscopy showed that camptothecin mainly interacts with tryptophan residues in the protein and changes the local conformation around it. Infrared spectra suggest that camptothecin can cause conformational changes of the protein, α-helix secondary structure decreased.