【作者】 李金华；

【导师】 胡之德；

【作者基本信息】 兰州大学 ， 分析化学， 2009， 博士

【摘要】 人血清白蛋白(Human serum albumin，HSA)是循坏系统中可溶性蛋白质的重要组成部分，是血浆中含量最丰富的蛋白质，具有很多生理学上的功能。它可以同许多内源及外源性物质结合，在体内起着存储和转运作用。蛋白质与药物的相互作用影响药物在体内的分布、代谢及排泄方式。药物与蛋白质相互作用的研究可为探讨人类疾病机制，诊断、预防疾病，制药和新药开发提供重要的理论基础，是毒理学、生命科学、化学及临床医学的一个重要研究领域。基于研究有机小分子和蛋白质的相互作用具有重要的意义，本论文在总结前人工作的基础上，综合各种实验技术及化学信息学，进行了以下几方面的创新性研究：(1)研究了四种中药活性组分葛根素、和厚朴酚、丹参酮ⅡA、甲基橙皮苷及杀菌剂甲基硫菌灵与人血清白蛋白的相互作用。(2)根据Stern-Volmer方程和Scatchard方程研究了上述小分子与HSA结合的作用机理，测定了结合常数、结合位点数，确定了结合部位和主要作用力类型。(3)用计算机分子模拟方法研究了以上小分子与HSA的对接，获得与实验一致的结果。(4)利用圆二色谱和傅里叶变换红外光谱考察了上述小分子对HSA二级结构的影响，获得了作用前后HSA二级结构含量的变化值。论文共分为七部分：第一章：简要介绍了蛋白质的结构、功能和性质；综述了药物与蛋白质相互作用的研究方法、研究内容及研究进展。第二章：用荧光光谱法、红外光谱法、圆二色谱法及对接技术对葛根素和人血清白蛋白的相互作用进行了详细的研究。结果表明，葛根素与蛋白质之间有很强的结合，结合后蛋白质的二级结构发生了轻微的改变。分子对接研究表明葛根素和蛋白质的结合区域位于蛋白质的亚结构域ⅡA中，主要通过疏水作用和氢键作用结合，这和键合模式所得到的结果是一致的。第三章：应用多种光谱方法和对接技术对和厚朴酚和人血清白蛋白的相互作用进行了详细的研究。荧光偏振结果表明和厚朴酚与蛋白质之间的强结合改变了蛋白质的微环境。圆二色谱和红外光谱实验结果说明了二者之间的结合改变了蛋白质的二级结构。分子对接研究表明了和厚朴酚和蛋白质的结合区域位于蛋白质的亚结构域ⅡA中，主要通过疏水作用结合，同时还存在着氢键和静电作用。第四章：本章研究了模拟生理条件下中药活性组分丹参酮ⅡA与人血清白蛋白的相互作用情况。利用荧光猝灭方法、CD和FTIR技术确定了反应的结合常数、主要作用力类型以及丹参酮ⅡA对蛋白质二级结构的影响；热力学及分子对接结果表明丹参酮ⅡA与人血清白蛋白的位置Ⅰ即亚结构域ⅡA结合，二者之间存在较强的疏水作用，同时还存在氢键作用。第五章：利用多种方法研究了模拟生理条件下甲基橙皮苷与人血清白蛋白的相互作用。结果表明，甲基橙皮苷与蛋白质之间有很强的结合并改变了蛋白质的二级结构。键合模式的结果表明二者之间的结合以疏水作用为主，同时还伴随着氢键作用。利用F(o|¨)rster能量转移理论，求得甲基橙皮苷与血清白蛋白间的距离距离r小于7nm，说明发生了能量转移。第六章：应用荧光方法在模拟人体生理条件下研究了不同温度下甲基硫菌灵和蛋白质相互作用的一些性质，包括结合机理、结合常数与结合位点数。同时，用紫外光谱和红外光谱研究了二者的结合对蛋白质二级结构所造成的影响。第七章：用淀粉作分散剂在室温条件下成功制备出了CdSe纳米颗粒，这种方法具有温和、简单、经济、有效等优点。将制备出的纳米颗粒用X射线衍射、高分辨透射显微镜、紫外吸收光谱及荧光光谱法进行了表征，结果表明所制备的纳米颗粒CdSe溶液性质稳定且分散性好。更多还原

【Abstract】 Human serum albumin (HSA), the major soluble protein constituents of thecirculatory system, is the most important drug carrier protein with a highconcentration in blood plasma and has many physiological functions. It can bindmany exogenous and endogenous ligands in blood, and realize transport anddistribution of many molecules and metabolites. Protein-drug interaction has a greatinfluence upon the distribution of the drugs in the body, upon their patterns ofmetabolism and excretion. Investigating the binding mechanism of drugs binding toHSA can provide an importance theoretical base on discussing human diseasemechanism, diagnosis and prevention of diseases, pharmaceutical industry anddevelopment new drugs. Thus, it has been an interesting research field of toxicology,life sciences, chemistry, pharmacokinetics, and clinical medicine. On the basis of theprevious research, the following major innovative works were carried out in thisdissertation:(1) Several methods were associated to study the interaction of four components of Chinese herb medicine (puerarin, honokiol, tanshinoneⅡA and methyl hesperidin) and methyl hesperidin.(2) The binding properties including the fluorescence quenching mechanisms, binding constants and the number of binding sites were investigated in detail, thermodynamic parameters were calculated, and the main interaction force between drugs and proteins was discussed.(3) The computational modeling method was used to study the drug-HSA interaction and the study results were in consistent with the experimental results.(4) The effects of drugs on HSA second structure were investigated with FT-IR and circular dichroism techniques.This dissertation consists of seven chapters:Chapter 1:The structures, functions and natures of proteins were briefly introducedThe contents、methods and evolvement of interaction of different kind of smallligands with protein were reviewed in detail. Chapter 2: The binding of puerarin to HSA has been investigated for the first timeby the fluorescence method, FT-TR, CD spectroscopy and molecular modeling. Theresult has clearly indicated that puerarin is a strong quencher and can bind tightly toHSA with changing slightly its molecular conformation. Meanwhile, from the resultsof binding mode and molecular modeling, it can be revealed that puerarin has boundwithin the subdomainⅡA of HSA mainly by the hydrophobic interaction andhydrogen bond.Chapter 3: The interaction between honokiol and HSA has been investigated bydifferent optical techniques and molecular modeling method. The data of fluorescenceanisotropy indicated that the binding of honokiol changed the microenvironment ofHSA. In addition, the results of CD and FT-IR spectroscopy showed that thesecondary structure of HSA was changed after honokiol bound to HSA. Furthermore,according to the molecular modeling study, honokiol can strongly bind to the site I(subdomainⅡA) of HSA mainly by hydrophobic force and there was also hydrogenbond interaction between honokiol and the residue Arg-222.Chapter 4: The binding of tanshinoneⅡA with HSA have been studied using UVabsorption spectroscopy, fluorescence spectroscopy, FT-IR spectra and molecularmodelling methods under simulative physiological conditions respectively. Thebinding constants, numbers of binding site, mainly intermolecular force and thechanges of HSA secondary structure induced by drugs binding were obtained. Inaddition, the results of binding mode and molecular modeling study showed thattanshinoneⅡA can strongly bind to the site I (subdomainⅡA) of HSA mainly byhydrophobic force and there was also hydrogen bond interaction between them.Chapter 5: The interaction between methyl hesperidin (MH) and HSA has beeninvestigated in vitro under simulated physiological conditions using different opticaltechniques. The results have clearly indicated that MH is a strong quencher and canbind tightly to HSA with changing its molecular conformation. Meanwhile, from theresults of binding mode, it can be revealed that the acting forces are mainly thehydrophobic interaction. According to the F(o|¨)rster theory of molecular resonanceenergy transfer, the distance r between the protein residue (donor) to MH (acceptor) in HSA is smaller than 7 nm suggesting that the energy transfer between HSA and MHcan occur with high possibility.Chapter 6: The binding properties (including binding mechanism, binding constant,and the number of binding sites) of thiophanate methyl (MT) to HSA at threetemperatures under simulative physiological conditions have been studied utilizingfluorescence method. Meanwhile, the effect of MT on the structure of HSA wasstudied using UV and Fourier transform infrared (FT-IR).Chapter 7: The nearly monodisperse starch capped CdSe nanoparticles weresuccessfully synthesized by a simple and "green" route at room temperature. It is amild, simple, cheap and efficient "green" route for producing nanoparticles. Theas-prepared nanoparticles were characterized by X-ray diffraction (XRD),Transmission Electron Microscope (TEM), UV-vis absorption andPhotoluminescence (PL) spectra. The results indicated stable and well dispersed CdSenanoparticles with fairly narrow size distributions were synthesized.更多还原