基于ESI-HRMS的分子间G-四链体DNA相关超分子化学研究

发布时间：2018-01-22 03:10

本文关键词： ESI-HRMS 分子间G-四链体DNA 阳离子黄连素Berberine　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：富含鸟嘌呤碱基(G)的DNA序列广泛存在于人体基因的多个重要领域且在生理条件下能自组装形成G-四链体结构,它是一种特殊的DNA二级结构,阳离子可通过嵌入其中心空腔通道减少鸟嘌呤上氧原子之间的静电斥力来稳定G-四链体结构。G-四链体根据组成DNA链数的不同可分为分子内和分子间G-四链体。由于G-四链体参与人体重要生命活动且与细胞增殖、癌变具有密切关系,特别是端粒G-四链体的形成使端粒不被端粒酶延伸,起到保护端粒、抑制癌细胞增殖的作用,从而引起人们对其巨大的研究兴趣,成为当今化学与生物学研究的热点。本文通过电喷雾质谱技术(ESI-HRMS)研究了有关分子间G-四链体及其复合物形成的一系列问题。1.基于ESI-HRMS的“软电离”优势研究了富G序列+NH_4~+、富G序列+NH_4~++Berberine体系的相互作用,研究了反应时间、干燥气温度、毛细管出口电压(Fragmentor电压)、流动相H_2O:CH_3OH比例、分析物浓度等因素对目标分子间G-四链体及其复合物形成和检测的影响,并获得了各因素的最佳条件,为后续研究打下了良好的基础。2.在上述研究的基础上,通过ESI-HRMS研究了2种可形成双分子G-四链体的富G序列(命名为G3G4、G4G4)和3种可形成四分子G-四链体的富G序列(命名为G41、G42、G43)与不同阳离子NH_4~+、K~+相互作用,得出分子间G-四链体结构信息及结合阳离子的数量等信息,从而直观地计算出与分子间G-四链体相关的化学计量变化;进一步研究了阳离子浓度变化对阳离子和分子间G-四链体结合率的影响,研究结果表明在一定浓度范围内该结合率与阳离子浓度有较好的线性关系。3.在此基础上进一步研究了小分子Berberine与NH_4~+、K~+存在下形成的分子间G-四链体相互作用,测得了超分子复合物的化学计量比,进一步研究表明在一定浓度范围内分子间G-四链体与Berberine的结合率与Berberine的浓度呈现较好的线性关系,取得了较好的实验结果。
[Abstract]:The DNA sequence rich in guanine base (G) exists widely in many important fields of human genes and can self-assemble to form G-quadruplex structure under physiological conditions. It is a special secondary structure of DNA. Cations can stabilize the structure of G- quaternary structure by embedding the channel in the central cavity to reduce the electrostatic repulsive force between oxygen atoms on guanine. According to the different number of DNA chains, it can be divided into intramolecular and intermolecular G. -Four-chain. G- quadruplex is involved in vital human life and cell proliferation. Carcinogenesis has a close relationship, especially the formation of telomere G-quadruplex makes telomere do not extend by telomerase, plays the role of protecting telomere, inhibiting the proliferation of cancer cells, thus causing great interest in its research. It has become a hot topic in chemistry and biology. In this paper, ESI-HRMSs were developed by electrospray mass spectrometry (ESI-HRMS). A series of problems related to the formation of intermolecular G- quadruplex and its complexes have been studied. 1. Based on the "soft ionization" advantage of ESI-HRMS, the G-rich NH _ 4s have been studied. The interaction of G sequence NH4- Berberine system was studied. The reaction time, drying gas temperature, capillary outlet voltage and Fragmentor voltage were studied. The influence of the ratio of H _ 2O: Ch _ 3OH in mobile phase and the concentration of analyte on the formation and detection of G- quadruplex and its complex between target molecules were obtained. The optimum conditions of each factor were obtained. On the basis of the above research, we studied two kinds of G-rich sequences (named G3G4) which can form bimolecular G-quadruplex by ESI-HRMS. G4G4) and three kinds of G-rich sequences (named G41G42G42G43) which can form four-molecule G-quad chains interact with different cations NH _ 4 ~ + K ~ +. The structure information and the number of binding cations were obtained, and the stoichiometric changes related to the intermolecular G- quaternary were calculated intuitively. The effect of the concentration of cations on the binding rate of cations and intermolecular G- quaternary was further studied. The results show that there is a good linear relationship between the binding rate and cationic concentration in a certain concentration range. 3. On the basis of this, the small molecule Berberine and NH _ 4 ~ are further studied. The stoichiometric ratio of supramolecular complexes was measured by the interaction of G- quadruplex in the presence of K ~. Further studies show that there is a good linear relationship between the binding rate of G- quadruplex and Berberine and the concentration of Berberine in a certain concentration range. Good experimental results have been obtained.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R3416

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