【作者】 杨培菊；

【导师】 宋玉民；

【作者基本信息】 西北师范大学 ， 无机化学， 2005， 硕士

【摘要】 小分子化合物与生物大分子相互作用的研究已经成为了化学生物学中重要的研究课题。DNA是生物体中重要的一类生物大分子,对生命遗传密码的翻译、转录、复制起着非常重要的作用,一方面,DNA靶向化合物成为很重要的核酸探针选择对象;另一方面,临床上使用的许多抗癌药物都以DNA为作用靶点。为了进一步探索和认识DNA的性质、结构、行为、形态、揭开生命的奥秘,人们研究了大量小分子与DNA之间的作用,并且许多小分子现已成功地用作DNA足迹试剂,定位碱基错配试剂,以及结构探针。小分子与DNA的相互作用的研究不仅有利于探索和开发新的核酸探针,而且有助于从分子水平上了解抗癌药物的作用机理,为设计临床上更为有效的抗癌药物提供理论指导。本文在此基础上采用光谱法、凝胶电泳、电化学、圆二色谱等方法研究了抗肿瘤药物维甲酸和桑色素金属配合物与DNA的相互作用。 本论文主要由以下三部分组成: 1.全反式维甲酸稀土配合物与DNA的相互作用 利用光谱法、凝胶电泳和粘度法研究了两种稀土配合物——维甲酸合钇(Ⅲ)、维甲酸合钐(Ⅲ)与DNA的相互作用。发现维甲酸合钇(Ⅲ)是一种有效的DNA切割试剂,在生理条件(pH近中性,温度37℃)下,0.01mM钇(Ⅲ)配合物与37mM质粒pBR322DNA反应2小时后超螺旋构型几乎完全消失。且钇(Ⅲ)配合物切割活性优于配体维甲酸,这可能是维甲酸合钇(Ⅲ)配合物的抗肿瘤活性优于配体的原因之一。通过改变切割体系的离子强度,pH,加入羟基自由基捕捉剂,发现DNA的切割对离子强度,pH表现出很强的敏感性,但几乎不受羟基自由基的影响,由此可见,反应没有产生羟基自由基。同时,我们通过EB(溴化乙锭)荧光探针竞争实验和粘度实验发现:这两种配合物使EB-DNA体系的荧光强度降低,DNA的粘度增加。钐(Ⅲ)配合物能使圆二色谱中DNA的负峰发生较大变化,DNA热变性温度升高。据此推断,这两种稀土配合物维甲酸合钇(Ⅲ)、钐(Ⅲ)主要以嵌入方式与DNA作用,这种作用方式可能是该配合物对HL-60、EJ癌细胞瘤株有较强抑制作用的又一原因。 2.全反式维甲酸过渡金属配合物与DNA的相互作用 本章利用光谱法、凝胶电泳、粘度和电化学方法研究了两种维甲酸过渡金属配合物——维甲酸合镍(Ⅱ)配合物、维甲酸合铜(Ⅱ)配合物与DNA的相互作用。发现镍(Ⅱ)、铜(Ⅱ)配合物在生理条件(pH近中性,温度37℃)下,能有效切割质粒pBR322 DNA,更多还原

【Abstract】 The nature and dynamics of binding small molecules to biopolymers represents an area of active investigation. Studies directed toward the design of site- and conformation-specific reagents provided routes toward rational drug design as well as a means to develop sensitive chemical probes of polymer structure. Deoxyribonucleic acid （DNA）is a kind of key biologic large molecule, it plays very important role in life genetic code’ interpretation, transcription and copy, it is the primary target molecule for most of anticancer and antiviral therapies according to the cell biology. The investigation of interaction of DNA with other molecules is of great importance in elucidating the structure of DNA and their functions. It is also helpful to understand some diseases and the mechanism by which some medicines （especially antitumor drugs） act. In this thesis the results of interaction of some antitumor compounds with DNA were reported.This thesis consists of three sections as follows:First, fluorescence spectral, agarose gel electrophoresis, viscometric and CD （circular dichroism） were used to study the interaction of the antitumor compounds Y（RA）₂·Ac·8H₂O and Sm（RA）₂·Ac·4H₂O （RA= retinoic acid, ）with DNA. The results indicate that the Y（RA）₂·Ac·8H₂O can more effectively promote the cleavage of plasmid DNA than all-trans retinoic acid at physiological pH and temperature, which may be the one of reasons why the inhibitory effect of Y（RA）₂·Ac-8H₂O on human bladder line EJ cells is much greater than that of retinoic acid. We increased ionic strength and changed pH of reaction systems and added radical scavengers and found that the process of plasmid DNA cleavage is sensitive to increasing ionic strength and changing pH, and these radical scavengers almost no any effect on the DNA cleavage reaction. The above results suggest that the cleavage of DNA by Y（RA）₂·Ac·8H₂O was not produced diffusible hydroxyl radicals via the Fenton reaction.On the side, we investigated the interaction of Y（RA）₂·Ac·8H₂O and Sm（RA）₂·Ac·4H₂O with Calf thymus DNA by means of fluorescence spectroscopy, viscometric and CD （circular dichroism）. The results show that the emission spectral intensity is decreased and the viscosity of DNA is increased by adding the tow complexes. Increasing fluorescence is seen for the complex with DNA addition. The denatured temperature of DNA is increased and the negativespectra of the CD of DNA is changed by adding Y（RA）₂·Ac·8H₂O. The above results suggest that the tow complexes can bind to DNA mainly by intercalation, which may be the other reason that the complex can inhibit the HL-6CK EJ cancer cell.Second, the interactions of the Cu（II）, Ni（II） complexes with all-trans retinoic acid （Cu（RA）₂·3H₂O, Ni（RA）₂·3H₂O） between DNA have been studied using agarose gel electrophoresis. We firstly found the Ni（RA）₂·3H₂O and Cu（RA）₂·3H₂O complexes can promote the cleavage of plasmid DNA at physiological pH and temperature. The Ni（RA）2 -3H2O complex can more effectively promote the cleavage of plasmid DNA than Cu（RA）₂·3H₂O complex, Y（RA）₂·Ac·8H₂O complex, all-trans retinoic acid and Ni²⁺, at the same conditions, and the efficiency of DNA cleavage by Ni（RA）₂·3H₂O complex was rather high and the reaction time was very short, which may be the one of reasons why the inhibitory effect of Ni（RA）₂·3H₂O on human bladder line EJ cells is much greater than that of retinoic acid. Otherwise, we increased ionic strength and changed pH of reaction systems and added radical scavengers and found that the process of plasmid DNA cleavage is sensitive to increasing ionic strength but the pH have almost not effect on the cleavage of DNA, and these radical scavengers almost no any effect on the DNA cleavage reaction. The above results suggest that the cleavage of DNA by Ni（RA）₂·3H₂O was not produced diffusible hydroxyl radicals via the Fenton reaction.In addition, we used to study the interactions of the Cu（RA）₂·3H₂O complex between DNA by fluorescence spectral, viscosity measurements and elect更多还原