【作者】 鲁慧丽；

【导师】 曾正志；

【作者基本信息】 兰州大学 ， 无机化学， 2007， 博士

【摘要】 综述了小分子与核酸相互作用研究的发展状况，小分子与核酸的作用方式及影响因素。总结了小分子与核酸的作用的研究方法、研究技术与研究手段，阐述了本研究领域当前的研究概况、发展方向及前景。DNA是生命体的基本分子，是分子药理学研究药物性质的主要靶向分子之一。喹诺酮类、双胍类、磺酰脲类药物具有广泛药理性质，水杨醛Schiff碱类化合物具有许多潜在的生物活性，为了揭示它们及其金属配合物在降血糖、抗菌、抗癌等药理学和生物学活性的分子机理，本文采用紫外一可见吸收光谱、荧光光谱、共振光散射、圆二色谱、粘度和红外光谱等方法，研究了加替沙星，甲苯磺丁脲，氯磺丙脲、水杨酰二甲双胍等4种药物及其稀土配合物、3个新型水杨醛衍生物Schiff碱及其Zn（Ⅱ）配合物等与DNA、核苷酸的相互作用。首先合成了4个新的HGA与稀土的固态配合物，元素分析、IR、摩尔电导、热重分析和荧光光谱等研究表明其化学组成式为[RE（HGA）₃（H₂O）₂]Cl₃(RE³⁺=La³⁺，Nd³⁺，Eu³⁺和Tb³⁺，配合物分别以LaL₃，NdL₃，EuL₃，TbL₃表示)，通过紫外吸收光谱，荧光光谱和粘度法研究了它们与DNA和核苷酸的相互作用。结果表明，配体HGA和4种配合物均以沟结合方式作用在DNA的大沟区，这与配体中哌嗪基不能和喹啉环共平面的结构特点有关，4种配合物与DNA之间还存在静电作用；4f电子层填充状态的不同导致各配合物的荧光光谱出现较明显的差异；4种配合物与DNA的结合常数均大于HGA，并呈现LaL₃＜NdL₃＜EuL₃＜TbL₃的顺序，说明稀土离子种类影响了配合物与DNA的结合能力，只是这种影响力比较小，并推测这些配合物有比配体HGA更强的抗菌活性。其次，研究了水杨酰二甲双胍钕配合物（Nd（SG）₃）与DNA的作用行为，发现它以非经典的插入模式与DNA作用。Nd（SG）₃的插入部分是水杨酰基芳香环，芳环上的羟基与胍基部分的氮原子形成了分子内氢键，增强了插入部分的共平面面积，再加上水杨酰二甲双胍配体与钕离子的“协同”效应，使配合物Nd（SG）₃拥有与DNA较显著的插入作用和结合能力，这与它们具有很高的降血糖作用的实验结果相一致。它们与DNA的紧密结合预示配合物Nd（SG）₃可能具有潜在的抗菌、抗癌等药理活性。第三，研究了Nd（Ⅲ）、Eu（Ⅲ）与降血糖药物甲苯磺丁脲(D₈₆₀，D)、氯磺丙脲（CP）的金属配合物NdD、EuD、NdCP、EuCP与DNA的相互作用。结果表明它们同样以非经典的插入模式与DNA结合，其结合能力比配合物Nd（SG）₃还要强。RLS光谱说明这些化合物在DNA分子表面进行长距组装，这与降低样品离子强度则化合物减色率升高的实验事实共同证明了它们与DNA之间还存在静电作用。D₈₆₀稀土配合物与DNA的结合常数大于配体D₈₆₀，表明D₈₆₀与稀土离子间存在“协同”效应，这可能是D₈₆₀形成配合物NdD后，破坏了与DNA磷酸根的氢键，减小了NdD插入DNA的阻力，从而提高了与DNA的结合能力所致。实验结果提示D₈₆₀稀土配合物的生物活性可能比配体D₈₆₀的更强。在紫外光谱和粘度实验中配合物表现的与DNA作用强弱顺序相同，均为NdD＞EuD，NdCP＞EuCP，不同离子的影响力在这两种药物的配合物中一致地表现为Nd³⁺＞Eu³⁺，与加替沙星稀土配合物中Eu³⁺＞Nd³⁺的顺序相反。看来与不同药物形成配合物以后，Eu³⁺、Nd³⁺离子对配合物与DNA作用强弱的影响力顺序并不相同。第四，设计、合成了3-甲醛基-5-甲基-水杨醛缩乙醇胺（H₂L¹）、3-羟甲基-5-甲基-水杨醛缩乙醇胺（H₃L²）和2-羟基-5-甲基-1，3-苯二醛缩邻氨基苯甲酸（H₃L³）3个新型水杨醛衍生物的Schiff碱，合成并表征了它们与Zn（Ⅱ）的配合物（ZnHL¹，ZnH₂L²和ZnHL³）。研究了3个配合物与DNA的结合行为及它们清除羟基自由基（·OH）的能力。发现ZnHL¹和ZnHL³以插入方式与DNA结合，且后者插入作用大于前者；ZnH₂L²则不能有效地插入到DNA碱基对间，而是通过氢键结合在沟处。这表明3个配体不同的取代基改变了它们配合物的空间构型和构象，进而影响它们与DNA的结合方式、结合能力和光谱行为。3种配体清除羟自由基能力的顺序是H₃L²＞H₂L¹＞H₃L³，恰好与配体中羟基的数量一致。这是配体上取代基不同，即H₃L²中的供电子基有活化作用，而H₂L¹和H₃L³中的吸电子基则产生钝化作用所致。配合物对·OH自由基的清除能力均大于相应配体，这是由于Zn²⁺离子与酚羟基配位后增加了酚羟基与·OH反应的活性，酚羟基更易释放出H⁺，H⁺会与·OH形成更稳定的化合物，导致对·OH的清除作用增强。这些结果为设计、筛选新的药物提供了有用的信息。更多还原

【Abstract】 The development of the interaction between small molecule and nucleic acid was fully described in the dissertation paper. It involves interaction modes and influence factors, research methods and research techniques. The development direction and development prospects were also expatiated.DNA is a main carrier of life information, is one of the logically potential target for drugs in pharmacology. Quinolones, biguanide, and sulfonylurea have extensive bioactivity. In order to explore the mechanism of them and their metal complexes in pharmacological activity including antibacterial, anticancer, and anti-diabetes activity, we investigated the interaction of DNA, nucleotide and four drugs and their rare earth complexes, three new salicylaldehyde derivative Schiff base and their Zn（II） complexes. Many methods were performed: UV-Vis absorption and fluorescence measurements, resonance light-scattering, circular dichroism, viscosity, and IR spectrum.Firstly, we prepared four novel rare earth complexes of HGA, the composition of complexes were investigated to be [RE（HGA）₃（H₂O）₂]Cl₃ (RE³⁺ = La³⁺, Nd³⁺, Eu³⁺, and Tb³⁺, the abbreviations of four complexes are LaL₃, NdL₃, EuL₃, and TbL₃), through elemental analysis, IR, molar conductivity, thermogravimetry/differential thermal analysis （TG-DTA）, and fluorescence spectra. The binding behaviors of complexes and HGA to DNA and nucleotide are presented and discussed using UV-Vis absorption and fluorescence spectroscopy, and viscosity.The results suggest that both complexes and HGA bind to DNA via groove interaction, which is associated with the characteristic of complex structure: the piperazynyl moiety in Hgand of present complexes can not coplanar with the quinoline nucleus. And electrostatic force is another binding mode between complexes and DNA. The quenching mechanism of HGA and LaL₃ by DNA is ascribed to the electron transfer from guanine to the compounds; this transfer process did not happen between other complexes and DNA because the different characterizations of 4f electron shell of RE³⁺ ions. In addition, the binding strength of complexes to DNA is stronger than that of HGA; it can be assembled in following order: LaL₃ < NdL₃< EuL₃ < TbL₃, indicating that the species of central ion can effect on the binding affinities of complexes to DNA, while the force is not stronger. This result also supports the reasoning that these complexes may have stronger antibacterial activity than ligand.Secondly, the DNA-binding of neodymium complex with salicylacyl dimethylbiguanide （Nd（SG）3） were investigated. It was found that Nd（SG）3 interacts to DNA through non-classic intercalation mode, the intercalative part is the salicylacyl of ligand. The form of hydrogen bonding between the -OH group of salicylacyl and the nitrogen atom of guanidine makes the intercalative part possesses a greater planar area, hence it together with the synergistic enhancement between ligand and rare earth ions play the important role in the result: Nd（SG）3 is engaged in DNA binding intimately, which is consistent with the result that Nd（SG）3 has good anti-diabetes. This stronger DNA binding strength foreshows that Nd（SG）3 may has potential antibacterial or anticancer activity.Thirdly, we explored the DNA binding behaviors of four Nd（III）, Eu（III） complexes containing tolbutamide (D₈₆₀, D) or chlorpropamide （CP）: NdD, EuD, NdCP, and EuCP. It has been proved that they also interact to DNA through non-classic intercalation mode, but they exhibit stronger DNA binding affinity than Nd（SG）3. RLS spectra show that there are obvious long range assembly of these complexes on the molecular surface of DNA, indicates electrostatic force is another binding mode between them and DNA. This result also can get from the fact: the hypochromism of present complexes decrease with the increasing concentration of NaCl in buffer. The K_b values of NdD and EuD are higher than that of D₈₆₀ itself, which is ascribed to the synergistic enhancement of the ligand and rare earth ions. In addition, the coordination with metal ions decrease the possibility of forming hydrogen bonding with DNA, and decrease their resistance of intercalating to DNA, hence enhance their affinity with DNA. Present observations lead us to suspect that complexes have stronger bioactivity than ligand. In both UV-Vis absorption and viscosity measurements, four complexes exhibit same DNA-binding strength order: NdD > EuD, NdCP > EuCP. For these complexes with D₈₆₀ or CP, the influence force order of Nd³⁺ and Eu³⁺ is same: Nd³⁺ > Eu³⁺, which is contrary to complexes with gatifloxacin: Eu³⁺ > Nd³⁺. So it becomes evident that for different drug complexes, the influence force of Nd³⁺ and Eu³⁺ in DNA-binding is different.Fourth, three new Schiff base ligandsN-（3-formyl-5-methylsalicylidene）-2-aminoethanol （H₂L¹）,N-（3-hydroxylmethyl-5-methylsalicylidene）-2-aminoethanol （H₃L²）,2,6-bis（o-carboxyphenyliminomethene）-4-methylphenol （H₃L³） and their binuclear Zn（ II） complexes [Zn₂（HL¹）₂]Cl₂-2H₂O （ZnHL¹）, [Zn₂（H₂L²）₂]Cl₂·H₂O （ZnH₂L²） and [Zn₂（HL³）Cl₂]·H₂O （ZnHL³） were synthesized and characterized by ¹H NMR, elemental analysis, IR and molar conductivity. The DNA-binding of these complexes were investigated. Mechanistic studies show that ZnHL¹ and ZnHL³ can bind to DNA by intercalative mode, and the latter intercalates into DNA more efficiently than the former, while ZnH₂L² binds to DNA by hydrogen bonding interaction on the grooves of DNA host. All of these results further support the fact that modification of the ligands can produce interesting differences in the space configuration, which lead to some differences in spectral properties, DNA binding mode and strength of complexes.The scavenging ability of ligands can be assembled in following order: H₃L²>H₂L¹>H₃L³. It can be first elucidated by the mechanism that the electron-releasing group （-CH2OH） can stabilize the phenoxyl radical, in contrast, electron-attracting groups （-CHO,-C=N-Ph） induces inverse result. Second, the phenoxyl radical derived from H₃L² can be further stabilized by forming intramolecular hydrogen bonding between itself and o-position group. Moreover, the scavenging ability accords with the amount of hydroxyl in ligands. After coordination with Zn²⁺, the phenolic hydroxyl can more easily give off H⁺, and H⁺ will form a stable compound with·OH. So the scavenging ability of complexes is stronger than their corresponding ligands. This experimental and theoretical information will be useful in design of new drugs and therapeutic reagents.更多还原