DNA-binding And Triplex RNA Stability Together With Conformation Regulation By Ruthenium(Ⅱ) Complexes

Nucleic acid is not only important genetic material but also dynamicmacromolecules in biological system. Its structures are varied under the influence ofvarious internal and external factors. Many studies have shown that small moleculesare important factors affecting the structural diversity of nucleic, and thus being anrelatively important parts in the structure and conformational studies of nucleic acids.Ruthenium (II) polypyridyl complexes, due to a combination of easily constructedspatial structures spanning all three spatial dimensions and a rich photophysicalrepertoire, have become the leader parts among the small molecule compounds.We have synthesized four ruthenium complexes in this article, two of theminvolve the reactive naphthyl anhydride groups and the other two contain thefunctional dual oxygen groups. To explore their interaction with the CT-DNA andRNA triplexes, a serious of test methods have been employed integrated. Followingare the research details:1. In chapter one, a brief development of Bioinorganic Chemistry and some basicknowledge about the composition of nucleic acid have been introduced, along withthe binding mode between complexes and nucleic acid.2. In chapter two, a novel kind of Ruthenium(II) polypyridyl complexes weresynthesized by adding a functional group to the intercalative ligand. The interactionand DNA photocleavage activity was explored by chemical and biological testingmethods. The results suggested that this two complexes bind to DNA by intercalationmode and possess positive DNA photoleavage efficiency. In addition, strongerbinding action was indicated in the case of [Ru(phen)2(pnip)]2+(Ru1), compared with[Ru(bpy)2(pnip)]2+(Ru2).3. Based on the research in chapter two, we further investigated the bindingproperties of naphthalenic complexes with regard to poly(U) poly(A)*poly(U) inchapter three. Electronic spectra establish that the binding modes are proved to beintercalative, and UV melting studies indicate that, contrary to Ru2, the Hoogsteenbase paired third strand stabilized by Ru1is stronger than the duplex structure.Circular dichroic studies suggested that the triplex RNA experiences a conformationaltransition in the presence of Ru1.4. In chapter four, we synthesized the other two complexes containing functionaldual oxygen group,[Ru(4,7-dmp)2(mip)]2+(Ru3)and [Ru(phen)2(mip)]2+(Ru4), their binding actions with poly(U) poly(A)*poly(U) were studied using the similarmethods adopted in chapter three. In comparison with Ru3, remarkably higherbinding affinity of Ru4with the triplex RNA achieved by changing the ancillaryligands and the stabilization of the Hoogsteen base paired third strand was furtherimproved. The results revealed that-CH3on the ancillary ligand will lead to greatersteric hindrance and higher LUMO energy, resulting in the binding and stabilitydifferences.