Interaction Of Ruthenium(?) Polypyridyl Complexes With Nucleic Acids

Ruthenium??? polypyridyl complexes have received considerable attentions in bioinorganic chemistry due to their prominent photochemical and photophysical properties,biological activities and nucleic acids binding properties.This dissertation is mainly about the interactions of ruthenium???polypyridyl complexes with c-myc G-quadruplex DNA,yeast RNA and calf thymus?ct?DNA.The dissertation includes the followings:1.Two dinuclear ruthenium??? complexes 1,2 and a mononuclear ruthenium???complexes 3 have been synthesized and characterized by elemental analysis,FAB-MS,¹H NMR,¹³C NMR and IR.2.The interactions of complexes 1 and 2 with c-myc Pu27 DNA have been investigated by UV-vis and fluorescence spectroscopy,Job plot,circular dichroism?CD?spectroscopy,polymerase chain reaction?PCR?stop assay,color reaction and fluorescence resonance energy transfer?FRET?melting assay.The results suggested that:Complexes 1 and 2 could bind to c-myc Pu27 G-quadruplex DNA through groove mode with the high affinity of 6.2×10⁷ M^-1,1.18×10⁷ M^-11 and the binding stoichiometries of 2:1,1:1,respectively;Both the complexes 1and 2 could efficiently induce c-myc Pu27 DNA to form G-quadruplex structure,and particularly,complex 1 displayed superior G-quadruplex stability and selectivity over duplex DNA with the?T_m value of c-myc Pu27 G-quadruplex DNA being 13.5-15.5°C;Complex 1could act as a promising"G-quadruplex DNA light switch"with 8.82-fold fluorescence enhancements at binding saturation in K⁺buffer.3.The interactions of ruthenium complex 3 with ct-DNA has been investigated by UV-visible and emission spectroscopy titrations,steady-state emission quenching,ethidium bromide?EB?competition,viscosity measurements,DNA thermal denaturation,salt effect,agarose gel electrophoresis and DFT method.The results indicated that:Complex 3 bond to ct-DNA via an intercalation mode due to planar aromatic structure of the main ligand,and the binding constant was 1.32×10⁶ M^-1;Complex 3 could stabilize the double helix structure of DNA by increasing the DNA melting temperature by 10°C;Complex 3 is an effective photocleavage reagent for pBR322 plasmid DNA.4.The interactions of ruthenium complexes 1,2 with yeast RNA have been investigated by electron absorption spectra,emission spectroscopy,steady-state emission quenching and salt effect.the results suggested that:The RNA binding constants of complexes 1 and 2 were5.65×10⁵ M^-11 and 3.50×10⁶ M^-1,respectively,which were smaller than those of DNA binding;These complexes bond to RNA probably through an intercalation mode with high strength not only at low salt concentration but also at high salt concentration.