| The discovery of triplex enriches the understanding of nucleic acid structure and broadens the understanding of cell activities in lives.The RNA triplex is the Hoogsteen base-paired strand(third-strand),which binds to the Watson-Crick base-paired duplex through hydrogen bonds without destroying the pre-formed template duplex.The triplex is generated in the cell and participates in guiding a variety of biological activities,and it combines with ligands and ions to play important roles in regulating ribosomal gene expression.Its potential application value is also reflected in the fields of biology,chemistry and medicine.However,the stability of the triplex is relatively weak under physiological conditions.A varity of small moleculars have been designed to improve the stability of the triple-helical nucleic acids.And among them,based on the excellent photophysical properties,three-dimensional framework which easy to build and chiral characteristics of the ruthenium(II)metal complexes,it has a stable combination with the triplexes.This work will study on the binding mechanism and stable regulation of Ru(?)metal complexes with the RNA triplex.The content is mainly divided into five parts:The first chapter,the composition and structure of RNA triplex are introduced in detail,and the biological functions and applications of triplex nucleic acids in life activities are discussed in detail,and the research status of regulating the stability of RNA triplex is described in particular.The second chapter,on the basis of classical"molecular light-switches"Ru(?)polypyridine complex[Ru(bpy)2(dppz)]2+,the chiral Ru(?)complexes?/?-[Ru(bpy)2(7-CH3-dppz)]2+(?-1 and?-1)were designed and synthesized.The binding effect of the two enantiomers?-1 and?-1 on the RNA triplex poly(U-A*U)were tested by various methods.The results of spectroscopic and hydrodynamic experiments showed that two enantiomers?-1 and?-1 both had packing-effect with the triplex by insertion binding mode.UV-vis spectra titration experiments showed that?-1 and?-1 have good stable effect on the RNA triplex poly(U-A*U)by insertion binding mode.In addition,fluorescence experiments showed that both of them can act as"molecular light switches"to the triplex RNA,and both have good stabilizing effect on the triplex poly(U-A*U)and duplex poly(A-U),but there are differences in the stability specificity of the two complexes?-1 and?-1 for the triplex by thermal denaturation experiments.The third chapter,the racemic complex[Ru(bpy)2(11-CN-dppz)]2+(rac-2)were synthesized,and the enantiomorphism isomers?/?-[Ru(bpy)2(11-CN-dppz)]2+(?-2and?-2)were resolved to synthesize.The results show that rac-2,?-2 and?-2 were mainly bound to the triplex RNA in an insertion mode by spectroscopic and hydrodynamic experiments.And the binding strength of?-2 to the RNA triplex is stronger than those of rac-2 and?-2,but the binding affinity of rac-2 and?-2 to the RNA triplex is not significantly different from?-2,?-2 and rac-2 are more likely to stabilize the third-strand compared with the enantiomer?-2.It is also interesting to find that the binding properties of racemic complexes cannot be simply understood as the average value of right-handed and left-handed complexes.The forth chapter,we studied on the binding stabilization of Ru(?)-arene complexes[((?)6-C6H6)Ru(7-CH3-dppz)Cl]+(Ru1)and[((?)6-C6H6)Ru(7-NO2-dppz)Cl]+(Ru2)respectively with the RNA triplex poly(U-A*U).The viscosity test showed that two complexes Ru1 and Ru2 were both bound by the insertion mode,but the binding strength of Ru2 was stronger than that of Ru1,which might be caused by the different functional groups in the two Ru(?)-arene complexes Ru1 and Ru2.In addition,Ru(?)-arene complexes Ru1 and Ru2 have prominent stabilization effects on the RNA triplex poly(U-A*U),but Ru1 and Ru2 have preferrential stability on the third strand,and almost no more stabilization on the template duplex.The fifth chapter,we synthesized and characterized chiral complexes?/?-[Ru(bpy)2dpoq]2+(?-3 and?-3).And we studied the interaction between the chiral complexes?-3 or?-3 and RNA triplex poly(U-A*U).The results show that the chiral complexes?-3 and?-3 have no significant difference in the binding specificity of the triplex,and the complexes have no obvious stabilization effect on the triplex. |
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