title: DNA binding and cleavage properties of a newly synthesised Ru(II)-polypyridyl complex.
abstract: The single crystal X-ray structure of the newly synthesized ruthenium (II)-polypyridyl complex, [(bpy)(2)Ru(L)](PF(6))(2) (1) (bpy is 2,2'-bipyridyl and L is 2-methyl-2H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-ol revealed a near planar conformation for the fused imidazole moiety, suggesting the complex may be capable of binding to duplex DNA. Binding-induced changes in spectral properties, along with thermal denaturation and viscosity measurement studies confirmed that the complex binds to CT-DNA with a moderately high binding constant value (4.1 x 10(5) M(-1)) through intercalation. Photocleavage studies with the pBR322 plasmid DNA were performed following excitation of this complex into the Ru(dpi) --> bpy/L(pi*)-based MLCT band and have shown that this complex cleaves the circular pBR322 DNA into linear DNA. Inhibitor studies revealed that the hydroxyl radicals were mainly responsible for the DNA photocleavage reaction. Preliminary studies indicate that the -OH functionality in 1 was also found to hydrolyse the phosphodiester linkage of pBR322 in the dark.
authors.affiliation: Central Salt and Marine Chemicals Research Institute (CSIR), Bhavnagar. 364002, Gujarat, India.
authors.forename: Amrita
authors.initials: A
authors.lastname: Ghosh
authors.forename: Amit
authors.initials: A
authors.lastname: Mandoli
authors.forename: D Krishna
authors.initials: DK
authors.lastname: Kumar
authors.forename: Narendra Singh
authors.initials: NS
authors.lastname: Yadav
authors.forename: Tamal
authors.initials: T
authors.lastname: Ghosh
authors.forename: Bhavanath
authors.initials: B
authors.lastname: Jha
authors.forename: Jim A
authors.initials: JA
authors.lastname: Thomas
authors.forename: Amitava
authors.initials: A
authors.lastname: Das
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D053837:DNA Cleavage; D008968:Molecular Conformation; D009691:Nucleic Acid Denaturation; D010782:Photolysis; D012428:Ruthenium / Q000737:chemistry*; D014783:Viscosity
chemical_list: D056831:Coordination Complexes; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D004247:DNA