DNA binding and bending by dinuclear complexes comprising ruthenium polypyridyl centres linked by a bis(pyridylimine) ligand

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The interaction of enantiomerically pure dinuclear complexes of the form [Ru-2(L-L)(4)L-1](4+) (where L-L = 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) and L-1 = bis(pyridylimine) ligand ((C5H4N)C=N(C6H4))(2)CH2)) with ct-DNA have been investigated by absorbance, circular dichroism, fluorescence displacement assays, thermal analysis, linear dichroism and gel electrophoresis. The complexes all bind more strongly to DNA than ethidium bromide, stabilise DNA and have a significant bending effect on DNA. The data for Delta,Delta-[Ru-2(bpy)(4)L-1](4+) are consistent with it binding to DNA outside the grooves wrapping the DNA about it. By way of contrast the other complexes are groove-binders. The phen complexes provide a chemically and enantiomerically stable alternative to the DNA-coiling di-iron triple-helical cylinder previously studied. In contrast to the di-iron helicates, the phen complexes show DNA sequence effects with Delta,Delta-[Ru-2(phen)(4)L-1](4+) binding preferentially to GC and Lambda,Lambda-[Ru-2(phen)(4)L-1](4+) to AT. (C) 2008 Elsevier Inc. All rights reserved.


Original languageEnglish
Pages (from-to)2052-2059
Number of pages8
JournalJournal of Inorganic Biochemistry
Issue number12
Publication statusPublished - 1 Dec 2008


  • Linear dichroism, DNA bending, DNA binding, Bimetallo complexes, Ruthenium metal complexes