A Rigid Dinuclear Ruthenium(II) Complex as an Efficient Photoactive Agent for Bridging Two Guanine Bases of a Duplex or Quadruplex Oligonucleotide |
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| Authors: | Stéphane Rickling Dr Liana Ghisdavu Dr Frédéric Pierard Dr Pascal Gerbaux Dr Mathieu Surin Dr Pierre Murat Eric Defrancq Prof Cécile Moucheron Prof Andrée Kirsch‐De?Mesmaeker Prof |
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| Institution: | 1. Organic Chemistry and Photochemistry, Université libre de Bruxelles, 50 avenue F.D. Roosevelt, 1050 Bruxelles (Belgium), Fax: (+32)?2‐650‐3018;2. Laboratoire de Chimie Organique, Centre de Spectrométrie de Masse, Université de Mons, 20 Place du Parc, 7000 Mons (Belgium);3. Laboratory for Chemistry of Novel Materials, Université de Mons, 20 Place du Parc, 7000 Mons (Belgium);4. Département de Chimie Moléculaire, UMR CNRS 5250 Université Joseph Fourier BP 53, 38041 Grenoble cedex 9 (France) |
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| Abstract: | The rigid dinuclear (tap)2Ru(tpac)Ru(tap)2]4+ complex ( 1 ) (TAP=1,4,5,8‐tetraazaphenanthrene, TPAC=tetrapyridoacridine) is shown to be much more efficient than the mononuclear bis‐TAP complexes at photodamaging oligodeoxyribonucleotides (ODNs) containing guanine (G). This is particularly striking with the G‐rich telomeric sequence d(T2AG3)4. Complex 1 , which interacts strongly with the ODNs as determined by surface plasmon resonance (SPR) and emission anisotropy experiments, gives rise under illumination to the formation of covalent adducts with the G units of the ODNs. The yield of photocrosslinking of the two strands of duplexes by 1 is the highest when the G bases of each strand are separated by three to four base pairs. This corresponds with each Ru(tap)2 moiety of complex 1 forming an adduct with the G base. This separation distance of the G units of a duplex could be determined thanks to the rigidity of complex 1 . On the basis of results of gel electrophoresis, mass spectrometry, and molecular modelling, it is suggested that such photocrosslinking can also occur intramolecularly in the human telomeric quadruplex d(T2AG3)4. |
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| Keywords: | DNA N ligands oligonucleotides photochemistry ruthenium |
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