title: Oxidizing Ru(II) complexes as irreversible and specific photo-cross-linking agents of oligonucleotide duplexes.
abstract: Oxidizing polyazaaromatic Ru(II) complexes containing two TAP ligands (TAP = 1,4,5,8-tetraazaphenanthrene) are able under illumination to cross-link irreversibly the two strands of an oligonucleotide (ODN) duplex by covalent bond formation. The cross-linking proceeds by two successive absorptions of a photon. An adduct of the metallic complex on a guanine (G) base of one ODN strand is first photoproduced, followed by a second photoaddition of the same Ru species to a G base of the complementary strand, provided that the two G moieties are separated by 0 or 1 base pair. These two processes lead to the cross-linking of the two strands. Such a photo-cross-linking is easily detected with [Ru(TAP)(2)(phen)](2+) (1; phen = 1,10-phenanthroline) and [Ru(HAT)(2)(phen)](2+) (2; HAT = 1,4,5,8,9,12-hexaazatriphenylene), whereas it is not observed with [Ru(TAP)(2)TPAC](2+) (3; TPAC = tetrapyridoacridine) at the same level of loading of the duplex by 3. With a concentration of 3 similar to that of 1 and 2, when the loading of the duplex by 3 is much more important than with 1 and 2, the photo-cross-linking with 3 can thus also be observed. As 3 intercalates its TPAC ligand into the base pairs stack, its mobility is restricted in the duplex. In contrast, 1 and 2 can adopt different geometries of interaction, which probably facilitate the photo-cross-linking.
authors.affiliation: Université libre de Bruxelles, Chimie Organique et Photochimie CP 160/08, av. F.D. Roosevelt 50, B-1050 Brussels, Belgium.
authors.forename: Liana
authors.initials: L
authors.lastname: Ghizdavu
authors.forename: Frédéric
authors.initials: F
authors.lastname: Pierard
authors.forename: Stéphane
authors.initials: S
authors.lastname: Rickling
authors.forename: Sabrina
authors.initials: S
authors.lastname: Aury
authors.forename: Mathieu
authors.initials: M
authors.lastname: Surin
authors.forename: David
authors.initials: D
authors.lastname: Beljonne
authors.forename: Roberto
authors.initials: R
authors.lastname: Lazzaroni
authors.forename: Pierre
authors.initials: P
authors.lastname: Murat
authors.forename: Eric
authors.initials: E
authors.lastname: Defrancq
authors.forename: Cécile
authors.initials: C
authors.lastname: Moucheron
authors.forename: Andrée
authors.initials: A
authors.lastname: Kirsch-De Mesmaeker
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009841:Oligonucleotides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003432:Cross-Linking Reagents; D008024:Ligands; D009841:Oligonucleotides; D009942:Organometallic Compounds; D012428:Ruthenium