Ru-Labeled Oligonucleotides for Photoinduced Reactions on Targeted DNA Guanines

Abstract

As a strategy to synthesize new sequence-specific DNA photoreagents, oligodeoxyribonucleotides bearing a photoreactive [Ru II (tap) 2 (dip)] 2 complex (tap 1,4,5,8-tetraazaphenanthrene; dip 4,7-diphenylphenanthroline) tethered to a central nucleotide base have been prepared and characterized. The resulting Ru-labeled oligonucleotides exhibit absorption and emission properties of the tethered metal complex and bind to complementary single-stranded DNA sequences. The thermal denaturation curves are not significantly affected by the chemical attachment of the complex. Steady-state and time-resolved emission data reveal a significant luminescence quenching upon hybridization of the Ru-labeled oligonucleotide with the complementary target strand, if the strand contains guanines. Based on the behavior of the free complex, the quenching process is attributed to a photoinduced electron transfer from the guanines of the target strand. This primary process is related to the formation of photoproduct(s) on the duplex that generate an irreversible photocrosslinking of the two strands. This work constitutes an initial step in the design of sequence-specific photocrosslinking agents.

Unexpected DNA binding properties with correlated downstream biological applications in mono vs. bis-1,8-naphthalimide Ru(ii)-polypyridyl conjugates

“…The resulting residue was stirred with 0.1 M HCl, filtered and washed with water. Purification was performed by silica column chromatography eluting with CH 2 Cl 2 /MeOH 10% the product was obtained as a pale brown solid (0.14 g, 83%); calculated for C 29 40 g, 1.01 mmol, 2.1 eq.) and 4,4′-bis(carbonylchloride)-2,2′-bipyridine (0.14 g, 0.48 mmol, 1 eq. …”

“…through intercalation, groove binding and electrostatic interactions. [22][23][24][25][26][27][28][29] We have also developed several examples of DNA targeting binders, based on the use of 1,8-naphthalimide derivatives. [30][31][32][33][34][35][36][37][38] Such structures have tuneable electronic properties, and have been shown to exhibit good DNA binding affinity through either intercalation or groove binding.…”

A theoretical study of Ru(II) polypyridyl DNA intercalators

“…Absorption and emission spectral features of a series of [Ru(L) 2 (L′)] 2+ complexes (L = bipyridine, 1,10 phenanthroline (phen) and 1,4,5,8 tetraazaphenanthrene (tap) and L′ = dipyridophenazine (dppz) and related derivatives) have been investigated by UV/visible and circular dichroism in various environments such as water, acetonitrile, synthetic polynucleotides and calf thymus DNA [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The literature devoted to the spectroscopic properties of [Ru(phen) 2 (dppz)] 2+ and [Ru(tap) 2 (dppz)] 2+ is particularly abundant with absorption/emission data reported in H 2 O, CH 3 CN, for the Ru(II) complexes bound to the double-stranded synthetic polynucleotides [poly(dG-dC)] 2 (G = guanine, and C = cytosine) [2][3][4]6,7,10,11,13,14] and in the presence of calf thymus DNA (CT-DNA).…”

Production and characterization of a polyclonal antibody for Os(II) and Ru(II) polypyridyl complexes

“…Os(II) and Ru(II) polypyridyl complexes have been shown to be effective and versatile biomolecular probes [9][10][11][12][13][14][15][16][17]. Both Os(II) and Ru(II) complexes are stable depending on the ligands used.…”

“…In the case of DNA they have been used as sequence-specific photo reagents. For example, luminescence quenching of a Ru-labeled oligonucleotide occurred upon hybridization to a complementary target strand where the strand contained guanines [9]. They have also been developed as photosensitizers for strand cleavage in DNA [10].…”