Detection of secondary structures in 17-mer Ru(ii)-labeled single-stranded oligonucleotides from luminescence lifetime studies

Abstract

The emission properties of a non intercalating complex, [Ru(TAP)2(dip)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene; dip = 4,7-diphenyl-1,10-phenanthroline), tethered to 17-mer single-stranded oligodeoxyribonucleotides (ODNs) either in the middle or at the 5'-end of the sequence, are determined. The results highlight the fact that the luminescence of this metallic compound is sufficiently sensitive to its microenvironment to probe self-structuration of these short single-stranded ODNs. It is shown that the weighted averaged emission lifetimes (tau(M)) along with the quenching rate constants of luminescence by oxygen reflect particularly well different structures adopted by the different ODNs sequences. The determination of these parameters thus offers an elegant way to examine possible structurations of synthetic single-stranded ODNs that play important roles in biological applications.

Photooxidation of Guanine by a Ruthenium Dipyridophenazine Complex Intercalated in a Double‐Stranded Polynucleotide Monitored Directly by Picosecond Visible and Infrared Transient Absorption Spectroscopy

“…[11][12][13][14][15] As such electron transfers are fast chemical processes, they are usually initiated by short laser-pulse excitation of sensitizers such as phenothiazonium dyes, [16,17] anthraquinones [18,19] or metal complexes. [20][21][22][23][24] The study of compounds intercalated into DNA is especially appropriate for theoretical treatment as the relative orientation of the electron donor and acceptor is well defined.…”

A Photoreactive Ruthenium(II) Complex Tethered to a Guanine‐Containing Oligonucleotide: A Biomolecular Tool that Behaves as a “Seppuku Molecule”

“…The weighted average lifetime ( τ m ) for Ru(T)‐ODN (G) is shorter than the lifetime of the corresponding free Ru II complex ( τ 0 ; Table 1, entry 3), with a short component of 89 ns. In contrast, neither τ tm nor the discrete lifetime components are shorter than the corresponding τ 0 values for Ru(P)‐ODN (G) and Ru(T)‐ODN (T) (Table 1, entries 1, 2) 10. These data show clearly that no PET, which is responsible for the luminescence quenching [Figure 1 b, Eq.…”

Luminescent Transition Metal Complexes as Biological Labels and Probes

“…Photoadduct formation between the guanine and the ruthenium label means that cross-linking of the two DNA strands occurs upon irradiation; the results have been confirmed by gel electrophoresis experiments. In another study, 17-mer single-stranded DNA molecules labelled with the same ruthenium(II) complex have been synthesised [39]. Some of these oligonucleotides possess a sequence that allows the formation of secondary structures (selfstructuration).…”