Book of Abstracts: Albany 2005
Novel DNA Detectors Based on Resonance Energy-Transfer Between Ruthenium(II) and Osmium(II) Tris(2,2'-bipyridyl) Chromophores
The creation of reliable and highly specific methods for in situ detection of nucleic acids and other biomacromolecules is crucial for development of novel approaches in genomic and post-genomic molecular diagnostic (1-3). Recently we reported the evidence of self-assembly of heterobinuclear d-f complexes in protic media, using d-block complexes as potential sensitizers, and lanthanide ions acting as potential energy acceptors (4). This approach provided a basis for potential application of visible metal-to-ligand charge-transfer (MLCT) luminescence to DNA probes, sensors and bio-assays. We report here the first example of the use of a pair of metallo-chromophores covalently attached to oligonucleotide split-probes to detect mutations and mismatches in short DNA fragments via resonance energy-transfer on target-directed assembly. Octahedral tris-chelate complexes [MII(bpy)3]2+ (M = Ru or Os, bpy = 2,2'-bipyridyl), covalently attached to the 3'- and 5'-phosphates of two oligonucleotides, are juxtaposed when hybridized contiguously to a fully complementary DNA target. Visible metal-to-ligand charge-transfer excitation of the [RuII(bpy)3]2+ unit leads to resonance energy-transfer (ET) to the MLCT state of the [OsII(bpy)3]2+ moiety. The extent of attenuation of the intense red luminescence from the RuII chromophore allows highly sensitive structural probing of the assembly and constitutes a novel approach to DNA detection and mismatch discrimination.
Figure 1: Target-directed self-assembly of the split-probe DNA system functionalized by metallochromophore parners. D and A represent the [OsII(bpy)3]2+ and [RuII(bpy)3]2+ partners attached through linkers to respective oligonucleotides via the 5' or 3' terminal phosphate groups.
References and Footnotes
Elena V. Bichenkova1
1Wolfson Centre for Rational Structure-Based Design of Molecular Diagnostics