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Updated: Dec 31, 2025
Synthesis of Wavelength-shifting DNA Hybridization Probes by Using Photostable Cyanine Dyes
Published on: July 6, 2016
Long-Lifetime Metal-Ligand Complexes as Luminescent Probes for DNA
Henryk Malak1, Ignacy Gryczynski1, Joseph R Lakowicz1
1Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, Maryland 21201.
Abstract:
We examined the intensity and anisotropy decays of DNA labeled with two ruthenium metal-ligand complexes, [Ru(bpy)2(dppz)]2+ and [Ru(phe)2(dppz)]2+. Both complexes display high emission anisotropies in the absence of rotational diffusion, making them suitable probes for rotational motions. When bound to DNA, these complexes display decay times as long as 294 ns, providing long-lived probes of DNA dynamics. The decay times of both complexes were rather insensitive to dissolved oxygen. We examined anisotropy decays of these complexes bound to B-form DNA. The anisotropy decays revealed correlation times near 10, 50, and several hundred nanoseconds, suggesting that these probes are sensitive to a wide range of DNA motions. The use of metal-ligand complexes should allow resolution of both the torsional and bending motions of DNA, the latter of which has been mostly inaccessible using shorter-lived fluorescent probes bound to DNA.
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