Intercalation of ethidium bromide into a triple-stranded oligonucleotide.
We have examined the ability of a cationic planar chromophore, ethidium bromide, to intercalate into a short, defined triple helix. Using UV absorption, fluorescence spectroscopy and a gel retardation assay we demonstrate that ethidium bromide is able to bind to a triple helix with a lower affinity than to the corresponding duplex. Energy transfer from base triplets to ethidium shows that ethidium is intercalated into the triple helix. The spectroscopic characteristics of ethidium intercalated into a triplex are similar to those observed for intercalation into duplex DNA.
Mergny
J L
JL
Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, INSERM U 201, CNRS UA 481, Paris, France.
Collier
D
D
Rougée
M
M
Montenay-Garestier
T
T
Hélène
C
C
D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D004735:Energy Transfer; D004996:Ethidium / Q000737:chemistry*; D007364:Intercalating Agents / Q000737:chemistry*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
D007364:Intercalating Agents; D009838:Oligodeoxyribonucleotides; D004996:Ethidium