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Intercalation of ethidium bromide into a triple-stranded oligonucleotide
J L Mergny1, D Collier, M Rougée
1Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, INSERM U 201, CNRS UA 481, Paris, France.
Nucleic Acids Research
|April 11, 1991
Summary
Ethidium bromide intercalates into DNA triple helices, but with lower affinity than duplex DNA. Spectroscopic analysis confirms intercalation and shows similarities to duplex binding.
Area of Science:
- Molecular Biology
- Biophysical Chemistry
Background:
- DNA structure can be altered to form triple helices.
- Ethidium bromide is a known DNA intercalator.
Purpose of the Study:
- To investigate ethidium bromide intercalation into DNA triple helices.
- To compare binding affinity to triple helix versus duplex DNA.
Main Methods:
- UV absorption spectroscopy
- Fluorescence spectroscopy
- Gel retardation assay
Main Results:
- Ethidium bromide binds to triple helices with lower affinity than duplex DNA.
- Energy transfer confirms ethidium bromide intercalation into the triple helix.
- Spectroscopic properties of intercalated ethidium are similar in triplex and duplex DNA.
Conclusions:
- Ethidium bromide can intercalate into DNA triple helices.
- Triple helix DNA exhibits altered binding characteristics for intercalating agents compared to duplex DNA.