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Fluorescence energy transfer between dimethyldiazaperopyrenium dication and ethidium intercalated in poly d(A-T)
J L Mergny1, A Slama-Schwok, T Montenay-Garestier
1Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, Paris, France.
Photochemistry and Photobiology
|April 1, 1991
Summary
Dimethyldiazaperopyrenium, a large DNA intercalator, showed fluorescence energy transfer with ethidium on poly d(A-T). Intercalation likely induced conformational changes affecting transfer efficiency.
Area of Science:
- Molecular Biology
- Biophysics
Background:
- Dimethyldiazaperopyrenium is a large DNA intercalator.
- DNA intercalators are molecules that insert between base pairs in DNA.
Purpose of the Study:
- To investigate fluorescence energy transfer (FRET) between dimethyldiazaperopyrenium and ethidium.
- To understand the impact of dimethyldiazaperopyrenium intercalation on DNA conformation.
Main Methods:
- Utilized fluorescence spectroscopy to study FRET.
- Employed poly d(A-T) as a model double-stranded polynucleotide.
- Measured fluorescence lifetime changes upon ethidium bromide addition.
Main Results:
- Observed FRET between dimethyldiazaperopyrenium (donor) and ethidium (acceptor) on poly d(A-T).
- Ethidium bromide addition shortened dimethyldiazaperopyrenium fluorescence lifetime, indicating energy transfer.
- Calculated Förster distance of 3.8 nm; observed transfer efficiency was lower than predicted.
Conclusions:
- Dimethyldiazaperopyrenium intercalation induces conformational changes in double-stranded DNA.
- These conformational changes influence the efficiency of fluorescence energy transfer.