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Dynamics in the DNA recognition by DAPI: exploration of the various binding modes
Debapriya Banerjee1, Samir Kumar Pal
1Unit for Nano Science & Technology, Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
The Journal of Physical Chemistry. B
|January 4, 2008
Summary
The fluorescent probe 4
Area of Science:
- Biophysical Chemistry
- Molecular Biology
- Spectroscopy
Background:
- The fluorescent probe 4',6-diamidino-2-phenylindole (DAPI) exhibits distinct DNA binding modes.
- Understanding these interactions is crucial for molecular biology applications.
Purpose of the Study:
- To investigate the solvation dynamics of DAPI during its interaction with DNA oligomers of varying sequences.
- To elucidate the structure-dynamics correlation in DAPI-DNA complexes.
Main Methods:
- Picosecond-resolved fluorescence spectroscopy.
- Polarization-gated anisotropy measurements.
- Utilizing Hoechst 33258 as a control for minor-groove binding.
Main Results:
- DAPI binds to CGCGAATTCGCG (oligo1) via minor-groove interaction, evidenced by solvation dynamics.
- DAPI intercalates into GCGCGCGCGCGC (oligo2), showing fluorescence quenching and a fast fluorescence lifetime component due to electron transfer.
- DAPI dynamics in random-sequence DNA resemble minor-groove binding.
Conclusions:
- Solvation dynamics effectively differentiate DAPI's DNA binding modes.
- DAPI exhibits sequence-dependent interactions with DNA, including minor-groove binding and intercalation.
- The study provides insights into the photophysical properties of DAPI in different DNA-binding states.
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