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Radiation-induced luminescence in DNA: evidence for long-range electron migration
A T al-Kazwini1, G E Adams, P O'Neill
1MRC Radiobiology Unit, Didcot, Oxon, United Kingdom.
Radiation Research
|June 1, 1994
Summary
Electron acceptors like metronidazole reduce DNA luminescence. Their efficiency correlates with electron affinity, suggesting long-range electron migration in DNA.
Area of Science:
- Biophysics
- Radiation Chemistry
- Molecular Biology
Background:
- Radiation-induced luminescence in DNA is a key phenomenon.
- Understanding energy transfer and quenching mechanisms in DNA is crucial.
Purpose of the Study:
- To investigate the effect of electron acceptors on DNA luminescence.
- To determine the relationship between additive properties and luminescence quenching.
Main Methods:
- Investigated in-pulse luminescence of solid DNA with metronidazole or 5-nitrofuran.
- Used electron pulses (<260 keV) in vacuum at 293 K.
- Varied additive concentration (3-2000 bp/molecule).
Main Results:
- Luminescence intensity at 450 nm decreased with increasing additive concentration.
- High additive concentrations reduced luminescence to ~50% of DNA alone.
- Quenching efficiency correlated with the redox potential (E1(7)) of additives.
Conclusions:
- Electron acceptors (metronidazole, 5-nitrofuran) effectively reduce DNA luminescence.
- Additive's electron affinity is key to luminescence quenching.
- Proposed electron migration distances of at least 300 base pairs in DNA.