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Stability of radiation-damaged DNA after multiple strand breaks
Fabio Landuzzi1, Pier Luca Palla, Fabrizio Cleri
1Institut d'Electronique, Microelectronique et Nanotechnologie (IEMN Cnrs UMR 8520), Université de Lille I, 59652 Villeneuve d'Ascq, France. fabrizio.cleri@univ-lille1.fr.
Physical Chemistry Chemical Physics : PCCP
|May 25, 2017
Summary
DNA backbone damage from radiotherapy creates breaks. Molecular dynamics reveal these DNA defects are stable unless close, impacting protein recognition and DNA fragmentation.
Area of Science:
- Molecular Biophysics
- Radiation Biology
- Computational Biology
Background:
- DNA backbone damage, including single- and double-strand breaks (DSBs), is induced by natural sources and radiotherapy.
- Understanding the immediate molecular dynamics post-damage is critical for determining DNA fragment fate.
Purpose of the Study:
- To investigate the molecular-scale dynamics of DNA single- and double-strand breaks immediately after formation.
- To determine the factors influencing DNA cohesion and defect evolution following backbone cleavage.
Main Methods:
- All-atom molecular dynamics simulations were employed.
- Simulations analyzed force spectra and thermal stability of various single- and multiple-defect configurations in a 31 bp DNA sequence.
Main Results:
- DNA defects exhibit complex dynamics, with collective bond rearrangements being more significant than simple bond cleavage.
- Defects remain stable against thermal disruption unless they are very closely spaced.
- The study establishes conditions necessary for DNA fragmentation.
Conclusions:
- Findings shed light on early-stage DNA damage recognition and signaling by proteins.
- The non-uniqueness of identifying and counting DSBs by different experimental methods is implied.
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