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Atomic Force Microscopy Investigations of DNA Lesion Recognition in Nucleotide Excision Repair
Published on: May 24, 2017
Changes in DNA flexibility after irradiation with gamma rays and neutrons studied with the perturbed angular
E Tsoulou1, C A Kalfas, E G Sideris
1NCSR Demokritos, Institute of Nuclear Physics, Athens, Grece.
Radiation Research
|December 21, 2002
Summary
Neutron and gamma irradiation decreased DNA flexibility, with neutrons being 35 times more effective. DNA dynamics changes were modeled based on radiation dose and lesion formation.
Area of Science:
- Molecular Biology
- Radiation Biology
- Biophysics
Background:
- Ionizing radiation, including neutrons and gamma rays, can induce significant alterations in the structure and dynamics of biological macromolecules like DNA.
- Understanding the effects of radiation on DNA is crucial for assessing biological damage and developing protective strategies.
Purpose of the Study:
- To investigate the impact of neutron and gamma irradiation on the molecular dynamics of calf thymus DNA.
- To quantify the relative effectiveness of neutrons versus gamma rays in altering DNA dynamics.
- To develop a model describing DNA dynamic changes as a function of radiation dose and molecular parameters.
Main Methods:
- Buffered solutions of calf thymus DNA were subjected to controlled doses of 239Pu-Be neutrons and 60Co gamma rays.
- The rotational correlation time (tau C) of DNA molecules was measured using the perturbed angular correlation (PAC) technique.
- Data analysis focused on the low-dose region to observe initial dynamic changes.
Main Results:
- Both neutron and gamma irradiation led to a decrease in DNA flexibility, evidenced by slower molecular rotation.
- Neutron irradiation was found to be approximately 35 times more effective than 60Co gamma rays in altering DNA dynamics.
- The observed changes in rotational correlation time (tau C) exhibited a linear-exponential behavior in response to radiation dose.
Conclusions:
- Irradiation significantly impacts DNA molecular dynamics, reducing its flexibility.
- Neutrons are substantially more potent than gamma rays in inducing these dynamic changes.
- A mathematical model was proposed to describe DNA dynamic alterations based on radiation dose, threshold energy for lesion formation, and available intact DNA sites.
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