Tsoulou, E., Kalfas, C. A. and Sideris, E. G. Changes in DNA Flexibility after Irradiation with γ Rays and Neutrons Studied with the Perturbed Angular Correlation Method. Radiat. Res. 159, 33–39 (2003).
Neutron and γ irradiation of buffered solutions of calf thymus DNA resulted in changes in the dynamics of the macromolecule. In the low-dose region (0.8–10 cGy of 239Pu-Be neutrons and 0.34–3 Gy of 60Co γ rays), the flexibility of DNA decreased as indicated by slower rotation of the molecules. Neutrons appeared to be approximately 35 times more effective than 60Co γ rays. The rotational correlation time, τC, was measured using the perturbed angular correlation (PAC) method. Its variation appears to follow a linear-exponential behavior. An attempt is made to formulate this behavior as a function of the energy deposited on the macromolecule (radiation dose), the average threshold energy (dose) required to form new lesions, and the available population of intact DNA sites.