Resonant formation of DNA strand breaks by low-energy (3 to 20 eV) electrons.
Most of the energy deposited in cells by ionizing radiation is channeled into the production of abundant free secondary electrons with ballistic energies between 1 and 20 electron volts. Here it is shown that reactions of such electrons, even at energies well below ionization thresholds, induce substantial yields of single- and double-strand breaks in DNA, which are caused by rapid decays of transient molecular resonances localized on the DNA's basic components. This finding presents a fundamental challenge to the traditional notion that genotoxic damage by secondary electrons can only occur at energies above the onset of ionization, or upon solvation when they become a slowly reacting chemical species.
Boudaïffa
B
B
Canadian Medical Research Council Group in Radiation Sciences, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine, University of Sherbrooke, Québec J1H 5N4, Canada.
Cloutier
P
P
Hunting
D
D
Huels
M A
MA
Sanche
L
L
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000737:chemistry / Q000528:radiation effects*; D004249:DNA Damage; D004269:DNA, Bacterial / Q000737:chemistry / Q000528:radiation effects*; D004278:DNA, Superhelical / Q000737:chemistry / Q000528:radiation effects; D004583:Electrons; D004926:Escherichia coli / Q000235:genetics; D009690:Nucleic Acid Conformation; D017785:Photons; D010957:Plasmids; D011789:Quantum Theory; D011829:Radiation Dosage; D011839:Radiation, Ionizing
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004247:DNA