Dissociative electron attachment to phosphoric acid esters: the direct mechanism for single strand breaks in DNA.
We use dibutyl phosphate to simulate the behavior of the phosphate group in DNA towards the attack of low energy electrons. We find that the compound undergoes effective dissociative electron attachment within a low energy resonant feature at 1 eV and a further resonance peaking at 8 eV. The dissociative electron attachment (DEA) reactions are associated with the direct cleavage of the C-O and the P-O bond but also the excision of the PO-, PO3-, H2PO3- units. For the phosphate group coupled in the DNA network these reactions represent single strand breaks. We hence propose that the most direct mechanism of single strand breaks occurring in DNA at subexcitation energies (< 4 eV) is due to DEA directly to the phosphate group.
König
Constanze
C
Institut für Chemie und Biochemie - Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany.
Kopyra
Janina
J
Bald
Ilko
I
Illenberger
Eugen
E
D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D053904:DNA Breaks, Single-Stranded / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004583:Electrons; D008956:Models, Chemical; D008958:Models, Molecular; D010755:Organophosphates / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage
D010755:Organophosphates; D004247:DNA