Sensitizing DNA Towards Low‐Energy Electrons with 2‐Fluoroadenine

Abstract

Abstract 2‐Fluoroadenine ( 2F A) is a therapeutic agent, which is suggested for application in cancer radiotherapy. The molecular mechanism of DNA radiation damage can be ascribed to a significant extent to the action of low‐energy (<20 eV) electrons (LEEs), which damage DNA by dissociative electron attachment. LEE induced reactions in 2F A are characterized both isolated in the gas phase and in the condensed phase when it is incorporated into DNA. Information about negative ion resonances and anion‐mediated fragmentation reactions is combined with an absolute quantification of DNA strand breaks in 2F A‐containing oligonucleotides upon irradiation with LEEs. The incorporation of 2F A into DNA results in an enhanced strand breakage. The strand‐break cross sections are clearly energy dependent, whereas the strand‐break enhancements by 2F A at 5.5, 10, and 15 eV are very similar. Thus, 2F A can be considered an effective radiosensitizer operative at a wide range of electron energies.