TY  - JOUR
A1  - Rackwitz, Jenny
A1  - Kopyra, Janina
A1  - Dabkowska, Iwona
A1  - Ebel, Kenny
A1  - Rankovic, MiloS Lj.
A1  - Milosavljevic, Aleksandar R.
A1  - Bald, Ilko
T1  - Sensitizing DNA Towards Low-Energy Electrons with 2-Fluoroadenine
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - 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.
KW  - ab initio calculations
KW  - dissociative electron attachment
KW  - DNA origami
KW  - DNA radiation damage
KW  - fludarabine
Y1  - 2016
U6  - https://doi.org/10.1002/anie.201603464
SN  - 1433-7851
SN  - 1521-3773
VL  - 55
SP  - 10248
EP  - 10252
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Rackwitz, Jenny
A1  - Ranković, Miloš Lj.
A1  - Milosavljević, Aleksandar R.
A1  - Bald, Ilko
T1  - A novel setup for the determination of absolute cross sections for low-energy electron induced strand breaks in oligonucleotides
BT  - the effect of the radiosensitizer 5-fluorouracil*
JF  - The European physical journal : D, Atomic, molecular, optical and plasma physics
N2  - Low-energy electrons (LEEs) play an important role in DNA radiation damage. Here we present a method to quantify LEE induced strand breakage in well-defined oligonucleotide single strands in terms of absolute cross sections. An LEE irradiation setup covering electron energies <500 eV is constructed and optimized to irradiate DNA origami triangles carrying well-defined oligonucleotide target strands. Measurements are presented for 10.0 and 5.5 eV for different oligonucleotide targets. The determination of absolute strand break cross sections is performed by atomic force microscopy analysis. An accurate fluence determination ensures small margins of error of the determined absolute single strand break cross sections sigma SSB. In this way, the influence of sequence modification with the radiosensitive 5-Fluorouracil (U-5F) is studied using an absolute and relative data analysis. We demonstrate an increase in the strand break yields of U-5F containing oligonucleotides by a factor of 1.5 to 1.6 compared with non-modified oligonucleotide sequences when irradiated with 10 eV electrons.
Y1  - 2017
U6  - https://doi.org/10.1140/epjd/e2016-70608-4
SN  - 1434-6060
SN  - 1434-6079
VL  - 71
PB  - Springer
CY  - New York
ER  -