TY  - JOUR
A1  - Schuermann, Robin
A1  - Tanzer, Katrin
A1  - Dabkowska, Iwona
A1  - Denifl, Stephan
A1  - Bald, Ilko
T1  - Stability of the Parent Anion of the Potential Radiosensitizer 8-Bromoadenine Formed by Low-Energy (< 3 eV) Electron Attachment
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - 8-Bromoadenine ((8Br)A) is a potential DNA radiosensitizer for cancer radiation therapy due to its efficient interaction with low-energy electrons (LEEs). LEEs are a short-living species generated during the radiation damage of DNA by high-energy radiation as it is applied in cancer radiation therapy. Electron attachment to (8Br)A in the gas phase results in a stable parent anion below 3 eV electron energy in addition to fragmentation products formed by resonant exocyclic bond cleavages. Density functional theory (DFT) calculations of the (8Br)A(-) anion reveal an exotic bond between the bromine and the C8 atom with a bond length of 2.6 angstrom, where the majority of the charge is located on bromine and the spin is mainly located on the C8 atom. The detailed understanding of such long-lived anionic states of nucleobase analogues supports the rational development of new therapeutic agents, in which the enhancement of dissociative electron transfer to the DNA backbone is critical to induce DNA strand breaks in cancerous tissue.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.jpcb.7b02130
SN  - 1520-6106
VL  - 121
SP  - 5730
EP  - 5734
PB  - American Chemical Society
CY  - Washington
ER  - 
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  -