TY  - GEN
A1  - Bald, Ilko
A1  - Kopyra, Janina
A1  - Keller, Adrian
T1  - On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy
N2  - Gemcitabine (2′,2′-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2′-deoxycytidine, 2′-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 167 
KW  - low-energy electrons
KW  - single-strand breaks
KW  - gas-phase
KW  - chemoradiation therapy
KW  - molecular-mechanisms
KW  - resonant formation
KW  - damage
KW  - attachment
KW  - drugs
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-73412
SP  - 6825
EP  - 6829
ER  - 
TY  - GEN
A1  - Bald, Ilko
A1  - Keller, Adrian
T1  - Molecular processes studied at a single-molecule level using DNA origami nanostructures and atomic force microscopy
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM) which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1146 
KW  - DNA origami
KW  - atomic force microscopy
KW  - single-molecule analysis
KW  - DNA radiation damage
KW  - protein binding
KW  - enzyme reactions
KW  - G quadruplexes
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-475843
SN  - 1866-8372
IS  - 9
SP  - 13803
EP  - 13823
ER  -