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Sascha Gohlke

Publications and source records attributed to Sascha Gohlke.

5 recordsLinked to original sources
PubMed2006

Dissociative electron attachment to furan, tetrahydrofuran, and fructose.

We study dissociative electron attachment to furan (FN) (C(4)H(4)O), tetrahydrofuran (THF) (C(4)H(8)O), and fructose (FRU) (C(6)H(12)O(6)) using crossed electron/molecular beams experiments with mass spectrometric detection of the anions. We find that FN and THF are weak electron scavengers and subjected to dissociative electron attachment essentially in the energy range above 5.5 eV via core excited resonances. In striking contrast to that, FRU is very sensitive towards low energy electrons generating a variety of fragment ions via a pronounced low energy feature close to 0 eV. These reactions are associated with the degradation of the ring structure and demonstrate that THF cannot be used as surrogate to model deoxyribose in DNA with respect to the attack of electrons at subexcitation energies (<3 eV). The results support the picture that in DNA the sugar moiety itself is an active part in the initial molecular processes leading to single strand breaks.

Anions↗
PubMed2004

Degradation of N-acetyl tryptophan by low-energy (<12 eV) electrons.

Secondary low-energy electrons are abundantly created during the early moments following the deposition of energy by radiation into cells. Here we show the ability of slow (<12 eV) electrons to effectively decompose gas-phase N-acetyl tryptophan (NAT) which can model a simple protein. The fragmentation of NAT, initiated via a resonant electron-molecule interaction exclusively at the peptide bridge, produces a large variety of negative species. The present findings contribute to the molecular description of the initial step in the radiation-induced damage.

Electrons↗
PubMed2004

Site-specific dissociation of DNA bases by slow electrons at early stages of irradiation.

At the very early time of irradiation, ballistic secondary electrons are produced as the most abundant of the radiolytic species directly within DNA or its environment. Here, we demonstrate the propensity of such low-energy (<3 eV) electrons to damage DNA bases via an effective loss of hydrogen located at the specific nitrogen positions. Since this site is directly implicated in the bonding of nucleobases within DNA and since dehydrogenation of the nucleic acid bases has been observed to be the predominant dissociative channel, the present findings foreshadow significant implications for the initial molecular processes leading to genotoxicity in living cells following unwanted or intended exposure to ionizing radiation (e.g., sunbathing, air travel, radiotherapy, etc.).

Adenine↗