TY - CONF A1 - Hallier, Dorothea C. T1 - Inonizing Radiation Damage to Nucleoprotein Filaments . Literaturseminar N2 - Literaure Seminar on progress of doctoral thesis with title "ionizing radiation damage to nucleoprotein filaments involved in DNA recombination, replication and repair" T2 - Literaturseminar Uni Potsdam CY - Potsdam, Germany DA - 25.01.2022 KW - Radiation KW - Radiation damage KW - Nucleoprotein filaments KW - Radiation damage dosimetry KW - Gene-V Protein KW - Single-stranded DNA-binding protein KW - GVP G5P KW - Protein purification and expression KW - DNA PY - 2022 AN - OPUS4-56537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hallier, Dorothea C. T1 - Jahresvortrag Ionizing radiation damage to nucleoprotein filaments N2 - Jahresvortrag AG Seitz Fraunhofer IZI BB Potsdam about progress of doctoral thesis with the title "Ionizing Radiation Damage to Nucleoprotein filaments involved in DNA recombination, replication and repair T2 - Jahresmeeting Fraunhofer IZI-BB Potsdam, AG Biomarkervalidierung und Assayentwicklung CY - Potsdam, Germany DA - 18.02.2022 KW - Radiation KW - Radiation damage KW - Nucleoprotein filaments KW - Single-stranded DNA-binding protein KW - Protein expression and purification KW - DNA KW - Radiation damage dosimetry PY - 2022 AN - OPUS4-56539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Radnik, Jörg A1 - Dietrich, P. M. T1 - Near-ambient-pressure Xray photoelectron spectroscopy (XPS) to monitor DNA radiation damage directly in water N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - RADeleven CY - Herceg Novi, Montenegro DA - 19.06.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - ESCA KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydrated electrons KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionisation KW - Ionization KW - LEE KW - DEA KW - DET KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Protein KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - Single-stranded DNA-binding proteins KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray photo electron spectrocopy PY - 2023 AN - OPUS4-57782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Standard procedure for the irradiation of biomolecules with radiation of different linear energy transfer T2 - Proceedings of International Radiation Protection Association Conference 2018 America N2 - The damage caused by ionizing radiation to DNA and proteins is the reason to treat cancer by radiation therapy. A better understanding of the molecular processes and quantification of the different damaging mechanisms is the prerequisite to develop more efficient therapies. Hereby the understanding of the processes involved in the damage to DNA are of key interest due to its central role in reproduction and mutation. For radiation with low linear energy transfer (LET), most of the damage is caused by the secondary particles produced by scattering of the ionizing radiation with water. Thereby a multitude of species are produced, whereby especially kinetic low energy electrons, prehydrated electrons, OH-radicals and ions are of importance. With higher LET the relative amount of the direct damaging effects increases. This is especially important considering the increased usage of high LET nucleons in radiation therapy. Therefore, the quantification of the contribution to DNA damage of direct and indirect effects and the different secondary species is of high interest due to the increase of radio biological efficiency when applying high LET radiation. Here we present an approach to investigate the relative contributions to DNA strand break yield for radiation of different LET within a single electron microscope in combination with electron scattering simulations. T2 - XI International Radiation Protection Association Conference 2018 America CY - Havanna, Cuba DA - 16.04.2018 KW - Dosimetry KW - Linear energy transfer KW - Radiation damage KW - LET KW - Electron irradiation KW - Low energy electrons KW - Hydroxyl radicals KW - DEA KW - DET KW - Microdosimetry KW - Geant4 KW - Electron irradiation of DNA KW - DNA PY - 2018 VL - 2018 SP - 1 EP - 5 AN - OPUS4-44848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Combined experimental and simulational approaches to access radiation damage to DNA-Protein complexes N2 - We combine irradiation experiments at DNA, proteins and their complexes with Geant4 based particle-scattering simulations to understand the degradation mechanisms on a molecular level. T2 - High performance computing workshop CY - Allan, Jordan DA - 26.06.2023 KW - DNA KW - Protein KW - Radiadion damage KW - Geant4 KW - Geant4-DNA KW - MCS KW - Particle scattering simulations KW - gold nanoparticles PY - 2023 AN - OPUS4-57645 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Solomun, Tihomir A1 - Cordsmeier, Leo A1 - Hallier, Dorothea C. A1 - Seitz, Harald A1 - Hahn, Marc Benjamin T1 - Interaction of a Dimeric Single-Stranded DNA-Binding Protein (G5P) with DNA Hairpins. A Molecular Beacon Study JF - The Journal of Physical Chemistry B N2 - Gene-V protein (G5P/GVP) is a single-stranded (ss)DNA-binding protein (SBP) of bacteriophage f1 that is required for DNA synthesis and repair. In solution, it exists as a dimer that binds two antiparallel ssDNA strands with high affinity in a cooperative manner, forming a left-handed helical protein–DNA filament. Here, we report on fluorescence studies of the interaction of G5P with different DNA oligonucleotides having a hairpin structure (molecular beacon, MB) with a seven base-pair stem (dT24-stem7, dT18-stem7), as well as with DNA oligonucleotides (dT38, dT24) without a defined secondary structure. All oligonucleotides were end-labeled with a Cy3-fluorophore and a BHQ2-quencher. In the case of DNA oligonucleotides without a secondary structure, an almost complete quenching of their strong fluorescence (with about 5% residual intensity) was observed upon the binding of G5P. This implies an exact alignment of the ends of the DNA strand(s) in the saturated complex. The interaction of the DNA hairpins with G5P led to the unzipping of the base-paired stem, as revealed by fluorescence measurements, fluorescence microfluidic mixing experiments, and electrophoretic mobility shift assay data. Importantly, the disruption of ssDNA’s secondary structure agrees with the behavior of other single-stranded DNA-binding proteins (SBPs). In addition, substantial protein-induced fluorescence enhancement (PIFE) of the Cy3-fluorescence was observed. KW - DNA KW - Protein KW - ssDNA KW - Fluorescence KW - Raman KW - G5P KW - Hairpin KW - Molecular beacon KW - Quencher KW - Amino Acids KW - SBP KW - SSB KW - Cy3 KW - PIFE KW - Protein-induced fluorescence enhancement KW - Protein–DNA filament KW - Single-stranded DNA-binding protein KW - Bacteriophage f1 KW - Oligonucleotides PY - 2023 DO - https://doi.org/10.1021/acs.jpcb.3c03669 SN - 1520-6106 VL - 127 IS - 38 SP - 8131 EP - 8138 PB - ACS Publications AN - OPUS4-58295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - DNA basierte Dosimetrie N2 - We propose the development of a standardized DNA based dosimeter. This dosimeter will improve the comparability between the results of different laboratories in radiation research. Compared to conventional methods in dosimetry, this Approach provides direct access to the relation between radiation interaction and biological damage. Moreover, it enables the systematic investigation of the relation between the microscopic characteristics of radiation and DNA damage over a wide dose range. T2 - Zertkom CY - Online meeting DA - 13.05.2020 KW - DNA KW - Dosimetrie KW - Dosimetry KW - Effective dose KW - Energy dose KW - Energiedosis KW - Equivalent dose KW - Absorbed dose PY - 2020 AN - OPUS4-50779 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Radnik, Jörg A1 - Dietrich, P. M. T1 - Near-Ambient-Pressure XPS to investigate radiation damage to DNA N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - Physical and Chemical Analysis of Polymers seminar CY - Online meeting DA - 12.10.2021 KW - Base damage KW - Base loss KW - Cancer therapy KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break KW - DSB KW - Dry DNA KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionization KW - LEE KW - Low energy electrons KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Prehydrated electron KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Reactive oxygen species KW - Single-strand break KW - SSB KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy PY - 2021 AN - OPUS4-53611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. T1 - BP150: Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. T2 - DPG Frühjahrstagung CY - Dresden, Germany DA - 26.03.2023 KW - Bio-SAXS KW - BioSAXS KW - Compatible solute KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - G5P KW - GVP KW - Gene five protein KW - Geant4 KW - Geant4-DNA KW - Hydroxyectoine KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Osmolyte KW - Particle scattering simulations KW - Protein KW - Proteins KW - Protein unfolding KW - ROS KW - Radiation damage KW - Radical Scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas KW - Topas-MC KW - Topas-nBio KW - X-ray scattering KW - Radical scavenger KW - ssDNA PY - 2023 AN - OPUS4-57254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Dietrich, Paul M. A1 - Radnik, Jörg T1 - Near-ambient-pressure XPS as as tool to monitor DNA radiation damage directly in water N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - Miller Conference CY - Furiani, France DA - 03.06.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - ESCA KW - Energy deposit KW - G5P KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydroxyl radical KW - Indirect damage KW - Ionisation KW - Ionization KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Protein KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - Single-stranded DNA-binding proteins KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - Hydration shell PY - 2023 AN - OPUS4-57646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -