Absolute cross section for loss of supercoiled topology induced by 10 eV electrons in highly uniform /DNA/1,3-diaminopropane films deposited on highly ordered pyrolitic graphite

Boulanouar, Omar; Fromm, M.; Bass, A. D.; Cloutier, Pierre; Sanche, Léon

doi:10.1063/1.4817323

Cited by 28 publications

(43 citation statements)

References 43 publications

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“…1,3,[5][6][7]9,24 Two of these are shape resonances located at 0.8 and 2.2 eV in the yield function of SSB, with cross sections varying from 10 −13 to 10 −15 cm 2 within the 0.5-4.5 eV range. 5 The energies of these resonances correlate with those determined from gas-phase electron scattering from the bases.…”

Section: A Tni Manifold Of Dnamentioning

confidence: 99%

“…In many of these investigations the yields of specific damages, including single-and double-strand breaks (SSB and DSB) [1][2][3][4][5][6][7][8] and crosslinks (CL), 9 as well as the formation of neutral species 7,10 and stable anions 1,2 has been measured as a function of electron energy within the range 0-20 eV. Whereas the electron energy dependencies of DNA conformational changes (i.e., formation of SSB, DSB, and CL) has been observed in films of bacterial DNA, 1,3 the yield functions for other specific products were mainly obtained in experiments with films of short synthetic DNA strands, e.g., self-assembled monolayer oligonucleotides, [1][2][3]11 with lengths ranging from 3 to 40 bases.…”

Section: Introductionmentioning

confidence: 99%

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Cisplatin Radiosensitization of DNA Irradiated with 2–20 eV Electrons: Role of Transient Anions

et al. 2014

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Platinum chemotherapeutic agents, such as cisplatin (cis-diamminedichloroplatinum(II)), can act as radiosensitizers when bound covalently to nuclear DNA in cancer cells. This radiosensitization is largely due to an increase in DNA damage induced by low-energy secondary electrons, produced in large quantities by high-energy radiation. We report the yields of single-and doublestrand breaks (SSB and DSB) and interduplex cross-links (CL) induced by electrons of 1.6-19.6 eV (i.e., the yield functions) incident on 5 monolayer (ML) films of cisplatin-DNA complexes. These yield functions are compared with those previously recorded with 5 ML films of unmodified plasmid DNA. Binding of five cisplatin molecules to plasmid DNA (3197 base pairs) enhances SSB, DSB, and CL by factors varying, from 1.2 to 2.8, 1.4 to 3.5, and 1.2 to 2.7, respectively, depending on electron energy. All yield functions exhibit structures around 5 and 10 eV that can be attributed to enhancement of bond scission, via the initial formation of core-excited resonances associated with π → π* transitions of the bases. This increase in damage is interpreted as arising from a modification of the parameters of the corresponding transient anions already present in nonmodified DNA, particularly those influencing molecular dissociation. Two additional resonances, specific to cisplatin-modified DNA, are formed at 13.6 and 17.6 eV in the yield function of SSB. Furthermore, cisplatin binding causes the induction of DSB by electrons of 1.6-3.6 eV, i.e., in an energy region where a DSB cannot be produced by a single electron in pure DNA. Breaking two bonds with a subexcitation-energy electron is tentatively explained by a charge delocalization mechanism, where a single electron occupies simultaneously two σ* bonds linking the Pt atom to guanine bases on opposite strands.

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Section: A Tni Manifold Of Dnamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cisplatin Radiosensitization of DNA Irradiated with 2–20 eV Electrons: Role of Transient Anions

et al. 2014

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“…34 TNI increase the electron-molecule interactions leading to higher total energy-loss CS, which shorten the AL. The AL value for 9.6 eV electrons can be compared to those previously reported by Rezaee et al 33 and Boulanouar et al 37 (i.e., 10.4 ± 5.4 nm and 14.1 ± 5.4, respectively). It is particularly encouraging to find that the present AL of 14.1 ± 2.4 nm is in excellent agreement with that of 14.1 ± 5.4 nm obtained from diaminopropane (Dap)-DNA films, 37 whose thickness was verified to be highly uniform by AFM.…”

Section: A Yields and Als For Lee-induced Dna Damagementioning

confidence: 92%

“…One expects different morphologies between the films in the experiment of Boulanouar et al 37 and those in the others. In the former, the plasmid was different and stacked by intercalating Dap molecules.…”

Section: B Penetration Factor (F) and Absolute Csmentioning

confidence: 94%

“…Such measurements can be made by atomic force microscopy, when the plasmids are ordered by self-assembly. 37 In this case, they lie parallel to the surface. As shown by electron stimulated desorption of anions from self-assembled monolayers of DNA, 38 orientation could influence LEE-induced damage near the film surface, since the initial electron capture probability is expected to depend on the orientation of the electron beam with respect to that of the basic units within DNA.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons

Chen

Dong

et al. 2016

Phys. Chem. Chem. Phys.

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Absolute cross sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions. To determine CSs for various conformational DNA damage induced by 2-20 eV electrons, we investigated the influence of the attenuation length (AL) and penetration factor (f) using a mathematical model. Solid films of super-coiled plasmid DNA with thicknesses of 10, 15 and 20 nm were irradiated with 4.6, 5.6, 9.6 and 14.6 eV electrons. DNA conformational changes were quantified by gel electrophoresis, and the respective yields were extrapolated from exposureresponse curves. The absolute CS, AL and f values were generated by applying the model developed by Rezaee et al. The values of AL were found to lie between 11 and 16 nm with the maximum at 14.6 eV. The absolute CSs for the loss of the supercoiled (LS) configuration and production of crosslinks (CL), single strand breaks (SSB) and double strand breaks (DSB) induced by 4.6, 5.6, 9.6 and 14.6 eV electrons are obtained. The CSs for SSB are smaller, but similar to those for LS, indicating that SSB are the main conformational damage. The CSs for DSB and CL are about one order of magnitude smaller than those of LS and SSB. The value of f is found to be independent of electron energy, which allows extending the absolute CSs for these types of damage within the range 2-20 eV, from previous measurements of effective CSs. When comparison is possible, the absolute CSs are found to be in good agreement with those obtained from previous similar studies with double-stranded DNA. The high values of the absolute CSs of 4.6 and 9.6 eV provide quantitative evidence for the high efficiency of low energy electrons to induce DNA damage via the formation of transient anions.

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High-Resolution Electron Energy Loss Spectroscopy: Absolute Cross Section Measurements for Low Energy Electron Scattering from Biomolecules

Lemelin

Sanche

2019

Radiation in Bioanalysis

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Absolute cross section for loss of supercoiled topology induced by 10 eV electrons in highly uniform /DNA/1,3-diaminopropane films deposited on highly ordered pyrolitic graphite

Cited by 28 publications

References 43 publications

Cisplatin Radiosensitization of DNA Irradiated with 2–20 eV Electrons: Role of Transient Anions

Cisplatin Radiosensitization of DNA Irradiated with 2–20 eV Electrons: Role of Transient Anions

Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons

High-Resolution Electron Energy Loss Spectroscopy: Absolute Cross Section Measurements for Low Energy Electron Scattering from Biomolecules

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