Observation of dissociative quasi-free electron attachment to nucleoside via excited anion radical in solution

Ma, Jun; Kumar, Anil; Muroya, Yusa; Yamashita, Seizo; Sakurai, Tsuneaki; Denisov, Sergey A.; Sevilla, Michael D.; Adhikary, Amitava; Seki, Shu; Mostafavi, Mehran

doi:10.1038/s41467-018-08005-z

Cited by 66 publications

(128 citation statements)

References 51 publications

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“…Ionizing radiation within the human body causes DNA damage [1] both physically (i.e., energy deposition) [2,3] and chemically (i.e., free radical) reacting to the DNA target [4][5][6][7]. Among various 2 of 13 DNA damage types [8,9], DNA double-strand breaks (DSBs), defined as two strand breaks within 10 base pairs (bp) [2,10,11] are conventionally recognized as fatal DNA damage, which can lead to cell death with a certain probability [12].…”

Section: Introductionmentioning

confidence: 99%

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields

Matsuya

Nakano

Kai

et al. 2020

IJMS

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Complex DNA damage, defined as at least two vicinal lesions within 10–20 base pairs (bp), induced after exposure to ionizing radiation, is recognized as fatal damage to human tissue. Due to the difficulty of directly measuring the aggregation of DNA damage at the nano-meter scale, many cluster analyses of inelastic interactions based on Monte Carlo simulation for radiation track structure in liquid water have been conducted to evaluate DNA damage. Meanwhile, the experimental technique to detect complex DNA damage has evolved in recent decades, so both approaches with simulation and experiment get used for investigating complex DNA damage. During this study, we propose a simplified cluster analysis of ionization and electronic excitation events within 10 bp based on track structure for estimating complex DNA damage yields for electron and X-ray irradiations. We then compare the computational results with the experimental complex DNA damage coupled with base damage (BD) measured by enzymatic cleavage and atomic force microscopy (AFM). The computational results agree well with experimental fractions of complex damage yields, i.e., single and double strand breaks (SSBs, DSBs) and complex BD, when the yield ratio of BD/SSB is assumed to be 1.3. Considering the comparison of complex DSB yields, i.e., DSB + BD and DSB + 2BD, between simulation and experimental data, we find that the aggregation degree of the events along electron tracks reflects the complexity of induced DNA damage, showing 43.5% of DSB induced after 70 kVp X-ray irradiation can be classified as a complex form coupled with BD. The present simulation enables us to quantify the type of complex damage which cannot be measured through in vitro experiments and helps us to interpret the experimental detection efficiency for complex BD measured by AFM. This simple model for estimating complex DNA damage yields contributes to the precise understanding of the DNA damage complexity induced after X-ray and electron irradiations.

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Section: Introductionmentioning

confidence: 99%

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields

Matsuya

Nakano

Kai

et al. 2020

IJMS

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“…The last few years have seen a surge in the experimental data on the electron attachment dynamics of solvated nucleobases and nucleotides. Very accurate ultrafast transient spectroscopy results are available for the rate of electron attachment to solvated nucleobases . The theoretical calculation can be an excellent aid in understanding and interpreting the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Interactions of Solvated Electrons with Nucleobases: The Effect of Base Pairing

2020

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We have investigated the effect of base pairing on the electron attachment to nucleobases in bulk water, taking the guanineÀ cytosine (GC) base pair as a test case. The presence of the complementary base reinforces the stabilization effect provided by water and preferentially stabilizes the anion by hydrogen bonding. The electron attachment in bulk-solvated GC happens through a doorway mechanism, where the initial electron attached state is water bound, and it subsequently gets converted to a GC bound state. The additional electron in the final GC bound state is localized on the cytosine, similar to that in the gas phase. The transfer of the electron from the initial water-bound state to the final GC bound state happens due to the mixing of electronic and nuclear degrees of freedom and takes place at a picosecond time scale.[a] Dr.

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“…The electron energy scale was calibrated by using SF 6 gas, yielding the well-known SF 6 À resonance near 0eV. The components were housed in aU HV chamber at ab ase pressure of 2 10 À8 mbar.A ne lectron beam with well-defined energy (full-width at half-maximum (FWHM) % 180 meV) was generated by at rochoidal electron monochromator (TEM) and focused into the reaction region.…”

Section: Methodsmentioning

confidence: 99%

“…[5,6] Halogenated compounds are frequently used as radio-sensitisers, whichm ake the tumour tissue more sensitivet or adiation. [5,6] Halogenated compounds are frequently used as radio-sensitisers, whichm ake the tumour tissue more sensitivet or adiation.…”

Section: Introductionmentioning

confidence: 99%

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Electron‐Induced Reactions in 3‐Bromopyruvic Acid

Silva

Varella

Jones

et al. 2019

Chemistry A European J

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3-Bromopyruvic acid (3BP) is ap otential anticancer drug, the action of which on cellular metabolism is not yet entirely clear.T he presenceo fabromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour radiation therapy.D etailed knowledge of the interaction of 3BP with secondary electrons is aprerequisite to gain acomplete picture of the effects of 3BP in different forms of cancer therapy.H erein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using ac rossed-beam setupa nd theoretically through scattering and quantum chemical calculations.T hese results are complemented by av acuum ultraviolet absorption spec-trum. The main fragmentation channel is the formation of Br À close to 0eVand within severalr esonant features at 1.9 and 3-8 eV.A tl ow electron energies, Br À formation proceeds through s*a nd p*s hape resonances,a nd at higher energies through core-excited resonances.I ti sf ound that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altereda sw ell. The 3BP transient negative ion is subject to al ower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifyingt he electron-transport chains within oxidative phosphorylation.I tc ould also act as aradio-sensitiser.

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Observation of dissociative quasi-free electron attachment to nucleoside via excited anion radical in solution

Cited by 66 publications

References 51 publications

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields

Interactions of Solvated Electrons with Nucleobases: The Effect of Base Pairing

Electron‐Induced Reactions in 3‐Bromopyruvic Acid

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