Relative abundance and reactivity of primary ion radicals in .gamma.-irradiated DNA at low temperatures. 2. Single- vs double-stranded DNA

Yan, Mengyao; Becker, Dávid; Summerfield, Stephen; Renke, Paul; Sevilla, Michael D.

doi:10.1021/j100183a082

Cited by 114 publications

(83 citation statements)

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“…On the other hand, from the proposed differences in electron and hole transfer boundaries, the yield of reduced DNA radicals would be expected to be 1.6 times greater than that of oxidized free radicals (for Γ > 24). This agrees well with earlier work in the deconvolution of the DNA spectrum (7,56,(59)(60)(61). Other factors may also contribute to this observed imbalance [particularly since it is observed at low levels of hydration as well as high levels of hydration (7)]; these include holehole combination (7), the presence of undetected oxidized species (59) [i.e.…”

Section: Target Mass γ and Target Mass Free Radical Yieldssupporting

confidence: 89%

The Effect of Packing and Conformation on Free Radical Yields in Films of Variably Hydrated DNA

Milano¹,

Bernhard²

1999

Radiation Research

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This work investigates the direct-type action of radiation (involving electron addition and electron abstraction) on DNA. Specifically, the effects of DNA hydration, conformation and packing on free radical yields are examined. The fact that these variables are interdependent complicates the analysis of how each variable affects free radical yields. The hydration dependence of free radical yields in films of both Li and Na DNA was examined. At low levels of DNA hydration (less than 25 waters per nucleotide), the relatively high free radical yields and the lack of water-derived radicals are evidence that damage transfer from the DNA solvation shell to the DNA molecule occurs. The scatter of measured free radical yields is significant (50-70%) in Li DNA, while in Na DNA it is much less (<25%). Our conclusions hinge upon two known differences between Li DNA and Na DNA: (1) At low DNA hydrations, the conformation of Na DNA undergoes several changes with increasing hydration, while the conformation of Li DNA is relatively constant over the same range. (2) Compared to Na DNA, Li DNA is more prone to self-associate, giving rise to macroscopic and microscopic crystalline domains in Li DNA films. The greater scatter of free radical yields in Li DNA films is therefore attributed to variability in packing. By virtue of the greater reproducibility of free radical yields in Na DNA films, the effects of DNA packing, conformation and hydration can be ascertained. In Na DNA, hydration-dependent changes in free radical yields are attributed primarily to changes in DNA packing.

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Section: Target Mass γ and Target Mass Free Radical Yieldssupporting

confidence: 89%

The Effect of Packing and Conformation on Free Radical Yields in Films of Variably Hydrated DNA

Milano¹,

Bernhard²

1999

Radiation Research

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“…Thus, the formation of stable anions in the DNA environment, where proton donors, polar and conjugated species are present seems to be quite probable. Indeed, an EPR signal that had to originate from the stable T − and C − anions was registered in the past by Sevilla et al [35]. As a consequence one can assume that the primary role of resonance states is to allow for energy transfer between the impinging electron and the neutral target [36].…”

Section: Dna Damage Induced By Low Energy Electronsmentioning

confidence: 96%

Stable Valence Anions of Nucleic Acid Bases and DNA Strand Breaks Induced by Low Energy Electrons

Rak

Mazurkiewicz

Kobyłecka

et al. 2008

Challenges and Advances in Computational Chemistry and Physics

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Abstract:The last decade has witnessed immense advances in our understanding of the effects of ionizing radiation on biological systems. As the genetic information carrier in biological systems, DNA is the most important species which is prone to damage by high energy photons. Ionizing radiations destroy DNA indirectly by forming low energy electrons (LEEs) as secondary products of the interaction between ionizing radiation and water. An understanding of the mechanism that leads to the formation of single and double strand breaks may be important in guiding the further development of anticancer radiation therapy. In this article we demonstrate the likely involvement of stable nucleobases anions in the formation of DNA strand breaks -a concept which the radiation research community has not focused on so far. In Section 21.1 we discuss the current status of studies related to the interaction between DNA and LEEs. The next section is devoted to the description of proton transfer induced by electron attachment to the complexes between nucleobases and various proton donorsa process leading to the strong stabilization of nucleobases anions. Then, we review our results concerning the anionic binary complexes of nucleobases with particular emphasize on the GC and AT systems. Next, the possible consequences of interactions between DNA and proteins in the context of electron attachment are briefly discussed. Further, we focus on existing proposal of single strand break formation in DNA. Ultimately, open questions as well perspectives of studies on electron induced DNA damage are discussed

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“…One-electron oxidations in DNA have recently received considerable attention due to their connection with DNA damage caused by ionizing radiation [1][2][3][4][5], oxidation agents [6][7][8]. The electrontransfer reactions of guanine (G) are central to understanding both hole transfer along DNA [9][10][11][12] and biological damage to nucleic acids [4][5][6]13].…”

Section: Introductionmentioning

confidence: 99%

Oxidative damage to DNA: Theoretical determination of ionization potential of deoxyriboguanosine (dG)–deoxyribocytidine (dC) and proton transfer in its cation

Sun

2009

Journal of Molecular Structure: THEOCHEM

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Relative abundance and reactivity of primary ion radicals in .gamma.-irradiated DNA at low temperatures. 2. Single- vs double-stranded DNA

Cited by 114 publications

References 0 publications

The Effect of Packing and Conformation on Free Radical Yields in Films of Variably Hydrated DNA

The Effect of Packing and Conformation on Free Radical Yields in Films of Variably Hydrated DNA

Stable Valence Anions of Nucleic Acid Bases and DNA Strand Breaks Induced by Low Energy Electrons

Oxidative damage to DNA: Theoretical determination of ionization potential of deoxyriboguanosine (dG)–deoxyribocytidine (dC) and proton transfer in its cation

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