Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment.

Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Research Abstract Details 

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Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Abstract Text:

Anil Kumar,Michael D Sevilla,

Mechanisms of low-energy electron (LEE) attachment and subsequent single-strand break (SSB) formation are investigated by density functional theory treatment of a simple model for DNA, i.e., the nucleotide, 5'-thymidine monophosphate (5'-dTMPH). In the present study, the C5'-O5' bond dissociation due to LEE attachment has been followed along the adiabatic as well as on the vertical (electron attached to the optimized geometry of the neutral molecule) anionic surfaces using B3LYP functional and 6-31G* and 6-31++G** basis sets. Surprisingly, it is found that the PES of C5'-O5' bond dissociation in the anion radicals have approximately the same barrier for both adiabatic and vertical pathways. These results provide support for the hypothesis that transiently bound electrons (shape resonances) to the virtual molecular orbitals of the neutral molecule likely play a key role in the cleavage of the sugar-phosphate C5'-O5' bond in DNA resulting in the direct formation of single strand breaks without significant molecular relaxation. To take into account the solvation effects, we considered the neutral and anion radical of 5'-dTMP surrounded by 5 or 11 water molecules with Na+ as a counterion. These structures were optimized using the B3LYP/6-31G** level of theory. We find the barrier height for adiabatic C5'-O5' bond dissociation of 5'-dTMP anion radical in aqueous environment is so substantially higher than in the gas phase that the adiabatic route will not contribute to DNA strand cleavage in aqueous systems. This result is in agreement with experiment.

Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Publishing Authors By Initials

A Kumar,MD Sevilla,

For similar heterocyclic compounds: heterocyclic compounds, 1-ring: pyrimidines: pyrimidine nucleotides: thymine nucleotides: thymidine monophosphate research abstracts see: heterocyclic compounds: heterocyclic compounds, 1-ring: pyrimidines: pyrimidine nucleotides: thymine nucleotides: thymidine monophosphate research

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Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Journal Published:

PUBLICATION TYPE: Research Support, N.I.H., Extr

Journal: The journal of physical chemistry. B

VOLUME: 111

Page Numbers: 5464-74

Journal Abbreviation:

ISSN: 1520-6106

DAY: 13

MONTH: 04

YEAR: 2007

Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Information

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LANGUAGE: eng

NlmUniqueID: 101157530

Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Keywords Mesh Terms:

KEYWORDS: Thymidine Monophosphate

MESH TERMS: chemistry

Chemical & Substance for Abstract: Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment. Information

Substance Name: Thymidine Monophosphate

Registry Number: 365-07-1

Grant and Affiliation Information for Low-energy electron attachment to 5'-thymidine monophosphate: modeling single strand breaks through dissociative electron attachment.

AFFILIATION: Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA.

Country: United States

AGENCY: United States NCI

GRANT: R01CA045424

ACRONYM: CA

MEDLINETA: J Phys Chem B

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