Characterization of DNA with an 8-oxoguanine modification

Sreelekha K. Singh, Marta W. Szulik, Manjori Ganguly, Irine Khutsishvili, Michael P. Stone, Luis A Marky, Barry Gold

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The oxidation of DNA resulting from reactive oxygen species generated during aerobic respiration is a major cause of genetic damage that, if not repaired, can lead to mutations and potentially an increase in the incidence of cancer and aging. A major oxidation product generated in cells is 8-oxoguanine (oxoG), which is removed from the nucleotide pool by the enzymatic hydrolysis of 8-oxo-20-deoxyguanosine triphosphate and from genomic DNA by 8-oxoguanine-DNA glycosylase. Finding and repairing oxoG in the midst of a large excess of unmodified DNA requires a combination of rapid scanning of the DNA for the lesion followed by specific excision of the damaged base. The repair of oxoG involves flipping the lesion out of the DNA stack and into the active site of the 8-oxoguanine- DNA glycosylase. This would suggest that thermodynamic stability, in terms of the rate for local denaturation, could play a role in lesion recognition. While prior X-ray crystal and NMR structures show that DNA with oxoG lesions appears virtually identical to the corresponding unmodified duplex, thermodynamic studies indicate that oxoG has a destabilizing influence. Our studies show that oxoG destabilizes DNA (δ δG of 2-8 kcal mol -1 over a 16-116mM NaCl range) due to a significant reduction in the enthalpy term. The presence of oxoG has a profound effect on the level and nature of DNA hydration indicating that the environment around n oxoG•C is fundamentally different than that found at G•C. The temperature-dependent imino proton NMR spectrum of oxoG modified DNA confirms the destabilization of the oxoG•C pairing and those base pairs that are 50 of the lesion. The instability of the oxoG modification is attributed to changes in the hydrophilicity of the base and its impact on major groove cation binding.

Original languageEnglish (US)
Pages (from-to)6789-6801
Number of pages13
JournalNucleic acids research
Volume39
Issue number15
DOIs
StatePublished - Aug 1 2011

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DNA
DNA Glycosylases
Thermodynamics
8-hydroxyguanine
Hydrophobic and Hydrophilic Interactions
Base Pairing
Cations
Protons
Reactive Oxygen Species
Catalytic Domain
Respiration
Hydrolysis
Nucleotides
X-Rays
Mutation
Temperature
Incidence
Neoplasms

ASJC Scopus subject areas

  • Genetics

Cite this

Singh, S. K., Szulik, M. W., Ganguly, M., Khutsishvili, I., Stone, M. P., Marky, L. A., & Gold, B. (2011). Characterization of DNA with an 8-oxoguanine modification. Nucleic acids research, 39(15), 6789-6801. https://doi.org/10.1093/nar/gkr275

Characterization of DNA with an 8-oxoguanine modification. / Singh, Sreelekha K.; Szulik, Marta W.; Ganguly, Manjori; Khutsishvili, Irine; Stone, Michael P.; Marky, Luis A; Gold, Barry.

In: Nucleic acids research, Vol. 39, No. 15, 01.08.2011, p. 6789-6801.

Research output: Contribution to journalArticle

Singh, SK, Szulik, MW, Ganguly, M, Khutsishvili, I, Stone, MP, Marky, LA & Gold, B 2011, 'Characterization of DNA with an 8-oxoguanine modification', Nucleic acids research, vol. 39, no. 15, pp. 6789-6801. https://doi.org/10.1093/nar/gkr275
Singh SK, Szulik MW, Ganguly M, Khutsishvili I, Stone MP, Marky LA et al. Characterization of DNA with an 8-oxoguanine modification. Nucleic acids research. 2011 Aug 1;39(15):6789-6801. https://doi.org/10.1093/nar/gkr275
Singh, Sreelekha K. ; Szulik, Marta W. ; Ganguly, Manjori ; Khutsishvili, Irine ; Stone, Michael P. ; Marky, Luis A ; Gold, Barry. / Characterization of DNA with an 8-oxoguanine modification. In: Nucleic acids research. 2011 ; Vol. 39, No. 15. pp. 6789-6801.
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