Reactions of the OOH radical with guanine: Mechanisms of formation of 8-oxoguanine and other products

Kumar, Nagendra; Pk, Shukla; Mishra, P. C.

doi:10.1016/j.chemphys.2010.08.004

Cited by 18 publications

(7 citation statements)

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“…The hydroperoxyl radial is a conjugate acid of superoxide anion ( À O 2 ), which is a very important intermediate in combustion chemistry and known to play a major role in oxidation reactions. 33,34 Moreover, this chemical is more stable in the atmosphere than superoxide. Additionally, its well known that the formation of hydroperoxyl radial can be through direct photolysis of H 2 O 2 as well as through the Fenton reaction.…”

Section: Catalytic Activity With Different Mass Of Catalystmentioning

confidence: 99%

Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound

et al. 2015

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Section: Catalytic Activity With Different Mass Of Catalystmentioning

confidence: 99%

Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound

et al. 2015

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“…OOH), hydrogen peroxide (H 2 O 2 ), nitric oxide radical ( . NO), superoxide radical anion (O 2 .− ) are toxic ROS . Although ROS are involved in regulating signal transduction pathways, stimulating growth factor, and generating inflammatory response, their ability to modify biomolecules is a worrisome concern.…”

Section: Introductionmentioning

confidence: 99%

Manganese‐Coordinated Tyrosine Bio Materials for the Sensing of Reactive Oxygen Species

Jena

2019

ChemistrySelect

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Design of biosensor materials for the recognition of reactive oxygen species (ROS) inside living cells is necessary for the early diagnosis of cancer and other diseases induced by ROS. Here, the B3LYP−D3 dispersion‐corrected and Mo6 hybrid density functional theoretical methods and a polarized continuum model to account for the aqueous medium are used to propose models of manganese (Mn+2)‐coordinated tyrosine (Tyr) nano rods and porous bio materials to detect various ROS, such as .OH, .OOH, H2O2, .NO, ONOO−, and O2.−. It is found that the nano rods and porous polymers may sense the presence of different ROS by utilizing their edges and pores respectively. It is further revealed that due to stable binding and adsorption energies, entrapment of different ROS by the porous polymers would be sustained for longer time compared to the nano rods. However, the edges of nano rods are reactive and may initiate oxidation reactions by converting Mn+2 to Mn+3. It is thus expected that these bio materials would act as excellent ROS sensors.

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“…A number of computational studies have addressed the reactions of guanine radical. ,,,− Sevilla and co-workers have investigated guanine oxidation and reduction, protonation and deprotonation of guanine radical, and hydroxyl radical adding to guanine. − We have used DFT calculations to examine the mechanisms for the formation of 8oxoG, Sp, Gh, and FAPyG from guanine radical, , the formation of guanine-lysine cross-links during oxidation mediated by type I and type II photosensitizers, , and the p K a ’s and redox potentials of nucleobases and intermediates in the pathway from guanine radical to Sp and Gh. − Dumont and co-workers have investigated the addition of singlet oxygen to guanine to form 8oxoG and Sp. − Liu and co-workers have used guided ion beam mass spectrometry and density functional calculations to examine gas-phase singlet oxygen reactions with guanine and its oxidation products. − Wetmore, Boyd, and co-workers have calculated ionization potentials and electron affinities of nucleobases, NO 2 radical addition to guanine radical, and hydroxyl radical addition to nucleobases . Mishra and co-workers have published numerous studies of guanine oxidation by reactive oxygen species, − …”

Section: Introductionmentioning

confidence: 99%

Computational Study of the pH-Dependent Competition between Carbonate and Thymine Addition to the Guanine Radical

Hebert

Schlegel

2018

Chem. Res. Toxicol.

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When oligonucleotides are oxidized by carbonate radical, thymine and carbonate can add to guanine radical, yielding either a guanine-thymine cross-link product (G∧T) or 8-oxo-7,8-dehydroguanine (8oxoG) and its further oxidation products such as spiroiminodihydantoin (Sp) and guanidinohydantoin (Gh). The ratio of thymine addition to carbonate addition depends strongly on the pH. Details of the mechanism have been explored by density functional calculations using the ωB97XD/6-31+G(d,p) level of theory with the SMD implicit solvation method, augmented with a few explicit waters. Free energies of intermediates and transition states in aqueous solution have been calculated along the pathways for addition of thymine, CO3 2–/HCO3 – and carbonate radical to guanine radical. The pH dependence was examined by using appropriate explicit proton donors/acceptors as computational models for buffers at pH 2.5, 7, and 10. Deprotonation of thymine is required for nucleophilic addition at C8 of guanine radical, and thus is favored at higher pH. The barrier for carbonate radical addition is lower than for bicarbonate or carbonate dianion addition; however, for low concentrations of carbonate radical, the reaction may proceed by addition of bicarbonate/carbonate dianion to guanine radical. Thymine and bicarbonate/carbonate dianion addition are followed by oxidation by O2, loss of a proton from C8 and decarboxylation of the carbonate adduct. At pH 2.5, guanine radical cation can be formed by oxidization with sulfate radical. Water addition to guanine radical cation is the preferred path for forming 8oxoG at pH 2.5.

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Reactions of the OOH radical with guanine: Mechanisms of formation of 8-oxoguanine and other products

Cited by 18 publications

References 50 publications

Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound

Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound

Manganese‐Coordinated Tyrosine Bio Materials for the Sensing of Reactive Oxygen Species

Computational Study of the pH-Dependent Competition between Carbonate and Thymine Addition to the Guanine Radical

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Reactions of the OOH radical with guanine: Mechanisms of formation of 8-oxoguanine and other products

Cited by 18 publications

References 50 publications

Performance of cobalt titanate towards H2O2 based catalytic oxidation of lignin model compound

Performance of cobalt titanate towards H2O2 based catalytic oxidation of lignin model compound

Manganese‐Coordinated Tyrosine Bio Materials for the Sensing of Reactive Oxygen Species

Computational Study of the pH-Dependent Competition between Carbonate and Thymine Addition to the Guanine Radical

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Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound

Performance of cobalt titanate towards H₂O₂ based catalytic oxidation of lignin model compound