Fate of the 2‘-Deoxyadenosin-5‘-yl Radical under Anaerobic Conditions

Flyunt, Roman; Bazzanini, Rita; Chatgilialoglu, Chryssostomos; Mulazzani, Quinto G.

doi:10.1021/ja9941577

Cited by 58 publications

(72 citation statements)

References 21 publications

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“…Reaction of hydrated electrons (e aq À ) with 8 and 12: Radiolysis of neutral water leads to e aq À , HOC, and HC, as shown in Equation (1). The values in parentheses represent the radiation chemical yields (G) in mmol J…”

Section: Resultsmentioning

confidence: 99%

“…The reactions of hydrated electrons (e aq À ) with 8-bromoadenine [1][2][3] and 8-bromoguanine nucleosides [4][5][6] have recently been investigated by radiolytic methods. It was found that 8-bromo-2'-deA C H T U N G T R E N N U N G oxyA C H T U N G T R E N N U N G adenosine (1) captures electrons and rapidly loses a bromide ion to give the corresponding C8 radical 2.…”

Section: Introductionmentioning

confidence: 99%

“…This intermediate intramolecularly abstracts a hydrogen atom from the C5' position to selectively afford the 2'-de-A C H T U N G T R E N N U N G oxyA C H T U N G T R E N N U N G adenosin-5'-yl radical 3 (Scheme 1). [1,2,7] This allowed the reactivity of 3 to be studied properly for the first time, particularly the cyclization step 3!4, which occurs with a rate constant (k c ) of 1.6 10 5 s À1 . In the analogous reaction with 8-bromoadenosine, the intramolecular hydrogen abstraction by the initially formed C8 radical is partitioned between two channels to generate both the C5' and C2' radicals with similar rate constants.…”

Section: Introductionmentioning

confidence: 99%

“…Workup of the reaction in entry 3 allowed the isolation and characterization of the two diastereoisomers 21 and 23. Support for the correct configuration assignment at the C5' position was provided by 1 H NMR analyses and, in particular, by the magnitude of JA C H T U N G T R E N N U N G (H4',H5').…”

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Chemical Radiation Studies of 8‐Bromo‐2′‐deoxyinosine and 8‐Bromoinosine in Aqueous Solutions

Russo

Jiménez

Mulazzani

et al. 2006

Chemistry A European J

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The reactions of hydrated electrons (e(aq) (-)) with 8-bromo-2'-deoxyinosine (8) and 8-bromoinosine (12) have been investigated by radiolytic methods coupled with product studies and have been addressed computationally by means of BB1K-HMDFT calculations. Pulse radiolysis revealed that one-electron reductive cleavage of the C--Br bond gives the C8 radical 9 or 13 followed by a fast radical translocation to the sugar moiety. Selective generation of a C5' radical occurs in the 2'-deoxyribo derivative, whereas in the ribo analogue the reaction is partitioned between the C5' and C2' positions with similar rates. Both C5' radicals undergo cyclizations, 10-->11 and 14-->15, with rate constants of 1.4 x 10(5) and of 1.3 x 10(4) s(-1), respectively. The redox properties of radicals 10 and 11 have also been investigated. A synthetically useful photoreaction has also been developed as a one-pot procedure that allows the conversion of 8 to 5',8-cyclo-2'-deoxyinosine in a high yield and a diastereoisomeric ratio (5'R)/(5'S) of 4:1. The present results are compared with data previously obtained for 8-bromoadenine and 8-bromoguanine nucleosides. Theory suggests that the behavior of 8-bromopurine derivatives with respect to solvated electrons can be attributed to differences in the energy gap between the pi*- and sigma*-radical anions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Chemical Radiation Studies of 8‐Bromo‐2′‐deoxyinosine and 8‐Bromoinosine in Aqueous Solutions

Russo

Jiménez

Mulazzani

et al. 2006

Chemistry A European J

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“…[1][2][3][4] DNA damage induced by low-energy excess electrons (EEs) has attracted increasing attentionm ainly because EEs are created in large amountsb yi onizing radiation and they are thought to play an important role in radiation-induced DNA damage. [5][6][7] Both experimental and theoretical studies have shown that EEs are responsible for av ariety of damage types within DNA, such as strand breaks, nucleobase (NB) damage, base release, and base modification.…”

Section: Introductionmentioning

confidence: 99%

Hydrated Electron Transfer to Nucleobases in Aqueous Solutions Revealed by Ab Initio Molecular Dynamics Simulations

et al. 2015

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We present an ab initio molecular dynamics (AIMD) simulation study into the transfer dynamics of an excess electron from its cavity-shaped hydrated electron state to a hydrated nucleobase (NB)-bound state. In contrast to the traditional view that electron localization at NBs (G/A/C/T), which is the first step for electron-induced DNA damage, is related only to dry or prehydrated electrons, and a fully hydrated electron no longer transfers to NBs, our AIMD simulations indicate that a fully hydrated electron can still transfer to NBs. We monitored the transfer dynamics of fully hydrated electrons towards hydrated NBs in aqueous solutions by using AIMD simulations and found that due to solution-structure fluctuation and attraction of NBs, a fully hydrated electron can transfer to a NB gradually over time. Concurrently, the hydrated electron cavity gradually reorganizes, distorts, and even breaks. The transfer could be completed in about 120-200 fs in four aqueous NB solutions, depending on the electron-binding ability of hydrated NBs and the structural fluctuation of the solution. The transferring electron resides in the π*-type lowest unoccupied molecular orbital of the NB, which leads to a hydrated NB anion. Clearly, the observed transfer of hydrated electrons can be attributed to the strong electron-binding ability of hydrated NBs over the hydrated electron cavity, which is the driving force, and the transfer dynamics is structure-fluctuation controlled. This work provides new insights into the evolution dynamics of hydrated electrons and provides some helpful information for understanding the DNA-damage mechanism in solution.

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Reactivity of Nucleic Acid Sugar Radicals

Chatgilialoglu

2009

Radical and Radical Ion Reactivity in Nucleic Acid Chemistry

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Fate of the 2‘-Deoxyadenosin-5‘-yl Radical under Anaerobic Conditions

Cited by 58 publications

References 21 publications

Chemical Radiation Studies of 8‐Bromo‐2′‐deoxyinosine and 8‐Bromoinosine in Aqueous Solutions

Chemical Radiation Studies of 8‐Bromo‐2′‐deoxyinosine and 8‐Bromoinosine in Aqueous Solutions

Hydrated Electron Transfer to Nucleobases in Aqueous Solutions Revealed by Ab Initio Molecular Dynamics Simulations

Reactivity of Nucleic Acid Sugar Radicals

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