Issue 9, 1999

Hydroxyl radical-induced degradation of 2′-deoxyguanosine under reducing conditions

Abstract

Addition of hydroxyl radical to the base moiety of 2′-deoxyguanosine (dGuo) leads to the formation of two main radicals exhibiting oxidising and reducing properties, respectively. The oxidising radical reacts with oxygen to yield 2,2-diamino-5-[2-deoxy-β-D-erythro-pentofuranosyl)amino]oxazol-5(2H)-one (oxazolone) as the final product. The reducing radical is either preferentially oxidised into 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) or reduced into a 2,6-diamino-4-hydroxy-5-formamidopyrimidine derivative (FapydGuo) depending on conditions. We report here that the presence of reducing compounds (ascorbate or cysteine) strongly modifies the distribution of modified nucleosides upon γ irradiation of an aerated aqueous solution of dGuo. The yield of oxazolone decreases while that of 8-oxodGuo and FapydGuo increases. This was explained by the reduction of the oxidising radical which prevents the occurrence of the restitution of dGuo through a reaction between the oxidising and the reducing purine radicals. The study was extended to the decomposition of dGuo upon photochemical release of ˙OH by N-hydroxypyrimidine-2-thione (HPT). The analysis of the base modification products of dGuo induced by the latter system showed that HPT exhibits reducing properties and cannot be used as a pure photochemical source of ˙OH radical.

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 2, 1999, 1875-1880

Hydroxyl radical-induced degradation of 2′-deoxyguanosine under reducing conditions

T. Douki, S. Spinelli, J. Ravanat and J. Cadet, J. Chem. Soc., Perkin Trans. 2, 1999, 1875 DOI: 10.1039/A903690C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements