In Situ Sensing of DNA Damage by a Nitric Oxide‐Releasing Compound

Abstract

Oxidative stress can be caused by in vivo chemical generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) besides ultraviolet and ionizing radiation. Recently, DNA damage due to RNS became an interesting subject since high nitric oxide (NO) concentration in cells was reported to produce genotoxic effects. The DNA biosensor has been shown to represent a powerful tool for the study of biomolecular interaction mechanisms. The double strand DNA (dsDNA) biosensor was used to study the interaction between dsDNA immobilized on a glassy carbon surface and RNS released by a NO‐releasing compound, diethylenetriamine/nitric oxide (DETA/NO). The results showed that it is possible to electrochemically generate NO metabolites such as peroxynitrite that damage dsDNA structures, causing contact between purinic bases and the electrode surface so that their oxidation can be easily detected. The formation of modified DNA bases such as 8‐nitroguanine was observed after interaction of DNA with peroxynitrite radicals electrochemically generated at the electrode surface. The importance of DNA biosensors in the determination of the interaction between DNA and nitric oxide and its metabolites is clearly demonstrated.

Keywords:

• DNA damage
• oxidative damage
• reactive nitrogen species
• nitric oxide
• peroxinitrite
• electrochemical DNA biosensor
• 8‐oxoguanine
• 8‐nitroguanine

Acknowledgments

Financial support from Fundação para a Ciência e Tecnologia (FCT), Post‐Doctoral Grant SFRH/BPD/18824/2004 (V. C. Diculescu.), POCTI (cofinanced by the European Community Fund FEDER), ICEMS (Research Unit 103), and European Project HPRN‐CT‐2002‐00186 is gratefully acknowledged.