DNA photocleaving agents attract a lot of attention due to the specific advantages of this class of molecules. Firstly, photochemically activated molecules can bind to the DNA before activation process; secondly, photoactivation can be controlled by light. Dipyridinium phenanthrene dihydrodioxin (PDHD) binds to the DNA molecule by intercalation of planar fragment - phenanthrene moiety between DNA base pairs and by the electrostatic interactions between the positively charged pyridinium ‘arms’ and negatively charged DNA phosphate backbone. The key step of PDHD synthesis is the Schönberg-Mustafa photoreaction that occurs with visible light irradiation to form dihydrodioxins from <i>ortho</i>-quinones and olefins. The reaction is reversible under shorter wavelength light irradiation (UV or short wavelength visible light). Electron transfer from phenanthrene ring to the pyridinium salt eventually results in the formation of the <i>ortho</i>-quinone and the olefin. The process is illustrated below. The ability of PDHD to release phenanthrenequinone under UV light irradiation was used in the study of PDHD as a DNA cleaving agent. PDHD showed strong DNA binding properties that were quantified by UV titrations and optical melting experiments. The results of ΦΧ174 plasmid DNA photocleavage assay showed the effectiveness of PDHD as DNA cutting agent. The results of this study will be presented on the poster.

Dipyridinium phenanthrene dihydrodioxin (PDHD): Synthesis, photochemistry, DNA binding and cleaving properties

256th National Meeting (2018)

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