Excited-state hydrogen atom abstraction initiates the photochemistry of beta-2 '-deoxycytidine

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Authors	SZABLA Rafal Kazimierz CAMPOS Jesus ŠPONEROVÁ Judit ŠPONER Jiří GORA Robert W. SUTHERLAND John D.
Year of publication	2015
Type	Article in Periodical
Magazine / Source	CHEMICAL SCIENCE
MU Faculty or unit	Central European Institute of Technology
Citation
Web	http://pubs.rsc.org/en/content/articlepdf/2015/SC/C4SC03761H
Doi	http://dx.doi.org/10.1039/c4sc03761h
Field	Physical chemistry and theoretical chemistry
Keywords	ULTRAFAST IR SPECTROSCOPY; CONICAL INTERSECTIONS; CYTOSINE DERIVATIVES; PREBIOTIC SYNTHESIS; BUILDING-BLOCKS; NUCLEIC-ACIDS; GAS-PHASE; DYNAMICS; NUCLEOSIDES; DNA
Description	Understanding the effects of ultraviolet radiation on nucleotides in solution is an important step towards a comprehensive description of the photochemistry of nucleic acids and their constituents. Apart from having implications for mutagenesis and DNA photoprotection mechanisms, the photochemistry of cytidines is a central element in UV-assisted syntheses of pyrimidine nucleotides under prebiotically plausible conditions. In this contribution, we present UV-irradiation experiments of beta-2'-deoxycytidine in aqueous solution involving H-D exchange followed by NMR spectroscopic analysis of the photoproducts. We further elucidate the outcome of these experiments by means of high-level quantum chemical calculations. In particular, we show that prolonged UV-irradiation of cytidine may lead to H-C1' hydrogen atom abstraction by the carbonyl oxygen atom of cytosine. This process may enable photoanomerisation and nucleobase loss, two previously unexplained photoreactions observed in pyrimidine nucleotides.
Related projects:	CEITEC - Central European Institute of Technology