title: Reactivity pattern of bromonucleosides induced by 2-hydroxypropyl radicals: photochemical, radiation chemical, and computational studies.
abstract: The bromonucleosides (BrdX's) 5-bromo-2'-deoxyuridine (BrdU), 5-bromo-2'-deoxycytidine (BrdC), 8-bromo-2'-deoxyadenosine (BrdA), and 5-bromo-2'-deoxyguanosine (BrdG) may substitute for ordinary nucleosides in DNA. As indicated by electron-stimulated desorption experiments, such a modified biopolymer is greater than 2-3-fold more sensitive to damage induced by excess electrons. The other major product of water radiolysis, the (•)OH radical, may form a number of other radicals in chemical reactions with the complex content of the cell. Thus, the well-proved BrdU-labeled DNA radiosensitivity may be, at least in part, related to secondary organic radicals. Therefore, in the current study, the propensity of BrdX's to damage induced by 2-hydroxypropyl radical (OHisop(•))-a prototype radical species-was investigated. The HPLC and LC-MS analyses revealed the formation of two major products from the brominated pyrimidine nucleosides, a native nucleoside and an adduct of BrdX and OHisop(•) , and only an adduct of BrdX from the bromopurine nucleosides. Quantum chemical calculations ascribed this evident difference between purines and pyrimidines to the electron transfer from OHisop(•) to BrdX that is especially favorable in pyrimidines.
authors.affiliation: †Faculty of Chemistry, University of Gdañsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zdrowowicz
authors.affiliation: †Faculty of Chemistry, University of Gdañsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
authors.forename: Lidia
authors.initials: L
authors.lastname: Chomicz
authors.affiliation: †Faculty of Chemistry, University of Gdañsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Miloch
authors.affiliation: †Faculty of Chemistry, University of Gdañsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Wiczk
authors.affiliation: †Faculty of Chemistry, University of Gdañsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Rak
authors.affiliation: ‡Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Kciuk
authors.affiliation: ‡Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Bobrowski
mesh_terms: D000096:Acetone / Q000737:chemistry; D001966:Bromine / Q000737:chemistry*; D004579:Electron Transport; D005609:Free Radicals / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009705:Nucleosides / Q000737:chemistry*; D055668:Photochemical Processes; D011854:Radiochemistry
chemical_list: D005609:Free Radicals; D009705:Nucleosides; D000096:Acetone; D001966:Bromine