title: UV photoreactions of the extremely haloalkaliphilic euryarchaeon Natronomonas pharaonis.
abstract: The objective of this study was to investigate the photobiological responses of the haloalkaliphilic euryarchaeon Natronomonas pharaonis to environmentally relevant polychromatic UV radiation, simulating either the present UV radiation climate (lambda>290 nm) or that of the early Earth (lambda>220 nm), and to monochromatic UVC radiation (lambda=254 nm) for comparison with the literature data. UV-induced bipyrimidine DNA photoproducts were determined using a sensitive and accurate HPLC tandem mass spectrometry assay, allowing to identify and quantify each type of photoproducts formed in the DNA of a UV-irradiated halophilic archaeon. The thymine cytosine (TC) pyrimidine (6-4) pyrimidone photoproduct and the TC cyclobutane pyrimidine dimer accounted for almost 80% of the total induced DNA photolesions, regardless of the wavelength range tested. These prominent formation rates of TC photoproducts correlated with the genomic frequencies of TC dinucleotides in N. pharaonis.
authors.affiliation: Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Köln, Germany. ralf.moeller@dlr.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Moeller
authors.forename: Günther
authors.initials: G
authors.lastname: Reitz
authors.forename: Thierry
authors.initials: T
authors.lastname: Douki
authors.forename: Jean
authors.initials: J
authors.lastname: Cadet
authors.forename: Gerda
authors.initials: G
authors.lastname: Horneck
authors.forename: Helga
authors.initials: H
authors.lastname: Stan-Lotter
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004249:DNA Damage; D019641:DNA, Archaeal / Q000032:analysis; D006216:Halobacteriaceae / Q000528:radiation effects*; D050296:Microbial Viability; D011740:Pyrimidine Dimers / Q000032:analysis*; D053719:Tandem Mass Spectrometry; D014466:Ultraviolet Rays
chemical_list: D019641:DNA, Archaeal; D011740:Pyrimidine Dimers