title: DNA photochemistry: geometrically unconstrained pyrimidine (6-4) pyrimidone photoproducts do photoisomerize.
abstract: Structural features are of major importance for the formation of mutagenic photoproducts in DNA. It was recently reported that lack of constraints between two adjacent nucleosidic units prevents the conversion of pyrimidine (6-4) pyrimidone photoproducts into their Dewar valence isomers. We here report that this is not the case for the thymidine photoproducts which, although unconstrained, are quantitatively converted into photolysis products identified as Dewar valence isomers by mass spectrometry and NMR and infrared spectroscopies.
authors.affiliation: Univ. Grenoble Alpes, INAC, LCIB, LAN , F-38000 Grenoble, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Douki
authors.forename: Silvestre
authors.initials: S
authors.lastname: Rebelo-Moreira
authors.forename: Nadège
authors.initials: N
authors.lastname: Hamon
authors.forename: Pierre-Alain
authors.initials: PA
authors.lastname: Bayle
mesh_terms: D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D015226:Dinucleoside Phosphates / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010777:Photochemistry; D010782:Photolysis; D011743:Pyrimidines / Q000737:chemistry*; D011744:Pyrimidinones / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D015226:Dinucleoside Phosphates; D011743:Pyrimidines; D011744:Pyrimidinones; D004247:DNA; C030986:pyrimidine