title: A new photoreactivating enzyme that specifically repairs ultraviolet light-induced (6-4)photoproducts.
abstract: Cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts ((6-4)photoproducts) are the two major classes of cytotoxic, mutagenic and carcinogenic DNA photoproducts produced by ultraviolet light irradiation of cells. The phenomenon of photoreactivation, the reduction of the lethal and mutagenic effects of ultraviolet radiation by simultaneous or subsequent irradiation with near ultraviolet or visible light, has been identified in several organisms and in some cases the enzymes that catalyse this process have been characterized in sufficient detail. CPDs are the only known substrate for the photoreactivating enzymes so far analysed and enzymatic photoreactivation of (6-4)photoproducts has not yet been reported. We report here that an enzyme that catalyses the light-dependent repair of (6-4)photoproduct exists in Drosophila melanogaster. This is, to our knowledge, the first report of such photoreactivating activity specific for (6-4)photoproducts in any organism.
authors.affiliation: Department of Radiation Biology, Faculty of Medicine, Osaka University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Todo
authors.forename: H
authors.initials: H
authors.lastname: Takemori
authors.forename: H
authors.initials: H
authors.lastname: Ryo
authors.forename: M
authors.initials: M
authors.lastname: Ihara
authors.forename: T
authors.initials: T
authors.lastname: Matsunaga
authors.forename: O
authors.initials: O
authors.lastname: Nikaido
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Nomura
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx; D002460:Cell Line; D004247:DNA / Q000737:chemistry / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D015252:Deoxyribonucleases, Type II Site-Specific; D004331:Drosophila melanogaster / Q000196:embryology; D004625:Embryo, Nonmammalian / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011740:Pyrimidine Dimers / Q000378:metabolism*; D012474:Salmon; D013094:Spermatozoa; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; C058406:pyrimidine-pyrimidone dimer; D004247:DNA; D015252:Deoxyribonucleases, Type II Site-Specific; C032229:GANTC-specific type II deoxyribonucleases