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DESTRUCTION OF PHOTOREACTIVATING ENZYME BY 365 nm RADIATION*
Author(s) -
Webb Robert B.,
Brown Mickey S.
Publication year - 1973
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1973.tb06420.x
Subject(s) - photolyase , pyrimidine dimer , escherichia coli , in vivo , irradiation , chemistry , dna , enzyme , biophysics , ultraviolet , radiation , yeast , dna damage , dna repair , biochemistry , radiochemistry , biology , materials science , physics , optoelectronics , optics , genetics , gene , nuclear physics
— Following the observation that in vivo photoreactivation of 365‐nm‐induced pyrimidine dimers could not be observed chemically, a study was made of the inactivation of photoreactivating enzyme activity by this near‐ultraviolet wavelength. It was observed that: (1) Dimers induced in extracted bacterial DNA by 365 nm radiation are completely photoreactivable and are monomerized as an exponential function of the photoreactivation time. (2) Photoreactivability of 254‐nm‐induced damage in Escherichia coli B/r Hcr is progressively destroyed in vivo as a function of the dose of 365 nm radiation. (3) The ability of the yeast photoreactivating enzyme to monomerize dimers induced at 365 nm in bacterial DNA is destroyed in vitro as a function of the dose of 365 nm radiation, and at a rate comparable to killing of E. coli. These results are consistent with biological measurements which indicate that photoreactivability of ultraviolet (near and far) lethal damage is reduced by exposure of the bacteria to 365 nm radiation.