title: Enzymatic repair of UV-irradiated DNA in vitro.
abstract: Excision repair of UV-damaged Bacillus subtilis transforming DNA has been carried out by a sequential enzyme system in vitro. Incision adjacent to the pyrimidine dimer in the DNA strand by correndonuclease II-initiated excision of the damage by the 5' in equilibrium 3'-directed exonuclease of the Micrococcus luteus DNA polymerase. Reinsertion of nucleotides into the gap in the strand by the DNA polymerase at 10 degrees C terminated in a single-strand break which was sealed by a polynucleotide ligase, thereby repairing the DNA strand. This restored biological activity to damaged DNA up to doses resulting in 60% inactivation of transforming activity. At higher doses, less repair was achieved, due to the development of double-strand breaks during the in vitro incision and excision steps.
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism* / Q000528:radiation effects; D004260:DNA Repair; D004269:DNA, Bacterial / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004720:Endonucleases / Q000378:metabolism; D005092:Exonucleases / Q000378:metabolism; D007700:Kinetics; D008837:Micrococcus / Q000201:enzymology; D011118:Polynucleotide Ligases / Q000378:metabolism; D011742:Pyrimidine Nucleotides / Q000378:metabolism; D011830:Radiation Effects; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D011742:Pyrimidine Nucleotides; D004720:Endonucleases; D005092:Exonucleases; D011118:Polynucleotide Ligases