title: Studies on DNA repair in Bacillus subtilis. III. Identification of an exonuclease which enhances the priming activity of gamma-irradiated dna by "cleaning' damaged ends.
abstract: An enzyme which enhances the priming activity of gamma-irradiated DNA for type I DNA polymerase (EC 2.7.7.7) was identified and partially purified from extracts of Bacillus subtilis cells. The enzyme preferentially degraded gamma-irradiated DNA into acid-soluble materials. DNA preparations treated with heat, ultraviolet light, pancreatic DNAase (EC 3.1.4.5) or micrococcal DNAase (EC 3.1.4.7) were not susceptible to the enzyme. However, sonication rendered DNA susceptible to the enzyme to some extent. From these results, it is supposed that this enzyme may function by 'cleaning' damaged terminals produced by gamma-irradiation to serve as effective priming sites for repair synthesis by the type I DNA polymerase.
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D004256:DNA Polymerase I / Q000378:metabolism; D004260:DNA Repair; D004269:DNA, Bacterial / Q000528:radiation effects*; D005092:Exonucleases / Q000302:isolation & purification / Q000378:metabolism*; D005720:Gamma Rays; D013379:Substrate Specificity; D013698:Templates, Genetic
chemical_list: D004269:DNA, Bacterial; D004256:DNA Polymerase I; D005092:Exonucleases