title: S1-sensitive sites in DNA after gamma-irradiation.
abstract: DNA from gamma-irradiated T1 bacteriophages was analyzed for "single-stranded" sites by cleavage with S1 nuclease from Aspergillus oryzae as lesion probe. The ratio of "S1-sensitive sites" to the amount of radiation-induced single-strand breaks was about one. Presumably these "denatured" sites were associated with single-strand breaks. The subsequent check for the persistence of "single-stranded" sites within the DNA molecule by thermokinetics demonstrated a strong affinity of the nuclease to its substrate, the single-stranded lesion, and a perfect excision. It is assumed that the direct absorption of radiation energy in the DNA gives rise to the formation of such bulky lesions.
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology; D004277:DNA, Single-Stranded / Q000528:radiation effects; D004279:DNA, Viral / Q000528:radiation effects*; D004720:Endonucleases / Q000378:metabolism*; D005720:Gamma Rays; D007700:Kinetics; D008970:Molecular Weight; D015719:Single-Strand Specific DNA and RNA Endonucleases; D013604:T-Phages / Q000528:radiation effects*
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases