Deficiency of 8-hydroxyguanine dna endonuclease activity and accumulation of the 8-hydroxyguanine in mutator mutant (mutM) of Escherichia coli

Tadayoshi Bessho, Keizo Tano, Hiroshi Kasai, Susumu Nishimura

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In this report, we have characterized mutM mutant with respect to its ability to repair 8-hydroxyguanine (oh8Gua) in DNA. The oh8Gua DNA endonuclease activity in mutM strain was minimal as compared with that in the wild-type cells. The presence of oh8Gua in DNA of mutM was 6-fold that of the wild-type strain corresponding to a characteristically higher frequency of G•C → T•A transversions in this mutant strain. These results suggest that mutator phenotype of mutM is at least partially due to a spontaneous accumulation of oh8Gua resulting from a greatly reduced oh8Gua DNA endonuclease activity.

Original languageEnglish (US)
Pages (from-to)372-378
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Oct 15 1992


ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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