title: Deficiency of 8-hydroxyguanine DNA endonuclease activity and accumulation of the 8-hydroxyguanine in mutator mutant (mutM) of Escherichia coli.
abstract: 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.
authors.affiliation: Banyu Tsukuba Research Institute, Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Bessho
authors.forename: K
authors.initials: K
authors.lastname: Tano
authors.forename: H
authors.initials: H
authors.lastname: Kasai
authors.forename: S
authors.initials: S
authors.lastname: Nishimura
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial / Q000378:metabolism; D043382:DNA-Formamidopyrimidine Glycosylase; D003853:Deoxyribonucleosides / Q000032:analysis; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000235:genetics* / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D004269:DNA, Bacterial; D003853:Deoxyribonucleosides; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; C024829:8-hydroxyguanine; D006147:Guanine; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli