Deficiency of 8-hydroxyguanine DNA endonuclease activity and accumulation of the 8-hydroxyguanine in mutator mutant (mutM) of Escherichia coli.
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.
Bessho
T
T
Banyu Tsukuba Research Institute, Ibaraki, Japan.
Tano
K
K
Kasai
H
H
Nishimura
S
S
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
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