Abstract
Strains of Escherichia coli containing reduced levels of exonuclease VII activity due to mutations in the xseB gene have been isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Seven mutants of independent origin deficient in exonuclease VII activity were obtained. Four of these contained defects in xseA, a locus which has been previously identified, and three others contained mutations in a gene distinct from xseA, which we have designated xseB. Genetic mapping studies place the xseB locus between proC and dnaZ. Exonuclease VII purified from KLC835 (xseA+ xseB3) is more heat labile than enzyme purified from the parent strain PA610 (xse+), showing that xseB is a structural gene for exonuclease VII. The isolation of λ transducing phage carrying xseA is also described.
Original language | English (US) |
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Pages (from-to) | 1116-1122 |
Number of pages | 7 |
Journal | Journal of bacteriology |
Volume | 155 |
Issue number | 3 |
State | Published - 1983 |
Externally published | Yes |
ASJC Scopus subject areas
- Microbiology
- Molecular Biology