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Literature summary for 3.1.11.6 extracted from

  • Jung, H.; Liang, J.; Jung, Y.; Lim, D.
    Characterization of cell death in Escherichia coli mediated by XseA, a large subunit of exonuclease VII (2015), J. Microbiol., 53, 820-828 .
    View publication on PubMed
Search for more literature for 3.1.11.6

Cloned(Commentary)

Cloned (Comment) Organism
genes xseA and xseB, overexpression of small subunit-encoding gene xseB in Escherichia coli, N- and C-terminal ends of large subunit-encoding xseA are separately amplified, cloned independently into a T-vector, and then joined together in pCC1fos, a vector with a very low copy number Escherichia coli

Protein Variants

Protein Variants Comment Organism
A188T site-directed mutagenesis of a highly conserved residue. The A188T mutant shows a msDNA cleavage indistinguishable from that of the wild-type, and lethality is reduced. About 10times more colonies are observed from the A188T mutant than from the wild-type Escherichia coli
D155N site-directed mutagenesis of a highly conserved residue. The D155N mutant loses the ability to cleave msDNA and displays little lethality Escherichia coli
G237R site-directed mutagenesis of a residue in the glycine-rich motif. No msDNA cleavage is found for the G237R mutant but a low level of cell killing is still observed. The culture viability drops to about 30% after a 2 h induction Escherichia coli
L88R site-directed mutagenesis Escherichia coli
additional information construction of ExoVII- (xseB) and ExoVII-(xseA) deficient mutant strains which are both inactive with msDNA. Construction of promoter deletion mutants, i.e. by deletion of entire promoter (large deletion from -125 to -11) or promoter-element mutation (-36T->C). Overexpression of the large subunit XseA is lethal, but the small subunit counteracts the toxicity of the large subunit. In samples containing both pCC-XseA and pT-XseB, overproduction of XseA by induction has little effect on the viability. RecA also protects cells from death by XseA overexpression. MsDNA cleavage and cell death at various subunit ratios, overview Escherichia coli
V19A site-directed mutagenesis of a highly conserved residue Escherichia coli
W31R site-directed mutagenesis of a highly conserved residue Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli P04994 AND P0A8G9 large and small subunits, XseA and XseB
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Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information exonuclease VII cleaves msDNA, e.g. Ec78 and Ec83 Escherichia coli ?
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 ?
msDNA Ec78 + H2O exonucleolytic cleavage Escherichia coli ?
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 ?
msDNA Ec83 + H2O exonucleolytic cleavage Escherichia coli ?
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 ?

Subunits

Subunits Comment Organism
dimer exonuclease VII of Escherichia coli is composed of two different subunits, the large subunit, XseA, and the small subunit, XseB Escherichia coli

Synonyms

Synonyms Comment Organism
exonuclease VII
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 Escherichia coli
ExoVII
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 Escherichia coli

General Information

General Information Comment Organism
malfunction the ExoVII- (xseB) and ExoVII- (xseA) deficient mutant strains are both inactive with msDNA. Overexpression of the large subunit is lethal, and cells harboring a plasmid encoding xseA have much lower ExoVII activity than wild-type cells. MsDNA cleavage and cell death at various subunit ratios, overview. The N-terminal domain of XseA causes cell death, and the chromosome is fragmented and condensed in the cells dying by XseA Escherichia coli
additional information under apoptotic conditions, the N-terminal domain of XseA is released from ExoVII through proteolysis by a caspase-like protease and the N-terminal fragment functions in the apoptosis-like cell death of Escherichia coli. ExoVII is composed of two different subunits encoded by xseA (large subunit) and xseB (small subunit) which are both required for catalytic activity Escherichia coli
physiological function exonuclease VII (ExoVII) of Escherichia coli is a single strand-specific DNA nuclease, exonuclease VII cleaves msDNA. The biochemical activity of XseA causing cell death is counteracted by the extra amount of the small subunit, XseB. Although the ability to induce cell death is not identical with the single-strand DNA specific nuclease activity, the residues important for nuclease activity are also important for lethality. The N-terminal domain of XseA causes cell death, and the chromosome is fragmented and condensed in the cells dying by XseA. Model for the function of XseA, overview Escherichia coli