Abstract
Helicobacter hepaticus, a causal agent of hepatocarcinoma in mice, exhibits a cytolethal distending toxin activity. The three subunits of this holotoxin, CdtA, CdtB, and CdtC, and three CdtB mutants were produced as recombinant histidine-tagged proteins by using an in vitro cell-free protein expression system. We found that the presence of the three H. hepaticus Cdt subunits is required for cellular toxicity and that only a C-terminal CdtB mutation abolishes the activity of the complex. In vitro, H. hepaticus CdtB exhibits a DNase activity which is also abolished by this C-terminal CdtB mutation. These results suggest that the effect of H. hepaticus CDT probably involves the DNase activity of CdtB.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amino Acid Substitution
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Animals
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Bacterial Toxins / biosynthesis*
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Bacterial Toxins / chemistry
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Bacterial Toxins / genetics
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Bacterial Toxins / toxicity*
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Cell Survival / drug effects
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Cells, Cultured
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Deoxyribonucleases / metabolism
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Gene Expression
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Helicobacter hepaticus / genetics
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Helicobacter hepaticus / metabolism*
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Liver / cytology
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Mice
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Mice, Inbred C3H
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Molecular Sequence Data
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Protein Biosynthesis
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Protein Structure, Tertiary
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Protein Subunits
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / toxicity
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Sequence Alignment
Substances
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Bacterial Toxins
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Protein Subunits
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Recombinant Proteins
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cytolethal distending toxin
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Deoxyribonucleases