Abstract
Autotransporters are the most common virulence factors secreted from Gram-negative pathogens. Until recently, autotransporter folding and outer membrane translocation were thought to be self-mediated events that did not require accessory factors. Here, we report that two variants of the autotransporter plasmid-encoded toxin are secreted by a lab strain of Escherichia coli. Biophysical analysis and cell-based toxicity assays demonstrated that only one of the two variants was in a folded, active conformation. The misfolded variant was not produced by a pathogenic strain of enteroaggregative E. coli and did not result from protein overproduction in the lab strain of E. coli. Our data suggest a host-specific factor is required for efficient folding of plasmid-encoded toxin.
2009 Elsevier Masson SAS. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Bacterial Toxins / chemistry*
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Bacterial Toxins / genetics
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Bacterial Toxins / metabolism
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CHO Cells
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Chromatography, Gel
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Circular Dichroism
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Cricetinae
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Cricetulus
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Enterotoxins / chemistry*
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Enterotoxins / genetics
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Enterotoxins / metabolism
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Escherichia coli Proteins / chemistry*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Escherichia coli*
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Models, Molecular
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Mutation
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Protein Conformation
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Protein Denaturation
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Protein Folding*
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Protein Renaturation
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Serine Endopeptidases / chemistry*
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Serine Endopeptidases / genetics
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Serine Endopeptidases / metabolism
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Species Specificity
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Spectrometry, Fluorescence
Substances
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Bacterial Toxins
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Enterotoxins
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Escherichia coli Proteins
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Pet protein, E coli
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Serine Endopeptidases