A host-specific factor is necessary for efficient folding of the autotransporter plasmid-encoded toxin.
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.
Nemec
Kathleen N
KN
University of Central Florida, Orlando, 32826, USA.
Scaglione
Patricia
P
Navarro-García
Fernando
F
Huerta
Jazmín
J
Tatulian
Suren A
SA
Teter
Ken
K
D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016466:CHO Cells; D002850:Chromatography, Gel; D002942:Circular Dichroism; D006224:Cricetinae; D003412:Cricetulus; D004768:Enterotoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D020673:Protein Renaturation; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D013050:Spectrometry, Fluorescence
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C530786:Pet protein, E coli; D012697:Serine Endopeptidases