title: Secretion of toxin A from Pseudomonas aeruginosa PAO1, PAK, and PA103 by Escherichia coli.
abstract: The exotoxin A gene (toxA) from Pseudomonas aeruginosa PAO1 was expressed from the lac promoter in Escherichia coli, and the localization of the toxin A protein was determined. Throughout the growth cycle, the ADP-ribosyltransferase activity of toxin A was gradually reduced in the periplasm of E. coli, with no apparent degradation of the toxin A protein. This suggests the presence of an E. coli periplasmic factor that interferes with the ADP-ribosyltransferase activity in toxin A. Such an inactivating factor was found in the periplasmic extract from control E. coli cells. The processing of toxin A in E. coli was examined by pulse-chase immunoprecipitation experiments. Mature toxin was detected in both the periplasm and cytoplasm, whereas the membranes contained both mature and precursor forms. Toxin A precursor appears to be processed in both the cytoplasm and the periplasm of E. coli. Toxin A proteins from P. aeruginosa PAO1, PA103, and PAK were compared for their secretion in E. coli. Despite the differences in the amino acid sequences of their leader peptides, toxin A proteins from strains PAO1, PA103, and PAK were processed and secreted to the periplasm of E. coli.
authors.affiliation: Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York 14642.
authors.forename: A N
authors.initials: AN
authors.lastname: Hamood
authors.forename: M J
authors.initials: MJ
authors.lastname: Wick
authors.forename: B H
authors.initials: BH
authors.lastname: Iglewski
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism; D000595:Amino Acid Sequence; D001427:Bacterial Toxins; D015153:Blotting, Western; D002451:Cell Compartmentation; D004926:Escherichia coli / Q000235:genetics; D005098:Exotoxins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000472:pathogenicity*; D011994:Recombinant Proteins / Q000235:genetics; D013329:Structure-Activity Relationship; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D005098:Exotoxins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A