title: Efficient production of heat-labile enterotoxin mutant proteins by overexpression of dsbA in a degP-deficient Escherichia coli strain.
abstract: Escherichia coli heat-labile enterotoxin (LT) mutants containing Val60-->Gly or Ser114-->Lys substitutions in the A subunit do not produce the A subunit efficiently in E. coli. These mutants accumulate mostly the B pentamer devoid of the A subunit in the periplasmic space. Here we show that overproduction of the periplasmic chaperone DsbA, which is involved in disulfide bond formation, in a strain deficient in the periplasmic protease DegP allows efficient production of the mutant LT molecules. Our results suggest that the formation of the oligomeric toxin is influenced by DsbA, which helps protein folding, and by DegP, which removes the folded intermediates that can be untoxic for the cell.
authors.affiliation: IRIS, Chiron Vaccines Immunobiological Research Institute Siena, Via Fiorentina 1, 53100 Siena, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Wülfing
authors.forename: R
authors.initials: R
authors.lastname: Rappuoli
mesh_terms: D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004768:Enterotoxins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D006360:Heat-Shock Proteins; D007535:Isomerases / Q000096:biosynthesis; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D033903:Periplasmic Proteins; D010957:Plasmids / Q000235:genetics; D017354:Point Mutation; D011487:Protein Conformation; D019704:Protein Disulfide-Isomerases; D017510:Protein Folding; D012697:Serine Endopeptidases / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D009838:Oligodeoxyribonucleotides; D033903:Periplasmic Proteins; C027538:heat-labile enterotoxin, E coli; C061682:DegP protease; D012697:Serine Endopeptidases; D007535:Isomerases; D019704:Protein Disulfide-Isomerases