title: Chaperone function of FkpA, a heat shock prolyl isomerase, in the periplasm of Escherichia coli.
abstract: The nature of molecular chaperones in the periplasm of Escherichia coli that assist newly translocated proteins to reach their native state has remained poorly defined. Here, we show that FkpA, a heat shock periplasmic peptidyl-prolyl cis/trans isomerase (PPIase), suppresses the formation of inclusion bodies from a defective-folding variant of the maltose-binding protein, MalE31. This chaperone-like activity of FkpA, which is independent of its PPIase activity, requires a full-length structure of the protein. In vitro, FkpA does not catalyse a slow rate-limiting step in the refolding of MalE31, but prevents its aggregation at stoichiometric amounts and promotes the reactivation of denaturated citrate synthase. We propose that FkpA functions as a chaperone for envelope proteins in the bacterial periplasm.
authors: Unité de Programmation Moléculaire et de Toxicologie Génétique/CNRS-URA1444, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
authors: J P
authors: JP
authors: Arié
authors: N
authors: N
authors: Sassoon
authors: J M
authors: JM
authors: Betton
mesh_terms: D018528:ATP-Binding Cassette Transporters; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000378:metabolism; D002942:Circular Dichroism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response; D020104:Immunophilins / Q000235:genetics / Q000378:metabolism*; D002479:Inclusion Bodies; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins; D019696:Peptidylprolyl Isomerase / Q000378:metabolism*; D019897:Periplasm / Q000378:metabolism*; D033902:Periplasmic Binding Proteins; D017510:Protein Folding; D017433:Protein Structure, Secondary; D021381:Protein Transport; D017384:Sequence Deletion
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; C461599:maltose transport system, E coli; D002950:Citrate (si)-Synthase; D020104:Immunophilins; D019696:Peptidylprolyl Isomerase; C068254:FkpA protein, E coli