Degradation versus aggregation of misfolded maltose-binding protein in the periplasm of Escherichia coli.
The periplasmic fates of misfolded MalE31, a defective folding mutant of the maltose-binding protein, were determined by manipulating two cellular activities affecting the protein folding pathway in host cells: (i) the malEp promoter activity, which is controlled by the transcriptional activator MalT, and (ii) the DegP and Protease III periplasmic proteolytic activity. At a low level of expression, the degradation of misfolded MalE31 was partially impaired in cells lacking DegP or Protease III. At a high level of expression, misfolded MalE31 rapidly formed periplasmic inclusion bodies and thus escaped degradation. However, the manipulated host cell activities did not enhance the production of periplasmic, soluble MalE31. A kinetic competition between folding, aggregation, and degradation is proposed as a general model for the biogenesis of periplasmic proteins.
Betton
J M
JM
Unité de Programmation Moléculaire et de Toxicologie Génétique/CNRS-URA1444, Département des Biotechnologies, Institut Pasteur, 25, rue du Docteur Roux 75015 Paris, France. jmbetton@pasteur.fr
Sassoon
N
N
Hofnung
M
M
Laurent
M
M
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005838:Genotype; D006360:Heat-Shock Proteins; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D008666:Metalloendopeptidases / Q000378:metabolism; D008956:Models, Chemical; D009004:Monosaccharide Transport Proteins; D016296:Mutagenesis; D019897:Periplasm / Q000378:metabolism*; D033902:Periplasmic Binding Proteins; D033903:Periplasmic Proteins; D011401:Promoter Regions, Genetic; D011489:Protein Denaturation; D017510:Protein Folding; D012697:Serine Endopeptidases / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C461619:MalE protein, E coli; C058976:MalT protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D033903:Periplasmic Proteins; D014157:Transcription Factors; C461599:maltose transport system, E coli; D008320:Maltose; C061682:DegP protease; D012697:Serine Endopeptidases; D008666:Metalloendopeptidases; C046583:pitrilysin