The general protein-export pathway is directly required for extracellular pullulanase secretion in Escherichia coli K12.
Pullulanase is an extracellular, cell surface-anchored lipoprotein produced by Gram-negative bacteria belonging to the genus Klebsiella. Its correct localization in recombinant Escherichia coli requires the products of 14 genes that are linked to the enzyme structural gene in the Klebsiella chromosome. In addition, we show here that six sec genes (secA, secB, secD, secE, secF and secY) are all required for processing of the prepullulanase signal peptide to occur. This implies that pullulanase crosses the cytoplasmic membrane via the general export pathway of which the sec gene products are essential components. Removal or drastic alteration of the prepullulanase signal peptide cause the enzyme to remain cytoplasmic. We propose that pullulanase secretion occurs in two steps, the first of which is common to all signal peptide-bearing precursors of exported and secreted proteins, whereas the second is specifically involved in translocating pullulanase to the cell surface.
Pugsley
A P
AP
Unité de Génétique Moléculaire, CNRS URA 1149, Institut Pasteur, Paris, France.
Kornacker
M G
MG
Poquet
I
I
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D010450:Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000378:metabolism*; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000378:metabolism; D012697:Serine Endopeptidases
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; C461599:maltose transport system, E coli; D006026:Glycoside Hydrolases; C100181:pullulanase; D010450:Endopeptidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase