No specific recognition of leader peptide by SecB, a chaperone involved in protein export.
Most proteins destined for export from Escherichia coli are made as precursors containing amino-terminal leader sequences that are essential for export and that are removed during the process. The initial step in export of a subset of proteins, which includes maltose-binding protein, is binding of the precursor by the molecular chaperone SecB. This work shows directly that SecB binds with high affinity to unfolded maltose-binding protein but does not specifically recognize and bind the leader. Rather, the leader modulates folding to expose elements in the remainder of the polypeptide that are recognized by SecB.
Biochemistry/Biophysics Program, Washington State University, Pullman 99164-4660.
L L
LL
Randall
T B
TB
Topping
S J
SJ
Hardy
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins; D011487:Protein Conformation; D011498:Protein Precursors / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; C057842:SecB protein, Bacteria; C461599:maltose transport system, E coli