Electrochemical potential releases a membrane-bound secretion intermediate of maltose-binding protein in Escherichia coli.
A secretionary intermediate of the Escherichia coli maltose-binding protein accumulated in the inner membrane when the membrane electrochemical potential was reduced and the cytosolic ATP concentration was normal. The intermediate was mature in size, but maintained a conformation similar to the cytosolic precursor form, and not the mature periplasmic protein, as measured by differences in susceptibility to proteinase K in vitro. The intermediate was located on the periplasmic side of the inner membrane. Restoration of the membrane electrochemical potential resulted in the movement of the intermediate from the inner membrane to the periplasm. In other experiments in which the ATP concentration was reduced by 96% and the electrochemical potential remained normal, no intermediate accumulated. Thus, the final step in the export of maltose-binding protein requires the electrochemical potential of the inner membrane and does not require ATP.
Department of Microbiology, Oregon State University, Corvallis 97331-3804.
B L
BL
Geller
D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate / Q000378:metabolism; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism / Q000502:physiology*; D029968:Escherichia coli Proteins; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000378:metabolism*; D008623:Mercaptoethanol / Q000494:pharmacology; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins
D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D029968:Escherichia coli 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; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D008623:Mercaptoethanol; D002701:Chloramphenicol; D008320:Maltose; D000255:Adenosine Triphosphate