title: Factors necessary for the export process of colicin E1 across cytoplasmic membrane of Escherichia coli.
abstract: Factors necessary for the export process of colicin E1 across the cytoplasmic membrane of Escherichia coli were investigated. beta-Galactosidase activities from gene fusions between the colicin E1 and lacZ genes were recovered in the inner membrane fraction of E. coli when the region containing the internal signal-like sequence of colicin E1 [M. Yamada et al. (1982) Proc. Natl Acad. Sci. USA 79, 2827-2831] was present, but were found in the soluble fraction when the region was eliminated. The colicin E1 export was reduced upon insertion mutation in a gene that is located downstream from the colicin E1 gene in the same operon and responsible for mitomycin-C-induced killing of the host cell. A frame shift mutation of the colicin E1 plasmid was constructed to direct the protein which had lost the COOH-terminal 13 residues of original colicin E1 and was altered in 6 residues of the new COOH-terminal portion. The aberrant colicin E1 that was inducibly synthesized remained inside the cells. These results indicate that colicin E1 is exported with the aid of a product of the downstream gene and that the COOH-terminal portion is necessary for the export. The binding of colicin E1 to the cytoplasmic membrane through the internal signal-like sequence may be a step in the protein export process.
mesh_terms: D001345:Autoradiography; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003087:Colicins / Q000235:genetics / Q000378:metabolism*; D004274:DNA, Recombinant; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010957:Plasmids; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D003087:Colicins; D004274:DNA, Recombinant; D001616:beta-Galactosidase