Translocation of colicin E1 through cytoplasmic membrane of Escherichia coli.

The product of the malE-lacZ gene fusion was reported to compete with some proteins including outer membrane lipoprotein in the protein translocation across the Escherichia coli membrane. The fusion product also inhibited colicin E1 export. Furthermore, globomycin, which accumulated prolipoprotein in the membrane, inhibited the translocation of colicin E1 in the wild-type cells, but not in lipoprotein-negative mutant cells. Since colicin E1 contains the internal signal-like sequence [Proc. Natl. Acad. Sci. USA (1982) 79, 2827-2831], these results suggest that colicin E1 is exported by the aid of this sequence at a common site for maltose-binding protein and lipoprotein translocation.