The ultimate localization of an outer membrane protein of Escherichia coli K-12 is not determined by the signal sequence.

Abstract

To study the role of the signal sequences in the biogenesis of outer membrane proteins, we have constructed two hybrid genes: a phoE‐ompF hybrid gene, which encodes the signal sequence of outer membrane PhoE protein and the structural sequence of outer membrane OmpF protein, and a bla‐phoE hybrid gene which encodes the signal sequence as well as 158 amino acids of the structural sequence of the periplasmic enzyme beta‐lactamase and the complete structural sequence of PhoE protein. The products of these genes are normally transported to and assembled into the outer membrane These results show: (i) that signal sequences of exported proteins are export signals which function independently of the structural sequence, and (ii) that the information which determines the ultimate location of an outer membrane protein is located in the structural sequence of this protein, and not in the signal sequence.

Interaction domains in the Pseudomonas aeruginosa type II secretory apparatus component XcpS (GspF)

“…Strains used in this study are listed in Table 1. P. aeruginosa and Escherichia coli strains were grown at 37 uC in a modified Luria-Bertani (LB) broth (Tommassen et al, 1983). For plasmid maintenance, the following antibiotics were used: for E. coli ampicillin (50 mg ml 21 ), kanamycin (25 mg ml 21 ), tetracycline (15 mg ml 21 ) and gentamicin (15 mg ml 21 ); for P. aeruginosa gentamicin (40 mg ml 21 ) and carbenicillin (300 mg ml 21 ).…”

Expression of the Lipopolysaccharide-Modifying Enzymes PagP and PagL Modulates the Endotoxic Activity ofBordetella pertussis

“…All bacterial strains used are described in Table 1. Typically, the E. coli strains were grown at 37°C in a modified Luria-Bertani broth, designated LB (57), with shaking at 200 rpm. The medium was supplemented with 0.2% glucose.…”

The purification of eukaryotic polypeptides synthesized in Escherichia coli

“…The proteins are synthesized as precursors, with an N-terminal signal sequence which may be cleaved during secretion. Signal sequences are an absolute requirement for export (Silhavy et al, 1983) but there may also be information in the mature protein sequence which affects its localization (Tommassen et al, 1983;Ghrayeb et al, 1984;Freundl et al, 1985).…”