title: Subcellular localization of a PhoE-LacZ fusion protein in E. coli by protease accessibility experiments reveals an inner-membrane-spanning form of the protein.
abstract: Protease accessibility experiments were employed to localize a PhoE-LacZ hybrid protein, encompassing a large N-terminal fragment of the outer membrane PhoE protein of E. coli, fused to beta-galactosidase, at the subcellular level. In previous studies, this protein was shown to co-fractionate with the outer membrane, whereas immunocytochemical methods suggested a cytoplasmic location. The present results confirm the latter localization. Moreover, it appears that a minor amount of hybrid protein spans the inner membrane, with the PhoE moiety in the periplasm and the beta-galactosidase moiety in the cytoplasm. These membrane-spanning proteins might be responsible for the lethal jamming of the export machinery, observed upon induction of synthesis of the protein.
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000032:analysis*; D005696:Galactosidases / Q000032:analysis*; D011993:Recombinant Fusion Proteins / Q000032:analysis*; D011994:Recombinant Proteins / Q000032:analysis*; D014357:Trypsin / Q000494:pharmacology; D001616:beta-Galactosidase / Q000032:analysis*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D004492:Edetic Acid; D005696:Galactosidases; D001616:beta-Galactosidase; D014357:Trypsin