Open AccessPore formation by pho ‐controlled outer‐membrane proteins of various Enterobacteriaceae in lipid bilayers
Author(s) -
BAUER Katharina,
SCHMID Angela,
BOOS Winfried,
BENZ Roland,
TOMMASSEN Jan
Publication year - 1988
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1988.tb14082.x
Subject(s) - porin , bacterial outer membrane , escherichia coli , regulon , chemistry , lipid bilayer , inner membrane , membrane , biology , biochemistry , microbiology and biotechnology , gene
The structural genes of the PhoE porins of Klebsiella pneumonia, Enterobacter cloacae and Escherichia coli C, cloned in multicopy plasmids, were transfered into a porin‐deficient E. coli K‐12 strain, which was constitutive for the pho regulon, and the PhoE porins were isolated and purified. PhoE of Salmonella typhimurium could not be cloned but was isolated from a pho ‐constitutive strain. Reconstitution experiments with artificial lipid bilayer membranes showed that the different PhoE proteins formed pores exhibiting a single‐channel conductance of about 200 pS at 0.1 M KCl. All PhoE porins formed anion‐selective channels in KCl at neutral pH. The degree of the selectivity was dependent on the PhoE species. The different PhoE porins formed general diffusion pores similar to the general porins but exhibited a considerable advantage for the permeation of phosphate through the outer membrane as compared to the constitutive OmpC and OmpF porins of E. coli K‐12.