Overproduction of the outer-membrane proteins FepA and FhuE responsible for iron transport in Escherichia coli hfq::cat mutant.
We found that 82- and 76-kDa proteins in the outer-membrane fractions were overproduced in the hfq::cat mutant cells when grown in synthetic media. Expression of these proteins was repressed by addition of FeCl(3) in the mutant as well as in the wild type. It was revealed that these are FepA and FhuE proteins involved in iron transport. The hfq::cat mutant was more susceptible to killing by hydrogen peroxide, probably due to the excess incorporation of iron, which potentially generates hydroxyl radicals. Increased incorporation of iron in the hfq::cat mutant was also confirmed by the suppressive effect on the ftsH1 mutation. These results suggest that the hfq gene product is involved in the defense mechanism against oxidative stress.
Wachi
M
M
Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan. mwachi@bio.titech.ac.jp
Takada
A
A
Nagai
K
K
D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D001692:Biological Transport; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D002712:Chlorides; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D005290:Ferric Compounds / Q000494:pharmacology; D035001:Host Factor 1 Protein; D006861:Hydrogen Peroxide / Q000494:pharmacology; D034982:Integration Host Factors; D007501:Iron / Q000378:metabolism; D009154:Mutation; D018384:Oxidative Stress; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D013696:Temperature
D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D002712:Chlorides; D029968:Escherichia coli Proteins; C064531:FHUE protein, E coli; D005290:Ferric Compounds; D035001:Host Factor 1 Protein; D034982:Integration Host Factors; D011956:Receptors, Cell Surface; C029489:enterobactin receptor; C440502:integration host factor, E coli; D006861:Hydrogen Peroxide; D007501:Iron; C024555:ferric chloride