Abstract
Inorganic polyphosphate [poly(P)] levels in Escherichia coli were reduced to barely detectable concentrations by expression of the plasmid-borne gene for a potent yeast exopolyphosphatase [poly(P)ase]. As a consequence, resistance to H2O2 was greatly diminished, particularly in katG (catalase HPI) mutants, implying a major role for the other catalase, the stationary-phase KatE (HPII), which is rpoS dependent. Resistance was restored to wild-type levels by complementation with plasmids expressing ppk, the gene for PPK [the polyphosphate kinase that generates poly(P)]. Induction of expression of both katE and rpoS (the stationary-phase sigma factor) was prevented in cells in which the poly(P)ase was overproduced. Inasmuch as this inhibition by poly(P)ase did not affect the levels of the stringent-response guanosine nucleotides (pppGpp and ppGpp) and in view of the capacity of additional rpoS expression to suppress the poly(P)ase inhibition of katE expression, a role is proposed for poly(P) in inducing the expression of rpoS.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acid Anhydride Hydrolases / biosynthesis*
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Acid Anhydride Hydrolases / genetics
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Bacterial Proteins / biosynthesis*
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Catalase / biosynthesis*
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Escherichia coli / drug effects
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Escherichia coli / genetics*
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Escherichia coli / metabolism*
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Gene Expression Regulation, Bacterial*
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Gene Transfer Techniques
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Genetic Complementation Test
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Hydrogen Peroxide / pharmacology
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Kinetics
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Phosphotransferases (Phosphate Group Acceptor) / biosynthesis
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Phosphotransferases (Phosphate Group Acceptor) / genetics
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Plasmids
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Polyphosphates / metabolism*
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Recombinant Fusion Proteins / biosynthesis
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Sigma Factor / biosynthesis*
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Suppression, Genetic
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Transcription, Genetic
Substances
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Bacterial Proteins
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Polyphosphates
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Recombinant Fusion Proteins
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Sigma Factor
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sigma factor KatF protein, Bacteria
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Hydrogen Peroxide
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hydroperoxidase II
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Catalase
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Phosphotransferases (Phosphate Group Acceptor)
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polyphosphate kinase
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Acid Anhydride Hydrolases
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exopolyphosphatase