Peroxynitrite-induced nitration of tyrosine-34 does not inhibit Escherichia coli iron superoxide dismutase

2001 ◽  
Vol 360 (3) ◽  
pp. 563-567 ◽  
Author(s):  
Laurent SOULÈRE ◽  
Catherine CLAPAROLS ◽  
Jacques PÉRIÉ ◽  
Pascal HOFFMANN
Keyword(s):  
Escherichia Coli ◽  
Superoxide Dismutase ◽  
Protonation State ◽  
Iron Superoxide Dismutase ◽  
E Coli ◽  
Tyrosine Residues ◽  
Physiological Conditions ◽  
Spectral Changes ◽  
Diffusion Limited ◽  
Peroxynitrite Anion

The peroxynitrite anion is a potent oxidizing agent, formed by the diffusion-limited combination of nitric oxide and superoxide, and its production under physiological conditions is associated with the pathologies of a number of inflammatory and neurodegenerative diseases. Nitration of Escherichia coli iron superoxide dismutase (Fe-SOD) by peroxynitrite was investigated, and demonstrated by spectral changes and electrospray mass spectroscopic analysis. HPLC and mass studies of the tryptic digests of the mono-nitrated Fe-SOD indicated that tyrosine-34 was the residue most susceptible to nitration by peroxynitrite. Exclusive nitration of this residue occurred when Fe-SOD was exposed to a cumulative dose of 0.4mM peroxynitrite. Unlike with human Mn-SOD, this single modification did not inactivate E. coli Fe-SOD at pH7.4. When Fe-SOD was exposed to higher concentrations of peroxynitrite (7mM), eight tyrosine residues per subunit of the protein, of the nine available, were nitrated without loss of catalytic activity of the enzyme. The pKa of nitrated tyrosine-34 was determined to be 7.95±0.15, indicating that the peroxynitrite-modified enzyme appreciably maintains its protonation state under physiological conditions.

Characterization of the sodF gene region of Frankia sp. strain ACN14a and complementation of Escherichia coli sod mutant

2003 ◽  
Vol 49 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Joëlle Maréchal ◽  
Renata Santos ◽  
Yasser Hammad ◽  
Nicole Alloisio ◽  
Anne-Marie Domenach ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Superoxide Dismutase ◽  
Root Exudates ◽  
Alnus Glutinosa ◽  
Triple Mutant ◽  
Iron Superoxide Dismutase ◽  
E Coli ◽  
Its Gene ◽  
Tac Promoter ◽  
The One

The Frankia sp. strain ACN14a superoxide dismutase SodF was previously shown to be induced in response to Alnus glutinosa root exudates, and its gene was sequenced. We report here the sequence of the 9-kb genomic segment surrounding the sodF gene and further characterize this gene and its product. Nine ORFs coding for various proteins, such as regulators, acetyl-CoA transferases, and a bacterioferritin A next to the sodF gene, were found. Northern blot analysis showed that the sodF gene was expressed as a major 1-kb transcript, which indicates that it has its own promoter. The sodF gene strongly complemented an Escherichia coli triple mutant (sodA sodB recA), restoring aerobic growth when the gene was expressed from the synthetic tac promoter but when expressed from its own promoter showed only slight rescue, suggesting that it was poorly recognized by the E. coli RNA polymerase. It is noteworthy that this is the first time that a Frankia gene has been reported to complement an E. coli mutant. The superoxide dismutase activity of the protein was inactivated by hydrogen peroxide, indicating that the metal ligand is iron, which is supported by analysis of the protein sequence. Thus, the SodF protein induced in Frankia by root exudates is an iron-containing enzyme similar to the one present in the nodules.Key words: Frankia, iron superoxide dismutase, sodF, E. coli complementation.

Response of hydroperoxidase and superoxide dismutase deficient mutants of Escherichia coli K-12 to oxidative stress

1988 ◽  
Vol 34 (10) ◽  
pp. 1171-1176 ◽  
Author(s):  
Herb E. Schellhorn ◽  
Hosni M. Hassan
Keyword(s):  
Escherichia Coli ◽  
Superoxide Dismutase ◽  
Oxidant Stress ◽  
Relative Importance ◽  
E Coli ◽  
Redox Active ◽  
Chemical Oxidants ◽  
Dependent Growth ◽  
K 12 ◽  
Generalized Transduction

In Escherichia coli, the coordinate action of two antioxidant enzymes, superoxide dismutase and hydroperoxidase (catalase), protect the cell from the deleterious effects of oxyradicals generated during normal aerobic respiration. To evaluate the relative importance of these two classes of enzymes, strains of E. coli deficient in superoxide dismutase and (or) hydroperoxidase were constructed by generalized transduction and their physiological responses to oxygen and oxidant stress examined. Superoxide dismutase was found to be more important than hydroperoxidase in preventing oxygen-dependent growth inhibition and mutagenesis, and in reducing sensitivity to redox-active compounds known to generate the superoxide anion. However, both types of enzymes were required for an effective defense against chemical oxidants that generate superoxide radicals and hydrogen peroxide.

Further investigation of the mechanism of Vitreoscilla hemoglobin (VHb) protection from oxidative stress in Escherichia coli

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Meltem Akbas ◽  
Tugrul Doruk ◽  
Serhat Ozdemir ◽  
Benjamin Stark
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Stationary Phase ◽  
Exponential Phase ◽  
Vitreoscilla Hemoglobin ◽  
Sod Activity ◽  
E Coli ◽  
Hydrogen Peroxide Treatment

AbstractIn Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures of SOD+ or SOD− E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels.

scholarly journals Escherichia coliLrp regulates one-third of the genome via direct, cooperative, and indirect routes

2018 ◽  
Author(s):  
Grace M. Kroner ◽  
Michael B. Wolfe ◽  
Peter L. Freddolino
Keyword(s):  
Escherichia Coli ◽  
Crucial Role ◽  
Regulatory Activity ◽  
Global Regulator ◽  
Full Spectrum ◽  
Global Trends ◽  
Cooperative Action ◽  
E Coli ◽  
Physiological Conditions ◽  
Regulatory Behavior

AbstractThe global regulator Lrp plays a crucial role in regulating metabolism, virulence and motility in response to environmental conditions. Lrp has previously been shown to activate or repress approximately 10% of genes inEscherichia coli. However, the full spectrum of targets, and how Lrp acts to regulate them, has stymied earlier study. We have combined matched ChIP-seq and RNA sequencing under nine physiological conditions to map the binding and regulatory activity of Lrp as it directs responses to nutrient abundance. In addition to identifying hundreds of novel Lrp targets, we observe two new global trends: first, that Lrp will often bind to promoters in a poised position under conditions when it has no regulatory activity, and second, that nutrient levels induce a global shift in the equilibrium between non-specific and sequence-specific DNA binding. The overall regulatory behavior of Lrp, which as we now show regulates 35% ofE. coligenes directly or indirectly under at least one condition, thus arises from the interaction between changes in Lrp binding specificity and cooperative action with other regulators.

scholarly journals Characterization of iron superoxide dismutase cDNAs from plants obtained by genetic complementation in Escherichia coli.

1990 ◽  
Vol 87 (24) ◽  
pp. 9903-9907 ◽  
Author(s):  
W. Van Camp ◽  
C. Bowler ◽  
R. Villarroel ◽  
E. W. Tsang ◽  
M. Van Montagu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Superoxide Dismutase ◽  
Genetic Complementation ◽  
Iron Superoxide Dismutase

scholarly journals Endogenous Superoxide Dismutase Levels Regulate Iron-Dependent Hydroxyl Radical Formation in Escherichia coli Exposed to Hydrogen Peroxide

1998 ◽  
Vol 180 (3) ◽  
pp. 622-625 ◽  
Author(s):  
Michael L. McCormick ◽  
Garry R. Buettner ◽  
Bradley E. Britigan
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Superoxide Dismutase ◽  
Hydroxyl Radical ◽  
Iron Chelator ◽  
Spin Adduct ◽  
Control Strain ◽  
Paramagnetic Resonance ◽  
Fenton Chemistry ◽  
E Coli

ABSTRACT Aerobic organisms contain antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, to protect them from both direct and indirect effects of reactive oxygen species, such as O2 ·− and H2O2. Previous work by others has shown that Escherichia colimutants lacking SOD not only are more susceptible to DNA damage and killing by H2O2 but also contain larger pools of intracellular free iron. The present study investigated if SOD-deficient E. coli cells are exposed to increased levels of hydroxyl radical (·OH) as a consequence of the reaction of H2O2 with this increased iron pool. When the parental E. coli strain AB1157 was exposed to H2O2 in the presence of an α-(4-pyridyl-1-oxide)-N-tert-butyl-nitrone (4-POBN)–ethanol spin-trapping system, the 4-POBN–·CH(CH3)OH spin adduct was detectable by electron paramagnetic resonance (EPR) spectroscopy, indicating ·OH production. When the isogenic E. coli mutant JI132, lacking both Fe- and Mn-containing SODs, was exposed to H2O2 in a similar manner, the magnitude of ·OH spin trapped was significantly greater than with the control strain. Preincubation of the bacteria with the iron chelator deferoxamine markedly inhibited the magnitude of·OH spin trapped. Exogenous SOD failed to inhibit·OH formation, indicating the need for intracellular SOD. Redox-active iron, defined as EPR-detectable ascorbyl radical, was greater in the SOD-deficient strain than in the control strain. These studies (i) extend recent data from others demonstrating increased levels of iron in E. coli SOD mutants and (ii) support the hypothesis that a resulting increase in ·OH formation generated by Fenton chemistry is responsible for the observed enhancement of DNA damage and the increased susceptibility to H2O2-mediated killing seen in these mutants lacking SOD.

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