Role of the thioredoxin system and the thiol-peroxidases Tpx and Bcp in mediating resistance to oxidative and nitrosative stress in Helicobacter pylori.

  title={Role of the thioredoxin system and the thiol-peroxidases Tpx and Bcp in mediating resistance to oxidative and nitrosative stress in Helicobacter pylori.},
  author={Spencer L Comtois and Mark D Gidley and David J. Kelly},
  volume={149 Pt 1},
Helicobacter pylori possesses two distinct thioredoxin proteins (Trx1 and Trx2) which may play important roles in the ability of this bacterium to survive oxidative stress. Trx1 has previously been shown to be an electron donor in vitro for alkyl-hydroperoxide reductase (AhpC), one of three members of the peroxiredoxin family of antioxidant peroxidases present in H. pylori. In this study, mutants in the trxA1 and trxA2 genes encoding Trx1 and Trx2, respectively, and in the tpx and bcp genes… 

Figures and Tables from this paper

Contribution of the Helicobacter pylori Thiol Peroxidase Bacterioferritin Comigratory Protein to Oxidative Stress Resistance and Host Colonization

By examining the profiles of protein expression within H. pylori cells, it is confirmed that AhpC is much more abundant than BCP, which probably explain why the bcp mutant displayed a relatively weak oxidative stress resistance phenotype.

Comparative Roles of the Two Helicobacter pylori Thioredoxins in Preventing Macromolecule Damage

It is demonstrated that both TrxA and TrxC are important in protecting H. pylori from oxidative stress and both deletion mutants were much more sensitive to O2-mediated viability loss than the parent.

Roles of thioredoxin and thioredoxin reductase in the resistance to oxidative stress in Lactobacillus casei.

The results suggest that the thiored toxin-thioredoxin reductase system is the major thiol/disulfide redox system and is essential to allow the facultative anaerobe L. casei to grow under aerobic conditions.

Structural and Biochemical Characterization of Thioredoxin-2 from Deinococcus radiodurans

Thioredoxin (Trx), a ubiquitous protein showing disulfide reductase activity, plays critical roles in cellular redox control and oxidative stress response and, from this study, the crystal structure of full-length DrTrx2 at 1.96 Å resolution is solved and is clearly distinguished from those of the other Trx2 structures.

Involvement of thioredoxin domain-containing 5 in resistance to nitrosative stress.

Two Lactococcus lactis thioredoxin paralogues play different roles in responses to arsenate and oxidative stress.

Overall the phenotype of the ΔtrxA mutant matches established functions of WCGPC-type Trx while TrxD appears to play a more restricted role in stress resistance of Lac.

Oxygen- and NssR-dependent Globin Expression and Enhanced Iron Acquisition in the Response of Campylobacter to Nitrosative Stress*

The effect of oxygen availability on nitrosative stress tolerance; cells cultured at higher rates of oxygen diffusion have elevated levels of hemoglobins, are more resistant to inhibition by NO of both growth and respiration, and consume NO more rapidly.

An NADPH Quinone Reductase of Helicobacter pylori Plays an Important Role in Oxidative Stress Resistance and Host Colonization

It is proposed that the physiological function of the H. pylori MdaB protein is that of an NADPH quinone reductase that plays an important role in managing oxidative stress and contributes to successful colonization of the host.

The thioredoxin antioxidant system.

S-Nitrosylation of Peroxiredoxin II E Promotes Peroxynitrite-Mediated Tyrosine Nitration[W][OA]

It is concluded that NO regulates the effects of its own radicals through the S-nitrosylation of crucial components of the antioxidant defense system that function as common triggers for reactive oxygen species– and NO-mediated signaling events.



Essential Thioredoxin-Dependent Peroxiredoxin System from Helicobacter pylori: Genetic and Kinetic Characterization

Allelic replacement mutagenesis revealed ahpC to be essential, suggesting a critical role for AhpC in defending H. pylori against oxygen toxicity.

Thioredoxin-dependent Hydroperoxide Peroxidase Activity of Bacterioferritin Comigratory Protein (BCP) as a New Member of the Thiol-specific Antioxidant Protein (TSA)/Alkyl Hydroperoxide Peroxidase C (AhpC) Family*

Data suggest that Escherichia coli bacterioferritin comigratory protein is a new member of thioredoxin-dependent TSA/AhpC family, acting as a general hydroperoxide peroxidase.

Oxidative-Stress Resistance Mutants of Helicobacter pylori

Of the four types of mutants, the double mutant was the most sensitive to growth inhibition by oxygen and by organic peroxides and it had the highest spontaneous mutation frequency, suggesting H. pylori can readily modulate the expression of other resistance factors as a compensatory response to loss of a major oxidative-stress resistance component.

The Thioredoxin System of Helicobacter pylori*

Observations suggest that Trx may conceivably assist H. pylori in the process of colonization by inducing focal disruption of the oligomeric structure of mucin while rendering host antibody inactive through catalytic reduction.

Growth of Campylobacter jejuni Supported by Respiration of Fumarate, Nitrate, Nitrite, Trimethylamine-N-Oxide, or Dimethyl Sulfoxide Requires Oxygen

The results indicate that strict anaerobiosis is a stress condition for C. jejuni but that alternative respiratory pathways can contribute significantly to energy conservation under oxygen-limited conditions, as might be found in vivo.

Peroxynitrite reductase activity of bacterial peroxiredoxins

It is shown that the peroxiredoxin alkylhydroperoxide reductase subunit C from Salmonella typhimurium catalytically detoxifies peroxynitrite to nitrite fast enough to forestall the oxidation of bystander molecules such as DNA.

Alkyl Hydroperoxide Reductase Is the Primary Scavenger of Endogenous Hydrogen Peroxide in Escherichia coli

Analysis of candidate genes revealed that the residual activity is due to alkyl hydroperoxide reductase (Ahp), and mutants that lack both Ahp and catalase could not scavenge H(2)O(2), but damage is averted by the scavenging activity of Ahp.

Metronidazole resistance in Helicobacter pylori is due to null mutations in a gene (rdxA) that encodes an oxygen‐insensitive NADPH nitroreductase

It is shown that MtzR results from loss of oxygen‐insensitive NADPH nitroreductase activity, and suggests that many rdxA (MtzR) mutations may have been selected by prior use of Mtz against other infections.

Roles of thiol-redox pathways in bacteria.

There is mounting evidence that, in addition to the thiol redox potential, the spatial distribution within different cell compartments and the overall redox state of the cell are equally important.

Identification of carboxylation enzymes and characterization of a novel four-subunit pyruvate:flavodoxin oxidoreductase from Helicobacter pylori

N-terminal sequence analysis showed that this enzyme was found to mediate the reduction of a number of artificial electron acceptors in addition to a flavodoxin isolated from H. pylori extracts, which is likely to be the in vivo electron acceptor.