Substrate specificity and redox potential of AhpC, a bacterial peroxiredoxin

Parsonage, Derek; Karplus, P. Andrew; Poole, Leslie B.

doi:10.1073/pnas.0708308105

Cited by 146 publications

(164 citation statements)

References 61 publications

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“…For other Cys-based peroxidases, substrate specificity correlates well with hyperoxidation rates (8,(37)(38)(39), which is consistent with the fact that oxidation to Cys-SOH and hyperoxidation are both reactions dependent on hydroperoxide concentration (Fig. 3A).…”

Section: Resultssupporting

confidence: 65%

Ohr plays a central role in bacterial responses against fatty acid hydroperoxides and peroxynitrite

Alegria

Meireles

Cussiol

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Organic hydroperoxide resistance (Ohr) enzymes are unique Cysbased, lipoyl-dependent peroxidases. Here, we investigated the involvement of Ohr in bacterial responses toward distinct hydroperoxides. In silico results indicated that fatty acid (but not cholesterol) hydroperoxides docked well into the active site of Ohr from Xylella fastidiosa and were efficiently reduced by the recombinant enzyme as assessed by a lipoamide-lipoamide dehydrogenase-coupled assay. Indeed, the rate constants between Ohr and several fatty acid hydroperoxides were in the 10 7 -10 8 M −1 ·s −1 range as determined by a competition assay developed here. Reduction of peroxynitrite by Ohr was also determined to be in the order of 10 7 M −1 ·s −1 at pH 7.4 through two independent competition assays. A similar trend was observed when studying the sensitivities of a Δohr mutant of Pseudomonas aeruginosa toward different hydroperoxides. Fatty acid hydroperoxides, which are readily solubilized by bacterial surfactants, killed the Δohr strain most efficiently. In contrast, both wild-type and mutant strains deficient for peroxiredoxins and glutathione peroxidases were equally sensitive to fatty acid hydroperoxides. Ohr also appeared to play a central role in the peroxynitrite response, because the Δohr mutant was more sensitive than wild type to 3-morpholinosydnonimine hydrochloride (SIN-1 , a peroxynitrite generator). In the case of H 2 O 2 insult, cells treated with 3-amino-1,2,4-triazole (a catalase inhibitor) were the most sensitive. Furthermore, fatty acid hydroperoxide and SIN-1 both induced Ohr expression in the wildtype strain. In conclusion, Ohr plays a central role in modulating the levels of fatty acid hydroperoxides and peroxynitrite, both of which are involved in host-pathogen interactions.hydroperoxides | thiols | Cys-based peroxidase | pathogenic bacteria | Pseudomonas aeruginosa

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Section: Resultssupporting

confidence: 65%

Ohr plays a central role in bacterial responses against fatty acid hydroperoxides and peroxynitrite

Alegria

Meireles

Cussiol

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…3B) is consistent with this hypothesis. The high catalytic efficiency of the 2-Cys Prxs with k cat /K m values of ∼10 7 M −1 ·s −1 and high affinity with K m values in the μM range (20)(21)(22) presumably ensure rapid oxidation kinetics of their Trx partner in response to small changes in low peroxide levels (24,25). In turn, the identified preference of ACHT4 disulfide transfer reaction toward APS1 (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Study of the thylakoids-associated ACHT1 revealed that it transmits a disulfide-based oxidative signal in feedback regulation of photosynthesis under homeostasis growth conditions (6). ACHT1 oxidation is driven by 2-Cys Prx, a peroxidase with a low K m for hydrogen peroxide (20)(21)(22) that is conceivably required for the low level of ROS that are typical in signaling events. ACHT1 undergoes rapid redox state changes during the transition of plants from dark to light and afterward, such that, after a short period of net reduction, the ACHT1 pool is maintained in a partially oxidized state in the light.…”

Section: Significancementioning

confidence: 99%

ACHT4-driven oxidation of APS1 attenuates starch synthesis under low light intensity in Arabidopsis plants

Eliyahu

Rog

Dangoor

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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The regulatory mechanisms that use signals of low levels of reactive oxygen species (ROS) could be obscured by ROS produced under stress and thus are better investigated under homeostatic conditions. Previous studies showed that the chloroplastic atypical thioredoxin ACHT1 is oxidized by 2-Cys peroxiredoxin (2-Cys Prx) in Arabidopsis plants illuminated with growth light and in turn transmits a disulfide-based signal via yet unknown target proteins in a feedback regulation of photosynthesis. Here, we studied the role of a second chloroplastic paralog, ACHT4, in plants subjected to low light conditions. Likewise, ACHT4 reacted in planta with 2-Cys Prx, indicating that it is oxidized by a similar disulfide exchange reaction. ACHT4 further reacted uniquely with the small subunit (APS1) of ADP-glucose pyrophosphorylase (AGPase), the first committed enzyme of the starch synthesis pathway, suggesting that it transfers the disulfides it receives from 2-Cys Prx to APS1 and turns off AGPase. In accordance, ACHT4 participated in an oxidative signal that quenched AGPase activity during the diurnal transition from day to night, and also in an attenuating oxidative signal of AGPase in a dynamic response to small fluctuations in light intensity during the day. Increasing the level of expressed ACHT4 or of ACHT4 ΔC , a C terminus-deleted form that does not react with APS1, correspondingly decreased or increased the level of reduced APS1 and decreased or increased transitory starch content. These findings imply that oxidative control mechanisms act in concert with reductive signals to fine tune starch synthesis during daily homeostatic conditions. oxidative signal | homeostasis | light intensity regulation | starch synthesis | chloroplast

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“…Bi-substrate Kinetic Analysis of Prx1 and Prx2-To determine the kinetic parameters, Prxs, AhpFNTD, and TrxA were pre-reduced by 100 M excess of DTT and then DTT was removed as described by Parsonage et al (15,21). Various concentrations of H 2 O 2 were added to the mixtures of pre-reduced Prx1 (100 nM) and AhpFNTD (5-30 M) in the reaction buffer (50 mM Hepes-NaOH, pH 7.0), and then incubated at 25°C.…”

Section: Nad(p)h Consumption Assay-peroxidase Activity Of Prx2 Was Dementioning

confidence: 99%

Distinct Characteristics of Two 2-Cys Peroxiredoxins of Vibrio vulnificus Suggesting Differential Roles in Detoxifying Oxidative Stress

Bang¹,

Oh²,

Choi

2012

Journal of Biological Chemistry

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Background: Peroxiredoxins are ubiquitous antioxidant enzymes reducing toxic peroxides. Results: Two 2-Cys peroxiredoxins of Vibrio vulnificus are different in expression patterns, sensitivities to overoxidation, and kinetic properties. Conclusion: The two peroxiredoxins are optimized for detoxifying different ranges of H 2 O 2 . Significance: This study is the first report on the coexistence of the two peroxiredoxins along with their distinct roles in a single bacterium.

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Substrate specificity and redox potential of AhpC, a bacterial peroxiredoxin

Cited by 146 publications

References 61 publications

Ohr plays a central role in bacterial responses against fatty acid hydroperoxides and peroxynitrite

Ohr plays a central role in bacterial responses against fatty acid hydroperoxides and peroxynitrite

ACHT4-driven oxidation of APS1 attenuates starch synthesis under low light intensity in Arabidopsis plants

Distinct Characteristics of Two 2-Cys Peroxiredoxins of Vibrio vulnificus Suggesting Differential Roles in Detoxifying Oxidative Stress

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