Reactive Sulfur Species: An Emerging Concept in Oxidative Stress

“…Reduction of the sulfenic acid requires reaction with two thiols to form first a mixed disulfide and then a sulfhydryl (5). Cysteine-sulfenic acid is reactive and, thus, short lived (23). However, the Cys-47-sulfenic acid of 1-cysPrx is stable because of its inaccessibility within a globular protein; homodimer formation of oxidized monomers (22) further limits its accessibility.…”

mentioning

confidence: 99%

Activation of the antioxidant enzyme 1-CYS peroxiredoxin requires glutathionylation mediated by heterodimerization with πGST

Manevich

Feinstein

Fisher

2004

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

322

266

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1-cys peroxiredoxin (1-cysPrx), a member of the peroxiredoxin superfamily, can protect cells against membrane oxidation through glutathione (GSH)-dependent reduction of phospholipid hydroperoxides to corresponding alcohols. However, purified native or recombinant enzyme in vitro generally lacks GSH peroxidase (GPx) activity because of oxidation of its single conserved cysteine. Reduction of the resultant oxidized cysteine is difficult because of its protected location within the homodimer formed by the oxidized protein monomers. Partial purification of 1-cysPrx from bovine lung revealed the presence of GST in an active preparation, while purification to homogeneity yielded enzyme that inactivated with time. We show that heterodimerization of 1-cysPrx with GSH-saturated GST results in glutathionylation of the oxidized cysteine in 1-cysPrx followed by subsequent spontaneous reduction of the mixed disulfide and restoration of enzymatic activity. Maximum activation of 1-cysPrx occurred with a 1:1 molar ratio of GSH-saturated GST and a 2:1 molar ratio of GSH to 1-cysPrx. Liposome-mediated delivery of oxidized recombinant enzyme into NCI-H441 cells that lack 1-cysPrx but express GST resulted in 1-cysPrx activation, whereas activation in MCF7 cells required co-delivery of GST. Our data indicate a physiological mechanism for glutathionylation of the oxidized catalytic cysteine of 1-cysPrx by its heterodimerization with GST followed by its GSH-mediated reduction and enzyme activation. P eroxiredoxins are a superfamily of nonheme and nonselenium peroxidases that are widely distributed throughout all phyla (1-4). Of the six mammalian peroxiredoxins, five (Prx I-V) contain two conserved cysteines that participate in intramolecular disulfide͞sulfhydryl redox cycling with thioredoxin resulting in reduction of H 2 O 2 and organic hydroperoxides into corresponding alcohols (2). By contrast, 1-cys peroxiredoxin (1-cysPrx or Prx VI) † has a single conserved cysteine (5) and does not use thioredoxin as reductant (5, 6). This peroxiredoxin is expressed in all tissues but at particularly high levels in brain, eye, testes, and lung (2,7,8). Expression of 1-cysPrx protein or mRNA is decreased in a mouse that is susceptible to experimental atherosclerosis (9) and is elevated in brains of patients with Parkinsonian dementia (10), sporadic Creutzfeldt-Jacob disease (11), and Pick disease (12), in lungs from newborns (13), in malignant mesothelioma (14), in the healing edge of skin wounds (15), and in experimental cellular premature senescence (16). 1-cysPrx can reduce phospholipid and other hydroperoxides (6) and protects against cellular membrane damage (17, 18). This enzyme has phospholipase A 2 activity (19), participates in the activation of neutrophil NADPH oxidase through its interaction with p67 phox (20), and prevent methemoglobin formation in erythrocyte hemolysates (21).1-cysPrx catalysis results in the peroxide-mediated oxidation of its Cys-47 to sulfenic acid as deduced from 1-cysPrx crystallization (22). Reduction of the sul...

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“…Due to a low reduction potential of thiols and their ease to be oxidized to sulfur species, disulfide chemistry is very rich, which can wreak havoc in tightly spaced cellular compartments if not properly controlled 7,34,35,37,39 .…”

Section: Discussionmentioning

confidence: 99%

Single-molecule studies of disulfide bond reduction pathways used by human thioredoxin

Szoszkiewicz

2013

Biophysical Chemistry

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How to cite this manuscriptIf you make reference to this version of the manuscript, use the following information: Szoszkiewicz, R. (2013). Single-molecule studies of disulfide bond reduction pathways used by human thioredoxin. Retrieved from http://krex.ksu.edu Published Version InformationCitation: Szoszkiewicz, R. (2013 8 molecules are stretched at constant force applied by a cantilever in a force-clamp mode of atomic force microscopy (FC-AFM). Disulfide reduction events are accurately detected from stepwise increases in the end-to-end length of (I27 SS ) 8 . Earlier FC-AFM studies observed one disulfide reduction pathway used by hTrx and suggested an additional electron tunnelling mechanism. Here, a very large set of unbiased FC-AFM data is collected in a range of clamping forces. By analyzing the data using exponential fits and dwell times histograms two disulfide reduction pathways used by hTrx are resolved. Based on previous studies one of these pathways is attributed to force-dependent Michaelis-Menten catalysis. The latter reduction pathway is weakly forceinhibited and occurs sporadically. Bimolecular nucleophilic substitutions (S N 2) and electron tunnelling (ET) mechanisms are discussed to explain the second pathway. Direct S N 2 and ET mechanisms cannot be discounted, but a hypothetical E2-S N 2 mechanism involving a hydride reducing a disulfide bond provides an interesting alternative, which needs to be verified in future experiments.

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Reactive Sulfur Species: An Emerging Concept in Oxidative Stress

Cited by 273 publications

References 83 publications

Antioxidants: An Overview on the Natural and Synthetic Types

Antioxidants: An Overview on the Natural and Synthetic Types

Activation of the antioxidant enzyme 1-CYS peroxiredoxin requires glutathionylation mediated by heterodimerization with πGST

Single-molecule studies of disulfide bond reduction pathways used by human thioredoxin

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