Recycling of the High Valence States of Heme Proteins by Cysteine Residues of Thimet-Oligopeptidase

Ferreira, Juliana C.; Icimoto, Marcelo Yudi; Marcondes, Marcelo F.; Oliveira, Vitor; Nascimento, Otaciro Rangel; Nantes, Iseli L.

doi:10.1371/journal.pone.0079102

Cited by 5 publications

(7 citation statements)

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“…SA-mediated oxidative and reductive bursts can lead to redox -based modifications of sensors which are proteins with higher chemical reactivity whose location and ionic state render them sensitive to oxidation by ROS (Mou et al, 2003 ). Interestingly, metazoan TOPs are described as thiol-dependent peptidases since their activity is markedly altered by thiols such as dithiothreitol (DTT) (Tisljar and Barrett, 1990 ) and are considered as likely participants in the cellular redox reactions where thiols are part of the antioxidant defense and signaling processes (Ferreira et al, 2013 ). Currently, the identity of plant redox sensors and the mechanistic basis of the complex relationship that exists between SA and ROS homeostasis remain largely unknown (Foyer and Noctor, 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Dimerization and thiol sensitivity of the salicylic acid binding thimet oligopeptidases TOP1 and TOP2 define their functions in redox-sensitive cellular pathways

et al. 2015

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A long-term goal in plant research is to understand how plants integrate signals from multiple environmental stressors. The importance of salicylic acid (SA) in plant response to biotic and abiotic stress is known, yet the molecular details of the SA-mediated pathways are insufficiently understood. Our recent work identified the peptidases TOP1 and TOP2 as critical components in plant response to pathogens and programmed cell death (PCD). In this study, we investigated the characteristics of TOPs related to the regulation of their enzymatic activity and function in oxidative stress response. We determined that TOP1 and TOP2 interact with themselves and each other and their ability to associate in dimers is influenced by SA and the thiol-based reductant DTT. Biochemical characterization of TOP1 and TOP2 indicated distinct sensitivities to DTT and similarly robust activity under a range of pH values. Treatments of top mutants with Methyl Viologen (MV) revealed TOP1 and TOP2 as a modulators of the plant tolerance to MV, and that exogenous SA alleviates the toxicity of MV in top background. Finally, we generated a TOP-centered computational model of a plant cell whose simulation outputs replicate experimental findings and predict novel functions of TOP1 and TOP2. Altogether, our work indicates that TOP1 and TOP2 mediate plant responses to oxidative stress through spatially separated pathways and positions proteolysis in a network for plant response to diverse stressors.

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Section: Introductionmentioning

confidence: 99%

Dimerization and thiol sensitivity of the salicylic acid binding thimet oligopeptidases TOP1 and TOP2 define their functions in redox-sensitive cellular pathways

et al. 2015

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“…The incubation of the microtube in an ethanolic solution of FITC‐PEG‐SH was made in air atmosphere and could lead to partial oxidation of FITC‐PEG‐SH. It is important to note that the natural oxidation of thiol groups exposed to air atmosphere produces typically sulfenic acid, sulfide, and sulfoxide . The formation of disulfide suggests catalyzed reaction probably promoted by the presence of AuNPs that is interesting for future investigations …”

Section: Resultsmentioning

confidence: 99%

Nanostructured Hematite Decorated with Gold Nanoparticles for Functionalization and Biocompatibility

Menezes

Sombrio

Costa

et al. 2019

Physica Status Solidi (a)

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Iron oxides have attracted the attention of researchers due to their abundance, low cost, low toxicity, and versatility of applications. According to the composition and crystalline structure, iron oxides may have characteristics of semiconductors and magnetic materials, such as hematite (α‐Fe2O3) and magnetite (Fe3O4), respectively. The property of biocompatibility of hematite is essential to be applied in the construction of micro‐/nanorobots (MNRs). Herein, the decoration of hierarchically structured core/shell Fe3O4/Fe2O3 microtubes and foils with gold nanoparticles (AuNPs) for functionalization and enhancement of biocompatibility that favor the use in MNR fabrication is presented. In this case, the synthesis of AuNPs takes advantage of the capacity of hematite to reduce Au3+ photochemically under excitation by a sunlight simulator. The yield of AuNPs covering the microtube surface is dependent on the gold salt concentration used for the synthesis. The AuNP‐decorated hematite surfaces of the microtube and foil are functionalized with thiol poly(ethylene glycol) fluorescein, exhibiting increase in conductivity favored by irradiation with visible light. AuNPs also favor cell adherence and proliferation with the maintenance of mitochondrial transmembrane potential. Therefore, the hematite surface of the microtubes decorated with AuNPs is a promising material for the application in micro‐/nanorobots and bioelectronics.

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“…The simulation resulted in a large Gaussian line width (3.77 G). For this tyrosyl-DBNBS adduct, the large linewidth results from the super hyperfine interactions in a highly heterogeneous microenvironment around nitroxide radical; these interactions were not resolved by the CW EPR spectrum [ 47 ]. The oxidative potential of tyrosine and tryptophan are similar; when these residues are neighbors in a protein structure, the unpaired electron density can be found in these amino acids in a population of hemeproteins treated with peroxides.…”

Section: Resultsmentioning

confidence: 99%

“…Direct continuous wave EPR of Cygb heme iron was measured as previously described for other hemeproteins with modifications [ 47 , 48 ]. The protein concentration was of 1.2 mmol.L -1 and when present, the peroxide concentration was of 12 mmol.L -1 .…”

Section: Methodsmentioning

confidence: 99%

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Intermediate Tyrosyl Radical and Amyloid Structure in Peroxide-Activated Cytoglobin

et al. 2015

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We characterized the peroxidase mechanism of recombinant rat brain cytoglobin (Cygb) challenged by hydrogen peroxide, tert-butylhydroperoxide and by cumene hydroperoxide. The peroxidase mechanism of Cygb is similar to that of myoglobin. Cygb challenged by hydrogen peroxide is converted to a Fe4+ oxoferryl π cation, which is converted to Fe4+ oxoferryl and tyrosyl radical detected by direct continuous wave-electron paramagnetic resonance and by 3,5-dibromo-4-nitrosobenzene sulfonate spin trapping. When organic peroxides are used as substrates at initial reaction times, and given an excess of peroxide present, the EPR signals of the corresponding peroxyl radicals precede those of the direct tyrosyl radical. This result is consistent with the use of peroxide as a reducing agent for the recycling of Cygb high-valence species. Furthermore, we found that the Cygb oxidation by peroxides leads to the formation of amyloid fibrils. This result suggests that Cygb possibly participates in the development of degenerative diseases; our findings also support the possible biological role of Cygb related to peroxidase activity.

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Recycling of the High Valence States of Heme Proteins by Cysteine Residues of Thimet-Oligopeptidase

Cited by 5 publications

References 49 publications

Dimerization and thiol sensitivity of the salicylic acid binding thimet oligopeptidases TOP1 and TOP2 define their functions in redox-sensitive cellular pathways

Dimerization and thiol sensitivity of the salicylic acid binding thimet oligopeptidases TOP1 and TOP2 define their functions in redox-sensitive cellular pathways

Nanostructured Hematite Decorated with Gold Nanoparticles for Functionalization and Biocompatibility

Intermediate Tyrosyl Radical and Amyloid Structure in Peroxide-Activated Cytoglobin

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