Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Biochemistry and pathology of radical-mediated protein oxidation.

ABSTRACT: Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several categories of reactive species, and a range of stable products whose chemistry is currently being elucidated. Among the reactive products, protein hydroperoxides can generate further radical fluxes on reaction with transition-metal ions; protein-bound reductants (notably dopa) can reduce transition-metal ions and thereby facilitate their reaction with hydroperoxides; and aldehydes may participate in Schiff-base formation and other reactions. Cells can detoxify some of the reactive species, e.g. by reducing protein hydroperoxides to unreactive hydroxides. Oxidized proteins are often functionally inactive and their unfolding is associated with enhanced susceptibility to proteinases. Thus cells can generally remove oxidized proteins by proteolysis. However, certain oxidized proteins are poorly handled by cells, and together with possible alterations in the rate of production of oxidized proteins, this may contribute to the observed accumulation and damaging actions of oxidized proteins during aging and in pathologies such as diabetes, atherosclerosis and neurodegenerative diseases. Protein oxidation may also sometimes play controlling roles in cellular remodelling and cell growth. Proteins are also key targets in defensive cytolysis and in inflammatory self-damage. The possibility of selective protection against protein oxidation (antioxidation) is raised.

SUBMITTER: Dean RT

PROVIDER: S-EPMC1218394 | biostudies-other | 1997 May

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

A supramolecular radical cation: folding-enhanced electrostatic effect for promoting radical-mediated oxidation.

Project description:We report a supramolecular strategy to promote radical-mediated Fenton oxidation by the rational design of a folded host-guest complex based on cucurbit[8]uril (CB[8]). In the supramolecular complex between CB[8] and a derivative of 1,4-diketopyrrolo[3,4-c]pyrrole (DPP), the carbonyl groups of CB[8] and the DPP moiety are brought together through the formation of a folded conformation. In this way, the electrostatic effect of the carbonyl groups of CB[8] is fully applied to highly improve the reactivity of the DPP radical cation, which is the key intermediate of Fenton oxidation. As a result, the Fenton oxidation is extraordinarily accelerated by over 100 times. It is anticipated that this strategy could be applied to other radical reactions and enrich the field of supramolecular radical chemistry in radical polymerization, photocatalysis, and organic radical battery and holds potential in supramolecular catalysis and biocatalysis.

| S-EPMC5994746 | biostudies-literature

Free Radical-Mediated Protein Radical Formation in Differentiating Monocytes.

Project description:Free radical-mediated activation of inflammatory macrophages remains ambiguous with its limitation to study within biological systems. U-937 and HL-60 cell lines serve as a well-defined model system known to differentiate into either macrophages or dendritic cells in response to various chemical stimuli linked with reactive oxygen species (ROS) production. Our present work utilizes phorbol 12-myristate-13-acetate (PMA) as a stimulant, and factors such as concentration and incubation time were considered to achieve optimized differentiation conditions. ROS formation likely hydroxyl radical (HO●) was confirmed by electron paramagnetic resonance (EPR) spectroscopy combined with confocal laser scanning microscopy (CLSM). In particular, U-937 cells were utilized further to identify proteins undergoing oxidation by ROS using anti-DMPO (5,5-dimethyl-1-pyrroline N-oxide) antibodies. Additionally, the expression pattern of NADPH Oxidase 4 (NOX4) in relation to induction with PMA was monitored to correlate the pattern of ROS generated. Utilizing macrophages as a model system, findings from the present study provide a valuable source for expanding the knowledge of differentiation and protein expression dynamics.

| S-EPMC8468151 | biostudies-literature

Protein Radical Formation Resulting from Eosinophil Peroxidase-catalyzed Oxidation of Sulfite.

Project description:Eosinophil peroxidase (EPO) is an abundant heme protein in eosinophils that catalyzes the formation of cytotoxic oxidants implicated in asthma, allergic inflammatory disorders, and cancer. It is known that some proteins with peroxidase activity (horseradish peroxidase and prostaglandin hydroperoxidase) can catalyze oxidation of bisulfite (hydrated sulfur dioxide), leading to the formation of sulfur trioxide anion radical ((.)SO(3)(-)). This free radical further reacts with oxygen to form peroxymonosulfate anion radical ((-)O(3)SOO(.)) and the very reactive sulfate anion radical (SO(4)()), which is nearly as strong an oxidant as the hydroxyl radical. However, the ability of EPO to generate reactive sulfur radicals has not yet been reported. Here we demonstrate that eosinophil peroxidase/H(2)O(2) is able to oxidize bisulfite, ultimately forming the sulfate anion radical (SO(4)()), and that these reactive intermediates can oxidize target proteins to protein radicals, thereby initiating protein oxidation. We used immuno-spin trapping and confocal microscopy to study protein oxidation by EPO/H(2)O(2) in the presence of bisulfite in a pure enzymatic system and in human promyelocytic leukemia HL-60 clone 15 cells, maturated to eosinophils. Polyclonal antiserum raised against the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) detected the presence of DMPO covalently attached to the proteins resulting from the DMPO trapping of protein free radicals. We found that sulfite oxidation mediated by EPO/H(2)O(2) induced the formation of radical-derived DMPO spin-trapped human serum albumin and, to a lesser extent, of DMPO-EPO. These studies suggest that EPO-dependent oxidative damage may play a role in tissue injury in bisulfite-exacerbated eosinophilic inflammatory disorders.

| S-EPMC2911282 | biostudies-literature

OH-Radical Oxidation of Lung Surfactant Protein B on Aqueous Surfaces.

Project description:Air pollutants generate reactive oxygen species on lung surfaces. Here we report how hydroxyl radicals (·OH) injected on the surface of water react with SP-B1-25, a 25-residue polypeptide surrogate of human lung surfactant protein B. Our experiments consist of intersecting microjets of aqueous SP-B1-25 solutions with O3/O2/H2O/N2(g) gas streams that are photolyzed into ·OH(g) in situ by 266 nm laser nanosecond pulses. Surface-sensitive mass spectrometry enables us to monitor the prompt (<10 μs) and simultaneous formation of primary O n -containing products/intermediates (n≤5) triggered by the reaction of ·OH with interfacial SP-B1-25. We found that O-atoms from both O3 and ·OH are incorporated into the reactive cysteine Cys8 and Cys11 and tryptophan Trp9 components of the hydrophobic N-terminus of SP-B1-25 that lies at the topmost layers of the air-liquid interface. Remarkably, these processes are initiated by ·OH additions rather than by H-atom abstractions from S-H, C-H, or N-H groups. By increasing the hydrophilicity of the N-terminus region of SP-B1-25, these transformations will impair its role as a surfactant.

| S-EPMC6245955 | biostudies-literature

Mapping protein-protein interactions by localized oxidation: consequences of the reach of hydroxyl radical.

Project description:Hydroxyl radicals generated from a variety of methods, including not only synchrotron radiation but also Fenton reactions involving chelated iron, have become an accepted macromolecular footprinting tool. Hydroxyl radicals react with proteins via multiple mechanisms that lead to both polypeptide backbone cleavage events and side chain modifications (e.g., hydroxylation and carbonyl formation). The use of site-specifically tethered iron chelates can reveal protein-protein interactions, but the interpretation of such experiments will be strengthened by improving our understanding of how hydroxyl radicals produced at a point on a protein react with other protein sites. We have developed methods for monitoring carbonyl formation on proteins as a function of distance from a hydroxyl generator, iron-(S)-1-[p-(bromoacetamido)benzyl]EDTA (FeBABE), conjugated to an engineered cysteine residue. After activation of the chelated iron with ascorbate and peroxide produces new protein carbonyl groups, their positions can be identified using element-coded affinity tagging (ECAT), with carbonyl-specific tags {e.g., rare earth chelates of (S)-2-[4-(2-aminooxy)acetamidobenzyl]-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (AOD)} that allow for affinity purification, identification, and relative quantitation of oxidation sites using mass spectrometry. Intraprotein oxidation of single-cysteine mutants of Escherichia coli sigma(70) by tethered FeBABE was used to calibrate the reach of hydroxyl radical by comparison to the crystal structure; the application to protein-protein interactions was demonstrated using the same sigma(70) FeBABE conjugates in complexes with the RNA polymerase core enzyme. The results provide fundamental information for interpreting protein footprinting experiments in other systems.

| S-EPMC2713361 | biostudies-literature

Gelsolin amyloidosis: genetics, biochemistry, pathology and possible strategies for therapeutic intervention.

Project description:Protein misassembly into aggregate structures, including cross-?-sheet amyloid fibrils, is linked to diseases characterized by the degeneration of post-mitotic tissue. While amyloid fibril deposition in the extracellular space certainly disrupts cellular and tissue architecture late in the course of amyloid diseases, strong genetic, pathological and pharmacologic evidence suggests that the process of amyloid fibril formation itself, known as amyloidogenesis, likely causes these maladies. It seems that the formation of oligomeric aggregates during the amyloidogenesis process causes the proteotoxicity and cytotoxicity characteristic of these disorders. Herein, we review what is known about the genetics, biochemistry and pathology of familial amyloidosis of Finnish type (FAF) or gelsolin amyloidosis. Briefly, autosomal dominant D187N or D187Y mutations compromise Ca(2+) binding in domain 2 of gelsolin, allowing domain 2 to sample unfolded conformations. When domain 2 is unfolded, gelsolin is subject to aberrant furin endoproteolysis as it passes through the Golgi on its way to the extracellular space. The resulting C-terminal 68 kDa fragment (C68) is susceptible to extracellular endoproteolytic events, possibly mediated by a matrix metalloprotease, affording 8 and 5 kDa amyloidogenic fragments of gelsolin. These amyloidogenic fragments deposit systemically, causing a variety of symptoms including corneal lattice dystrophy and neurodegeneration. The first murine model of the disease recapitulates the aberrant processing of mutant plasma gelsolin, amyloid deposition, and the degenerative phenotype. We use what we have learned from our biochemical studies, as well as insight from mouse and human pathology to propose therapeutic strategies that may halt the progression of FAF.

| S-EPMC3337338 | biostudies-literature

Light-Mediated Formal Radical Deoxyfluorination of Tertiary Alcohols through Selective Single-Electron Oxidation with TEDA2+.

Project description:The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light-mediated, catalyst-free methodology is fast and broadly applicable allowing for the preparation of C-F bonds from (hetero)benzylic, propargylic, and non-activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single-electron oxidation of cesium oxalates-which are readily available from the corresponding tertiary alcohols-with in situ generated TEDA2+. (TEDA: N-(chloromethyl)triethylenediamine), a radical cation derived from Selectfluor®.

| S-EPMC6899844 | biostudies-literature

Fast Protein Footprinting by X-ray Mediated Radical Trifluoromethylation.

Project description:Synchrotron radiolysis generates hydroxyl radicals (•OH) that are successful footprinting reagents. Here, we describe a new reagent for the synchrotron platform, the trifluoromethyl radical (•CF3). The radical is produced by •OH displacement of •CF3 from sodium triflinate (Langlois reagent). Upon X-ray beam exposure, the reagent labels proteins extensively without any additional chemicals on a millisecond or shorter time scale. The •CF3 is comparably reactive to •OH and produces footprinting information that complements that of •OH alone. This reagent in combination with •OH should enable novel chemistry for protein footprinting on the synchrotron platform.

| S-EPMC7486011 | biostudies-literature

Sulfite-mediated oxidation of myeloperoxidase to a free radical: immuno-spin trapping detection in human neutrophils.

Project description:Previous studies focused on catalyzed oxidation of (bi)sulfite, leading to the formation of the reactive sulfur trioxide ((•)SO3(-)), peroxymonosulfate ((-)O3SOO(•)), and sulfate (SO4(•-)) anion radicals, which can damage target proteins and oxidize them to protein radicals. It is known that these very reactive sulfur- and oxygen-centered radicals can be formed by oxidation of (bi)sulfite by peroxidases. Myeloperoxidase (MPO), an abundant heme protein secreted from activated neutrophils that play a central role in host defense mechanisms, allergic reactions, and asthma, is a likely candidate for initiating the respiratory damage caused by sulfur dioxide. The objective of this study was to examine the oxidative damage caused by (bi)sulfite-derived free radicals in human neutrophils through formation of protein radicals. We used immuno-spin trapping and confocal microscopy to study the protein oxidations driven by sulfite-derived radicals. We found that the presence of sulfite can cause MPO-catalyzed oxidation of MPO to a protein radical in phorbol 12-myristate 13-acetate-activated human neutrophils. We trapped the MPO-derived radicals in situ using the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide and detected them immunologically as nitrone adducts in cells. Our present study demonstrates that myeloperoxidase initiates (bi)sulfite oxidation leading to MPO radical damage, possibly leading to (bi)sulfite-exacerbated allergic reactions.

| S-EPMC3654059 | biostudies-literature

Aliphatic peptidyl hydroperoxides as a source of secondary oxidation in hydroxyl radical protein footprinting.

Project description:Hydroxyl radical footprinting is a technique for studying protein structure and binding that entails oxidizing a protein system of interest with diffusing hydroxyl radicals, and then measuring the amount of oxidation of each amino acid. One important issue in hydroxyl radical footprinting is limiting amino acid oxidation by secondary oxidants to prevent uncontrolled oxidation, which can cause amino acids to appear more solvent accessible than they really are. Previous work suggested that hydrogen peroxide was the major secondary oxidant of concern in hydroxyl radical footprinting experiments; however, even after elimination of all hydrogen peroxide, some secondary oxidation was still detected. Evidence is presented for the formation of peptidyl hydroperoxides as the most abundant product upon oxidation of aliphatic amino acids. Both reverse phase liquid chromatography and catalase treatment were shown to be ineffective at eliminating peptidyl hydroperoxides. The ability of these peptidyl hydroperoxides to directly oxidize methionine is demonstrated, suggesting the value of methionine amide as an in situ protectant. Hydroxyl radical footprinting protocols require the use of an organic sulfide or similar peroxide scavenger in addition to removal of hydrogen peroxide to successfully eradicate all secondary oxidizing species and prevent uncontrolled oxidation of sulfur-containing residues.

| S-EPMC2684652 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data