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1.
Biomolecules ; 10(8)2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32824289

RESUMO

To function as a metabolic hub, plant mitochondria have to exchange a wide variety of metabolic intermediates as well as inorganic ions with the cytosol. As identified by proteomic profiling or as predicted by MU-LOC, a newly developed bioinformatics tool, Arabidopsis thaliana mitochondria contain 128 or 143 different transporters, respectively. The largest group is the mitochondrial carrier family, which consists of symporters and antiporters catalyzing secondary active transport of organic acids, amino acids, and nucleotides across the inner mitochondrial membrane. An impressive 97% (58 out of 60) of all the known mitochondrial carrier family members in Arabidopsis have been experimentally identified in isolated mitochondria. In addition to many other secondary transporters, Arabidopsis mitochondria contain the ATP synthase transporters, the mitochondria protein translocase complexes (responsible for protein uptake across the outer and inner membrane), ATP-binding cassette (ABC) transporters, and a number of transporters and channels responsible for allowing water and inorganic ions to move across the inner membrane driven by their transmembrane electrochemical gradient. A few mitochondrial transporters are tissue-specific, development-specific, or stress-response specific, but this is a relatively unexplored area in proteomics that merits much more attention.

2.
Free Radic Biol Med ; 160: 433-446, 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-32860983

RESUMO

Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resistant healthcare-associated disease resulting in diarrhea and pseudomembranous colitis. The two cytotoxic proteins, toxin A (TcdA) and toxin B (TcdB) are the major virulence factor responsible for the disease symptoms. We examined time-dependent oxidative detoxification of TcdA and TcdB using different molar ratios of protein:Cu2+:H2O2. The metal-catalyzed oxidation (MCO) reaction in molar ratios of 1:60:1000 for protein:Cu2+:H2O2 at pH 4.5 resulted in a significant 6 log10 fold reduction in cytotoxicity after 120-min incubation at 37 °C. Circular dichroism revealed that MCO-detoxified TcdA and TcdB had secondary and tertiary structural folds similar to the native proteins. The conservation of immunogenic epitopes of both proteins was tested using monoclonal antibodies in an ELISA, comparing our MCO-detoxification approach to a conventional formaldehyde-detoxification method. The oxidative detoxification of TcdA and TcdB led to an average 2-fold reduction in antibody binding relative to native proteins, whereas formaldehyde cross-linking resulted in 3-fold and 5-fold reductions, respectively. Finally, we show that mice immunized with a vaccine consisting of MCO-detoxified TcdA and TcdB were fully protected against disease symptoms and death following a C. difficile infection and elicited substantial serum IgG responses against both TcdA and TcdB. The results of this study present copper ion-catalyzed oxidative detoxification of toxic proteins as a method highly suitable for the rapid production of safe, immunogenic and irreversible toxoid antigens for future vaccine development and may have the potential for replacing cross-linking reagents like formaldehyde.

3.
Mitochondrion ; 54: 133-135, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32569844
4.
Mitochondrion ; 52: 173-182, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32224234

RESUMO

Plant mitochondrial genomes are renowned for their structural complexity, extreme variation in size and mutation rates, and ability to incorporate foreign DNA. Parasitic flowering plants are no exception, and the close association between parasite and host may even enhance the likelihood of horizontal gene transfer (HGT) between them. Recent studies on mistletoes (Viscum) have revealed that these parasites have lost an exceptional number of mitochondrial genes, including all complex I genes of the respiratory chain. At the same time, an altered respiratory pathway has been demonstrated. Here we review the current understanding of mitochondrial evolution in parasitic plants with a special emphasis on HGT to and from parasite mitochondrial genomes, as well as the uniquely altered mitochondria in Viscum and related plants.

5.
Int J Mol Sci ; 21(4)2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32102473

RESUMO

Overexpression of phytoglobins (formerly plant hemoglobins) increases the survival rate of plant tissues under hypoxia stress by the following two known mechanisms: (1) scavenging of nitric oxide (NO) in the phytoglobin/NO cycle and (2) mimicking ethylene priming to hypoxia when NO scavenging activates transcription factors that are regulated by levels of NO and O2 in the N-end rule pathway. To map the cellular and metabolic effects of hypoxia in barley (Hordeum vulgare L., cv. Golden Promise), with or without priming to hypoxia, we studied the proteome and metabolome of wild type (WT) and hemoglobin overexpressing (HO) plants in normoxia and after 24 h hypoxia (WT24, HO24). The WT plants were more susceptible to hypoxia than HO plants. The chlorophyll a + b content was lowered by 50% and biomass by 30% in WT24 compared to WT, while HO plants were unaffected. We observed an increase in ROS production during hypoxia treatment in WT seedlings that was not observed in HO seedlings. We identified and quantified 9694 proteins out of which 1107 changed significantly in abundance. Many proteins, such as ion transporters, Ca2+-signal transduction, and proteins related to protein degradation were downregulated in HO plants during hypoxia, but not in WT plants. Changes in the levels of histones indicates that chromatin restructuring plays a role in the priming of hypoxia. We also identified and quantified 1470 metabolites, of which the abundance of >500 changed significantly. In summary the data confirm known mechanisms of hypoxia priming by ethylene priming and N-end rule activation; however, the data also indicate the existence of other mechanisms for hypoxia priming in plants.


Assuntos
Hemoglobinas/metabolismo , Hordeum/metabolismo , Metaboloma , Oxigênio/metabolismo , Proteínas de Plantas/metabolismo , Proteoma/metabolismo , Anaerobiose , Clorofila/metabolismo , Clorofila A/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Hemoglobinas/genética , Hordeum/genética , Metabolômica/métodos , Óxido Nítrico/metabolismo , Proteínas de Plantas/genética , Proteoma/genética , Proteômica/métodos , Espécies Reativas de Oxigênio/metabolismo , Plântula/genética , Plântula/metabolismo
6.
Plant Cell ; 32(3): 573-594, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31911454

RESUMO

Mitochondria function as hubs of plant metabolism. Oxidative phosphorylation produces ATP, but it is also a central high-capacity electron sink required by many metabolic pathways that must be flexibly coordinated and integrated. Here, we review the crucial roles of redox-associated posttranslational protein modifications (PTMs) in mitochondrial metabolic regulation. We discuss several major concepts. First, the major redox couples in the mitochondrial matrix (NAD, NADP, thioredoxin, glutathione, and ascorbate) are in kinetic steady state rather than thermodynamic equilibrium. Second, targeted proteomics have produced long lists of proteins potentially regulated by Cys oxidation/thioredoxin, Met-SO formation, phosphorylation, or Lys acetylation, but we currently only understand the functional importance of a few of these PTMs. Some site modifications may represent molecular noise caused by spurious reactions. Third, different PTMs on the same protein or on different proteins in the same metabolic pathway can interact to fine-tune metabolic regulation. Fourth, PTMs take part in the repair of stress-induced damage (e.g., by reducing Met and Cys oxidation products) as well as adjusting metabolic functions in response to environmental variation, such as changes in light irradiance or oxygen availability. Finally, PTMs form a multidimensional regulatory system that provides the speed and flexibility needed for mitochondrial coordination far beyond that provided by changes in nuclear gene expression alone.

7.
Genome Biol Evol ; 12(1): 3586-3598, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31774499

RESUMO

Plant mitogenomes can be difficult to assemble because they are structurally dynamic and prone to intergenomic DNA transfers, leading to the unusual situation where an organelle genome is far outnumbered by its nuclear counterparts. As a result, comparative mitogenome studies are in their infancy and some key aspects of genome evolution are still known mainly from pregenomic, qualitative methods. To help address these limitations, we combined machine learning and in silico enrichment of mitochondrial-like long reads to assemble the bacterial-sized mitogenome of Norway spruce (Pinaceae: Picea abies). We conducted comparative analyses of repeat abundance, intergenomic transfers, substitution and rearrangement rates, and estimated repeat-by-repeat homologous recombination rates. Prompted by our discovery of highly recombinogenic small repeats in P. abies, we assessed the genomic support for the prevailing hypothesis that intramolecular recombination is predominantly driven by repeat length, with larger repeats facilitating DNA exchange more readily. Overall, we found mixed support for this view: Recombination dynamics were heterogeneous across vascular plants and highly active small repeats (ca. 200 bp) were present in about one-third of studied mitogenomes. As in previous studies, we did not observe any robust relationships among commonly studied genome attributes, but we identify variation in recombination rates as a underinvestigated source of plant mitogenome diversity.


Assuntos
Genoma Mitocondrial , Picea/genética , Recombinação Genética , Simulação por Computador , Cycadopsida/genética , DNA de Plantas/química , Genes de Plantas , Variação Genética , Sequências Repetitivas de Ácido Nucleico , Máquina de Vetores de Suporte
8.
Proc Natl Acad Sci U S A ; 117(1): 741-751, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31871212

RESUMO

Seeds preserve a far developed plant embryo in a quiescent state. Seed metabolism relies on stored resources and is reactivated to drive germination when the external conditions are favorable. Since the switchover from quiescence to reactivation provides a remarkable case of a cell physiological transition we investigated the earliest events in energy and redox metabolism of Arabidopsis seeds at imbibition. By developing fluorescent protein biosensing in intact seeds, we observed ATP accumulation and oxygen uptake within minutes, indicating rapid activation of mitochondrial respiration, which coincided with a sharp transition from an oxidizing to a more reducing thiol redox environment in the mitochondrial matrix. To identify individual operational protein thiol switches, we captured the fast release of metabolic quiescence in organello and devised quantitative iodoacetyl tandem mass tag (iodoTMT)-based thiol redox proteomics. The redox state across all Cys peptides was shifted toward reduction from 27.1% down to 13.0% oxidized thiol. A large number of Cys peptides (412) were redox switched, representing central pathways of mitochondrial energy metabolism, including the respiratory chain and each enzymatic step of the tricarboxylic acid (TCA) cycle. Active site Cys peptides of glutathione reductase 2, NADPH-thioredoxin reductase a/b, and thioredoxin-o1 showed the strongest responses. Germination of seeds lacking those redox proteins was associated with markedly enhanced respiration and deregulated TCA cycle dynamics suggesting decreased resource efficiency of energy metabolism. Germination in aged seeds was strongly impaired. We identify a global operation of thiol redox switches that is required for optimal usage of energy stores by the mitochondria to drive efficient germination.


Assuntos
Arabidopsis/fisiologia , Ciclo do Ácido Cítrico/fisiologia , Germinação/fisiologia , Mitocôndrias/metabolismo , Sementes/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Glutationa Redutase/genética , Glutationa Redutase/metabolismo , Oxirredução , Oxigênio/metabolismo , Plantas Geneticamente Modificadas , Proteômica/métodos , Sementes/citologia , Sementes/crescimento & desenvolvimento , Tiorredoxina h/genética , Tiorredoxina h/metabolismo , Tiorredoxina Dissulfeto Redutase/genética , Tiorredoxina Dissulfeto Redutase/metabolismo
9.
J Exp Bot ; 71(1): 234-246, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494665

RESUMO

The biosynthesis of starch granules in plant plastids is coordinated by the orchestrated action of transferases, hydrolases, and dikinases. These enzymes either contain starch-binding domain(s) themselves, or are dependent on direct interactions with co-factors containing starch-binding domains. As a means to competitively interfere with existing starch-protein interactions, we expressed the protein module Carbohydrate-Binding Motif 20 (CBM20), which has a very high affinity for starch, ectopically in barley plastids. This interference resulted in an increase in the number of starch granules in chloroplasts and in formation of compound starch granules in grain amyloplasts, which is unusual for barley. More importantly, we observed a photosystem-independent inhibition of CO2 fixation, with a subsequent reduced growth rate and lower accumulation of carbohydrates with effects throughout the metabolome, including lower accumulation of transient leaf starch. Our results demonstrate the importance of endogenous starch-protein interactions for controlling starch granule morphology and number, and plant growth, as substantiated by a metabolic link between starch-protein interactions and control of CO2 fixation in chloroplasts.

10.
Front Plant Sci ; 10: 1003, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31428119

RESUMO

The xantha trait of a yellow leaf rice mutant (HYB), controlled epigenetically by elevated CHG methylation of the genomes uncoupled 4 (OsGUN4) promoter, has reduced chlorophyll content, altered tetrapyrrole biosynthesis, and deregulated transcription of photosynthesis-associated nuclear genes (PhANGs) compared to its wild-type progenitor Longtefu B (LTB). In the present study, we identified a suppressor mutant (CYB) of HYB and characterized its genetic, molecular, and physiological basis of the mutant phenotype. We found that the light-green phenotype of CYB was caused by a suppressor mutation in an unknown gene other than OsGUN4. Compared to HYB, the CHG methylation in the OsGUN4 promoter was reduced, while OsGUN4 transcript and protein abundance levels were increased in CYB. The contents of total chlorophyll and its intermediate metabolites (except protoporphyrin IX) in CYB plants were intermediate between HYB and LTB. The expression levels of 30 genes involved in tetrapyrrole biosynthesis in CYB were all partially reverted to those of LTB, so were the PhANGs. In summary, a suppressor mutation caused the reversion of the xantha trait via reducing CHG methylation in OsGUN4 promoter.

11.
Redox Biol ; 26: 101262, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31284117

RESUMO

Copper ion-catalyzed oxidation of yeast SOD1 (ySOD1) was examined to determine early oxidative modifications, including oxidation of a crucial disulfide bond, and the structural and functional repercussions of these events. The study used distinct oxidative conditions: Cu2+/H2O2, Cu2+/H2O2/AscH- and Cu2+/H2O2/glucose. Capillary electrophoresis experiments and quantification of protein carbonyls indicate that ySOD1 is highly susceptible to oxidative modification and that changes can be detected within 0.1 min of the initiation of the reaction. Oxidation-induced structural perturbations, characterized by circular dichroism, revealed the formation of partially-unfolded ySOD1 species in a dose-dependent manner. Consistent with these structural changes, pyrogallol assay indicates a partial loss of enzymatic activity. ESI-MS analyses showed seven distinct oxidized ySOD1 species under mild oxidation within 0.1 min. LC/MS analysis after proteolytic digestion demonstrated that the copper-coordinating active site histidine residues, His47 and His49, were converted into 2-oxo-histidine. Furthermore, the Cu and Zn bridging residue, His64 is converted into aspartate/asparagine. Importantly, the disulfide-bond Cys58-Cys147 which is critical for the structural and functional integrity of ySOD1 was detected as being oxidized at Cys147. We propose, based on LC/MS analyses, that disulfide-bond oxidation occurs without disulfide bond cleavage. Modifications were also detected at Met85 and five surface-exposed Lys residues. Based on these data we propose that the Cys58-Cys147 bond may act as a sacrificial target for oxidants and protect ySOD1 from oxidative inactivation arising from exposure to Cu2+/H2O2 and auto-inactivation during extended enzymatic turnover.


Assuntos
Cobre/metabolismo , Peróxido de Hidrogênio/metabolismo , Íons/metabolismo , Oxirredução , Superóxido Dismutase-1/metabolismo , Catálise , Cobre/química , Ativação Enzimática , Peróxido de Hidrogênio/química , Íons/química , Estresse Oxidativo , Análise Espectral , Relação Estrutura-Atividade , Superóxido Dismutase-1/química
12.
J Biol Chem ; 294(11): 4215-4232, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30655291

RESUMO

Aggregation of α-synuclein (αSN) is implicated in neuronal degeneration in Parkinson's disease and has prompted searches for natural compounds inhibiting αSN aggregation and reducing its tendency to form toxic oligomers. Oil from the olive tree (Olea europaea L.) represents the main source of fat in the Mediterranean diet and contains variable levels of phenolic compounds, many structurally related to the compound oleuropein. Here, using αSN aggregation, fibrillation, size-exclusion chromatography-multiangle light scattering (SEC-MALS)-based assays, and toxicity assays, we systematically screened the fruit extracts of 15 different olive varieties to identify compounds that can inhibit αSN aggregation and oligomer toxicity and also have antioxidant activity. Polyphenol composition differed markedly among varieties. The variety with the most effective antioxidant and aggregation activities, Koroneiki, combined strong inhibition of αSN fibril nucleation and elongation with strong disaggregation activity on preformed fibrils and prevented the formation of toxic αSN oligomers. Fractionation of the Koroneiki extract identified oleuropein aglycone, hydroxyl oleuropein aglycone, and oleuropein as key compounds responsible for the differences in inhibition across the extracts. These phenolic compounds inhibited αSN amyloidogenesis by directing αSN monomers into small αSN oligomers with lower toxicity, thereby suppressing the subsequent fibril growth phase. Our results highlight the molecular consequences of differences in the level of effective phenolic compounds in different olive varieties, insights that have implications for long-term human health.


Assuntos
Frutas/química , Iridoides/farmacologia , Olea/química , alfa-Sinucleína/antagonistas & inibidores , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cromatografia em Gel , Relação Dose-Resposta a Droga , Humanos , Iridoides/química , Iridoides/isolamento & purificação , Luz , Agregados Proteicos/efeitos dos fármacos , Relação Estrutura-Atividade , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo
13.
Plant Methods ; 14: 72, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30159003

RESUMO

Background: Sample preparation is a critical process for proteomic studies. Many efficient and reproducible sample preparation methods have been developed for mass spectrometry-based proteomic analysis of human and animal tissues or cells, but no attempt has been made to evaluate these protocols for plants. We here present an LC-MS/MS-based proteomics study of barley leaf aimed at optimization of methods to achieve efficient and unbiased trypsin digestion of proteins prior to LC-MS/MS based sequencing and quantification of peptides. We evaluated two spin filter-aided sample preparation protocols using either sodium dodecyl-sulphate or sodium deoxycholate (SDC), and three in-solution digestion (ISD) protocols using SDC or trichloroacetic acid/acetone precipitation. Results: The proteomics workflow identified and quantified up to 1800 barley proteins based on sequencing of up to 6900 peptides per sample. The two spin filter-based protocols provided a 12-38% higher efficiency than the ISD protocols, including more proteins of low abundance. Among the ISD protocols, a simple one-step reduction and S-alkylation method (OP-ISD) was the most efficient for barley leaf sample preparation; it identified and quantified 1500 proteins and displayed higher peptide-to-protein inference ratio and higher average amino acid sequence coverage of proteins. The two spin filter-aided sample preparation protocols are compatible with TMT labelling for quantitative proteomics studies. They exhibited complementary performance as about 30% of the proteins were identified by either one or the other protocol, but also demonstrated a positive bias for membrane proteins when using SDC as detergent. Conclusions: We provide detailed protocols for efficient plant protein sample preparation for LC-MS/MS-based proteomics studies. Spin filter-based protocols are the most efficient for the preparation of leaf samples for MS-based proteomics. However, a simple protocol provides comparable results although with different peptide digestion profile.

14.
Biochemistry ; 57(34): 5145-5158, 2018 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-30067901

RESUMO

The intrinsically disordered protein α-synuclein (aSN) forms insoluble aggregates in the brains of Parkinson's disease (PD) patients. Cytotoxicity is attributed to a soluble aSN oligomeric species that permeabilizes membranes significantly more than monomers and fibrils. In humans, the A53T mutation induces early onset PD and increases the level of aSN oligomerization and fibrillation propensity, but Thr53 occurs naturally in aSNs of most animals. We compared aSNs from elephant, bowhead whale, and pig with human aSN. While all three animal aSNs showed significantly weakened fibrillation, elephant aSN formed much more oligomer, and pig aSN much less, than human aSN did. However, all animal aSN oligomers showed weakened permeabilization toward anionic lipid vesicles, indicative of decreased cytotoxicity. These animal aSNs share three substitutions compared to human aSN: A53T, G68E, and V95G. We analyzed aggregation and membrane binding of all eight mutants combining these three mutations. While the G68E mutation is particularly important in weakening fibrillation and possible toxicity, the strongest effect is seen when all three mutations are present. Thus, a small number of mutations can significantly decrease aSN toxicity.


Assuntos
Amiloide/química , Permeabilidade da Membrana Celular , Mutação , alfa-Sinucleína/metabolismo , Animais , Baleia Franca , Elefantes , Humanos , Conformação Proteica , Suínos , alfa-Sinucleína/química , alfa-Sinucleína/genética
15.
Free Radic Biol Med ; 121: 38-50, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29689296

RESUMO

Previous studies on metal-ion catalyzed oxidation of α-synuclein oxidation have mostly used conditions that result in extensive modification precluding an understanding of the early events in this process. In this study, we have examined time-dependent oxidative events related to α-synuclein modification using six different molar ratios of Cu2+/H2O2/protein and Cu2+/H2O2/ascorbate/protein resulting in mild to moderate extents of oxidation. For a Cu2+/H2O2/protein molar ratio of 2.3:7.8:1 only low levels of carbonyls were detected (0.078 carbonyls per protein), whereas a molar ratio of 4.7:15.6:1 gave 0.22 carbonyls per α-synuclein within 15 min. With the latter conditions, rapid conversion of 3 out of 4 methionines (Met) to methionine sulfoxide, and 2 out of 4 tyrosines (Tyr) were converted to products including inter- and intra-molecular dityrosine cross-links and protein oligomers, as determined by SDS-PAGE and Western blot analysis. Limited histidine (His) modification was observed. The rapid formation of dityrosine cross-links was confirmed by fluorescence and mass-spectrometry. These data indicate that Met and Tyr oxidation are early events in Cu2+/H2O2-mediated damage, with carbonyl formation being a minor process. With the Cu2+/H2O2/ascorbate system, rapid protein carbonyl formation was detected with the first 5 min, but after this time point, little additional carbonyl formation was detected. With this system, lower levels of Met and Tyr oxidation were detected (2 Met and 1 Tyr modified with a Cu2+/H2O2/ascorbate/protein ratio of 2.3:7.8:7.8:1), but greater His oxidation. Only low levels of intra- dityrosine cross-links and no inter- dityrosine oligomers were detected under these conditions, suggesting that ascorbate limits Cu2+/H2O2-induced α-synuclein modification.


Assuntos
Cobre/farmacologia , Metionina/análogos & derivados , Tirosina/análogos & derivados , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Catálise , Humanos , Peróxido de Hidrogênio/farmacologia , Metionina/química , Oxidantes/farmacologia , Oxirredução , Estresse Oxidativo , Oligoelementos/farmacologia , Tirosina/química
16.
Bioinformatics ; 34(14): 2518-2520, 2018 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-29509874

RESUMO

Motivation: Oxidative stress and protein damage have been associated with over 200 human ailments including cancer, stroke, neuro-degenerative diseases and aging. Protein carbonylation, a chemically diverse oxidative post-translational modification, is widely considered as the biomarker for oxidative stress and protein damage. Despite their importance and extensive studies, no database/resource on carbonylated proteins/sites exists. As such information is very useful to research in biology/medicine, we have manually curated a data-resource (CarbonylDB) of experimentally-confirmed carbonylated proteins/sites. Results: The CarbonylDB currently contains 1495 carbonylated proteins and 3781 sites from 21 species, with human, rat and yeast as the top three species. We have made further analyses of these carbonylated proteins/sites and presented their occurrence and occupancy patterns. Carbonylation site data on serum albumin, in particular, provides a fine model system to understand the dynamics of oxidative protein modifications/damage. Availability and implementation: The CarbonylDB is available as a web-resource and for download at http://digbio.missouri.edu/CarbonylDB/. Supplementary information: Supplementary data are available at Bioinformatics online.


Assuntos
Biologia Computacional/métodos , Estresse Oxidativo , Carbonilação Proteica , Análise de Sequência de Proteína/métodos , Software , Animais , Biomarcadores , Humanos , Oxirredução , Proteínas/metabolismo , Ratos , Leveduras
17.
Sci Rep ; 7(1): 5550, 2017 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-28717198

RESUMO

Targeted chemical modification of peptides and proteins by laser pulses in a biologically relevant environment, i.e. aqueous solvent at room temperature, allows for accurate control of biological processes. However, the traditional laser methods of control of chemical reactions are applicable only to a small class of photosensitive biomolecules because of strong and ultrafast perturbations from biomolecule-solvent interactions. Here, we report excitation of harmonics of vibration modes of solvent molecules by femtosecond laser pulses to produce controlled chemical modifications of non-photosensitive peptides and proteins in polar liquids under room conditions. The principal modifications included lysine formylation and methionine sulfoxidation both of which occur with nearly 100% yield under atmospheric conditions. That modification occurred only if the laser irradiance exceeded certain threshold level. The threshold, type, and extent of the modifications were completely controlled by solvent composition, laser wavelength, and peak irradiance of ultrashort laser pulses. This approach is expected to assist in establishing rigorous control over a broad class of biological processes in cells and tissues at the molecular level.


Assuntos
Bioquímica/métodos , Peptídeos/química , Solventes/química , Aminas/química , Bioquímica/instrumentação , Monóxido de Carbono/química , Insulina/química , Lasers , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
18.
Elife ; 62017 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-28716182

RESUMO

Growth and development of plants is ultimately driven by light energy captured through photosynthesis. ATP acts as universal cellular energy cofactor fuelling all life processes, including gene expression, metabolism, and transport. Despite a mechanistic understanding of ATP biochemistry, ATP dynamics in the living plant have been largely elusive. Here, we establish MgATP2- measurement in living plants using the fluorescent protein biosensor ATeam1.03-nD/nA. We generate Arabidopsis sensor lines and investigate the sensor in vitro under conditions appropriate for the plant cytosol. We establish an assay for ATP fluxes in isolated mitochondria, and demonstrate that the sensor responds rapidly and reliably to MgATP2- changes in planta. A MgATP2- map of the Arabidopsis seedling highlights different MgATP2- concentrations between tissues and within individual cell types, such as root hairs. Progression of hypoxia reveals substantial plasticity of ATP homeostasis in seedlings, demonstrating that ATP dynamics can be monitored in the living plant.


Assuntos
Trifosfato de Adenosina/análise , Arabidopsis/fisiologia , Metabolismo Energético , Células Vegetais/fisiologia , Técnicas Biossensoriais , Genes Reporter , Homeostase , Hipóxia , Proteínas Luminescentes/análise , Plântula/fisiologia , Coloração e Rotulagem
19.
J Proteomics ; 156: 40-51, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28062376

RESUMO

Protein carbonylation is an irreversible protein oxidation correlated with oxidative stress, various diseases and ageing. Here we describe a peptide-centric approach for identification and characterisation of up to 14 different types of carbonylated amino acids in proteins. The modified residues are derivatised with biotin-hydrazide, enriched and characterised by tandem mass spectrometry. The strength of the method lies in an improved elution of biotinylated peptides from monomeric avidin resin using hot water (95°C) and increased sensitivity achieved by reduction of analyte losses during sample preparation and chromatography. For the first time MS/MS data analysis utilising diagnostic biotin fragment ions is used to pinpoint sites of biotin labelling and improve the confidence of carbonyl peptide assignments. We identified a total of 125 carbonylated residues in bovine serum albumin after extensive in vitro metal ion-catalysed oxidation. Furthermore, we assigned 133 carbonylated sites in 36 proteins in native human plasma protein samples. The optimised workflow enabled detection of 10 hitherto undetected types of carbonylated amino acids in proteins: aldehyde and ketone modifications of leucine, valine, alanine, isoleucine, glutamine, lysine and glutamic acid (+14Da), an oxidised form of methionine - aspartate semialdehyde (-32Da) - and decarboxylated glutamic acid and aspartic acid (-30Da). BIOLOGICAL SIGNIFICANCE: Proteomic tools provide a promising way to decode disease mechanisms at the protein level and help to understand how carbonylation affects protein structure and function. The challenge for future research is to identify the type and nature of oxidised residues to gain a deeper understanding of the mechanism(s) governing carbonylation in cells and organisms and assess their role in disease.


Assuntos
Aminoácidos/metabolismo , Proteínas Sanguíneas/química , Carbonilação Proteica , Animais , Sítios de Ligação , Biotina/química , Proteínas Sanguíneas/metabolismo , Bovinos , Humanos , Estresse Oxidativo , Soroalbumina Bovina/química
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