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1.
Free Radic Biol Med ; 175: 206-215, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34506903

RESUMO

Flavonoids are natural polyphenolic compounds with a diverse array of biological activities and health-promoting effects. Recent studies have found that 4,4'-dimethoxychalcone (DMC) promoted longevity via autophagy; however, its targets are currently unknown. Herein, we employed an unbiased thermal proteome profiling (TPP) method and identified multiple targets of DMC, including ALDH1A3, ALDH2, and PTGES2. We further determined the dissociation constant (Kd) of DMC and ALDH1A3 to be 2.8 µM using microscale thermophoresis (MST) analysis, which indicated that DMC inhibited ALDH1A3 activity and aggravated cellular oxidative stress. DMC treatment significantly increased cellular reactive oxygen species (ROS) production and inhibited cancer cell growth. Quantitative proteomic analysis showed that DMC upregulated proteins associated with stress-responses and downregulated proteins associated with cell cycle progression, and this was confirmed using cell cycle analysis. Taken together, we showed that TPP is an effective tool with which to identify flavonoid targets and set a precedent for deciphering flavonoid function in the future. We have demonstrated that DMC inhibited cell proliferation via ROS-induced cell cycle arrest and is an anti-proliferative agent in cancer treatment.


Assuntos
Flavonoides , Proteômica , Apoptose , Proliferação de Células , Flavonoides/farmacologia , Estresse Oxidativo , Oxirredutases , Espécies Reativas de Oxigênio
2.
Biomed Environ Sci ; 34(8): 616-622, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34474721

RESUMO

Objective: To evaluate multidrug resistant loop-mediated isothermal amplification (MDR-LAMP) assay for the early diagnosis of multidrug-resistant tuberculosis and to compare the mutation patterns associated with the rpoB, katG, and inhA genes at the Chinese Center for Disease Control and Prevention. Methods: MDR-LAMP assay was evaluated using 100 Mycobacterium tuberculosis ( Mtb) isolates obtained from the National Reference Laboratory for Tuberculosis in China. Phenotypic resistance to isoniazid and rifampicin and whole-genome sequencing served as reference standards. Results: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MDR-LAMP were 85.5%, 93.6%, 96.7%, and 74.4% for the detection of resistance to isoniazid and rifampicin, respectively, and 80.5%, 92.3%, 98.6%, and 41.4% for the detection of Mtb cultured from smear-positive sputum samples, respectively. When DNA sequencing was used as the reference standard, the sensitivity, specificity, PPV, and NPV of MDR-LAMP were 93.1%, 92.3%, 97.2%, and 82.8% for the detection of katG and inhA gene mutations, respectively, and 89.1%, 88.9%, 93.4%, and 81.1% for the detection of rpoB gene mutation, respectively. Conclusion: MDR-LAMP is a rapid and accessible assay for the laboratory identification of rifampicin and isoniazid resistance of Mtb isolates.


Assuntos
DNA Bacteriano/análise , Farmacorresistência Bacteriana Múltipla/genética , Técnicas de Diagnóstico Molecular/métodos , Mycobacterium tuberculosis/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Antituberculosos , Proteínas de Bactérias/genética , Catalase/genética , RNA Polimerases Dirigidas por DNA/genética , Isoniazida , Mutação , Mycobacterium tuberculosis/isolamento & purificação , Oxirredutases/genética , Fenótipo , Rifampina , Sequenciamento Completo do Genoma
3.
Nat Commun ; 12(1): 5236, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475399

RESUMO

New drugs are urgently needed to combat the global TB epidemic. Targeting simultaneously multiple respiratory enzyme complexes of Mycobacterium tuberculosis is regarded as one of the most effective treatment options to shorten drug administration regimes, and reduce the opportunity for the emergence of drug resistance. During infection and proliferation, the cytochrome bd oxidase plays a crucial role for mycobacterial pathophysiology by maintaining aerobic respiration at limited oxygen concentrations. Here, we present the cryo-EM structure of the cytochrome bd oxidase from M. tuberculosis at 2.5 Å. In conjunction with atomistic molecular dynamics (MD) simulation studies we discovered a previously unknown MK-9-binding site, as well as a unique disulfide bond within the Q-loop domain that defines an inactive conformation of the canonical quinol oxidation site in Actinobacteria. Our detailed insights into the long-sought atomic framework of the cytochrome bd oxidase from M. tuberculosis will form the basis for the design of highly specific drugs to act on this enzyme.


Assuntos
Grupo dos Citocromos b/química , Grupo dos Citocromos d/química , Complexo de Proteínas da Cadeia de Transporte de Elétrons/química , Mycobacterium tuberculosis/enzimologia , Proteínas de Bactérias/química , Sítios de Ligação , Microscopia Crioeletrônica , Simulação de Dinâmica Molecular , Oxirredutases/química , Conformação Proteica , Subunidades Proteicas , Vitamina K 2/análogos & derivados , Vitamina K 2/química
5.
BMJ Case Rep ; 14(9)2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34544705

RESUMO

Immune-mediated necrotising myopathy is a subtype of idiopathic inflammatory myopathy characterised by muscle fibre necrosis without significant inflammatory infiltrate. Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) myopathy is seen in 6%-10% of idiopathic inflammatory myopathy and is diagnosed in the context of elevated serum creatine kinase levels, proximal muscle weakness and anti-HMGCR autoantibodies. We recently encountered a 61-year-old man with anti-HMGCR myopathy with an atypical skin manifestation, partially responsive to triple therapy with steroids, intravenous immunoglobulin (IVIG) and rituximab. To our knowledge, there have been only four reported cases of skin rash associated with anti-HMGCR myopathy. Our case demonstrates the importance of recognising atypical manifestations of anti-HMGCR myopathy. Early addition of IVIG and rituximab is also critical in patients not responding to steroid monotherapy. Delay in achieving remission leads to prolonged steroid use, lower likelihood of beginning physical therapy and overall worse clinical outcomes.


Assuntos
Doenças Musculares , Miosite , Coenzimas , Humanos , Hidroximetilglutaril-CoA Redutases , Masculino , Pessoa de Meia-Idade , Doenças Musculares/induzido quimicamente , Doenças Musculares/diagnóstico , Doenças Musculares/tratamento farmacológico , Miosite/induzido quimicamente , Miosite/diagnóstico , Miosite/tratamento farmacológico , Oxirredutases
6.
Nat Commun ; 12(1): 5493, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34535675

RESUMO

Macromolecular dynamics manifest as disorder in structure determination, which is subsequently accounted for by displacement parameters (also called temperature factors, or B-factors) or alternate conformations. Though B-factors contain detailed information about structural dynamics, they are the total of multiple sources of disorder, making them difficult to interpret and thus little-used in structural analysis. We report here an analytical approach for decomposing molecular disorder into a parsimonious hierarchical series of contributions, providing an intuitive basis for quantitative structural-dynamics analysis. We demonstrate the decomposition of disorder on example SARS-CoV-2 and STEAP4 structures, from both crystallographic and cryo-electron microscopy data, and reveal how understanding of the macromolecular disorder leads to deeper understanding of molecular motions and flexibility, and suggests hypotheses for molecular mechanisms.


Assuntos
Proteases 3C de Coronavírus/química , Substâncias Macromoleculares/química , Simulação de Dinâmica Molecular , SARS-CoV-2/enzimologia , COVID-19 , Microscopia Crioeletrônica , Humanos , Proteínas de Membrana/química , Oxirredutases/química , Conformação Proteica
7.
Enzyme Microb Technol ; 150: 109880, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34489033

RESUMO

The ene reductases (ERs) from the old yellow enzymes (OYEs) family have the ability to reduce activated alkenes to generate up to two stereocenters, therefore they have been received extensive attention as powerful biocatalysts. In this study, through gene mining, four ERs were identified from the genomes of Ensifer adhaerens, Pseudomonas fluorescens, and Pseudomonas veronil. The biocatalytic properties of these four ERs were identified, and their applications in the synthesis process of dihydrocarvone and profen derivatives were further evaluated. Among them, three ERs (EaER2, PvER1, and PvER2) belonging to the classic OYEs showed the best catalytic activity at 30 °C and pH 7.0 (100 mM potassium phosphate buffer) and the PfER2, which belongs to the thermophilic-like OYEs exhibited the best catalytic at 40 °C and pH 7.0 (100 mM potassium phosphate buffer). When exploring the influence of organic solvents on the catalytic efficiency, it was found that the four ERs were more sensitive to toluene and had tolerance to several other selected organic solvents. In addition, EaER2, PfER2, PvER1 and PvER2 showed excellent catalytic activity toward carvone, and the stereoselectivity of PvER2 toward carvone could reach up to 88.7 % de. EaER2 and PfER2 can catalyze the synthesis of a variety of profen derivatives with a stereoselectivity over 99 % ee. Moreover, through homology modeling and molecular docking, we preliminarily explained the mechanism of catalytic activity and stereoselectivity of the four ERs, which provided a solid base on the rational design of their stereo-preference in the future. The discovery of EaER2, PfER2, PvER1, and PvER2 provides four new enzyme sources for the study of the OYEs family and enriches the biocatalytic toolbox of ERs. Our exploration of the enzymatic properties of these four ERs will provide the sufficient data basis for future research and industrialization progress.


Assuntos
Oxirredutases , Biocatálise , Monoterpenos Cicloexânicos , Simulação de Acoplamento Molecular , Oxirredução , Oxirredutases/genética , Oxirredutases/metabolismo , Rhizobiaceae
8.
Enzyme Microb Technol ; 150: 109884, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34489037

RESUMO

Tyrosinase plays an essential role in melanin biosynthesis and inherently exhibits both monophenolase and diphenolase activity. A first derivative synchronous fluorometric assay was established for directly monitoring monophenolase activity. The zero-crossing point at 322 nm for the first-derivative under synchronous fluorescence with Δλ = 67 nm was utilized to selectively quantify tyrosine in the presence of the reaction product dihydroxyphenylalanine (DOPA). The limit of detection (LOD) for tyrosine was 0.54 µM. The fluorescence intensity of tyrosine was monitored at intervals of 30 s to establish the time course of tyrosine consumption. The LOD for the monophenolase activity was 0.0706 U⋅ mL-1. The Michaelis-Menten e constant and maximum speed were 21.83 µM and 1.12 µM min-1, respectively. Zinc ions competitively inhibited the monophenolase activity, with an IC50 value of 14.36 µM. This assay is easily and rapidly executed and is of great significance for analyzing the kinetics of enzymatic reactions and in fundamental research on monophenolase. This approach has potential applications in the discovery of tyrosinase inhibitors for medicine and cosmetics, as well as in the industrial synthesis of substituted o-diphenol intermediates.


Assuntos
Monofenol Mono-Oxigenase , Oxirredutases , Monofenol Mono-Oxigenase/metabolismo , Oxirredução , Oxirredutases/metabolismo , Tirosina/metabolismo
9.
Sheng Wu Gong Cheng Xue Bao ; 37(8): 2870-2877, 2021 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-34472304

RESUMO

Asthma is a common respiratory disease that affects 300 million of people worldwide, posing a serious health risk and medical burden. Development of new anti-asthmatic drugs and alternative treatment regimens is therefore encouraged. Recent studies have shown that Epidermal Growth Factor Receptor (EGFR) is involved in asthma development. In order to construct nanoparticles targeting EGFR for asthma treatment, a single chain antibody fragment (scFv) against EGFR was genetically engineered and modified at the N-terminal end of the human ferritin H-chain (FTH1) to construct Anti EGFR scFv::FTH1/FTH1 nanoparticles. Transmission electron microscopy showed that the nanoparticles were self-assembled into hollow cage-like structures with the particle size of about 12 nm. Semi-quantitative analysis of the purified nanoparticles by SDS-PAGE revealed the mass ratio of FTH1 to Anti EGFR scFv::FTH1 was 7:3. In House Dust Mite (HDM) driven models, Anti EGFR scFv::FTH1/FTH1 nanoparticles efficiently attenuated several key features of asthma, including goblet cell hyperplasia, mucous metaplasia and subepithelial fibrosis, showing the potential of using ferritin based nanoparticle for asthma treatment.


Assuntos
Asma , Nanopartículas , Anticorpos de Cadeia Única , Asma/tratamento farmacológico , Ferritinas , Humanos , Oxirredutases , Anticorpos de Cadeia Única/genética
10.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445714

RESUMO

Phytochromobilin (PΦB) participates in the regulation of plant growth and development as an important synthetase of photoreceptor phytochromes (phy). In addition, Arabidopsis long hypocotyl 2 (HY2) appropriately works as a key PΦB synthetase. However, whether HY2 takes part in the plant stress response signal network remains unknown. Here, we described the function of HY2 in NaCl signaling. The hy2 mutant was NaCl-insensitive, whereas HY2-overexpressing lines showed NaCl-hypersensitive phenotypes during seed germination. The exogenous NaCl induced the transcription and the protein level of HY2, which positively mediated the expression of downstream stress-related genes of RD29A, RD29B, and DREB2A. Further quantitative proteomics showed the patterns of 7391 proteins under salt stress. HY2 was then found to specifically mediate 215 differentially regulated proteins (DRPs), which, according to GO enrichment analysis, were mainly involved in ion homeostasis, flavonoid biosynthetic and metabolic pathways, hormone response (SA, JA, ABA, ethylene), the reactive oxygen species (ROS) metabolic pathway, photosynthesis, and detoxification pathways to respond to salt stress. More importantly, ANNAT1-ANNAT2-ANNAT3-ANNAT4 and GSTU19-GSTF10-RPL5A-RPL5B-AT2G32060, two protein interaction networks specifically regulated by HY2, jointly participated in the salt stress response. These results direct the pathway of HY2 participating in salt stress, and provide new insights for the plant to resist salt stress.


Assuntos
Arabidopsis/genética , Arabidopsis/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Secas , Germinação/fisiologia , Oxirredutases/fisiologia , Fitocromo/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Plantas Geneticamente Modificadas , Estresse Salino/efeitos dos fármacos , Estresse Salino/genética , Estresse Salino/fisiologia , Sementes/metabolismo , Transdução de Sinais/fisiologia , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética
11.
Dokl Biochem Biophys ; 499(1): 220-224, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34426915

RESUMO

A reusable system for phenol determination in an aqueous medium was obtained by adsorption of extracellular oxidase from fungus Neonothopanus nambi onto modified nanodiamonds (MND) synthesized by detonation. It was found that the enzyme strongly binds to MND and exhibits catalytic activity in the reaction of co-oxidation of phenol with 4-aminoantipyrine without the addition of hydrogen peroxide. In the presence of the MND-oxidase complex, a significantly (by an order of magnitude) higher yield of the reaction product is recorded as compared to the yield in the presence of a free enzyme; the mechanism of the revealed effect is discussed. Model experiments have demonstrated the multiple use of the MND-oxidase complex for testing phenol in aqueous samples. The immobilized enzyme exhibits functional activity during long-term (2 months) storage of the MND-oxidase complex at 4°C. The data obtained create the prerequisites for using the created system in environmental monitoring of water pollution with phenol.


Assuntos
Basidiomycota/enzimologia , Técnicas Biossensoriais/métodos , Espaço Extracelular/enzimologia , Nanodiamantes/química , Oxirredutases/metabolismo , Fenol/análise , Água/química , Basidiomycota/citologia , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Oxirredutases/química
12.
Biosens Bioelectron ; 193: 113573, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34425520

RESUMO

NAD+-dependent dehydrogenase-based biosensors usually suffer from the low accuracy due to the interference of cofactors in the complex environment, such as fermentation samples. Herein, we demonstrate the example of an integrated biosensor device that can be applied for analyzing xylose fermentation samples. The device is composed of one chamber for the elimination of NAD+ and NADH in the fermentation broth and another chamber for the sample analysis. In the first chamber, a cyclic voltammetry method coupled with Ni foam as a working electrode was proven to be effective in removing NAD+ and NADH in the fermentation broth. In the other chamber, xylose dehydrogenase, as the recognition element, and diaphorase, used for the regeneration of bioactive NAD+ mediated by vitamin K3, were co-immobilized on the surface of the magnetic nanoparticles, which was further coated onto a magnetic glassy carbon electrode. The detection range of the constructed biosensor was from 0.5 to 10 g L-1 with a detection limit of 0.01 g L-1 at a signal-to-noise ratio of 3. Moreover, the biosensor achieved high selectivity, recovery, reproducibility, and good long-time stability when analyzing real xylose fermentation samples, suggesting its promising application potential.


Assuntos
Técnicas Biossensoriais , Fermentação , NAD/metabolismo , Oxirredutases , Reprodutibilidade dos Testes , Xilose
13.
Fish Shellfish Immunol ; 117: 220-227, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34418553

RESUMO

This study aimed to evaluate that dietary protein levels and culture salinity levels affect the health status of juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Graded protein levels of six diets were prepared, ranging from 18.20% to 49.49% (dry basis), and were used in cultured GIFT at two salinity levels (0‰ and 8‰) for 8 weeks. The results suggested that appropriate protein levels reduced pro-inflammatory gene expressions in the intestine including interleukin 1ß (IL-1ß), interleukin 8 (IL-8) and tumour necrosis factor-α (TNF-α) mRNA levels at two salinity levels (P < 0.05). 8‰ salinity significantly decreased the expression levels of IL-1ß, TNF-α and nuclear factor-kappa B (NF-κB) (P < 0.05). The anti-inflammatory factor interleukin 10 (IL-10) was significantly increased by 36.42% protein level (P < 0.05). Regarding antioxidant capacity, appropriate protein levels and 8‰ salinity significantly improved the antioxidant capacity of fish by regulating the activities of intestinal total superoxide dismutase (T-SOD), glutathione peroxidase (GPx), and the levels of glutathione (GSH) and malondialdehyde (MDA). Furthermore, appropriate protein levels and 8‰ salinity also significantly enhanced the antioxidant gene expressions associated with the Nrf2/keap1 signaling pathway by regulating the expression levels of heme oxygenase-1 (HO-1), GPx, catalase (CAT) and superoxide dismutase (SOD). According to GPx activities and the mRNA levels of IL-10, the optimum dietary protein levels for GIFT juveniles were 31.12%-32.18% (0‰) and 34.25-35.38% (8‰) based on second-degree polynomial regression analysis. The present study found that appropriate protein levels and 8‰ culture salinity are critical in maintaining the health of GIFT juveniles by improving antioxidant and immune capacity.


Assuntos
Ciclídeos/imunologia , Proteínas na Dieta/administração & dosagem , Proteínas de Peixes/imunologia , Fator 2 Relacionado a NF-E2/imunologia , Salinidade , Animais , Animais Geneticamente Modificados , Aquicultura , Ciclídeos/genética , Citocinas/imunologia , Expressão Gênica , Intestinos/imunologia , NF-kappa B/imunologia , Oxirredutases/genética , Transdução de Sinais
14.
Biomolecules ; 11(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34439809

RESUMO

Leaf senescence, the last stage of leaf development, is a well-regulated and complex process for investigation. For simplification, dark-induced leaf senescence has frequently been used to mimic the natural senescence of leaves because many typical senescence symptoms, such as chlorophyll (Chl) and protein degradation, also occur under darkness. In this study, we compared the phenotypes of leaf senescence that occurred when detached leaves or intact plants were incubated in darkness to induce senescence. We found that the symptoms of non-programmed cell death (non-PCD) with remaining green coloration occurred more heavily in the senescent leaves of whole plants than in the detached leaves. The pheophorbide a (Pheide a) content was also shown to be much higher in senescent leaves when whole plants were incubated in darkness by analyses of leaf Chl and its metabolic intermediates. In addition, more serious non-PCD occurred and more Pheide a accumulated in senescent leaves during dark incubation if the soil used for plant growth contained more water. Under similar conditions, the non-PCD phenotype was alleviated and the accumulation of Pheide a was reduced by overexpressing 7-hydroxymethyl Chl a (HMChl a) reductase (HCAR). Taken together, we conclude that a high soil water content induced non-PCD by decreasing HCAR activity when whole plants were incubated in darkness to induce senescence; thus, the investigation of the fundamental aspects of biochemistry and the regulation of leaf senescence are affected by using dark-induced leaf senescence.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Clorofila/análogos & derivados , Regulação da Expressão Gênica de Plantas , Oxirredutases/genética , Folhas de Planta/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Morte Celular , Clorofila/metabolismo , Escuridão , Oxirredutases/metabolismo , Fenótipo , Fotossíntese/genética , Células Vegetais/metabolismo , Folhas de Planta/metabolismo , Estabilidade Proteica , Proteólise , Solo/química , Água/metabolismo
15.
Life Sci ; 284: 119910, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34453939

RESUMO

AIMS: Quercetin has been investigated as an agent to treat rheumatoid arthritis. At high doses it improves inflammation and the antioxidant status of arthritic rats, but it also exerts mitochondriotoxic and pro-oxidant activities. Beneficial effects of quercetin have not been found at low doses because of its chemical instability and low bioavailability. In the hope of overcoming these problems this study investigated the effects of long-term administration of quercetin-loaded pectin/casein microparticles on the oxidative status of liver and brain of rats with adjuvant-induced arthritis. MAIN METHODS: Particle morphology was viewed with transmission electron microscopy and the encapsulation efficiency was measured indirectly by X-ray diffraction. Quercetin microcapsules (10 mg/Kg) were orally administered to rats during 60 days. Inflammation indicators and oxidative stress markers were measured in addition to the respiratory activity and ROS production in isolated mitochondria. KEY FINDINGS: Quercetin was efficiently encapsulated inside the polymeric matrix, forming a solid amorphous solution. The administration of quercetin microparticles to arthritic rats almost normalized protein carbonylation, lipid peroxidation, the levels of reactive oxygen species as well as the reduced glutathione content in both liver and brain. The paw edema in arthritic rats was not responsive, but the plasmatic activity of ALT and the mitochondrial respiration were not affected by quercetin, indicating absence of mitochondriotoxic or hepatotoxic actions. SIGNIFICANCE: Quercetin-loaded pectin/casein microcapsules orally administered at a low dose improve oxidative stress of arthritic rats without a strong anti-inflammatory activity. This supports the long-term use of quercetin as an antioxidant agent to treat rheumatoid arthritis.


Assuntos
Artrite Experimental/patologia , Caseínas/química , Microesferas , Estresse Oxidativo , Pectinas/química , Quercetina/farmacologia , Alanina Transaminase/sangue , Animais , Antioxidantes/farmacologia , Artrite Experimental/sangue , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Varredura Diferencial de Calorimetria , Respiração Celular/efeitos dos fármacos , Edema/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Oxirredutases/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
Biomolecules ; 11(7)2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34356667

RESUMO

During the last century, anthropogenic activities such as fertilization have led to an increase in pollution in many ecosystems by nitrogen compounds. Consequently, researchers aim to reduce nitrogen pollutants following different strategies. Some haloarchaea, owing to their denitrifier metabolism, have been proposed as good model organisms for the removal of not only nitrate, nitrite, and ammonium, but also (per)chlorates and bromate in brines and saline wastewater. Bacterial denitrification has been extensively described at the physiological, biochemical, and genetic levels. However, their haloarchaea counterparts remain poorly described. In previous work the model structure of nitric oxide reductase was analysed. In this study, a bioinformatic analysis of the sequences and the structural models of the nitrate, nitrite and nitrous oxide reductases has been described for the first time in the haloarchaeon model Haloferax mediterranei. The main residues involved in the catalytic mechanism and in the coordination of the metal centres have been explored to shed light on their structural characterization and classification. These results set the basis for understanding the molecular mechanism for haloarchaeal denitrification, necessary for the use and optimization of these microorganisms in bioremediation of saline environments among other potential applications including bioremediation of industrial waters.


Assuntos
Proteínas Arqueais/química , Proteínas Arqueais/metabolismo , Enzimas/metabolismo , Haloferax mediterranei/metabolismo , Coenzimas/metabolismo , Simulação por Computador , Desnitrificação , Enzimas/química , Haloferax mediterranei/enzimologia , Modelos Moleculares , Nitrato Redutase/química , Nitrato Redutase/metabolismo , Nitrito Redutases/química , Nitrito Redutases/metabolismo , Oxirredutases/química , Oxirredutases/metabolismo , Sinais Direcionadores de Proteínas , Alinhamento de Sequência
17.
Int J Mol Sci ; 22(16)2021 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-34445240

RESUMO

Nitroaromatic compounds (ArNO2) maintain their importance in relation to industrial processes, environmental pollution, and pharmaceutical application. The manifestation of toxicity/therapeutic action of nitroaromatics may involve their single- or two-electron reduction performed by various flavoenzymes and/or their physiological redox partners, metalloproteins. The pivotal and still incompletely resolved questions in this area are the identification and characterization of the specific enzymes that are involved in the bioreduction of ArNO2 and the establishment of their contribution to cytotoxic/therapeutic action of nitroaromatics. This review addresses the following topics: (i) the intrinsic redox properties of ArNO2, in particular, the energetics of their single- and two-electron reduction in aqueous medium; (ii) the mechanisms and structure-activity relationships of reduction in ArNO2 by flavoenzymes of different groups, dehydrogenases-electrontransferases (NADPH:cytochrome P-450 reductase, ferredoxin:NADP(H) oxidoreductase and their analogs), mammalian NAD(P)H:quinone oxidoreductase, bacterial nitroreductases, and disulfide reductases of different origin (glutathione, trypanothione, and thioredoxin reductases, lipoamide dehydrogenase), and (iii) the relationships between the enzymatic reactivity of compounds and their activity in mammalian cells, bacteria, and parasites.


Assuntos
Bactérias/enzimologia , Proteínas de Bactérias , Citotoxinas , Elétrons , Flavoproteínas , Nitrocompostos , Oxirredutases , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Citotoxinas/química , Citotoxinas/farmacologia , Flavoproteínas/química , Flavoproteínas/metabolismo , Humanos , Nitrocompostos/química , Nitrocompostos/farmacologia , Oxirredução , Oxirredutases/química , Oxirredutases/metabolismo
18.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445672

RESUMO

In mammalian cells, two cellular organelles, mitochondria and peroxisomes, share the ability to degrade fatty acid chains. Although each organelle harbors its own fatty acid ß-oxidation pathway, a distinct mitochondrial system feeds the oxidative phosphorylation pathway for ATP synthesis. At the same time, the peroxisomal ß-oxidation pathway participates in cellular thermogenesis. A scientific milestone in 1965 helped discover the hepatomegaly effect in rat liver by clofibrate, subsequently identified as a peroxisome proliferator in rodents and an activator of the peroxisomal fatty acid ß-oxidation pathway. These peroxisome proliferators were later identified as activating ligands of Peroxisome Proliferator-Activated Receptor α (PPARα), cloned in 1990. The ligand-activated heterodimer PPARα/RXRα recognizes a DNA sequence, called PPRE (Peroxisome Proliferator Response Element), corresponding to two half-consensus hexanucleotide motifs, AGGTCA, separated by one nucleotide. Accordingly, the assembled complex containing PPRE/PPARα/RXRα/ligands/Coregulators controls the expression of the genes involved in liver peroxisomal fatty acid ß-oxidation. This review mobilizes a considerable number of findings that discuss miscellaneous axes, covering the detailed expression pattern of PPARα in species and tissues, the lessons from several PPARα KO mouse models and the modulation of PPARα function by dietary micronutrients.


Assuntos
Ácidos Graxos/metabolismo , PPAR alfa/metabolismo , Peroxissomos/metabolismo , Acil-CoA Oxidase/metabolismo , Animais , Humanos , Fígado/metabolismo , Oxirredução , Oxirredutases/metabolismo , PPAR alfa/fisiologia , Proliferadores de Peroxissomos , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores do Ácido Retinoico/metabolismo , Elementos de Resposta/genética , Receptores X de Retinoides/metabolismo , Ativação Transcricional/genética
19.
Int J Mol Sci ; 22(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34445771

RESUMO

The dehydrogenase pathway and the succinylase pathway are involved in the synthesis of L-lysine in Corynebacterium glutamicum. Despite the low contribution rate to L-lysine production, the dehydrogenase pathway is favorable for its simple steps and potential to increase the production of L-lysine. The effect of ammonium (NH4+) concentration on L-lysine biosynthesis was investigated, and the results indicated that the biosynthesis of L-lysine can be promoted in a high NH4+ environment. In order to reduce the requirement of NH4+, the nitrogen source regulatory protein AmtR was knocked out, resulting in an 8.5% increase in L-lysine production (i.e., 52.3 ± 4.31 g/L). Subsequently, the dehydrogenase pathway was upregulated by blocking or weakening the tetrahydrodipicolinate succinylase (DapD)-coding gene dapD and overexpressing the ddh gene to further enhance L-lysine biosynthesis. The final strain XQ-5-W4 could produce 189 ± 8.7 g/L L-lysine with the maximum specific rate (qLys,max.) of 0.35 ± 0.05 g/(g·h) in a 5-L jar fermenter. The L-lysine titer and qLys,max achieved in this study is about 25.2% and 59.1% higher than that of the original strain without enhancement of dehydrogenase pathway, respectively. The results indicated that the dehydrogenase pathway could serve as a breakthrough point to reconstruct the diaminopimelic acid (DAP) pathway and promote L-lysine production.


Assuntos
Corynebacterium glutamicum/metabolismo , Ácido Diaminopimélico/metabolismo , Lisina/metabolismo , Transdução de Sinais/fisiologia , Aciltransferases/metabolismo , Compostos de Amônio/metabolismo , Oxirredutases/metabolismo
20.
Talanta ; 234: 122647, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364456

RESUMO

Nanozymes, as a new type of artificial enzyme, have recently become a research hotspot in the field of catalysis and biomedicine. However, the application of nanozyme is limited by catalytic activity changes of different substrates and low specificity. This work shows that citrate-capped platinum nanoparticles (Cit-PtNPs) exhibit stronger oxidase-like activity than other platinum nanozymes at different pH when 3-methyl-2-benzothiazolinonehydrazone hydrochloride (MBTH) and n-ethyl-n- (2-hydroxy-3-sulfopropyl)-m-toluidine sodium salt (TOOS) were used as chromogenic substrates. This phenomenon has important reference value for different nanozymes to choose chromogenic substrates in catalysis. In MBTH-TOOS chromogenic system, MBTH (-NH) radical is first produced during the reaction through catalytic oxidation of Cit-PtNPs, which reacts with TOOS to produce a colorless compound. The blue-purple quinoid dye was produced through the dismutation of the colorless compound. The catalytic mechanism of the oxidase-like activity of Cit-PtNPs is that two-electron reduction process and four-electron reduction process are simultaneously carried out in the catalytic process. Furthermore, to solve the problem of low specificity of metal nanozymes, protamine is designed as aggregation promoter of Cit-PtNPs and the specifichydrolysis substrate of trypsin. In this work, it can achieve one-step detection of trypsin by the boosting oxidase activity of Cit-PtNPs at pH8. The catalytic activity of Cit-PtNPs is proportional to the concentration of trypsin. The linear range for trypsin is 1.0-70.0 ngmL-1 and the limit of detection is measured to be 0.6 ngmL-1. This novel method has also been successfully applied to the detection of inhibitors and trypsin in urine samples.


Assuntos
Nanopartículas Metálicas , Platina , Catálise , Colorimetria , Oxirredutases , Sódio , Tripsina
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