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1.
J Mol Model ; 30(8): 294, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39080111

RESUMO

CONTEXT: Hydrazones have been studied for a myriad of chemical and physiochemical properties, such as sensors, chelators and numerous biological activities. Experimental data indicates that hydrazones are unstable under cathodic potentials irrespective of the solvent. The single electron reduction of hydrazones to produce radical anions result in unstable species that cleaves at the N-N bond in a heterolytic manner. The literature has proposed a mechanism favouring the radical on the imine moiety, however in this study DFT calculations suggest the radical on the amine product is more likely upon bond cleavage. This has implications on electrochemical mechanisms, and the active molecule in biological studies viz the method of delivery to target areas. METHODS: Density functional theory calculations were carried out using the GAMESS software package. The structures were optimized in the gas phase (B3LYP/6-31G(d,p)) as indicated by the absence of imaginary frequencies in the Hessian, and in CH3CN (B3LYP/6-31G(d,p)/SMD) with the Pople polarization functions. As a comparison, selected pathways were fully optimized using PBE0/6-31G(d,p) and PBE0/6-31G(d,p)/SMD for gas phase and CH3CN, respectively with the Pople polarization functions. The values were not significantly different (< 5% difference). As such only the B3LYP is evaluation is discussed.

2.
Int J Mol Sci ; 25(10)2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38791309

RESUMO

The protein scaffold that includes the caspases is ancient and found in all domains of life. However, the stringent specificity that defines the caspase biologic function is relatively recent and found only in multicellular animals. During the radiation of the Chordata, members of the caspase family adopted roles in immunity, events coinciding with the development of substrates that define the modern innate immune response. This review focuses on the switch from the non-inflammatory cellular demise of apoptosis to the highly inflammatory innate response driven by distinct members of the caspase family, and the interplay between these two regulated cell death pathways.


Assuntos
Caspases , Imunidade Inata , Piroptose , Humanos , Caspases/metabolismo , Animais , Evolução Molecular , Apoptose
3.
Int J Biol Macromol ; 270(Pt 1): 132294, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38735602

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are molecules with two or more fused aromatic rings that occur naturally in the environment due to incomplete combustion of organic substances. However, the increased demand for fossil fuels in recent years has increased anthropogenic activity, contributing to the environmental concentration of PAHs. The enzyme chlorocatechol 1,2-dioxygenase from Pseudomonas putida (Pp 1,2-CCD) is responsible for the breakdown of the aromatic ring of catechol, making it a potential player in bioremediation strategies. Pp 1,2-CCD can tolerate a broader range of substrates, including halogenated compounds, than other dioxygenases. Here, we report the construction of a chimera protein able to form biomolecular condensates with potential application in bioremediation. The chimera protein was built by conjugating Pp 1,2-CCD to low complex domains (LCDs) derived from the DEAD-box protein Dhh1. We showed that the chimera could undergo liquid-liquid phase separation (LLPS), forming a protein-rich liquid droplet under different conditions (variable protein and PEG8000 concentrations and pH values), in which the protein maintained its structure and main biophysical properties. The condensates were active against 4-chlorocatechol, showing that the chimera droplets preserved the enzymatic activity of the native protein. Therefore, it constitutes a prototype of a microreactor with potential use in bioremediation.


Assuntos
Biodegradação Ambiental , Dioxigenases , Hidrocarbonetos Policíclicos Aromáticos , Dioxigenases/metabolismo , Dioxigenases/química , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Pseudomonas putida/enzimologia , Catecóis/metabolismo , Catecóis/química , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo
4.
J Inorg Biochem ; 256: 112573, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38678913

RESUMO

This paper describes the synthesis, structural analysis, as well as the magnetic and spectroscopic characterizations of three new dicopper(II) complexes with dinucleating phenol-based ligands containing different thioether donor substituents: aromatic (1), aliphatic (2) or thiophene (3). Temperature-dependent magnetometry reveals the presence of antiferromagnetic coupling for 1 and 3 (J = -2.27 cm-1 and -5.01 cm-1, respectively, H = -2JS1S2) and ferromagnetic coupling for 2 (J = 5.72 cm-1). Broken symmetry DFT calculations attribute this behavior to a major contribution from the dz2 orbitals for 1 and 3, and from the dx2-y2 orbitals for 2, along with the p orbitals of the oxygens. The bioinspired catalytic activities of these complexes related to catechol oxidase were studied using 3,5-di-tert-butylcatechol as substrate. The order of catalytic rates for the substrate oxidation follows the trend 1 > 2 > 3 with kcat of (90.79 ± 2.90) × 10-3 for 1, (64.21 ± 0.99) × 10-3 for 2 and (14.20 ± 0.32) × 10-3 s-1 for 3. The complexes also cleave DNA through an oxidative mechanism with minor-groove preference, as indicated by experimental and molecular docking assays. Antimicrobial potential of these highly active complexes has shown that 3 inhibits both Staphylococcus aureus bacterium and Epidermophyton floccosum fungus. Notably, the complexes were found to be nontoxic to normal cells but exhibited cytotoxicity against epidermoid carcinoma cells, surpassing the activity of the metallodrug cisplatin. This research shows the multifaceted properties of these complexes, making them promising candidates for various applications in catalysis, nucleic acids research, and antimicrobial activities.


Assuntos
Antineoplásicos , Complexos de Coordenação , Oxirredução , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Ligantes , Sulfetos/química , Sulfetos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Platina/química , Platina/farmacologia , Linhagem Celular Tumoral
5.
Expert Opin Ther Targets ; 27(10): 911-925, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37772733

RESUMO

INTRODUCTION: Chagas disease (CD) imposes social and economic burdens, yet the available treatments have limited efficacy in the disease's chronic phase and cause serious adverse effects. To address this challenge, target-based approaches are a possible strategy to develop new, safe, and active treatments for both phases of the disease. AREAS COVERED: This review delves into target-based approaches applied to CD drug discovery, emphasizing the studies from the last five years. We highlight the proteins cruzain (CZ), trypanothione reductase (TR), sterol 14 α-demethylase (CPY51), iron superoxide dismutase (Fe-SOD), proteasome, cytochrome b (Cytb), and cleavage and polyadenylation specificity factor 3 (CPSF3), chosen based on their biological and chemical validation as drug targets. For each, we discuss its biological relevance and validation as a target, currently related challenges, and the status of the most promising inhibitors. EXPERT OPINION: Target-based approaches toward developing potential CD therapeutics have yielded promising leads in recent years. We expect a significant advance in this field in the next decade, fueled by the new options for Trypanosoma cruzi genetic manipulation that arose in the past decade, combined with recent advances in computational chemistry and chemical biology.


Assuntos
Doença de Chagas , Trypanosoma cruzi , Humanos , Doença de Chagas/tratamento farmacológico , Trypanosoma cruzi/genética , Descoberta de Drogas
6.
Plant Sci ; 336: 111817, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37562731

RESUMO

Carotenoid cleavage dioxygenase (CCD) gene family is organized in two subfamilies: (i) 9-cis epoxycarotenoid dioxygenase (NCED) genes and (ii) CCD genes. NCED genes are essential for catalyzing the first step of the abscisic-acid (ABA) biosynthesis, while CCD genes produce precursors of the strigolactones hormone. The functional characterization of these gene subfamilies has not been yet performed in chickpea and lentil. Herein, were identified and systematically characterized two NCED and five CCD genes in the chickpea and two NCED and six CCD genes in lentil. After in silico sequence analysis and phylogeny, the expression profile of the NCED/CCD genes was determined by meta-analysis and real-time PCR in plants under different stress conditions. Sequence data revealed that NCED/CCD genes are highly conserved between chickpea and lentil. This conservation was observed both at gene and protein sequence levels and phylogenetic relationships. Analysis of the promoter sequences revealed that all NCED/CCD genes have a considerable number of cis-regulatory elements responsive to biotic and abiotic stress. Protein sequence analysis evidenced that NCED/CCD genes share several conserved motifs and that they have a highly interconnected interaction network. Furthermore, the three-dimensional structure of these proteins was determined and indicated that some proteins have structures with considerable similarity. The meta-analysis revealed that NCED/CCD genes are dynamically modulated in different organs and under different stress conditions, but they have a positive correlation with plant tolerance. In accordance, real-time PCR data showed that both NCED and CCD genes are differentially modulated in plants under drought stress. In particular, CaNCED2, CaCCD5, LcNCED2, LcCCD1, and LcCCD2 genes have a positive correlation with improved plant tolerance to drought stress. Therefore, this study presented a detailed characterization of the chickpea and lentil NCED/CCD genes and provided new insights to improve abiotic stress tolerance in these two important crops.


Assuntos
Cicer , Dioxigenases , Lens (Planta) , Cicer/genética , Lens (Planta)/genética , Lens (Planta)/metabolismo , Filogenia , Dioxigenases/genética , Dioxigenases/metabolismo , Plantas/metabolismo , Proteínas de Plantas/metabolismo , Carotenoides/metabolismo , Estresse Fisiológico/genética , Regulação da Expressão Gênica de Plantas , Ácido Abscísico/metabolismo
7.
Chempluschem ; 88(10): e202300268, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37498229

RESUMO

The performance of mechanochemically synthesized supported bimetallic AgAu nanoalloy catalysts was evaluated in the oxidative cleavage of methyl oleate, a commonly available unsaturated bio-derived raw material. An extensive screening of supports (SiO2 , C, ZrO2 , Al2 O3 ), metallic ratios (Ag : Au), reaction times, temperatures, and use of solvents was carried out. The performance was optimized towards productivity and selectivity for the primary cleavage products (aldehydes and oxoesters). The optimal conditions were achieved in the absence of solvent, using Ag8 Au92 /SiO2 as catalyst, at 80 °C, reaction time of 1 h, substrate to catalyst=555 and 10 bar of molecular oxygen. A strong support effect was observed: the selectivity to aldehydes was best with silica as support, and to esters was best using zirconia. This shows not only that mechanochemical preparation of bimetallic catalysts is a powerful tool to generate useful catalyst compositions, but also that a safe, green, solventless synthesis of bio-derived products can be achieved by aerobic oxidative cleavage.

8.
Molecules ; 27(21)2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36364105

RESUMO

The C-X bond cleavage in different methyl halides (CH3X; X = Cl, Br, I) mediated by 5,6-dimethylbenzimidazole-bis(dimethylglyoximate)cobalt(II) (CoIICbx) was theoretically investigated in the present work. An SN2-like mechanism was considered to simulate the chemical process where the cobalt atom acts as the nucleophile and the halogen as the leaving group. The reaction path was computed by means of the intrinsic reaction coordinate method and analyzed in detail through the reaction force formalism, the quantum theory of atoms in molecules (QTAIM), and the calculation of one-electron density derived quantities, such as the source function (SF) and the spin density. A thorough comparison of the results with those obtained in the same reaction occurring in presence of 5,6-dimethylbenzimidazole-bis(dimethylglyoximate)cobalt(I) (CoICbx) was conducted to reveal the main differences between the two cases. The reactions mediated by CoIICbx were observed to be endothermic and possess higher activation energies in contrast to the reactions where the CoICbx complex is present. The latter was supported by the reaction force results, which suggest a relationship between the activation energy and the ionization potentials of the different nucleophiles present in the cleavage reaction. Moreover, the SF results indicates that the lower axial ligand (i.e., 5,6-dimethylbenzimidazole) exclusively participates on the first stage of the reaction mediated by the CoIICbx complex, while for the CoICbx case, it appears to have an important role along the whole process. Finally, the QTAIM charge analysis indicates that oxidation of the cobalt atom occurs in both cases; at the same time, it suggests the formation of an uncommon two-center one-electron bond in the CoIICbx case. The latter was confirmed by means of electron localization calculations, which resulted in a larger electron count at the Co-C interatomic region for the CoICbx case upon comparison with its CoIICbx counterpart.


Assuntos
Cobalto , Teoria Quântica , Cobalto/química , Modelos Teóricos , Ligantes , Elétrons
9.
JBRA Assist Reprod ; 17(6): 347-350, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35939553

RESUMO

OBJECTIVE: The main objective of this study was to evaluate the effectiveness of vitrification technique through embryo viability, embryo implantation rate and clinical pregnancy in patients undergoing controlled ovarian stimulation. MATERIAL AND METHODS: Viable embryos of patients deriving from in vitro fertilization were vitrified using the protocol of Irvine Scientific by closed system. 28 cycles of freezing and thawing of embryos were evaluated during the periods from January 2010 to December 2012 in the Clinical Reproduction, Presidente Prudente - SP. RESULTS: Total of 176 embryos was frozen. The average number of frozen/thawed embryos per patient was 5, totaling 140 thawed embryos. These thawed embryos, 78,6% (110/140) displayed viable morphologically (at least 50% from intact blastomeres) and 75% (105/140) of thawed embryos were transferred. In 28 cycles in which there was transference, an average of 3.75 embryos were transferred per patient, from which resulted in 17 biochemical pregnancies and of these 8 pregnancies reached term (28,6%) and embryonic implantation rate was 20%. CONCLUSION: It can be concluded that the method of embryos vitrification is an effective technique, with high survival rate, allowing the storage of surplus embryos with satisfactory pregnancy rates in thawing cycles.


Assuntos
Criopreservação , Implantação do Embrião , Transferência Embrionária , Taxa de Gravidez , Criopreservação/métodos , Transferência Embrionária/métodos , Feminino , Fertilização in vitro , Humanos , Gravidez , Vitrificação
10.
Braz J Microbiol ; 53(3): 1613-1621, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35831780

RESUMO

The present study was carried out to evaluate the antagonistic efficacy of Aspergillus versicolor against the soil and seed inhibiting destructive plant pathogen Macrophomina phaseolina. The tested antagonist was confirmed by rDNA sequencing of ITS and ß-tubulin genes with respective accession numbers MN719083 and MN736397. In dual culture bioassays, A. versicolor showed potent antagonist activity and reduced the pathogen's growth by 60% over control. To understand the mechanism of antagonistic fungus, DNA of the pathogenic fungus was incubated in secondary metabolites produced by the A. versicolor for 24 and 48 h. After 48 h, metabolites of A. versicolor fully degraded the DNA of M. phaseolina. Moreover, for the identification of bioactive compounds, the chloroform and ethyl acetate fractions of A. versicolor culture filtrates were subjected to GC-MS analysis. A total of 10 compounds were identified in each of the two fractions. Among these, chondrillasterol (37.43%) followed by 1,2-benzedicarboxylic acid, diisooctyl ester (25.93%), decane (16.63%), 9,12-octadecadienoic acid (Z,Z)- (13.32%), stigmasterol (11.16%), undecane (10.93%), cis-1-chloro-9-octadecene (8.66%), benzene, 1,3,5-trimethyl (8.46%), and hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester (8.13%) were the major compounds. Some of the identified compounds are known to possess strong antifungal, antibacterial, nematicidal, and antioxidant properties. The present study concludes that A. versicolor is an effective antagonist against M. phaseolina.


Assuntos
Ascomicetos , Aspergillus/genética , Ésteres , Doenças das Plantas/microbiologia
11.
J Virol ; 96(14): e0066522, 2022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35762760

RESUMO

Human astrovirus VA1 has been associated with neurological disease in immunocompromised patients, and its recent propagation in cell culture has opened the possibility to study its biology. Unlike classical human astroviruses, VA1 growth was found to be independent of trypsin during virus replication in vitro. In this work, we show that despite its independence on trypsin activation for cell infection, the VA1 capsid precursor protein, of 86 kDa (VP86), is processed intracellularly, and this proteolytic processing is important for astrovirus VA1 infectivity. Antibodies raised against different regions of the capsid precursor showed that the polyprotein can be processed starting at either its amino- or carboxy-terminal end, and they allowed us to identify those proteins of about 33 (VP33) and 38 (VP38) kDa constitute the core and the spike proteins of the mature infectious virus particles, respectively. The amino-terminal end of the spike protein was found to be Thr-348. Whether the protease involved in intracellular cleavage of the capsid precursor is of viral or cellular origin remains to be determined, but the cleavage is independent of caspases. Also, trypsin is able to degrade the capsid precursor but has no effect on VP33 and VP38 proteins when assembled into virus particles. These studies provide the basis for advancement of the knowledge of astrovirus VA1 cell entry and replication. IMPORTANCE Human astrovirus VA1 has been associated with neurological disease in immunocompromised patients. Its recent propagation in cell culture has facilitated the study of its biology. In this work, we show that despite the ability of this virus to grow in the absence of trypsin, a marked feature of human classical astroviruses, the capsid precursor protein of astrovirus VA1 is cleaved intracellularly to yield the mature infectious particles, formed by two polypeptides, VP33 that constitutes the core domain of the virus particle, and VP38 that forms the spike of the virus. These studies provide a platform to advance our knowledge on astrovirus VA1 cell entry and replication.


Assuntos
Infecções por Astroviridae , Proteínas do Capsídeo , Mamastrovirus , Precursores de Proteínas , Infecções por Astroviridae/virologia , Células CACO-2 , Capsídeo/metabolismo , Proteínas do Capsídeo/metabolismo , Humanos , Espaço Intracelular/virologia , Mamastrovirus/fisiologia , Precursores de Proteínas/metabolismo , Tripsina/metabolismo
12.
Nat Prod Bioprospect ; 12(1): 20, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35641706

RESUMO

From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1. The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the substrate yielding the 2-oxoaustroeupatol (2) and 2,19-dioxoaustroeupatol (3). The treatment of 2 with sodium periodate yields a heterocyclic derivative (ε-caprolactone derivate 4) formed by oxidative cleavage and unexpected intramolecular attack of the hydroxymethylene (C-19) oxygen to the ketonic carbon (C-2). A plausible mechanistic pathway for the obtention of compound 4 is proposed.

13.
Biochim Biophys Acta Mol Basis Dis ; 1868(6): 166371, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35218894

RESUMO

Cardiovascular manifestations account for marked morbi-mortality in autosomal dominant polycystic kidney disease (ADPKD). Pkd1- and Pkd2-deficient mice develop cardiac dysfunction, however the underlying mechanisms remain largely unclear. It is unknown whether impairment of polycystin-1 cleavage at the G-protein-coupled receptor proteolysis site, a significant ADPKD mutational mechanism, is involved in this process. We analyzed the impact of polycystin-1 cleavage on heart metabolism using Pkd1V/V mice, a model unable to cleave this protein and with early cardiac dysfunction. Pkd1V/V hearts showed lower levels of glucose and amino acids and higher lipid levels than wild-types, as well as downregulation of p-AMPK, p-ACCß, CPT1B-Cpt1b, Ppara, Nppa and Acta1. These findings suggested decreased fatty acid ß-oxidation, which was confirmed by lower oxygen consumption by Pkd1V/V isolated mitochondria using palmitoyl-CoA. Pkd1V/V hearts also presented increased oxygen consumption in response to glucose, suggesting that alternative substrates may be used to generate energy. Pkd1V/V hearts displayed a higher density of decreased-size mitochondria, a finding associated with lower MFN1, Parkin and BNIP3 expression. These derangements were correlated with increased apoptosis and inflammation but not hypertrophy. Notably, Pkd1V/V neonate cardiomyocytes also displayed shifts in oxygen consumption and p-AMPK downregulation, suggesting that, at least partially, the metabolic alterations are not induced by kidney dysfunction. Our findings reveal that disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice, expanding the understanding of heart dysfunction associated with Pkd1 deficiency and likely with human ADPKD.


Assuntos
Rim Policístico Autossômico Dominante , Canais de Cátion TRPP , Animais , Coração , Camundongos , Mitocôndrias/metabolismo , Mutação , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/metabolismo , Canais de Cátion TRPP/genética , Canais de Cátion TRPP/metabolismo
14.
Brain Plast ; 8(2): 133-142, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36721394

RESUMO

Brain-derived neurotrophic factor (BDNF) is the brain's most-produced neurotrophin during the lifespan, essentially involved in multiple mechanisms of nervous system development and function. The production/release of BDNF requires multi-stage processing that appears to be regulated at various stages in which the presence of a polymorphism "Val66Met" can exert a critical influence. Aim: To synthesize the knowledge on the BDNF Val66Met polymorphism on intracellular processing and function of BDNF. Methods: We performed a systematic review and collected all available studies on the post-translation processes of BDNF, regarding the Val66Met polymorphism. Searches were performed up to 21st March 2021. Results: Out of 129 eligible papers, 18 studies addressed or had findings relating to BDNF post-translation processes and were included in this review. Discussion: Compilation of experimental findings reveals that the Val66Met polymorphism affects BDNF function by slightly altering the processing, distribution, and regulated release of BDNF. Regarding the critical role of pro-BDNF as a pro-apoptotic factor, such alteration might represent a risk for the development of neuropsychiatric disorders.

15.
Artigo em Inglês | MEDLINE | ID: mdl-34923301

RESUMO

Isoniazid is a first-line drug for the treatment of tuberculosis, a bacterial disease caused by Mycobacterium tuberculosis. Its terminal amino group is highly reactive, leading to significant metabolic deactivation, drug interactions and hepatotoxicity. It is speculated that the activity of isoniazid derivatives is, in part, related to the cleavage of the protecting group. Therefore, this study aimed to evaluate the cleavage characteristics of previously developed isoniazid derivatives through kinetic studies by high-performance liquid chromatography with ultraviolet-diode array detectio to establish a comparison between the rates of the process and the respective activities against M. tuberculosis. Chromatographic separations were performed on an XDB C18 column coupled to an XDB C18 precolumn. The mobile phase consisted of ultrapure water and acetonitrile in gradient mode. The flow rate was 1.0 mL/min, the injection volume was 20 µL, and the detection wavelengths were 230 nm (derivatives and isatins) and 270 nm (isoniazid). Incubation of derivatives was carried out for 5 days in 10 mmol/L phosphate buffer solution (pH 3.0, 7.4, 8.0) or in fetal bovine serum at 37 °C. The incubation reduced the concentration of the derivatives and led to the formation of isoniazid in a first-order kinetic reaction. Isoniazid formation was logarithmically correlated with the minimum inhibitory concentration of the derivatives. The results showed that higher cleavage rates are associated with greater activities against M. tuberculosis, providing important information for the development of future generations of isoniazid derivatives and for screening drug candidates for the treatment of tuberculosis.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Hidrazinas/química , Isoniazida , Mycobacterium tuberculosis/efeitos dos fármacos , Isoniazida/análise , Isoniazida/química , Isoniazida/metabolismo , Isoniazida/farmacologia , Cinética , Limite de Detecção , Modelos Lineares , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes
16.
J Inorg Biochem ; 228: 111686, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34929540

RESUMO

The cellular prion protein (PrPC) is a membrane-anchored copper binding protein that undergoes proteolytic processing. ß-cleavage of PrPC is associated with a pathogenic condition and it yields two fragments: N2 with residues 23-89, and C2 including residues 90-231. The membrane-bound C2 fragment retains the Cu binding sites at His96 and His111, but it also has a free N-terminal NH2 group. In this study, the impact of ß-cleavage of PrPC in its Cu(II) binding properties was evaluated, using the peptide of the human prion protein hPrP(90-115) as a model for the C2 fragment. The Cu(II) coordination properties of hPrP(90-115) were studied using circular dichroism (CD) and electron paramagnetic resonance (EPR); while the H96A and H111A substitutions and its acetylated variants were also studied. Cu binding to hPrP(90-115) is dependent on metal ion concentration: At low copper concentrations the participation of His96 and free NH2-terminus is evident, while at high copper concentrations the His111 site is populated without participation of the N-terminal NH2 group. The presence of a free NH2-terminal group in the C2 fragment significantly impacts the Cu(II) coordination properties of the His96 site, where the NH2 group also anchors the metal ion. This study provides further insights into the impact of proteolytic processing of PrPC in the Cu binding properties of this important neuronal protein.


Assuntos
Cobre/química , Doenças Priônicas/metabolismo , Proteínas Priônicas/química , Proteínas Priônicas/metabolismo , Sítios de Ligação , Dicroísmo Circular , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Histidina/química , Humanos , Peptídeos/química , Príons/química , Príons/metabolismo , Ligação Proteica
17.
J Inorg Biochem ; 226: 111631, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34717251

RESUMO

The investigation of compounds capable of strongly and selectively interacting with DNA comprises a field of research in constant development. In this work, we demonstrate that a trinuclear coordination complex based on a dinuclear Fe(III)Zn(II) core designed for biomimicry of the hydrolytic enzyme kidney bean purple acid phosphatase, containing an additional pendant arm coordinating a Pd(II) ion, has the ability to interact with DNA and to promote its hydrolytic cleavage. These results were found through analysis of plasmid DNA interaction and cleavage by the trinuclear complex 1 and its derivatives 2 and 3, in addition to the analysis of alteration in the DNA structure in the presence of the complexes through circular dichroism and DNA footprinting techniques. The suggested covalent interaction of the palladium-containing complex with DNA was analysed using an electrophoretic mobility assay, circular dichroism, high resolution gel separation techniques and kinetic analysis. This is a new and promising metal complex targeted to nucleic acids and acting in two separate ways: strong DNA interaction and hydrolytic cleavage.


Assuntos
Complexos de Coordenação/química , Clivagem do DNA , Desoxirribonucleases/química , Metais/química , Plasmídeos/química
18.
Carbohydr Polym ; 275: 118684, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742414

RESUMO

Bioconversion of lignocellulosic biomass into value-added products relies on polysaccharides depolymerization by carbohydrate active enzymes. This work reports biochemical characterization of Paludibacter propionicigenes xylanase from GH10 (PpXyn10A) and its application for enzymatic xylooligosaccharides (XOS) production from commercial heteroxylans and liquor of hydrothermally pretreated corn cobs (PCC). PpXyn10A is tolerant to ethanol and NaCl, and releases xylobiose (X2) and xylotriose (X3) as the main hydrolytic products. The conversion rate of complex substrates into short XOS was approximately 30% for glucuronoxylan and 8.8% for rye arabinoxylan, after only 4 h; while for PCC, PpXyn10A greatly increased unbranched XOS yields. B. adolescentis fermentation with XOS from beechwood glucuronoxylan produced mainly acetic and lactic acids. Structural analysis shows that while the glycone region of PpXyn10A active site is well preserved, the aglycone region has aromatic interactions in the +2 subsite that may explain why PpXyn10A does not release xylose.


Assuntos
Bacteroidetes , Endo-1,4-beta-Xilanases/metabolismo , Glucuronatos/química , Oligossacarídeos/química , Xilanos/química , Animais , Bifidobacterium adolescentis/efeitos dos fármacos , Dissacarídeos/química , Fermentação , Glucuronatos/farmacologia , Humanos , Hidrólise , Oligossacarídeos/farmacologia , Prebióticos , Trissacarídeos/química , Xilose/química , Zea mays/química
19.
Protein Expr Purif ; 191: 106021, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34798273

RESUMO

Many recombinant proteins are products of great value in biomedical and industrial fields. The use of solubility and affinity tags are commonly used to increase yields and facilitate the purification process. However, it is of paramount importance in several applications to remove the fusion tag from the final product. In this regard, the Tobacco Etch Virus protease (TEV) is one of the most widely used for tag removal. The presence in the TEV of the same tag to be removed facilitates the separation of TEV and the tag from the cleaved recombinant protein in a single purification step. We generated a double-tagged (StrepTagII and HisTag) TEV variant with reported mutations that improve the activity, the expression yield in E.coli, and that decrease the auto-proteolysis. This TEV can be easily purified by two consecutive affinity chromatography steps with high yields and purity. The cleavage reaction can be done to almost completeness in as fast as 15 min at room temperature and the removal of the protease and tags is performed in a single purification step, independent of the previous presence of a StrepTagII or a HisTag on the target.


Assuntos
Endopeptidases , Escherichia coli , Proteínas Recombinantes de Fusão , Endopeptidases/biossíntese , Endopeptidases/química , Endopeptidases/genética , Endopeptidases/isolamento & purificação , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação
20.
JBRA Assist Reprod ; 25(4): 586-591, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34542251

RESUMO

OBJECTIVE: To investigate the association between cleavage stage development, embryonic competence, and euploidy in patients undergoing in vitro fertilization (IVF) with subsequent next generation sequencing. METHODS: The retrospective cohort study included patients at an academic fertility center who underwent IVF with at least one cleavage stage embryo from 2016 to 2019. Embryos were analyzed as slow (<6 cells), intermediate (6-8 cells), or fast (>8 cells); day 3 cell count was also analyzed as a continuous variable. Primary outcomes were blastulation rate, biopsied blastocyst rate, and euploid rate. Odds of blastulation, biopsy, and euploidy were also calculated. Additionally, we modeled the predicted probability of an embryo reaching blastulation, biopsy, and euploidy based on cleavage stage development. RESULTS: When compared with intermediate and slow cohorts, fast cleaving embryos had significantly higher rates of blastulation (82.70% vs. 75.13 vs. 42.48%), biopsy (55.04% vs. 44.00% vs. 14.98%), and euploidy (50.65% vs. 47.93% vs. 48.05%). After adjustment for covariates, there was a significant association between cleavage stage development and odds of blastulation (OR 1.38, 95% CI 1.29-1.48), biopsy (OR 1.42, 95% CI 1.34-1.51), and euploidy (OR 1.08, 95% CI 1.01-1.17). Finally, we observed significant associations between cleavage stage development and predicted probability of reaching blastulation (OR 1.29, 95% CI 1.27-1.32), biopsy (OR 1.24, 95% CI 1.22-1.26), and euploidy (OR 1.02, 95% CI 1.01-1.04). CONCLUSIONS: Cleavage stage embryos with greater mitotic activity perform as well as or better than intermediate or slower cleaving embryos. Rapidly cleaving embryos have high rates of euploidy and significant clinical potential.


Assuntos
Diagnóstico Pré-Implantação , Blastocisto , Implantação do Embrião , Feminino , Fertilização , Fertilização in vitro , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Gravidez , Taxa de Gravidez , Estudos Retrospectivos
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