RESUMO
MAIN CONCLUSION: The latex from Thevetia peruviana is rich in plant defense proteins, including a 120 kDa cysteine peptidase with structural characteristics similar to germin-like proteins. More than 20,000 plant species produce latex, including Apocynaceae, Sapotaceae, Papaveraceae and Euphorbiaceae. To better understand the physiological role played by latex fluids, a proteomic analysis of Thevetia peruviana (Pers.) Schum latex was performed using two-dimensional gel electrophoresis and mass spectrometry. A total of 33 proteins (86 %) were identified, including storage proteins, a peptidase inhibitor, cysteine peptidases, peroxidases and osmotins. An unusual cysteine peptidase, termed peruvianin-I, was purified from the latex by a single chromatographic step involving gel filtration. The enzyme (glycoprotein) was inhibited by E-64 and iodoacetamide and exhibited high specific activity towards azocasein (K m 17.6 µM), with an optimal pH and temperature of 5.0-6.0 and 25-37 °C, respectively. Gel filtration chromatography, two-dimensional gel electrophoresis, and mass spectrometry revealed that peruvianin-I possesses 120 kDa, pI 4.0, and six subunits (20 kDa). A unique N-terminal amino acid sequence was obtained to oligomer and monomers of peruvianin-I (1ADPGPLQDFCLADLNSPLFINGYPCRNPALAISDDF36). High-resolution images from atomic force microscopy showed the homohexameric structure of peruvianin-I may be organized as a trimer of dimers that form a central channel similar to germin-like proteins. Peruvianin-I exhibited no oxalate oxidase and superoxide dismutase activity or antifungal effects. Peruvianin-I represents the first germin-like protein (GLP) with cysteine peptidase activity, an activity unknown in the GLP family so far.
Assuntos
Látex/química , Proteínas de Plantas/metabolismo , Proteínas de Plantas/farmacologia , Thevetia/química , Antifúngicos/farmacologia , Caseínas/metabolismo , Cisteína Proteases/isolamento & purificação , Cisteína Proteases/metabolismo , Cisteína Proteases/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Látex/metabolismo , Espectrometria de Massas/métodos , Proteínas de Plantas/isolamento & purificação , Proteômica/métodosRESUMO
Hospital-acquired infections caused by antibiotic-resistant bacteria threaten the lives of many citizens all over the world. Discovery of new agents to hinder bacterial development would have a significant impact on the treatment of infections. Here, the purification and characterization of Rc-2S-Alb, a protein that belongs to the 2S albumin family, from Ricinus communis seed cake, are reported. Rc-2S-Alb was purified after protein extraction with Tris-HCl buffer, pH 7.5, fractionation by ammonium sulfate (50-75%), and chromatography on Phenyl-Sepharose and DEAE-Sepharose. Rc-2S-Alb, a 75 kDa peptide, displays trypsin inhibitory activity and has high in vitro antibacterial activity against Bacillus subtilis, Klebsiella pneumonia, and Pseudomonas aeruginosa, which are important human pathogenic bacteria. Atomic force microscopy studies indicated that Rc-2S-Alb disrupts the bacterial membrane with loss of the cytoplasm content and ultimately bacterial death. Therefore, Rc-2S-Alb is a powerful candidate for the development of an alternative drug that may help reduce hospital-acquired infections.
Assuntos
Albuminas 2S de Plantas/isolamento & purificação , Albuminas 2S de Plantas/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Sementes/química , Inibidores da Tripsina/isolamento & purificação , Inibidores da Tripsina/farmacologia , Albuminas 2S de Plantas/química , Antibacterianos/química , Brasil , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Proteínas de Plantas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Inibidores da Tripsina/químicaRESUMO
Although latex fluids are found in >20,000 plant species, the biochemical composition and biological function of their proteins are still poorly explored. Thus, this work aimed to conduct a proteomic analysis of Cryptostegia grandiflora latex (CgLP) for subsequent purification and characterization of an antifungal protein. After 2D-SDS-PAGE and mass spectrometry, 27 proteins were identified in CgLP, including a polygalacturonase inhibitor, cysteine peptidases, pathogenesis-related proteins (PR-4), and osmotins. Then, two osmotin isoforms (CgOsm) were purified, and a unique N-terminal sequence was determined (1ATFDIRSNCPYTVWAAAVPGGGRRLDRGQTWTINVAPGTA40). The PCR products revealed a cDNA sequence of 609 nucleotides for CgOsm, which encoded a polypeptide with 203 amino acid residues. The structure of CgOsm has features of typical osmotin or thaumatin-like proteins (TLPs), such as 16 conserved Cys residues, REDDD and FF motifs, an acidic cleft, and three main domains. Atomic force microscopy (AFM) and bioinformatics suggested that CgOsm is associated with three chain units. This result was interesting since the literature describes osmotins and TLPs as monomers. AFM also showed that Fusarium falciforme spores treated with CgOsm were drastically damaged. Therefore, it is speculated that CgOsm forms pores in the membrane of these cells, causing the leakage of cytoplasmic content.
Assuntos
Apocynaceae , Látex , Látex/química , Proteômica , Proteínas de Plantas/química , Isoformas de Proteínas/genética , Apocynaceae/químicaRESUMO
The outbreak caused by SARS-CoV-2 has taken many lives worldwide. Although vaccination has started, the development of drugs to either alleviate or abolish symptoms of COVID-19 is still necessary. Here, four synthetic peptides were assayed regarding their ability to protect Vero E6 cells from SARS-CoV-2 infection and their toxicity to human cells and zebrafish embryos. All peptides had some ability to protect cells from infection by SARS-CoV-2 with the D614G mutation. Molecular docking predicted the ability of all peptides to interact with and induce conformational alterations in the spike protein containing the D614G mutation. PepKAA was the most effective peptide, by having the highest docking score regarding the spike protein and reducing the SARS-CoV-2 plaque number by 50% (EC50) at a concentration of 0.15 mg mL-1. Additionally, all peptides had no toxicity to three lines of human cells as well as to zebrafish larvae and embryos. Thus, these peptides have potential activity against SARS-CoV-2, making them promising to develop new drugs to inhibit cell infection by SARS-CoV-2.
RESUMO
BACKGROUND: Plant lectins have shown promising biological activities in the central nervous system (CNS). OBJECTIVE: This study evaluated the effect of DAL, a lectin isolated from the seeds of the Dioclea altissima species, having binding affinity to D-glucose or D-mannose residues, on mice behavior. METHODS: Mice (n=6/group) were treated (i.p.) with DAL (0.25, 0.5 or 1 mg/kg) or vehicle and subjected to several tests (open field/OFT, marble-burying/MBT, hole-board/HBT, elevated plus maze/PMT, tail suspension/ TST, forced swimming/FST or rotarod/RRT). Pizotifen, cyproheptadine, flumazenil, L-NAME, 7-NI, Larginine or yohimbine were administered 15 min before DAL (0.5 mg/kg) and the animals were evaluated on PMT. It was also verified whether the DAL effect depended on its structural integrity and ability to interact with carbohydrates. RESULTS: The results showed there were no neurobehavioral changes in the mice at the RRT, FST and locomotion in the OFT. DAL (0.25, 0.5 or 1 mg/kg) increased the behavior of grooming and rearing in the OFT, head dips in the HBT, pedalling in the TST and decreased the number of marbles hidden in the MBT. In the PMT, DAL (0.25, 0.5 and 1 mg/kg) and Diazepam increased the frequency of entries in the open arms and the time of permanence in the open arms without affecting the locomotor activity. The effect of DAL was dependent on carbohydrate interaction and protein structure integrity and it prevented by pizotifen, cyproheptadine, flumazenil, L-NAME and 7-NI, but not by L-arginine or yohimbine. CONCLUSION: DAL was found to have an anxiolytic-like effect mediated by the 5-HT and GABAergic receptors and NO pathway.
Assuntos
Ansiolíticos , Dioclea , Animais , Ansiolíticos/farmacologia , Antidepressivos , Comportamento Animal , Lectinas , Camundongos , Extratos Vegetais , SementesRESUMO
The biocontrol activity of some soil strains of Chromobacterium sp. against pathogenic fungi has been attributed to secreted chitinases. The aim of this work was to characterize biochemically a recombinant chitinase (CvChi47) from C. violaceum ATCC 12472 and to investigate its effects on phytopathogenic fungi. CvChi47 is a modular enzyme with 450 amino acid residues, containing a type I signal peptide at the N-terminal region, followed by one catalytic domain belonging to family 18 of the glycoside hydrolases, and two type-3 chitin-binding domains at the C-terminal end. The recombinant enzyme was expressed in Escherichia coli as a His-tagged protein and purified to homogeneity. The native signal peptide of CvChi47 was used to direct its secretion into the culture medium, from where the recombinant product was purified by affinity chromatography on chitin and immobilized metal. The purified protein showed an apparent molecular mass of 46 kDa, as estimated by denaturing polyacrylamide gel electrophoresis, indicating the removal of the signal peptide. CvChi47 was a thermostable protein, retaining approximately 53.7% of its activity when heated at 100 °C for 1 h. The optimum hydrolytic activity was observed at 60 °C and pH 5. The recombinant chitinase inhibited the conidia germination of the phytopathogenic fungi Fusarium oxysporum and F. guttiforme, hence preventing mycelial growth. Furthermore, atomic force microscopy experiments revealed a pronounced morphological alteration of the cell surface of conidia incubated with CvChi47 in comparison to untreated cells. Taken together, these results show the potential of CvChi47 as a molecular tool to control plant diseases caused by these Fusarium species.
Assuntos
Antifúngicos/farmacologia , Quitinases/metabolismo , Chromobacterium/enzimologia , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/prevenção & controle , Proteínas Recombinantes/metabolismo , Sequência de Aminoácidos , Domínio Catalítico , Quitinases/química , Quitinases/genética , Clonagem Molecular , Estabilidade Enzimática , Fusarium/efeitos dos fármacos , Doenças das Plantas/microbiologia , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Homologia de Sequência , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , TemperaturaRESUMO
Mo-CBP3 is a chitin-binding 2S albumin from Moringa oleifera. This seed storage protein is resistant to thermal denaturation and shows biological activities that might be of practical use, such as antifungal properties against Candida sp., a pathogen that causes candidiasis, and against Fusarium solani, a soil fungus that can cause diseases in plants and humans. Previous work has demonstrated that Mo-CBP3 is a mixture of isoforms encoded by members of a small multigene family. Mature Mo-CBP3 is a small protein (â¼14â¯kDa), constituted by a small chain of approximately 4â¯kDa and a large chain of 8â¯kDa, which are held together by disulfide bridges. However, a more comprehensive picture on the spectrum of Mo-CBP3 isoforms which are found in mature seeds, is still lacking. In this work, genomic DNA fragments were obtained from M. oleifera leaves, cloned and completely sequenced, thus revealing new genes encoding Mo-CBP3. Moreover, mass spectrometry analysis showed that the mature protein is a complex mixture of isoforms with a remarkable number of molecular mass variants. Using computational predictions and calculations, most (â¼86%) of the experimentally determined masses were assigned to amino acid sequences deduced from DNA fragments. The results suggested that the complex mixture of Mo-CBP3 isoforms originates from proteins encoded by closely related genes, whose products undergo different combinations of distinct post-translational modifications, including cleavage at the N- and C-terminal ends of both subunits, cyclization of N-terminal Gln, as well as Pro hydroxylation, Ser/Thr phosphorylation, and Met oxidation.
Assuntos
Moringa oleifera/química , Proteínas de Plantas/metabolismo , Isoformas de Proteínas/metabolismo , Humanos , Proteínas de Plantas/química , Isoformas de Proteínas/química , Processamento de Proteína Pós-TraducionalRESUMO
Transitory allergies to cow milk proteins in infants or adults have become a public health problem. Although extensively or partially hydrolyzed cow milk protein formulas are available, these products are costly. Therefore, studies into innovative enzymes to digest cow milk proteins are needed. Danaus plexippus gut peptidases were purified and examined with regard to cow milk protein hydrolysis. The peptidases hydrolyzed caseins and whey proteins. However, after heat treatment, there was a significant improvement in ß-lactoglobulin hydrolysis. The hydrolyzed cow milk proteins were not recognized by anti-casein antibodies and only reacted slightly with antibodies against whey proteins. This performance was better than that of partially hydrolyzed formulas and similar to that of an extensively hydrolyzed formula. These results suggest that D. plexippus gut peptidases are suitable and innovative enzymes to produce hypoallergenic cow milk protein formulas.
Assuntos
Anticorpos/imunologia , Borboletas/enzimologia , Proteínas do Leite/química , Peptídeo Hidrolases/metabolismo , Adulto , Animais , Caseínas/química , Caseínas/imunologia , Bovinos , Feminino , Alimentos Formulados , Trato Gastrointestinal/enzimologia , Herbivoria , Temperatura Alta , Humanos , Hidrólise , Lactente , Lactoglobulinas/química , Proteínas do Leite/imunologia , Peptídeo Hidrolases/isolamento & purificação , Proteínas do Soro do Leite/química , Proteínas do Soro do Leite/imunologiaRESUMO
The present study was conducted to characterize the major proteome of ovarian follicular fluid from locally-adapted, "Canindé" goats in the northeast of Brazil. Eight estrous cycling goats received a hormonal treatment consisting of medroxyprogesterone acetate, D-cloprostenol and FSH. Fluid was collected by laparoscopy from small (<3mm), medium (3-4mm) and large (>4mm) follicles and then, proteins were analyzed by 2-D SDS-PAGE and tandem mass spectrometry. Thirty-six proteins were identified in the goat follicular fluid, including albumin, immunoglobulins, ceruloplasmin, complement factor B, alpha-1B-glycoprotein precursor, serotransferrin, complement C3 and serpins, among others. Albumin and immunoglobulins were the most abundant proteins. Protein concentrations were similar in the fluid from small (45.3±3.1mg/mL), medium (44.2±3.3mg/mL) and large follicles (45.1±2.3mg/mL). The intensities of spots identified in 2-D gels as serotransferrin, zinc-alpha-2-glycoprotein-like, complement factor B and complement protein C3 differed (P<0.05) among follicle categories. The amount of serotransferrin was greater in the medium than small follicles (P<0.05). Content of zinc-alpha-2-glycoprotein-like, complement factor B and complement C3 was greater (P<0.05) in the fluid of large follicles than in medium follicles. Based on gene ontology, the major molecular functions associated with goat follicular fluid proteins were binding and catalytic activity, while the main biological processes were related to regulation, cellular processing, location and the immune system. In conclusion, the major proteome of the follicular fluid from goats subjected to hormonal stimulation was elucidated in the present study. Also, molecules associated with follicle development are potential biomarkers of oocyte competence were prevalent.
Assuntos
Adaptação Fisiológica/fisiologia , Líquido Folicular/química , Cabras/fisiologia , Proteômica , Clima Tropical , Animais , Feminino , Regulação da Expressão GênicaRESUMO
Vicilins are 7S globulins which constitute the major seed storage proteins in leguminous species. Variant vicilins showing differential binding affinities for chitin have been implicated in the resistance and susceptibility of cowpea to the bruchid Callosobruchus maculatus. These proteins are members of the cupin superfamily, which includes a wide variety of enzymes and non-catalytic seed storage proteins. The cupin fold does not share similarity with any known chitin-biding domain. Therefore, it is poorly understood how these storage proteins bind to chitin. In this work, partial cDNA sequences encoding ß-vignin, the major component of cowpea vicilins, were obtained from developing seeds. Three-dimensional molecular models of ß-vignin showed the characteristic cupin fold and computational simulations revealed that each vicilin trimer contained 3 chitin-binding sites. Interaction models showed that chito-oligosaccharides bound to ß-vignin were stabilized mainly by hydrogen bonds, a common structural feature of typical carbohydrate-binding proteins. Furthermore, many of the residues involved in the chitin-binding sites of ß-vignin are conserved in other 7S globulins. These results support previous experimental evidences on the ability of vicilin-like proteins from cowpea and other leguminous species to bind in vitro to chitin as well as in vivo to chitinous structures of larval C. maculatus midgut.
Assuntos
Proteínas de Plantas/genética , Proteínas de Armazenamento de Sementes/genética , Vigna/genética , Animais , Sítios de Ligação , Quitina/química , Quitina/genética , Clonagem Molecular , Besouros/patogenicidade , DNA Complementar/genética , Resistência à Doença/genética , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Proteínas de Plantas/química , Ligação Proteica , Proteínas de Armazenamento de Sementes/química , Sementes/química , Sementes/genética , Vigna/crescimento & desenvolvimentoRESUMO
This study aimed to define sperm membrane protein markers of semen freezability of boars with the aid of a proteomic approach. Semen from fourteen adult boars were subjected to slow freezing and rapid thawing. After thawing, sperm vigor and motility were analyzed, and based on these results, animals were separated into two groups: good (GFEs) and poor freezability (PFEs). Sperm membrane proteins were extracted and subjected to two-dimensional electrophoresis. Stained gels were analyzed by computerized resources to indicate differentially expressed protein spots, that were identified by mass spectrometry. Six animals showed good freezability with average sperm vigor and motility of 2.2±0.8 and 41.8±22.9, respectively, whereas eight boars showed poor freezability, with 1.9±0.6 and 26.8±17.5 of sperm vigor sperm motility, respectively. An average of 263±62.2 spots per gel and 234.2±54.6 of spots consistently present in all gels were detected. The intensities of five spots were significantly different between groups. Fc fragment of IgG binding protein and lactadherin were more intense in the PFE group, while Arylsulfatase A and F-actin capping protein subunit alpha 1 were more expressed in the GEF group. Based on their functions and interactions with other proteins, we conclude that these four sperm membrane proteins may act as potential markers of boar semen freezability.
Assuntos
Criopreservação/veterinária , Proteínas de Membrana/metabolismo , Preservação do Sêmen/veterinária , Espermatozoides/fisiologia , Suínos/fisiologia , Animais , Masculino , Proteínas de Membrana/genéticaRESUMO
An antifungal class III peroxidase was purified from Marsdenia megalantha latex (named Mo-POX) using DEAE-cellulose and gel filtration chromatography on a Superose 12 HR 10/30 column. Mm-POX has an apparent molecular mass of 67.0kDa and a pI of 5.2, shares identity with other peroxidases, and follows Michaelis-Menten kinetics. It has a high affinity for guaiacol and hydrogen peroxide. The pH and temperature optima for Mm-POX were 5.0-7.0 and 60°C, respectively. The catalytic activity of Mm-POX was decreased in the presence of classic peroxidase inhibitors including azide, dithiothreitol, ethylenediamine tetraacetic acid, and sodium metabisulfite and high concentrations of Na+, Mn+, and salicylic acid. In contrast, Ca+ and Mg+, even at low concentrations, enhanced the Mm-POX enzymatic activity. This protein inhibited the germination of the conidia of the phytopathogenic fungi Fusarium oxysporum and Fusarium solani by acting through a membrane permeabilization mechanism. Mm-POX also induced oxidative stress in F. solani. Mm-POX is the first enzyme to be isolated from the M. megalantha species and it has potential use in the control of plant disease caused by important phytopathogenic fungi. This adds biotechnological value to this enzyme.
Assuntos
Permeabilidade da Membrana Celular/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Látex/química , Marsdenia/química , Peroxidase/isolamento & purificação , Peroxidase/farmacologia , Plantas/microbiologia , Sequência de Aminoácidos , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Fusarium/citologia , Fusarium/metabolismo , Fusarium/fisiologia , Concentração de Íons de Hidrogênio , Cinética , Metais/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Peso Molecular , Peroxidase/antagonistas & inibidores , Peroxidase/química , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Especificidade por Substrato , TemperaturaRESUMO
A cowpea class I chitinase (VuChiI) was expressed in the methylotrophic yeast P. pastoris. The recombinant protein was secreted into the culture medium and purified by affinity chromatography on a chitin matrix. The purified chitinase migrated on SDS-polyacrylamide gel electrophoresis as two closely-related bands with apparent molecular masses of 34 and 37 kDa. The identity of these bands as VuChiI was demonstrated by mass spectrometry analysis of tryptic peptides and N-terminal amino acid sequencing. The recombinant chitinase was able to hydrolyze colloidal chitin but did not exhibit enzymatic activity toward synthetic substrates. The highest hydrolytic activity of the cowpea chitinase toward colloidal chitin was observed at pH 5.0. Furthermore, most VuChiI activity (approximately 92%) was retained after heating to 50 °C for 30 min, whereas treatment with 5 mM Cu2+ caused a reduction of 67% in the enzyme's chitinolytic activity. The recombinant protein had antifungal activity as revealed by its ability to inhibit the spore germination and mycelial growth of Penicillium herquei. The three-dimensional structure of VuChiI was resolved at a resolution of 1.55 Å by molecular replacement. The refined model had 245 amino acid residues and 381 water molecules, and the final R-factor and Rfree values were 14.78 and 17.22%, respectively. The catalytic domain of VuChiI adopts an α-helix-rich fold, stabilized by 3 disulfide bridges and possessing a wide catalytic cleft. Analysis of the crystallographic model and molecular docking calculations using chito-oligosaccharides provided evidences about the VuChiI residues involved in sugar binding and catalysis, and a possible mechanism of antifungal action is suggested.
Assuntos
Antifúngicos/metabolismo , Quitinases/metabolismo , Pichia/enzimologia , Proteínas de Plantas/metabolismo , Vigna/enzimologia , Antifúngicos/química , Antifúngicos/farmacologia , Quitinases/química , Quitinases/farmacologia , Hidrólise , Penicillium/efeitos dos fármacos , Proteínas de Plantas/química , Proteínas de Plantas/farmacologia , Ligação ProteicaRESUMO
The mechanisms involved in the mitogenic effect of lectins are not fully understood and are thought to involve a cascade of intracellular signals related to T cell receptor activation. This study shows that frutalin, the alpha-D-galactose-binding lectin from Artocarpus incisa seeds, is a potent mitogenic activator of human lymphocytes. This effect is inhibited by D-galactose and PI3K inhibitors, and is accompanied by an increase in IL-2 receptor expression and by a PI3K-dependent IL-2 gene expression and IL-2 protein synthesis. Frutalin also induces Akt-phosphorylation and activates NF-kappaB, inducing its translocation from the cytosol to the nucleus. Both effects are blocked in the presence of D-galactose or by PI3K inhibitors. In summary, frutalin, interacting with alpha-D-galactose, activates signaling pathways related to TCR, and thereby triggers PI3K/Akt and NF-kappaB pathway, which modulates T cell proliferation, IL-2 synthesis and IL-2R expression. Frutalin might be a useful tool to study intracellular mechanisms following T cell activation that link upstream signaling pathways to downstream events.
Assuntos
Linfócitos/efeitos dos fármacos , NF-kappa B/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Lectinas de Plantas/farmacologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Transdução de Sinais/imunologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Artocarpus , Humanos , Interleucina-2/biossíntese , Interleucina-2/genética , Linfócitos/enzimologia , Mitógenos/farmacologia , Receptores de Interleucina-2/biossíntese , Receptores de Interleucina-2/genética , Sementes , Transdução de Sinais/efeitos dos fármacosRESUMO
Latex fractions from Calotropis procera, Cryptostegia grandiflora, Plumeria rubra, and Himatanthus drasticus were assayed in order to prospect for new plant peptidases with milk-clotting activities, for use as rennet alternatives. Only C. procera and C. grandiflora latex fractions exhibited proteolytic and milk-clotting activities, which were not affected by high concentrations of NaCl and CaCl2. However, pre-incubation of both samples at 75°C for 10min eliminated completely their activities. Both proteolytic fractions were able to hydrolyze k-casein and to produce peptides of 16kDa, a similar SDS-PAGE profile to commercial chymosin. RP-HPLC and mass spectrometry analyses of the k-casein peptides showed that the peptidases from C. procera or C. grandiflora hydrolyzed k-casein similar to commercial chymosin. The cheeses made with both latex peptidases exhibited yields, dry masses, and soluble proteins similar to cheeses prepared with commercial chymosin. In conclusion, C. procera and C. grandiflora latex peptidases with the ability to coagulate milk can be used as alternatives to commercial animal chymosin in the cheese manufacturing process.
RESUMO
Parotoid glands of amphibians are known for the production of several biologically active compounds having pharmacological and toxic effects in mammals. In the present work, a protein fraction obtained from Rhinella schneideri parotoid gland (RsPP) was characterized to study its biological and toxic effects. Rhinella schneideri parotoid secretion is composed of up to 30% (w/w) of soluble proteins. Tandem mass spectrometric analysis of the RsPP identified 104 proteins, including actin, beta-actin, ribosomal proteins, catalase, galectin, and uncharacterized proteins; however, no peptidases were found, and this result was reinforced by the absence of proteolytic activity. In addition, RsPP did not exhibit pro-coagulant or antibacterial effects. However, pretreatment of mice with different doses of RsPP intraperitoneally inhibited carrageenan-induced paw edema and increased tissue myeloperoxidase activity. RsPP also reduced interleukin 1ß levels in the peritoneal cavities and cell migration in the peritoneal cavities of an animal model of carrageenan-induced peritonitis. Subchronic treatment of animals with RsPP for 7 consecutive days did not alter the serum biochemical, renal, or liver parameters. However, a significant reduction in blood leukocyte count was observed. Our results showed that R. schneideri parotoid secretion contains proteins with anti-inflammatory and slight toxic effects.
Assuntos
Proteínas de Anfíbios/farmacologia , Venenos de Anfíbios/farmacologia , Anti-Inflamatórios/farmacologia , Edema/tratamento farmacológico , Peritonite/tratamento farmacológico , Proteínas de Anfíbios/análise , Proteínas de Anfíbios/toxicidade , Venenos de Anfíbios/química , Venenos de Anfíbios/toxicidade , Animais , Bufonidae/metabolismo , Edema/metabolismo , Extremidades , Feminino , Contagem de Leucócitos , Masculino , Camundongos , Peroxidase/efeitos dos fármacos , Espectrometria de Massas em TandemRESUMO
Proteins that share similar primary sequences to the protein originally described in salt-stressed tobacco cells have been named osmotins. So far, only two osmotin-like proteins were purified and characterized of latex fluids. Osmotin from Carica papaya latex is an inducible protein lacking antifungal activity, whereas the Calotropis procera latex osmotin is a constitutive antifungal protein. To get additional insights into this subject, we investigated osmotins in latex fluids of five species. Two potential osmotin-like proteins in Cryptostegia grandiflora and Plumeria rubra latex were detected by immunological cross-reactivity with polyclonal antibodies produced against the C. procera latex osmotin (CpOsm) by ELISA, Dot Blot and Western Blot assays. Osmotin-like proteins were not detected in the latex of Thevetia peruviana, Himatanthus drasticus and healthy Carica papaya fruits. Later, the two new osmotin-like proteins were purified through immunoaffinity chromatography with anti-CpOsm immobilized antibodies. Worth noting the chromatographic efficiency allowed for the purification of the osmotin-like protein belonging to H. drasticus latex, which was not detectable by immunoassays. The identification of the purified proteins was confirmed after MS/MS analyses of their tryptic digests. It is concluded that the constitutive osmotin-like proteins reported here share structural similarities to CpOsm. However, unlike CpOsm, they did not exhibit antifungal activity against Fusarium solani and Colletotrichum gloeosporioides. These results suggest that osmotins of different latex sources may be involved in distinct physiological or defensive events.
Assuntos
Antifúngicos/farmacologia , Látex/química , Proteínas de Plantas/farmacologia , Sequência de Aminoácidos , Antifúngicos/química , Cromatografia de Afinidade/métodos , Dados de Sequência Molecular , Proteínas de Plantas/química , Homologia de Sequência de AminoácidosRESUMO
CpOsm is an antifungal osmotin/thaumatin-like protein purified from the latex of Calotropis procera. The protein is relatively thermostable and retains its antifungal activity over a wide pH range; therefore, it may be useful in the development of new antifungal drugs or transgenic crops with enhanced resistance to phytopathogenic fungi. To gain further insight into the mechanism of action of CpOsm, its three-dimensional structure was determined, and the effects of the protein on Fusarium solani spores were investigated by atomic force microscopy (AFM). The atomic structure of CpOsm was solved at a resolution of 1.61Å, and it contained 205 amino acid residues and 192 water molecules, with a final R-factor of 18.12% and an Rfree of 21.59%. The CpOsm structure belongs to the thaumatin superfamily fold and is characterized by three domains stabilized by eight disulfide bonds and a prominent charged cleft, which runs the length of the front side of the molecule. Similarly to other antifungal thaumatin-like proteins, the cleft of CpOsm is predominantly acidic. AFM images of F. solani spores treated with CpOsm resulted in striking morphological changes being induced by the protein. Spores treated with CpOsm were wrinkled, and the volume of these cells was reduced by approximately 80%. Treated cells were covered by a shell of CpOsm molecules, and the leakage of cytoplasmic content from these cells was also observed. Based on the structural features of CpOsm and the effects that the protein produces on F. solani spores, a possible mechanism of action is suggested and discussed.
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Calotropis/química , Fusarium/efeitos dos fármacos , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Esporos Fúngicos/efeitos dos fármacos , Algoritmos , Sequência de Aminoácidos , Antifúngicos/química , Sequência de Bases , Látex/química , Microscopia de Força Atômica , Dados de Sequência Molecular , Proteínas de Plantas/farmacologia , Tetra-Hidrofolato DesidrogenaseRESUMO
Gummosis is an aggressive disease caused by the necrotrophic fungus Lasiodiplodia theobromae (Pat.) Griffon & Maubl that threatens commercial cashew orchads in Brazil. To study the molecular mechanisms involved in the cashew response to L. theobromae, a proteomic analysis of stems from the commercial cashew clone BRS 226 (resistant) was conducted at early times post-artificial infection. In addition, changes in the stem proteome profiles of gummosis resistant and susceptible cashew plants grown under field condition and naturally exposed to pathogen were also compared. After two-dimensional gel electrophoresis (2D-PAGE), 73 proteins showed statistically significant differences in spot abundance. Of these, 31 spots were identified in BRS 226 stems compared with mock-inoculated controls and 32 in stems collected from field-grown resistant and susceptible cashew plants. L. theobromae-responsive proteins were mainly involved in energy metabolism pathways, stress and defense, cell signaling and protein metabolism indicating modulation of various cellular functions upon fungal infection. As stress-inducing factors seem to be important for susceptibility to disease, the change in the abundance relative these proteins may possibly indicate an attempt to maintain cellular homeostasis, as resistance determinant factor, related with a possible role in the regulation of oxidative burst. These findings provide the first information about the cellular mechanisms acting in the Anacardium occidentale genotypes associated with the pathophysiological state of infection with L. theobromae. BIOLOGICAL SIGNIFICANCE: Gummosis caused by Lasiodiplodia theobromae, a necrotrophic fungus, is the major disease of cashew plants in the semi-arid conditions of northeastern Brazil. Although various studies were carried out on this pathosystem, there is no information available on the molecular mechanisms of plant defense related to the incompatible interaction of cashew with L. theobromae. Therefore, this original study comprises a differential proteomic analysis of cashew stems from: (i) resistant dwarf clone BRS 226 mock-inoculated (control) and artificially inoculated with L. theobromae; and (ii) cashew plants bearing resistant and susceptible traits to gummosis, originated from open pollination of BRS 226 in a commercial orchard with high disease incidence. The contribution of the reprogrammed proteins to molecular events triggered in cashew plants challenged by L. theobromae has a great relevance in the identification of the host candidate proteins linked to biological pathways that respond to L. theobromae infection. Furthermore this study may contribute to improve breeding programs aimed at selecting resistant/tolerant cashew clones toward this pathogen.
Assuntos
Anacardium/metabolismo , Ascomicetos , Resistência à Doença/fisiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/biossíntese , Proteômica , Anacardium/microbiologiaRESUMO
Mo-CBP3 is a chitin-binding protein from M. oleifera seeds that inhibits the germination and mycelial growth of phytopathogenic fungi. This protein is highly thermostable and resistant to pH changes, and therefore may be useful in the development of new antifungal drugs. However, the relationship of MoCBP3 with the known families of carbohydrate-binding domains has not been established. In the present study, full-length cDNAs encoding 4 isoforms of Mo-CBP3 (Mo-CBP3-1, Mo-CBP3-2, Mo-CBP3-3 and Mo-CBP3-4) were cloned from developing seeds. The polypeptides encoded by the Mo-CBP3 cDNAs were predicted to contain 160 (Mo-CBP3-3) and 163 amino acid residues (Mo-CBP3-1, Mo-CBP3-2 and Mo-CBP3-4) with a signal peptide of 20-residues at the N-terminal region. A comparative analysis of the deduced amino acid sequences revealed that Mo-CBP3 is a typical member of the 2S albumin family, as shown by the presence of an eight-cysteine motif, which is a characteristic feature of the prolamin superfamily. Furthermore, mass spectrometry analysis demonstrated that Mo-CBP3 is a mixture of isoforms that correspond to different mRNA products. The identification of Mo-CBP3 as a genuine member of the 2S albumin family reinforces the hypothesis that these seed storage proteins are involved in plant defense. Moreover, the chitin-binding ability of Mo-CBP3 reveals a novel functionality for a typical 2S albumin.