Structural Prediction and Characterization of Canavalia grandiflora (ConGF) Lectin Complexed with MMP1: Unveiling the Antiglioma Potential of Legume Lectins.

A glioblastoma (GBM) is a highly malignant primary brain tumor with a poor prognosis because of its invasiveness and high resistance to current therapies. In GBMs, abnormal glycosylation patterns are associated with malignancy, which allows for the use of lectins as tools for recognition and therapy. More specifically, lectins can interact with glycan structures found on the malignant cell surface. In this context, the present work aimed to investigate the antiglioma potential of ConGF, a lectin purified from Canavalia grandiflora seeds, against C6 cells. The treatment of C6 cells with ConGF impaired the mitochondrial transmembrane potential, reduced cell viability, and induced morphological changes. ConGF also induced massive autophagy, as evaluated by acridine orange (AO) staining and LC3AB-II expression, but without prominent propidium iodide (PI) labeling. The mechanism of action appears to involve the carbohydrate-binding capacity of ConGF, and in silico studies suggested that the lectin can interact with the glycan structures of matrix metalloproteinase 1 (MMP1), a prominent protein found in malignant cells, likely explaining the observed effects.

Canavalia ensiformis lectin induced oxidative stress mediate both toxicity and genotoxicity in Drosophila melanogaster.

Mannose/glucose-binding lectin from Canavalia ensiformis seeds (Concanavalin A - ConA) has several biological applications, such as mitogenic and antitumor activity. However, most of the mechanisms involved in the in vivo toxicity of ConA are not well known. In this study, the Drosophila melanogaster model was used to assess the toxicity and genotoxicity of different concentrations of native ConA (4.4, 17.5 and 70 µg/mL) in inhibited and denatured forms of ConA. The data show that native ConA affected: the survival, in the order of 30.6 %, and the locomotor performance of the flies; reduced cell viability to levels below 50 % (4.4 and 17.5 µg/mL); reduced nitric oxide levels; caused lipid peroxidation and increased protein and non-protein thiol content. In the Comet assay, native ConA (17.5 e 70 µg/mL) caused DNA damage higher than 50 %. In contrast, treatments with inhibited and denatured ConA did not affect oxidative stress markers and did not cause DNA damage. We believe that protein-carbohydrate interactions between ConA and carbohydrates of the plasma membrane are probably the major events involved in these activities, suggesting that native ConA activates mechanisms that induce oxidative stress and consequently DNA damage.

Anti-inflammatory and anti-necrotic effects of lectins from Canavalia ensiformis and Canavalia brasiliensis in experimental acute pancreatitis.

Lectins isolated from Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) are promising molecules to prevent cell death. Acute pancreatitis, characterized by acinar cell necrosis and inflammation, presents significant morbidity and mortality. This study has investigated the effects of ConA and ConBr in experimental acute pancreatitis and pancreatic acinar cell death induced by bile acid. Pancreatitis was induced by retrograde pancreatic ductal injection of 3% sodium taurocholate (Na-TC) in male Swiss mice. ConA or ConBr (0.1, 1 or 10 mg/kg) were intravenously applied to mice 1 h and 12 h after induction. After 24 h, the severity of pancreatitis was evaluated by serum amylase and lipase, histopathological changes and myeloperoxidase assay. Pancreatic acinar cells were incubated with ConA (200 µg/ml) or ConBr (200 µg/ml) and taurolithocholic acid 3-sulfate (TLCS; 500 µM). Necrosis and changes in mitochondrial membrane potential (ΔÑ°m) were detected by fluorescence confocal microscopy. Treatment (post-insult) with ConA and ConBr decreased pancreatic damage caused by retrograde injection of Na-TC in mice, reducing pancreatic neutrophil infiltration, edema and necrosis. In addition, ConA and ConBr decreased pancreatic acinar cell necrosis and depolarization of ΔÑ°m caused by TLCS. The inhibition of necrosis was prevented by the lectin domain blockade. In conclusion, ConA and ConBr markedly inhibited in vitro and in vivo damage, effects partly dependent on the interaction with mannose residues on acinar cells. These data support the potential application of these proteins for treatment of acute pancreatitis.

Thermal Stability of Anisoyl Kaempferol Glycosides in Jack Bean (Canavalia ensiformis (L.) DC) and Their Effect on α-Glucosidase Inhibition.

Kaempferol glycosides are functional components of jack bean. The chemical stability of kaempferol glycosides under simulated food processing conditions was evaluated in this study by subjecting the methanol extract and each compound to heat treatment. During the heat treatment, rearrangement of the anisoyl group on the rhamnose moiety of the kaempferol glycoside was observed, followed by hydrolysis upon long-term heat treatment. One of the two regioisomers produced under heating conditions showed higher α-glucosidase inhibitory activity than the dominant anisoyl kaempferol glycoside. This rearrangement reaction was also observed upon the heat treatment of methyl-3-O-anisoyl-rhamnose, with the rearrangement from the 3-position to the 2-position occurring preferentially. The approach adopted in this study can be used to design appropriate food processing conditions, which, in turn, will increase the functional value of foods.

Protein Modification at Tyrosine with Iminoxyl Radicals.

Post-translational modifications (PTMs) of proteins are a biological mechanism for reversibly controlling protein function. Synthetic protein modifications (SPMs) at specific canonical amino acids can mimic PTMs. However, reversible SPMs at hydrophobic amino acid residues in proteins are especially limited. Here, we report a tyrosine (Tyr)-selective SPM utilizing persistent iminoxyl radicals, which are readily generated from sterically hindered oximes via single-electron oxidation. The reactivity of iminoxyl radicals with Tyr was dependent on the steric and electronic demands of oximes; isopropyl methyl piperidinium oxime 1f formed stable adducts, whereas the reaction of tert-butyl methyl piperidinium oxime 1o was reversible. The difference in reversibility between 1f and 1o, differentiated only by one methyl group, is due to the stability of iminoxyl radicals, which is partly dictated by the bond dissociation energy of oxime O-H groups. The Tyr-selective modifications with 1f and 1o proceeded under physiologically relevant, mild conditions. Specifically, the stable Tyr-modification with 1f introduced functional small molecules, including an azobenzene photoswitch, to proteins. Moreover, masking critical Tyr residues by SPM with 1o, and subsequent deconjugation triggered by the treatment with a thiol, enabled on-demand control of protein functions. We applied this reversible Tyr modification with 1o to alter an enzymatic activity and the binding affinity of a monoclonal antibody with an antigen upon modification/deconjugation. The on-demand ON/OFF switch of protein functions through Tyr-selective and reversible covalent-bond formation will provide unique opportunities in biological research and therapeutics.

Neurotoxic and convulsant effects induced by jack bean ureases on the mammalian nervous system.

Ureases are microbial virulence factors either because of the enzymatic release of ammonia or due to many other non-enzymatic effects. Here we studied two neurotoxic urease isoforms, Canatoxin (CNTX) and Jack Bean Urease (JBU), produced by the plant Canavalia ensiformis, whose mechanisms of action remain elusive. The neurotoxins provoke convulsions in rodents (LD50 ∼2 mg/kg) and stimulate exocytosis in cell models, affecting intracellular calcium levels. Here, electrophysiological and brain imaging techniques were applied to elucidate their mode of action. While systemic administration of the toxins causes tonic-clonic seizures in rodents, JBU injected into rat hippocampus induced spike-wave discharges similar to absence-like seizures. JBU reduced the amplitude of compound action potential from mouse sciatic nerve in a tetrodotoxin-insensitive manner. Hippocampal slices from CNTX-injected animals or slices treated in vitro with JBU failed to induce long term potentiation upon tetanic stimulation. Rat cortical synaptosomes treated with JBU released L-glutamate. JBU increased the intracellular calcium levels and spontaneous firing rate in rat hippocampus neurons. MicroPET scans of CNTX-injected rats revealed increased [18]Fluoro-deoxyglucose uptake in epileptogenesis-related areas like hippocampus and thalamus. Curiously, CNTX did not affect voltage-gated sodium, calcium or potassium channels currents, neither did it interfere on cholinergic receptors, suggesting an indirect mode of action that could be related to the ureases' membrane-disturbing properties. Understanding the neurotoxic mode of action of C. ensiformis ureases could help to unveil the so far underappreciated relevance of these toxins in diseases caused by urease-producing microorganisms, in which the human central nervous system is affected.

Anti-Inflammatory Effect of Immature Sword Bean Pod (Canavalia gladiata) in Lipopolysaccharide-Induced RAW264.7 Cells.

Sword bean has been known as a traditional medicinal plant to treat cancer, sinus infection, and suppurative disease. It also possesses hypertension-relieving, antioxidation, and antibacterial effects. However, studies on the efficacy of sword bean are limited to mature beans. Few studies have focused on immature sword bean pod (ISBP). Therefore, this study aimed to investigate the anti-inflammatory effect of ISBP in RAW264.7 cells stimulated with lipopolysaccharide (LPS). After LPS-induced RAW264.7 cells were treated with ISBP at concentrations (0.5, 1, 2, and 5 mg/mL), levels of nitrite oxide (NO) and prostaglandin E2 (PGE2) production, protein, and mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), inflammatory cytokine secretion level, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity were determined. Under inflammatory conditions induced by LPS, ISBP reduced levels of inflammatory mediators NO and PGE2 by 60% and 23%, respectively. It also decreased protein and mRNA expression levels of iNOS and COX-2 known to synthesize inflammatory mediators. Inflammatory cytokines, interleukin (IL)-6, and IL-1ß, levels were decreased, while interferon gamma level was increased by ISBP based on enzyme-linked immunosorbent assay (ELISA) and real time-polymerase chain reaction results. Finally, ISBP showed the ability to inhibit NF-κB activity. In conclusion, ISBP can alleviate inflammation by controlling inflammation-related substances, and may have efficacy as a healthful functional food and natural anti-inflammatory drug.

Preliminary study of the production of metabolites from in vitro cultures of C. ensiformis.

BACKGROUND: Canavalia ensiformis is a legume native to Central and South America that has historically been a source of protein. Its main proteins, urease, and lectin have been extensively studied and are examples of bioactive compounds. In this work, the effect of pH and light effects on the growth of C. ensiformis were analyzed. Also, the bioactive compounds such as phenols, carotenoids, chlorophyll a/b, and the growth of callus biomass of C. ensiformis from the effect of different types of light treatments (red, blue and mixture) were evaluated. Likewise, the antioxidative activity of C. ensiformis extracts were studied and related to the production of bioactive compounds. For this, a culture of calluses obtained from seeds were carried out. For the light experiments, polypropylene boxes with red, blue, combination (1/3, 3/1 and 1/1 R-B, respectively) lights and white LED were used as control. In each treatment, three glass containers with 25 ml of MS salts containing 0.25 g of fresh callus were seeded. RESULTS: The results have shown that the pH of the culture medium notably affects the increase in callogenic biomass. It shows that the pH of 5.5 shows better results in the callogenic growth of C. ensiformis with an average increase of 1.3051 g (198.04%), regarding the initial weight. It was found that the pH 5.5 and the 1/3 R-B LED combination had higher production of bioactive compounds and better antioxidant activity. At the same time, the red-light treatment was least effective. CONCLUSIONS: It was possible to find the ideal conditions of important growth under conditions of pH and light of C. ensiformis. Likewise, it is evaluated whether the production of compounds of interest, such as phenolic compounds and carotenoids, occurs under these conditions. The highest production of calluses occurs in the 1/3 R-B LED combined light treatment, which showed a significant increase in biomass, followed by B. From this study, it could be demonstrated that C. ensiformis produces compounds such as phenols and carotenoids in vitro culture that are essential for the antioxidant activity of the plant.

Roasting and Cryogenic Grinding Enhance the Antioxidant Property of Sword Beans (Canavalia gladiata).

The objective of this study was to optimize the conditions for enhancing the antioxidant properties of sword bean (Canavalia gladiata) as a coffee substitute in two processing methods, roasting and grinding. The optimum conditions for removing off-flavor of the bean and maximizing functionality and efficiency were light roasting and cryogenic grinding (< 53 µm). In these conditions, extraction yield was 16.75%, total phenolic content (TPC) was 69.82 ± 0.35 mg gallic acid equivalents/g, and total flavonoid content (TFC) was 168.81 ± 1.64 mg quercetin equivalents/100 g. The antioxidant properties were 77.58 ± 0.27% for DPPH radical scavenging activity and 58.02 ± 0.76 mg Trolox equivalents/g for ABTS radical scavenging activity. The values for TFC and ABTS radical scavenging activity were significantly higher (p < 0.05) than in other conditions, and TPC and DPPH radical scavenging activity were second highest in lightly roasted beans, following raw beans. HS-SPME/GCMS analysis confirmed that the amino acids and carbohydrates, which are the main components of sword bean, were condensed into other volatile flavor compounds, such as derivatives of furan, pyrazine, and pyrrole during roasting. Roasted and cryogenically ground (cryo-ground) sword beans showed higher functionality in terms of TFC, DPPH, and ABTS radical scavenging activities compared to those of coffee. Overall results showed that light roasting and cryogenic grinding are the most suitable processing conditions for enhancing the bioactivity of sword beans.

Identification and Characterization of a-Glucosidase Inhibition Flavonol Glycosides from Jack Bean (Canavalia ensiformis (L.) DC.

Although the intake of jack bean (Canavalia ensiformis (L.) DC.), an underutilized tropical legume, can potentially decrease the risk of several chronic diseases, not much effort has been directed at profiling the polyphenolics contained therein. Hence, this work aimed to identify and quantify the dominant jack bean polyphenolics, which are believed to have antioxidant and other bioactivities. Four major compounds were detected and identified as kaempferol glycosides with three or four glycoside units. Their structures were established based on UV-visible, 1d, 2D NMR, and HR-ESI-MS analyses. Specifically, kaempferol 3-O-a-l-rhamnopyranosyl (1®6)- b-d-glucopyranosyl (1®2)-b-d-galactopyranosyl-7-O-[3-O-o-anisoyl]-a-l-rhamnopyranoside was detected for the first time, while the other three compounds have already been described in plants other than jack bean. This new compound was found to have a higher a-glucosidase inhibition activity compared to acarbose.

Surface-imprinted silica particles for Concanavalin A purification from Canavalia ensiformis.

Concanavalin A is a representative of the plant protein group known as lectins. Many lectin proteins have useful characteristics for studies on cell division and cell surfaces. In this study, a new adsorbent for the specific separation of Concanavalin A was prepared by applying a silica particle surface imprinting method. First, silica particles were activated via acidic treatment, and then, 3-methacryloyloxypropyl trimethoxysilane (MPTMS) was used for modification. For the preparation of Concanavalin A surface-imprinted silica particles (Con A-MISPs), N-methacryloyl-l-histidine methyl ester (MAH) was used as a functional monomer. The silica particles were characterized using a Zetasizer, scanning electron microscopy equipment (SEM), and Fourier transform infrared spectroscopy (FTIR). The effects of parameters such as the pH, initial concentration of Concanavalin A, and temperature on the adsorption of Concanavalin A were determined. The maximum Concanavalin A adsorption onto Con A-MISPs was observed to be 305.2 mg/g at a pH of 6. The reusability of the Con A-MISPs was approximately 93.5%. The non-imprinted silica particles (NISPs) were prepared in the same manner without Concanavalin A to compare the surface imprinting factor. Selective binding studies were carried out with lysozyme and hemoglobin molecules. The selectivity of the Con A-MISPs was also investigated by isolating Concanavalin A from Canavalia ensiformis. The purity of the Concanavalin A was shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE).

Thermal inactivation of jack bean urease.

Thermal inactivation of oligomeric enzymes results in complex structural changes. This work deals with thermal inactivation of a native hexamer, jack bean urease. In order to find the mechanism and kinetics of thermal inactivation corresponding well with the modification of tertiary and quaternary structure of this enzyme, several types of experiments were carried out in the temperature range of 65-85 °C. Inactivation data exhibited the characteristic biphasic character. Dynamic light scattering experiments revealed a significant increase of the mean hydrodynamic radius of urease with temperature and time. A significant contribution to understanding the mechanism of inactivation was provided by native gel electrophoresis data of inactivated samples. Simultaneous fit of inactivation data verified a two-step mechanism composed of reversible unfolding/folding reaction followed by a relatively fast aggregation of the denatured urease form. A complex reaction scheme containing numerous oligomeric forms was thus described by a relatively simple model which suitably represents the main types of reactions involved in the urease activity loss.

Anti-Inflammatory Effects of Canavalia gladiata in Macrophage Cells and DSS-Induced Colitis Mouse Model.

Canavalia gladiata, known as sword bean, has been used as a Chinese traditional medicine for anti-inflammatory effects. However, the action mechanisms of sword bean have not yet been clearly defined. In the present study, the whole parts of a ripened sword bean (RSB) and the green sword bean (GSB) containing bean pod were extracted with ethanol by reflux extraction. The two crude extracts (RSBE and GSBE) from RSB and GSB were validated by a liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis of gallic acid as a reference chemical. The anti-inflammatory effects of two sword bean extracts were extensively investigated using LPS-stimulated macrophage cells. First, RSBE and GSBE significantly inhibited the production of pro-inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandinE2 (PGE2), and nitric oxide (NO) in LPS-induced RAW264.7 cells. RSBE and GSBE showed no cytotoxicity to RAW264.7 cells and mouse peritoneal macrophage cells. In addition, the overexpression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) induced by LPS in RAW264.7 cells was significantly decreased by RSBE and GSBE. Western blotting and immunostaining analysis showed that RSBE and GSBE inhibited the nuclear translocation of NF-κB subunits, which correlated with the inhibitory effects on inhibitor kappa B (IκB) degradation. In dextran sulfated sodium (DSS)-induced colitis mice model, RSBE restored body weight, colon length, and the levels of pro-inflammatory cytokines, such as TNF-α, IL-6, interleukin-1ß (IL-1ß), and interferon-γ (IFN-γ). In addition, RSBE significantly suppressed the expression of COX-2, iNOS, and NF-κB.

Extraction and separation of acetanilide herbicides in beans based on metal-organic framework MIL-101 (Zn) as sorbent.

An extraction method based on metal-organic framework has been developed and applied to acetanilide herbicides, including metazachlor, propanil, pretilachlor, and butachlor, in black beans, red beans, and kidney beans. The acetanilide herbicides are extracted with a mixture of ethyl acetate and n-hexane. The extract solution is absorbed and purified with metal-organic framework MIL-101 (Zn). The separation and determination of four acetanilide herbicides were implemented by high-performance liquid chromatography. The experimental parameters were evaluated by a univariate method and orthogonal experiments. The presented method can obtain effective extraction and purification. The detection limits for metazachlor, propanil, pretilachlor, and butachlor were 0.58, 0.90, 1.78 and 1.18 µg/kg, respectively. The average recoveries of the acetanilide herbicides at spiked concentrations of 10, 50, and 100 µg/kg ranged from 86.9% to 119.0%, and relative standard deviations were equal to or lower than 2.80%.

Development of urea biosensor using non-covalent complexes of urease with aldehyde derivative of PEG and analysis on serum samples.

Non-covalent complexes of urease/polyethylene glycol (PEG)-aldehyde were synthesized using regular molar ratios of urease and PEG-aldehyde at room temperature. The physical properties of the non-covalent complexes were analyzed in order to investigate the impact of coupling ratio, temperature, pH, storage stability, and thermal stability. Urease activity was analyzed by UV-Vis spectrophotometer at 630 nm. The results showed that the strongest thermal resistance was obtained using nU/nPEG:1/1 (mg/mL) complex within all molar ratios tested. The enzymatic activity of nU/nPEG:1/1 complex doubled the activity of the free enzyme. Therefore, this complex was chosen to be used in the analyses. When coupled with PEG-aldehyde, urease exhibited improved activity between pH 4.0-9.0 and the optimum pH was found to be 7.0. The thermal inactivation results of the complex demonstrated that higher activity remained (40%) when compared with the free enzyme (10%) at 60 °C. The storage stability of the non-covalent complex was 4 weeks which was greater than the storage stability of the free enzyme. A kinetic model was suggested in order to reveal the mechanism of enzymatic conversion. Potentiometric urea biosensor was prepared using two different membranes: carboxylated poly vinyl chloride (PVC) and palmitic acid containing PVC. The potentiometric responses of both sensors were tested against pH and temperature and the best results were obtained at pH 7.0 and 20-30 °C. Also, selectivity of the suggested biosensors toward Na+, Li+ Ca2+, and K+ ions was evaluated and the reproducibility responses of the urea biosensors were measured with acceptable results.

Long-wavelength Mesh&Collect native SAD phasing from microcrystals.

Harnessing the anomalous signal from macromolecular crystals with volumes of less than 10 000 µm3 for native phasing requires careful experimental planning. The type of anomalous scatterers that are naturally present in the sample, such as sulfur, phosphorus and calcium, will dictate the beam energy required and determine the level of radiation sensitivity, while the crystal size will dictate the beam size and the sample-mounting technique, in turn indicating the specifications of a suitable beamline. On the EMBL beamline P13 at PETRA III, Mesh&Collect data collection from concanavalin A microcrystals with linear dimensions of ∼20 µm or less using an accordingly sized microbeam at a wavelength of 1.892 Š(6.551 keV, close to the Mn edge at 6.549 keV) increases the expected Bijvoet ratio to 2.1% from an expected 0.7% at 12.6 keV (Se K edge), thus allowing experimental phase determination using the anomalous signal from naturally present Mn2+ and Ca2+ ions. Dozens of crystals were harvested and flash-cryocooled in micro-meshes, rapidly screened for diffraction (less than a minute per loop) and then used for serial Mesh&Collect collection of about 298 partial data sets (10° of crystal rotation per sample). The partial data sets were integrated and scaled. A genetic algorithm for combining partial data sets was used to select those to be merged into a single data set. This final data set showed high completeness, high multiplicity and sufficient anomalous signal to locate the anomalous scatterers, and provided phasing information which allowed complete auto-tracing of the polypeptide chain. To allow the complete experiment to run in less than 2 h, a practically acceptable time frame, the diffractometer and detector had to run together with limited manual intervention. The combination of several cutting-edge components allowed accurate anomalous signal to be measured from small crystals.

ConBr, the Lectin from Canavalia brasiliensis Mart. Seeds: Forty Years of Research.

Lectins are defined as proteins or glycoproteins capable of specific and reversible binding to carbohydrates. Inside this group of proteins, the most well-studied lectins belong to the Leguminosae family, and inside this family, the Diocleinae subtribe includes the most characterized lectin Concanavalin A (ConA), as well as ConBr, the lectin from Canavalia brasiliensis, the subject of this review. Since 1979, several studies have been published in the literature regarding this lectin, from its isolation and characterization to its several biological activities. This year, 2019, will mark 40 years since researchers have begun to study ConBr and 100 years since the discovery of ConA, making 2019 a momentous year for lectinology. Owing to the abundance of studies involving ConBr, this review will focus on ConBr's purification, physicochemical properties, functional and structural analyses, biological activities and biotechnological applications. This will give researchers a broad glimpse into the potential of this lectin, as well as it characteristics, as we look ahead to its expanding applications in glycomics and biotechnology.

Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes.

AIM: A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high-binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method. METHODS AND RESULTS: ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, noncell-based mannose reduced the activity of ConA in inhibiting biofilms. CONCLUSIONS: ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA. SIGNIFICANCE AND IMPACT OF THE STUDY: ConA can be used as a promising anti-adherent and antibiofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins.

Cadmium-Substituted Concanavalin A and Its Trimeric Complexation.

Concanavalin A (ConA) interacts with carbohydrates as a lectin, and recent reports proposed its application for detecting a diversity of viruses and pathogens. Structural studies have detailed the interaction between ConA and carbohydrates and the metal coordination environment with manganese and calcium ions (Mn-Ca-ConA). In this study, ConA was crystallized with a cadmium-containing precipitant, and the refined structure indicates that Mn²âº was replaced by Cd²âº (Cd-Ca-ConA). The structural comparison with ConA demonstrates that the metal-coordinated residues of Cd-Ca-ConA, that is Glu8, Asp10, Asn14, Asp19, and His24, do not have conformational shifts, but residues for sugar binding, including Arg228, Tyr100, and Leu99, reorient their side chains, slightly. Previous studies demonstrated that excess cadmium ions can coordinate with other residues, including Glu87 and Glu183, which were not coordinated with Cd²âº in this study. The trimeric ConA in this study coordinated Cd²âº with other residues, including Asp80 and Asp82, for the complex generation. The monomers does not have specific interaction near interface regions with the other monomer, but secondary cadmium coordinated with two aspartates (Asp80 and Asp82) from monomer 1 and one aspartate (Asp16) from monomer 2. This study demonstrated that complex generation was induced via coordination with secondary Cd²âº and showed the application potential regarding the design of complex formation for specific interactions with target saccharides.

Structural analysis and anthelmintic activity of Canavalia brasiliensis lectin reveal molecular correlation between the carbohydrate recognition domain and glycans of Haemonchus contortus.

Haemonchus contortus is one of the most economically important parasites infecting small ruminants worldwide. This nematode has shown a great ability to develop resistance to anthelmintic drugs, calling for the development of alternative control approaches. Because lectins recognize and bind to specific carbohydrates and glycan structures present in parasites, they can be considered as an alternative to develop new antiparasitic drugs. Accordingly, this work aimed to investigate the anthelmintic effect of Canavalia brasiliensis (ConBr) lectin against H. contortus and to evaluate a possible interaction of ConBr with glycans of this parasite by molecular docking. ConBr showed significant inhibition of H. contortus larval development with an IC50 of 0.26 mg mL-1. Molecular docking assays revealed that glycans containing the core trimannoside [Man(α1-3)Man(α1-6)Man] of H. contortus interact in the carbohydrate recognition domain of ConBr with an interaction value of MDS = -248.77. Our findings suggest that the inhibition of H. contortus larval development is directly related to the recognition of the core trimannoside present in the glycans of these parasites. This work is the first to report on the structure-function relationships of the anthelmintic activity of plant lectins.