Biochemical characterization and N-terminal sequences of two new trypsin inhibitors from Copaifera langsdorffii seeds

Biochemical and hemostatic description of a thrombin-like enzyme TLBro from Bothrops roedingeri snake venom

Objective: The current study's objective is to characterize a new throm-bin-like enzyme called TLBro that was obtained from Bothrops roedingeris snake from a biochemical and hemostatic perspective. Methodology: One chromatographic step was used to purify it, producing the serine protease TLBro. Molecular mass was estimated by SDS-PAGE to be between reduced and unreduced by 35 kDa. Tryptic peptide sequencing using Swiss Prot provided the complete amino acid sequence. Expasy.org by conducting a search that is limited to Crotalinae snake serine proteases and displaying a high degree of amino acid sequence. Results: Ser (182) is inhibited by phenylmethylsulfonyl fluoride (PMSF), and TLBro demonstrated the presence of Asp (88) residues. It also deduced the positions of His (43) and Ser (182) in the set of three coordinated amino acids in serine proteases. It was discovered that this substrate had high specificity for BANA, Michaelis-Menten behavior with KM 0 point85 mM and Vmax 1 point89 nmoles -NA/L/min, and high stability between temperatures (15 to 70°C) and pHs (2 point0 to 10 point0). According to doses and incubation times, TLBro degraded fibrin preferentially on the B-chain; additionally, its activities were significantly diminished after preincubation with divalent ions (Zn2 and Cd2). When incubated with PMSF, a particular serine protease inhibitor, enzymatic activities and platelet aggregation were inhibited. Conclusion: The findings revealed distinct structural and functional differences between the serine proteases, adding to the information and assisting in the improvement of the structure-function relationship.

Evaluation of the biological activities of Copaiba (Copaifera spp): a comprehensive review based on scientometric analysis

Copaíba oil-resin is extracted from the trunk of the Copaíba tree and has medicinal, cosmetic, and industrial properties. As a result, widespread knowledge about the use of Copaíba oil-resin has evolved, attracting the scientific community's attention. This paper aims to map the global knowledge production regarding the biological activities of Copaíba (Copaifera spp.). Bibliometric methodological instruments were used to conduct a search of the Web of Science-Core Collection database. The search resulted in 822 references. After screening titles and abstracts, 581 references did not meet the eligibility criteria, leaving 246 references for full-text examination. Subsequently, 15 studies were excluded, resulting in a final set of 232 records for the bibliometric analysis. In vitro was the most published study type, mainly from Brazil, from 2010 to 2020. Regarding the authors, Bastos, JK, and Ambrosio, SR were the ones with the most significant number of papers included. The most frequent keywords were Copaíba oil, Copaíba, and Copaifera. Our findings revealed global study trends about Copaíba, mainly related to its various effects and use over time. In general, all countries have conducted more research on antimicrobial and anti-inflammatory activities, also exposing its antioxidant and healing properties. Copaifera reticulata was the most investigated, followed by Copaifera langsdorffi and Copaifera multijuga in both in vitro and in vivo studies. Therefore, there is a need for human reports, given the promising results that Copaíba oils have been demonstrating.

A novel cysteine proteinase inhibitor from seeds of Enterolobium contortisiliquum and its effect on Callosobruchus maculatus larvae

This study focused on the characterization of a novel cysteine proteinase inhibitor from Enterolobium contortisiliquum seeds targeting the inhibition of the growth of Callosobruchus maculatus larvae, an important cosmopolitan pest of the cowpea Vigna unguiculata during storage. The inhibitor was isolated by ion-exchange besides of size exclusion chromatography. EcCI molecular mass is 19,757 Da, composed of two polypeptide chains. It strongly inhibits papain (Kiapp 0.036 nM) and proteinases from the midguts of C. maculatus (80 μg mL-1, 60% inhibition). The inhibitory activity is reduced by 40% after a heat treatment at 100 °C for 2 h. The protein displayed noxious activity at 0.5% and 1% (w/w) when incorporated in artificial seeds, reducing larval mass in 87% and 92%, respectively. Treatment of C. maculatus larvae with conjugated EcCI-FIT and subsequent biodistribution resulted in high fluorescence intensity in midguts and markedly low intensity in malpighian tubules and fat body. Small amounts of labeled proteins were detected in larvae feces. The detection of high fluorescence in larvae midguts and low fluorescence in their feces indicate the retention of the FITC conjugated EcCI inhibitor in larvae midguts. These results demonstrate the potential of the natural protein from E. contortisiliquum to inhibit the development of C. maculatus.

Effects of Aqueous Extracts of Copaifera langsdorffii (Fabaceae) on the Growth and Reproduction of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is considered a pest of maize crops throughout the Western Hemisphere. We report on the effects of aqueous extracts of leaves and bark of Copaifera langsdorffii (Fabaceae) on the biology of S. frugiperda, as an alternative source of natural bioactive molecules for the sustainable management of this pest. Second instars were sprayed with aqueous extracts prepared with 5% (w/v) plant material and/or fed on an artificial diet containing extracts at a concentration equivalent to 0.25% (w/v) for 17 days. Both leaf and bark extracts of C. langsdorffii significantly reduced S. frugiperda food intake, feces, and larval weight and caused a delay in larval development. Additionally, C. langsdorffii-based extracts increased the oviposition period; induced morphological changes in the eggs, including deformation of the corium and malformation of the micropylar and aeropylar regions; and reduced egg viability. But, aqueous extracts of C. langsdorffii exhibited no negative effects on larval and pupal survival, duration of the pupal stage, survival of pupae, sex ratio, longevity, duration of pre-oviposition period, and female fecundity. Aqueous extracts of leaves and bark of C. langsdorffii are promising alternatives for the control of S. frugiperda in maize crops.

Primary Structure of a Trypsin Inhibitor (Copaifera langsdorffii Trypsin Inhibitor-1) Obtained from C. langsdorffii Seeds

In this study, the aim was to determine the complete sequence of the Copaifera langsdorffii trypsin inhibitor (CTI)-1 using 2-dimensional (2D)-PAGE, matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF), and quadrupole time-of-flight (QTOF) spectrometry. Spots A (CTI-1) and F (CTI-2) were submitted to enzymatic digestions with trypsin, SV8, and clostripain. The accurate mass of the peptide obtained from each digest was determined by mass spectrometry (MS) using MALDI-TOF. The most abundant peptides were purified and sequenced in a liquid chromatograph connected to an electrospray ionization-QTOF MS. When the purified trypsin inhibitor was submitted to 2D electrophoresis, different spots were observed, suggesting that the protein is composed of 2 subunits with microheterogeneity. Isoelectric points of 8.0, 8.5, and 9.0 were determined for the 11 kDa subunit and of 4.7, 4.6, and 4.3 for the 9 kDa subunit. The primary structure of CTI-1, determined from the mass of the peptide of the enzymatic digestions and the sequence obtained by MS, indicated 180 shared amino acid residues and a high degree of similarity with other Kunitz (KTI)-type inhibitors. The peptide also contained an Arg residue at the reactive site position. Its 3-dimensional structure revealed that this is because the structural discrepancies do not affect the canonical conformation of the reactive loop of the peptide. Results demonstrate that a detailed investigation of the structural particularities of CTI-1 could provide a better understanding of the mechanism of action of these proteins, as well as clarify its biologic function in the seeds. CTI-1 belongs to the KTI family and is composed of 2 polypeptide chains and only 1 disulfide bridge.

A hemagglutinin from northeast red beans with immunomodulatory activity and anti-proliferative and apoptosis-inducing activities toward tumor cells

A 64-kDa hemagglutinin from a Phaseolus vulgaris cultivar, the northeast red bean, was purified by a protocol composed of three chromatographic steps involving affinity chromatography on Affi-gel blue gel, cation exchange chromatography on SP-Sepharose and FPLC-gel filtration on Superdex 75. The purified hemagglutinin appeared as a single 32-kDa band in SDS-PAGE indicating its dimeric nature. The N-terminal amino acid sequence of the hemagglutinin resembled the sequences of lectins and hemagglutinins from a number of Phaseolus species. The hemagglutinin manifested moderate thermostability and pH stability. It retained full activity up to 65 °C and in the pH range 2-12. It did not interact with simple sugars such as glucose, mannose and galactose. The hemagglutinin exerted immunostimulatory effects by upregulating the expression of cytokines like interferon-γ and tumor necrosis factor-α. It also exhibited antiproliferative activity on a number of tumor cells including MCF7 (breast cancer), HepG2 (liver cancer), CNE1 and CNE2 (nasopharyngeal cancer) cells, with stronger activity toward MCF7 and CNE1 cells. The hemagglutinin induced phophatidylserine externalization, mitochondrial depolarization and DNA condensation in MCF7 cells, indicating initiation of apoptosis. However, at high hemagglutinin concentrations, severe damage to the MCF7 cells was detected.

Northeast red beans produce a thermostable and pH-stable defensin-like peptide with potent antifungal activity

A 5.4-kDa antifungal peptide was purified from Phaseolus vulgaris L. cv. "northeast red bean" using a protocol that entailed affinity chromatography, ion exchange chromatography, and gel filtration. The molecular mass was determined by matrix-assisted laser desorption ionization time-of-flight. The N-terminal amino acid sequence of the peptide was highly homologous to defensins and defensin-like peptides from several plant species. The peptide impeded the growth of a number of pathogenic fungi, including Mycosphaerella arachidicola Khokhr. (IC50 = 1.7 μM), Setosphaeria turcica Luttr., Fusarium oxysporum Schltdl., and Valsa mali Miyabe & G. Yamada. Antifungal activity of the peptide was fully preserved at temperatures up to 100 °C and pH values from 0 to 12. Congo red deposition at the hyphal tip of M. arachidicola was detected after exposure to the peptide, signifying that the peptide had suppressed hyphal growth. The antifungal peptide did not manifest antiproliferative activity toward human breast cancer MCF7 cells and hepatoma HepG2 cells, in contradiction to the bulk of previously reported plant defensins. The data suggest distinct structural requirements for antifungal and antiproliferative activities.

Using a Caesalpinia echinata Lam. protease inhibitor as a tool for studying the roles of neutrophil elastase, cathepsin G and proteinase 3 in pulmonary edema

Acute lung injury (ALI) is characterized by neutrophil infiltration and the release of proteases, mainly elastase (NE), cathepsin G (Cat G) and proteinase 3 (PR3), which can be controlled by specific endogenous inhibitors. However, inhibitors of these proteases have been isolated from different sources, including plants. For this study, CeEI, or Caesalpinia echinata elastase inhibitor, was purified from C. echinata (Brazil-wood) seeds after acetone fractionation, followed by ion exchange and reversed phase chromatographic steps. Characterization with SDS-PAGE, stability assays, amino acid sequencing and alignment with other protein sequences confirmed that CeEI is a member of the soybean Kunitz trypsin inhibitor family. Like other members of this family, CeEI is a 20 kDa monomeric protein; it is stable within a large pH and temperature range, with four cysteine residues forming two disulfide bridges, conserved amino acid residues and leucine-isoleucine residues in the reactive site. CeEI was able to inhibit NE and Cat G at a nanomolar range (with K(i)s of 1.9 and 3.6 nM, respectively) and inhibited PR3 within a micromolar range (K(i) 3.7 μM), leading to hydrolysis of specific synthetic substrates. In a lung edema model, CeEI reduced the lung weight and pulmonary artery pressure until 180 min after the injection of zymosan-activated polymorphonuclear neutrophils. In experiments performed in the presence of a Cat G and PR3, but not an NE inhibitor, lung edema was reduced only until 150 min and pulmonary artery pressure was similar to that of the control. These results confirm that NE action is crucial to edema establishment and progression. Additionally, CeEI appears to be a useful tool for studying the physiology of pulmonary edema and provides a template for molecular engineering and drug design for ALI therapy.

Isolation of a glucosamine binding leguminous lectin with mitogenic activity towards splenocytes and anti-proliferative activity towards tumor cells

A dimeric 64-kDa glucosamine-specific lectin was purified from seeds of Phaseolus vulgaris cv. “brown kidney bean.” The simple 2-step purification protocol involved affinity chromatography on Affi-gel blue gel and gel filtration by FPLC on Superdex 75. The lectin was absorbed on Affi-gel blue gel and desorbed using 1M NaCl in the starting buffer. Gel filtration on Superdex 75 yielded a major absorbance peak that gave a single 32-kDa band in SDS-PAGE. Hemagglutinating activity was completely preserved when the ambient temperature was in the range of 20°C–60°C. However, drastic reduction of the activity occurred at temperatures above 65°C. Full hemagglutinating activity of the lectin was observed at an ambient pH of 3 to 12. About 50% activity remained at pH 0–2, and only residual activity was observed at pH 13–14. Hemagglutinating activity of the lectin was inhibited by glucosamine. The brown kidney bean lectin elicited maximum mitogenic activity toward murine splenocytes at 2.5 µM. The mitogenic activity was nearly completely eliminated in the presence of 250 mM glucosamine. The lectin also increased mRNA expression of the cytokines IL-2, TNF-α and IFN-γ. The lectin exhibited antiproliferative activity toward human breast cancer (MCF7) cells, hepatoma (HepG2) cells and nasopharyngeal carcinoma (CNE1 and CNE2) cells with IC₅₀ of 5.12 µM, 32.85 µM, 3.12 µM and 40.12 µM respectively after treatment for 24 hours. Flow cytometry with Annexin V and propidum iodide staining indicated apoptosis of MCF7 cells. Hoechst 33342 staining also indicated formation of apoptotic bodies in MCF7 cells after exposure to brown kidney bean lectin. Western blotting revealed that the lectin-induced apoptosis involved ER stress and unfolded protein response.

A Kunitz trypsin inhibitor of Entada scandens seeds: another member with single disulfide bridge

Sword bean (Entada scandens) is a tree climber that belongs to Mimosoideae, a subfamily of Leguminosae. A potent Kunitz type trypsin inhibitor (ESTI) was purified to homogeneity from Entada scandens seeds by sequential ammonium sulfate precipitation, affinity chromatography on trypsin-Sepharose and DEAE-Sephacel ion-exchange chromatography. ESTI is a single polypeptide chain of 19,766 Da. Both native PAGE as well as isoelectric focusing showed a single inhibitor species with a pI of 7.43. MALDI-TOF analysis also confirmed the monomeric nature. The amino-terminal sequence of ESTI reveals significant homology to the Kunitz-type protease inhibitors of legume plants. ESTI is unique in that it contains a single disulfide bridge, and unlike other inhibitors from Mimosoideae species is a single chain polypeptide. ESTI inhibited bovine trypsin with a stoichiometry of 1:1 and the apparent K(i) was 4.9 x 10(-9) M. In vitro assay showed that ESTI inhibited the midgut proteinase of the fifth instar larvae of Rice moth (Corcyra cephalonica) with an IC(50) of 26.4+/-0.01 nM. ESTI exhibits a mixed type competitive inhibition at lower concentration and pure competitive at higher inhibitor concentrations. Phylogenetic analyses depicted a clear divergence of single disulfide containing inhibitors from other tree legume Kunitz inhibitors. The homology of ESTI to Kunitz inhibitors together with the absence of Bowman-Birk type inhibitors in sword bean further supports the theory that there exists an evolutionary relationship between the families of inhibitors found in Leguminosae.

Calliandra selloi Macbride trypsin inhibitor: isolation, characterization, stability, spectroscopic analyses

A trypsin inhibitor was purified from Calliandra selloi Macbride seeds (CSTI). SDS-PAGE under non-reducing conditions showed a single band of approximately 20,000 Da, while under reducing conditions two bands of 16,000 and 6000 Da were observed, indicating that CSTI consists of two polypeptide chains. Molecular masses of 20,078 and 20,279 were obtained by mass spectrometry, although only one pI of 4.0 was observed and one peak was obtained by reversed phase chromatography. Amino-terminal sequence analysis showed homology to Kunitz-type inhibitors. CSTI was able to inhibit trypsin (Ki 2.21 x 10(-7)M), alpha-chymotrypsin (Ki 4.95 x 10(-7)M) and kallikrein (Ki 4.20 x 10(-7)M) but had no effect on elastase. Trypsin inhibitory activity was stable over a wide range of pH and temperature. CSTI was particularly susceptible to DTT treatment, followed by addition of iodoacetamide. Far-UV circular dichroism measurements revealed that CSTI is a beta-II protein. Thermal unfolding showed a two-state transition with a midpoint at 68 degrees C. Far-UV CD spectra of CSTI at pH extremes showed little changes, while more pronounced differences in near-UV CD spectra were detected. Remarkably, treatment with 1mM DTT caused very slight changes in the far-UV CD spectrum, and only after carbamidomethylation was there was a marked loss observed in secondary structure.

Identification of a Kunitz-type proteinase inhibitor from Pithecellobium dumosum seeds with insecticidal properties and double activity

A trypsin inhibitor, PdKI, was purified from Pithecellobium dumosum seeds by TCA precipitation, trypsin-sepharose chromatography, and reversed-phase-HPLC. PdKI was purified 217.6-fold and recovered 4.7%. SDS-PAGE showed that PdKI is a single polypeptide chain of 18.9 kDa and 19.7 kDa by MALDI-TOF. The inhibition on trypsin was stable in the pH range 2-10 and at a temperature of 50 degrees C. The Ki values were 3.56 x 10(-8)and 7.61 x 10(-7) M with competitive and noncompetitive inhibition mechanisms for trypsin and papain, respectively. The N-terminal sequence identified with members of Kunitz-type inhibitors from the Mimosoideae and Caesalpinoideae subfamilies. PdKI was effective against digestive proteinase from Zabrotes subfasciatus, Ceratitis capitata, Plodia interpunctella, Alabama argillaceae, and Callosobruchus maculatus, with 69, 66, 44, 38, and 29% inhibition, respectively. Results support that PdKI is a member of the Kunitz inhibitor family and its insecticidal properties indicate a potent insect antifeedant.

Purification and primary structure determination of two Bowman-Birk type trypsin isoinhibitors from Cratylia mollis seeds

Two Bowman-Birk type trypsin inhibitors (CmTI(1) and CmTI(2)) were purified from Cratylia mollis seeds by acetone precipitation, ion exchange, gel filtration and reverse-phase chromatography. CmTI(1) and CmTI(2), with 77 and 78 amino acid residues, respectively, were sequenced in their entirety and show a high structural similarity to Bowman-Birk inhibitors from other Leguminosae. The putative reactive sites of CmTI(1) are a lysine residue at position 22 and a tyrosine residue at position 49. Different reactive sites, as identified by their alignment with related inhibitors, were found for CmTI(2): lysine at position 22 and leucine at position 49. The dissociation constant K(i) of the complex with trypsin is 1.4 nM. The apparent molecular mass is 17 kDa without DDT and 11 kDa with reducing agent and heating.

Three-dimensional structure of an unusual Kunitz (STI) type trypsin inhibitor from Copaifera langsdorffii

The crystallographic structure of a novel trypsin inhibitor (CTI) from Copaifera langsdorffii is reported. The structure was solved by MIRAS procedure and refined to a crystallographic residual of 17.3% (R(free) = 20.3%) at 1.8 A resolution. Two isomorphous derivatives were obtained by quick cryo-soaking approach. CTI is the first structure of a member of Kunitz (STI) family formed by two noncovalently bound polypeptide chains and only one disulfide bridge. A standard Kunitz-type inhibitor has a single polypeptide chain and two disulfide bridges. Structural features granting CTI high inhibitory activity are discussed.