Recombinant multiepitope proteins expressed in Escherichia coli cells and their potential for immunodiagnosis.

Recombinant multiepitope proteins (RMPs) are a promising alternative for application in diagnostic tests and, given their wide application in the most diverse diseases, this review article aims to survey the use of these antigens for diagnosis, as well as discuss the main points surrounding these antigens. RMPs usually consisting of linear, immunodominant, and phylogenetically conserved epitopes, has been applied in the experimental diagnosis of various human and animal diseases, such as leishmaniasis, brucellosis, cysticercosis, Chagas disease, hepatitis, leptospirosis, leprosy, filariasis, schistosomiasis, dengue, and COVID-19. The synthetic genes for these epitopes are joined to code a single RMP, either with spacers or fused, with different biochemical properties.

Crystal structure and interconversion of monomers and domain-swapped dimers of the walnut tree phytocystatin.

Biotechnological applications of phytocystatins have garnered significant interest due to their potential applications in crop protection and improve crop resistance to abiotic stress factors. Cof1 and Wal1 are phytocystatins derived from Coffea arabica and Juglans regia, respectively. These plants hold significant economic value due to coffee's global demand and the walnut tree's production of valuable timber and widely consumed walnuts with culinary and nutritional benefits.

rMELEISH: A Novel Recombinant Multiepitope-Based Protein Applied to the Serodiagnosis of Both Canine and Human Visceral Leishmaniasis.

Background: visceral leishmaniasis (VL) is a critical public health problem in over ninety countries. The control measures adopted in Brazil have been insufficient when it comes to preventing the spread of this overlooked disease. In this context, a precise diagnosis of VL in dogs and humans could help to reduce the number of cases of this disease.

Structure and function of cationic hylin bioactive peptides from the tree frog Boana pulchella in interaction with lipid membranes.

Amphibians have a great diversity of bioactive peptides in their skin. The cDNA prepro-peptide sequencing allowed the identification of five novel mature peptides expressed in the skin of Boana pulchella, four with similar sequences to hylin peptides having a cationic amphipathic-helical structure. Whole mature peptides and some of their fragments were chemically-synthesized and tested against Gram-positive and Gram-negative bacterial strains.

Structural and biochemical analysis reveals how ferulic acid improves catalytic efficiency of Humicola grisea xylanase.

Humicola grisea var. thermoidea is an aerobic and thermophilic fungus that secretes the GH11 xylanase HXYN2 in the presence of sugarcane bagasse. In this study, HXYN2 was expressed in Pichia pastoris and characterized biochemically and structurally in the presence of beechwood xylan substrate and ferulic acid (FA).

Blood pressure-lowering effects of a Bowman-Birk inhibitor and its derived peptides in normotensive and hypertensive rats.

Bioactive plant peptides have received considerable interest as potential antihypertensive agents with potentially fewer side effects than antihypertensive drugs. Here, the blood pressure-lowering effects of the Bowman-Birk protease inhibitor, BTCI, and its derived peptides, PepChy and PepTry, were investigated using normotensive (Wistar-WR) and spontaneously hypertensive rats (SHR). BTCI inhibited the proteases trypsin and chymotrypsin, respectively, at 6 µM and 40 µM, a 10-fold greater inhibition than observed with PepTry (60 µM) and PepChy (400 µM).

Biological Properties of a Novel Multifunctional Host Defense Peptide from the Skin Secretion of the Chaco Tree Frog, .

In recent years, the number of new antimicrobial drugs launched on the market has decreased considerably even though there has been an increase in the number of resistant microbial strains. Thus, antimicrobial resistance has become a serious public health problem. Amphibian skin secretions are a rich source of host defense peptides, which generally are cationic and hydrophobic molecules, with a broad-spectrum of activity.

Xylanase from Aspergillus tamarii shows different kinetic parameters and substrate specificity in the presence of ferulic acid.

A 22 kDa xylanase (AtXyl1) from Aspergillus tamarii was purified by two chromatographic steps and presented preference for oat spelt (OSX), birchwood (BrX) and beechwood (BeX) xylans respectively, as substrates. AtXyl1 displays the highest activity at pH 5.5 and 55 °C and showed tolerance over a range of different phenolic compounds.

Structural and functional characterization of a novel lipolytic enzyme from a Brazilian Cerrado soil metagenomic library.

Objective: To isolate putative lipase enzymes by screening a Cerrado soil metagenomic library with novel features.

Results: Of 6720 clones evaluated, Clone W (10,000 bp) presented lipolytic activity and four predicted coding sequences, one of them LipW. Characterization of a predicted esterase/lipase, LipW, showed 28% sequence identity with an arylesterase from Pseudomonas fluorescens (pdb|3HEA) from protein database (PDB).

Self-homodimerization of an actinoporin by disulfide bridging reveals implications for their structure and pore formation.

The Trp111 to Cys mutant of sticholysin I, an actinoporin from Stichodactyla helianthus sea anemone, forms a homodimer via a disulfide bridge. The purified dimer is 193 times less hemolytic than the monomer. Ultracentrifugation, dynamic light scattering and size-exclusion chromatography demonstrate that monomers and dimers are the only independent oligomeric states encountered.

Dendropsophin 1, a novel antimicrobial peptide from the skin secretion of the endemic Colombian frog Dendropsophus columbianus.

In efforts to find new antimicrobial peptides (AMPs), we studied the skin secretion of the endemic Colombian frog Dendropsophus columbianus belonging to a genus that has not been investigated previously. From HPLC-fractionated secretion, we identified one peptide with slightly antibacterial activity. Its peptide sequence showed no sequence similarity to current annotated peptides.

Crystal structure of VapC21 from Mycobacterium tuberculosis at 1.31 Å resolution.

Persisters are individual bacterial cells that exhibit a phenotype characterized by slow growth, low metabolic rate and multidrug tolerance. The processes that drive cells into a persistence state constitute an active but incipient research field, and structural data regarding its components are scarce. The molecular targets of many therapeutic drugs are involved in cell wall synthesis and cell division, and these cellular processes are down-regulated in persister cells, consequently these cells are more likely to survive antibiotic treatment.

Trichoderma harzianum Produces a New Thermally Stable Acid Phosphatase, with Potential for Biotechnological Application.

Acid phosphatases (ACPases) are produced by a variety of fungi and have gained attention due their biotechnological potential in industrial, diagnosis and bioremediation processes. These enzymes play a specific role in scavenging, mobilization and acquisition of phosphate, enhancing soil fertility and plant growth. In this study, a new ACPase from Trichoderma harzianum, named ACPase II, was purified and characterized as a glycoprotein belonging to the acid phosphatase family.

Structural and functional characterization of the recombinant thioredoxin reductase from Candida albicans as a potential target for vaccine and drug design.

The thioredoxin system plays a critical role in maintaining the cytoplasm redox state, participating in functions that are important to the cellular viability of fungi. Although functional and structural information on targets in human pathogenic fungi has been scarcely described in the literature, such studies are essential for in silico drug design and biotechnological applications. Therefore, the aims of the present study were to produce recombinant proteins of the thioredoxin system from Candida albicans and evaluate their possible use as prophylactic or alternative therapies against the most important pathogenic fungus associated with nosocomial infections.

Xylan-degrading enzymes from Aspergillus terreus: Physicochemical features and functional studies on hydrolysis of cellulose pulp.

Two endo-β-1,4-xylanases named XylT1 and XylT2, previously purified from Aspergillus terreus, were structurally investigated by fluorescence quenching and characterized with respect to their binding properties with phenolic compounds. Neutral and charged quenchers had access to both enzymes in neutral and alkaline pHs. The greatest access was noted for the negative quencher, possibly due to positive amino acid residues in the vicinity of tryptophan.

Bowman-Birk protease inhibitor from Vigna unguiculata seeds enhances the action of bradykinin-related peptides.

The hydrolysis of bradykinin (Bk) by different classes of proteases in plasma and tissues leads to a decrease in its half-life. Here, Bk actions on smooth muscle and in vivo cardiovascular assays in association with a protease inhibitor, Black eyed-pea trypsin and chymotrypsin inhibitor (BTCI) and also under the effect of trypsin and chymotrypsin were evaluated. Two synthetic Bk-related peptides, Bk1 and Bk2, were used to investigate the importance of additional C-terminal amino acid residues on serine protease activity.

Effects of an anticarcinogenic Bowman-Birk protease inhibitor on purified 20S proteasome and MCF-7 breast cancer cells.

Proteasome inhibitors have been described as an important target for cancer therapy due to their potential to regulate the ubiquitin-proteasome system in the degradation pathway of cellular proteins. Here, we reported the effects of a Bowman-Birk-type protease inhibitor, the Black-eyed pea Trypsin/Chymotrypsin Inhibitor (BTCI), on proteasome 20S in MCF-7 breast cancer cells and on catalytic activity of the purified 20S proteasome from horse erythrocytes, as well as the structural analysis of the BTCI-20S proteasome complex. In vitro experiments and confocal microscopy showed that BTCI readily crosses the membrane of the breast cancer cells and co-localizes with the proteasome in cytoplasm and mainly in nucleus.

A recombinant multiepitope protein for hepatitis B diagnosis.

Hepatitis B is a liver inflammation caused by hepatitis B virus (HBV) and can be diagnosed in clinical stage by hepatitis B core antibody from IgM class (anti-HBcIgM). Hepatitis B core antibody from IgG class (Anti-HBcIgG) appears quickly after IgM, reaching high titers in chronic hepatitis, and remains even after cure. Since hepatitis B core antibody (anti-HBc) is the first antibody identified and sometimes the only marker detected during the course of infection, it can be used both to indicate HBV acute infection (anti-HBc-IgM) and to identify individuals who have come into contact with the virus (anti-HBc-IgG).

The Trypanosoma cruzi virulence factor oligopeptidase B (OPBTc) assembles into an active and stable dimer.

Oligopeptidase B, a processing enzyme of the prolyl oligopeptidase family, is considered as an important virulence factor in trypanosomiasis. Trypanosoma cruzi oligopeptidase B (OPBTc) is involved in host cell invasion by generating a Ca(2+)-agonist necessary for recruitment and fusion of host lysosomes at the site of parasite attachment. The underlying mechanism remains unknown and further structural and functional characterization of OPBTc may help clarify its physiological function and lead to the development of new therapeutic molecules to treat Chagas disease.

The new kappa-KTx 2.5 from the scorpion Opisthacanthus cayaporum.

The kappa-KTx family of peptides, which is the newest K⁺-channel blocker family from scorpion venom, is present in scorpions from the families Scorpionidae and Liochelidae. Differently from the other scorpion KTx families, the three-dimensional structure of the known kappa-KTxs toxins is formed by two parallel α-helices linked by two disulfide bridges. Here, the characterization of a new kappa-KTx peptide, designated kappa-KTx 2.

Biochemical and Structural Characterization of Amy1: An Alpha-Amylase from Cryptococcus flavus Expressed in Saccharomyces cerevisiae.

An extracellular alpha-amylase (Amy1) whose gene from Cryptococcus flavus was previously expressed in Saccharomyces cerevisiae was purified to homogeneity (67 kDa) by ion-exchange and molecular exclusion chromatography. The enzyme was activated by NH(4) (+) and inhibited by Cu(+2) and Hg(+2). Significant biochemical and structural discrepancies between wild-type and recombinant α-amylase with respect to K(m) values, enzyme specificity, and secondary structure content were found.

Apoptosis and lysosome membrane permeabilization induction on breast cancer cells by an anticarcinogenic Bowman-Birk protease inhibitor from Vigna unguiculata seeds.

In this work, we report the effects of a Bowman-Birk protease inhibitor, the Black-Eyed Pea Trypsin/Chymotrypsin Inhibitor - BTCI, purified from Vigna unguiculata seeds, on the MCF-7 breast cancer cells. The treatment of MCF-7 with 200microM BTCI for 72h induced significant reduction of the cell viability and proliferation (arrest in S and G2/M phase). These cytostatic effects were accompanied by acute morphological modifications including the alteration of the nuclear morphology, plasma membrane fragmentation, cytoplasm disorganization, presence of double-membrane vesicles, mitochondrial swelling, and an increase in the size of lysosomes.