ABSTRACT We have investigated the antiproliferative effects of SCH 56592, a new experimental triazole, against Trypanosoma ( Schizotrypanum ) cruzi , etiological agent Chagas’ disease in Latin America. 56592 blocked proliferation epimastigote form parasite vitro at 30 nM, concentration 30- to 100-fold lower than that required with reference compounds ketoconazole and itraconazole. At all parasite’s endogenous sterols (ergosterol, 24-ethyl-cholesta-5,7,22-trien-3β-ol, its 22-dihydro analogs),...

We investigated the mechanism of action metabolically stable lysophospholipid analogues (LPAs), with potent anti-tumour and anti-protozoal activity against Trypanosoma cruzi, causative agent Chagas' disease. Against axenically grown epimastigote form parasite, IC50s after 120 h for ET-18-OCH3, miltefosine ilmofosine were 3, 1 3 μM, respectively; at higher concentrations immediate lytic effects observed. Eradication intracellular amastigote, inside Vero cells, was achieved 0.1, 0.1 μM...

Detailed analysis of the endogenous sterol content purified Pneumocystis carinii preparations by gas-liquid chromatography coupled to mass spectrometry suggested that this parasite can both synthesize de novo steroid skeletons (to produce delta7 sterols) and take them from infected host (leading delta5 sterols). In cases final products are 24-alkyl sterols, resulting action delta24(25) delta24(24') methyltransferases, enzymes not present in vertebrates. To investigate physiological...

RYBP (Ring1A and YY1 binding protein) is a zinc finger protein with an essential role during embryonic development, which binds transcriptional factors, Polycomb products, mediators of apoptosis, suggesting roles in, apparently, unrelated functions. To investigate mechanisms underlying its association functionally diverse partners, we set out to study structural properties using number biophysical (fluorescence, circular dichroism, Fourier transform infrared, NMR spectroscopies) hydrodynamic...

The HIV-1 gp41 envelope protein mediates entry of the virus into target cell by promoting membrane fusion. With a view toward possible new insights viral fusion mechanisms, we have investigated infrared, fluorescence, and nuclear magnetic resonance spectroscopies calorimetry fragment 19 amino acids corresponding to immunodominant region ectodomain, highly conserved sequence major epitope. Information on structure peptide both in solution presence model membranes, its incorporation location...

The ferric uptake regulator (Fur) is the main transcriptional of genes involved in iron homeostasis most prokaryotes. FurA from Anabaena sp. PCC 7120 contains five cysteine residues, four them arranged two redox-active CXXC motifs. protein needs not only metal but also reducing conditions to remain fully active vitro. Through a mutational study residues present FurA, we have investigated their involvement and DNA binding.Residue C101 that belongs conserved motif plays an essential role both...

The Y509E mutant of β-xylosidase from Geobacillus stearothermophilus (XynB2Y509E) (which also bears xylanase activity) has been immobilized in chitosan spheres through either entrapment or covalent bond formation methods. maximum immobilization yield by was achieved beads developed using a 2% solution after 1 h maturation time CFG buffer with ethanol. On the other hand, highest value observed when employing that were prepared 4 activation 1% glutaraldehyde at pH 8. activity expressed bonding...

In Paracoccidioides brasiliensis, a dimorphic fungus pathogenic for humans, no significant differences were observed in the phospholipid species of both morphological phases. The phosphatidylcholine (PC, 30–40%), phosphatidylethanolamine (PE, 27-28%), phosphatidylserine (16–19%), phosphatidylinositol (13–17%) and sphingomyelin (3–5–0025;). main fatty acids found yeast (Y) phase palmitate (56%), linoleate (18%) oleate (15%), while predominated (61 %) mycelial (M) phase, followed by (27%)...

Abstract This laboratory exercise presents a novel way to introduce undergraduate students the specific detection of enzymatic activity by electrophoresis. First, prepare crude peroxidase extract and then analyze homogenate via Zymography, that is, SDS‐PAGE method detect enzyme activity, is used specifically furthermore, total protein profile. After assay, may estimate apparent molecular mass discuss its structure. 4‐h experiment, gain knowledge concerning biological sample preparation, gel...

Abstract The N‐succinylamino acid racemases (NSAAR) belong to the enolase superfamily and they are large homooctameric/hexameric species that require a divalent metal ion for activity. We describe structure stability of NSAAR from Geobacillus kaustophilus (GkNSAAR) in absence presence Co 2+ by using hydrodynamic spectroscopic techniques. , among other assayed ions, provides maximal enzymatic activity at physiological pH. protein seems be tetramer with rather elongated shape, as shown AU...

Bacteriocins belong to the wide variety of antimicrobial ribosomal peptides synthesised by bacteria. Enterococci are Gram-positive, catalase-negative bacteria that produce lactic acid as major end product glucose fermentation. Many enterococcal strains bacteriocins, named enterocins. We describe in this work, structural characterisation 44 residues-long enterocin EJ97, produced Enterococcus faecalis EJ97. To end, we have used a combined theoretical and experimental approach. First,...

The LrtA protein of Synechocystis sp. PCC 6803 intervenes in cyanobacterial post-stress survival and stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family proteins, involved synthesis. In this work, we studied conformational preferences stability isolated solution. At physiological conditions, as shown by hydrodynamic techniques, was a self-association equilibrium. As indicated Nuclear Magnetic Resonance (NMR), circular dichroism (CD) fluorescence,...

Cross-linked enzyme aggregates (CLEAs) of the Y509E mutant glycoside hydrolase family 52 β-xylosidase from Geobacillus stearothermophilus with dual activity and xylanase (XynB2Y509E) were prepared. Ammonium sulfate was used as precipitant agent, glutaraldehyde cross-linking agent. The optimum conditions found to be 90% ammonium sulfate, 12.5 mM glutaraldehyde, 3 h reaction at 25 °C, pH 8.5. Under these (most effective) conditions, XynB2Y509E-CLEAs retained 92.3% their original activity....

Histidine ammonia-lyase (HAL) plays a pivotal role in the non-oxidative deamination of L-histidine to produce trans-urocanic, crucial process amino acid metabolism. This study examines cloning, purification, and biochemical characterization novel HAL from Geobacillus kaustophilus (GkHAL) eight active site mutants assess their effects on substrate binding, catalysis, thermostability, secondary structure. The GkHAL enzyme was successfully overexpressed purified homogeneity. Its primary...