50 resultados para affinity chromatography


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Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP-HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407 ± 15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N-acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed β(1-4) glycosidic bonds linking 2-acetoamido-2-deoxy-β-d-glucopyranose units in chitin. The full-length amino acid sequence of Parkia platycephala lectin 2, determined by N-terminal sequencing and cDNA cloning, and its three-dimensional structure, established by X-ray crystallography at 1.75 Å resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (βα) 8 barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182. © 2006 The Authors.

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Dengue virus is a mosquito-borne flavivirus that has a large impact in global health. It is considered as one of the medically important arboviruses, and developing a preventive or therapeutic solution remains a top priority in the medical and scientific community. Drug discovery programs for potential dengue antivirals have increased dramatically over the last decade, largely in part to the introduction of high-throughput assays. In this study, we have developed an image-based dengue high-throughput/high-content assay (HT/HCA) using an innovative computer vision approach to screen a kinase-focused library for anti-dengue compounds. Using this dengue HT/HCA, we identified a group of compounds with a 4-(1-aminoethyl)-N-methylthiazol-2-amine as a common core structure that inhibits dengue viral infection in a human liver-derived cell line (Huh-7.5 cells). Compounds CND1201, CND1203 and CND1243 exhibited strong antiviral activities against all four dengue serotypes. Plaque reduction and time-of-addition assays suggests that these compounds interfere with the late stage of viral infection cycle. These findings demonstrate that our image-based dengue HT/HCA is a reliable tool that can be used to screen various chemical libraries for potential dengue antiviral candidates. © 2013 Cruz et al.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The properties of a previously unknown enzyme, denominated cyclodextrin glycosyltransferase, produced from Bacillus lehensis, were evaluated using affinity chromatography for protein purification. Enzyme characteristics (optimum pH and temperature; pH and temperature stability), the influence of substances on the enzyme activity, enzyme kinetics, and cyclodextrin production were analysed. Cyclodextrin glycosyltransferase was purified up to 320.74-fold by affinity chromatography using beta-cyclodextrin as the binder and it exhibited 8.71% activity recovery. This enzyme is a monomer with a molecular weight of 81.27 kDa, as estimated by SDS-PAGE. Optimum temperature and pH for cydodextrin glycosyltransferase were 55 degrees C and 8.0, respectively. The Michaelis-Menten constant was 8.62 g/l during maximum velocity of 0.858 g/l.h.