Crystallization and preliminary X-ray diffraction analysis of importin-alpha acomplexed with NLS peptidomimetics

Importin-alpha is the nuclear import receptor that recognizes cargo proteins with nuclear localization sequences (NLSs). Tile study of NLS peptidomimetics can provide a better understanding of the requirements for the molecular recognition of cargo proteins by importin-alpha, and potentially engender a large number of applications in medicine. Importin-a was crystallized with a set of six NLS peptidomimetics, and X-ray diffraction data were collected in the range 2.1-2.5 angstrom resolution. Preliminary electron density calculations show that the ligands are present in the crystals. (c) 2005 Elsevier B.V All rights reserved.

Crystallization and preliminary X-ray diffraction analysis of a myotoxic Lys49-PLA(2) from Bothrops jararacussu venom complexed with p-bromophenacyl bromide

For the first time, a non-catalytic and myotoxic Lys49-PLA(2) (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities. This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA(2)s, and other toxicological activities of Lys49-PLA(2)s.

Crystallization and preliminary X-ray diffraction analysis of a Lys49-phospholipase A(2) complexed with caffeic acid, a molecule with inhibitory properties against snake venoms

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

Crytallization and high-resolution X-ray diffraction data collection of an Asp49 PLA(2) from Bothrops jararacussu venom both in the presence and absence of Ca2+ ions

Snake venom PLA(2)s have been extensively studied due to their role in mediating and disrupting physiological processes such as coagulation, platelet aggregation and myotoxicity. The Ca2+ ion bound to the putative calcium-binding loop is essential for hydrolytic activity. We report the crystallization in the presence and absence of Ca2+ and X-ray diffraction data collection at 1.60 Angstrom (with Ca2+) and 1.36 Angstrom (without Ca2+) of an Asp49 PLA(2) from Bothrops jararacussu venom. The crystals belong to orthorhombic space group C222(1). Initial refinement and electron density analysis indicate significant conformational. changes upon Ca2+ binding. (C) 2004 Elsevier B.V. All fights reserved.

Ethanol electro-oxidation in an alkaline medium using Pd/C, Au/C and PdAu/C electrocatalysts prepared by electron beam irradiation

Carbon-supported Pd, Au and bimetallic PdAu (Pd:Au 90:10, 50:50 and 30:70 atomic ratios) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their catalytic activities toward ethanol electro-oxidation were evaluated in an alkaline medium using electrochemical techniques, in situ attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) analysis and a single alkaline direct ethanol fuel cell (ADEFC). EDX analyses showed that the actual Pd: Au atomic ratios were very similar to the nominal ones. X-ray diffractograms of PdAu/C electrocatalysts evidenced the presence of Pd-rich (fcc) and Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles on the carbon support, with an average size in the range of 3-5 nm and broad size distributions. Cyclic voltammetry (CV) and chronoamperometry (CA) experiments revealed the superior ambient activity toward ethanol electro-oxidation of PdAu/C electrocatalysts with Pd: Au ratios of 90:10 and 50:50. In situ ATR-FTIR spectroscopy measurements have shown that the mechanism for ethanol electro-oxidation is dependent on catalyst composition, leading to different reaction products, such as acetaldehyde and acetate, depending on the number of electrons transferred. Experiments on a single ADEFC were conducted between 50 and 900 C, and the best performance of 44 mW cm-2 in 2.0molL-1 ethanol was obtained at 850C for the Pd:Au 90:10 catalysts. This superior performance is most likely associated with enhancement of ethanol adsorption on Pd, oxidation of the intermediates, the presence of gold oxide-hydroxyl species, low mean particle diameters and better distribution of particles on the support. © 2013 Elsevier Ltd. All rights reserved.

Potentiated Electron Transference in alpha-Ag2WO4 Microcrystals with Ag Nanofilaments as Microbial Agent

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)