Organic-inorganic membranes prepared from polyether diamine and epoxy silane

Organic-inorganic polymer membranes were prepared by reacting 3-glycidoxypropyl trimethoxysilane with diamines containing polyether segments, followed by hydrolysis and condensation with acid catalysis. The films were characterized by nuclear magnetic resonance and by dynamic mechanical analysis. The rigidity of the films increased with increasing epoxy content and also with addition of tetraethoxy silane (TEOS) to the reacting medium. Water absorption experiments showed that the diffusivity is decreased with increasing TEOS content. Membranes were evaluated for nanofiltration giving cut offs down to 860 g/mol (with a water flux of 2.5 l/h m(2) bar). For gas separation, CO2/N-2 selectivity values up to 89 were obtained with CO2 permeability of 125 Barrer. (C) 1999 Elsevier Science B.V. All rights reserved.1594167119720

DENSE HYDROPHILIC COMPOSITE MEMBRANES FOR ULTRAFILTRATION

Dense hydrophilic composite membranes for ultrafiltration were prepared from an asymmetric porous PVDF support coated with a thin (< 1 mu m) layer of polyether-block-polyamide copolymer. Membranes with a molecular weight cut-off between 800 and 4500 g/mol and water permeability between 2.3 and 9.4 1 h(-1) m(-2) bar(-1) were obtained. The dry membrane surface was characterized as a dense non-porous layer when observed by scanning electron microscopy. When compared to other commercial membranes and to the non-coated porous PVDF support in the ultrafiltration of oil-water waste, the performance of the composite membranes was comparable to the Amicon YM30 cellulose membrane with lower susceptibility to fouling.10641671495

Poly(dimethylsiloxane) networks modified with poly (phenylsilsesquioxane)s: Synthesis, structural characterisation and evaluation of the thermal stability and gas permeability

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Self-supported translucent films constituted of semi-inorganic polymeric materials were prepared by sol-gel process from poly(phenylsilsesquioxane) (PPSQ) and poly(dimethylsiloxane) (PDMS), modified by diphenylsilanediol (DPS), phenyltriethoxysilane (PTES) and/or tetraethoxysilane (TEOS). These materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). Permeability to N-2, O-2, CH4 and CO2 and selectivity for a specific gas pair were investigated using the time-lag method. In the gas separation process high permeability and selectivity coefficients were observed, particularly for the membrane containing DPS and PTES as additives, which presented potential applications in the separation of CO2/CH4 and CO2/N-2. The materials also showed good thermal stability, which could be correlated to the relative amounts between di-functional (D), tri-functional (T) and tetra-functional (Q) silicon units. (c) 2008 Elsevier Ltd. All rights reserved.441030803086Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [03/09962-1]CNPq [305916/2006-8

Structural characterization of the H-NS protein from Xylella fastidiosa and its interaction with DNA

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The nucleoid-associated protein H-NS is a major component of the bacterial nucleoid involved in DNA compaction and transcription regulation. The NMR solution structure of the Xylella fastidiosa H-NS C-terminal domain (residues 56-134) is presented here and consists of two beta-strands and two alpha helices, with one loop connecting the two beta-strands and a second loop connecting the second beta strand and the first helix. The amide H-1 and N-15 chemical shift signals for a sample of XfH-NS56-134 were monitored in the course of a titration series with a 14-bp DNA duplex. Most of the residues involved in contacts to DNA are located around the first and second loops and in the first helix at a positively charged side of the protein surface. The overall structure of the Xylella H-NS C-terminal domain differ significantly from Escherichia coil and Salmonella enterica H-NS proteins, even though the DNA binding motif in loop 2 adopt similar conformation, as well as beta-strand 2 and loop 1. Interestingly, we have also found that the DNA binding site is expanded to include helix 1, which is not seen in the other structures. (C) 2012 Elsevier Inc. All rights reserved.52612228Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [07/50573-6, 07/55128-0, 02/02772-6

The NMR-derived solution structure of a new cationic antimicrobial peptide from the skin secretion of the anuran Hyla punctata

Amphibian skin secretions constitute an important source of molecules for antimicrobial drug research in order to combat the increasing resistance of pathogens to conventional antibiotics. Among the various types of substances secreted by the dermal granular amphibian glands, there is a wide range of peptides and proteins, often displaying potent antimicrobial activities and providing an effective defense system against parasite infection. In the present work, we report the NMR solution structure and the biological activity of a cationic 14-residue amphiphilic alpha-helical polypeptide named Hylaseptin P1 ( HSP1), isolated from the skin secretion of the hylid frog Hyla punctata. The peptide antimicrobial activity was verified against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, whereas no significant lytic effect was detected toward red or white blood cells.27913130181302

Structural Analysis of Intermolecular Interactions in the Kinesin Adaptor Complex Fasciculation and Elongation Protein Zeta 1/Short Coiled-Coil Protein (FEZ1/SCOCO)

Cytoskeleton and protein trafficking processes, including vesicle transport to synapses, are key processes in neuronal differentiation and axon outgrowth. The human protein FEZ1 (fasciculation and elongation protein zeta 1 / UNC-76, in C. elegans), SCOCO (short coiled-coil protein / UNC-69) and kinesins (e. g. kinesin heavy chain / UNC116) are involved in these processes. Exploiting the feature of FEZ1 protein as a bivalent adapter of transport mediated by kinesins and FEZ1 protein interaction with SCOCO (proteins involved in the same path of axonal growth), we investigated the structural aspects of intermolecular interactions involved in this complex formation by NMR (Nuclear Magnetic Resonance), cross-linking coupled with mass spectrometry (MS), SAXS (Small Angle X-ray Scattering) and molecular modelling. The topology of homodimerization was accessed through NMR (Nuclear Magnetic Resonance) studies of the region involved in this process, corresponding to FEZ1 (92-194). Through studies involving the protein in its monomeric configuration (reduced) and dimeric state, we propose that homodimerization occurs with FEZ1 chains oriented in an anti-parallel topology. We demonstrate that the interaction interface of FEZ1 and SCOCO defined by MS and computational modelling is in accordance with that previously demonstrated for UNC-76 and UNC-69. SAXS and literature data support a heterotetrameric complex model. These data provide details about the interaction interfaces probably involved in the transport machinery assembly and open perspectives to understand and interfere in this assembly and its involvement in neuronal differentiation and axon outgrowth.810Fundacao de Amparo a Pesquisa do Estado Sao PauloConselho Nacional de Pesquisa e Desenvolvimento [471355/2010-0]Centro Nacional de Pesquisa em Energia e Materiais / Laboratorio Nacional de BiocienciasConselho Nacional de Pesquisa e Desenvolvimento [471355/2010-0

Functional Diversification of Cerato-Platanins in Moniliophthora perniciosa as Seen by Differential Expression and Protein Function Specialization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Cerato-platanins (CP) are small, cysteine-rich fungal-secreted proteins involved in the various stages of the host-fungus interaction process, acting as phytotoxins, elicitors, and allergens. We identified 12 CP genes (MpCP1 to MpCP12) in the genome of Moniliophthora perniciosa, the causal agent of witches' broom disease in cacao, and showed that they present distinct expression profiles throughout fungal development and infection. We determined the X-ray crystal structures of MpCP1, MpCP2, MpCP3, and MpCP5, representative of different branches of a phylogenetic tree and expressed at different stages of the disease. Structure-based biochemistry, in combination with nuclear magnetic resonance and mass spectrometry, allowed us to define specialized capabilities regarding self-assembling and the direct binding to chitin and N-acetyl-glucosamine (NAG) tetramers, a fungal cell wall building block, and to map a previously unknown binding region in MpCP5. Moreover, fibers of MpCP2 were shown to act as expansin and facilitate basidiospore germination whereas soluble MpCP5 blocked NAG6-induced defense response. The correlation between these roles, the fungus life cycle, and its tug-of-war interaction with cacao plants is discussed.261112811293Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)LNBio [D03B-MX1, W01B-MX2]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2010/51884-8, 2010/14504-2, 2010/51891-4]CNPq [400796/2012-0]LNBio [D03B-MX1, W01B-MX2

Enabling adoption of 2D-NMR for the higher order structure assessment of monoclonal antibody therapeutics

The increased interest in using monoclonal antibodies (mAbs) as a platform for biopharmaceuticals has led to the need for new analytical techniques that can precisely assess physicochemical properties of these large and very complex drugs for the purpose of correctly identifying quality attributes (QA). One QA, higher order structure (HOS), is unique to biopharmaceuticals and essential for establishing consistency in biopharmaceutical manufacturing, detecting process-related variations from manufacturing changes and establishing comparability between biologic products. To address this measurement challenge, two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) methods were introduced that allow for the precise atomic-level comparison of the HOS between two proteins, including mAbs. Here, an inter-laboratory comparison involving 26 industrial, government and academic laboratories worldwide was performed as a benchmark using the NISTmAb, from the National Institute of Standards and Technology (NIST), to facilitate the translation of the 2D-NMR method into routine use for biopharmaceutical product development. Two-dimensional 1H,15N and 1H,13C NMR spectra were acquired with harmonized experimental protocols on the unlabeled Fab domain and a uniformly enriched-15N, 20%-13C-enriched system suitability sample derived from the NISTmAb. Chemometric analyses from over 400 spectral maps acquired on 39 different NMR spectrometers ranging from 500 MHz to 900 MHz demonstrate spectral fingerprints that are fit-for-purpose for the assessment of HOS. The 2D-NMR method is shown to provide the measurement reliability needed to move the technique from an emerging technology to a harmonized, routine measurement that can be generally applied with great confidence to high precision assessments of the HOS of mAb-based biotherapeutics