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71.
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Structural and Dynamic Characterization of the Molecular Hub Early Region 1A (E1A) from Human Adenovirus 下载免费PDF全文
Marcela Oliveira Nogueira Michele Salvi Dr. Talita Duarte Pagani Prof. Isabella C. Felli Prof. Roberta Pierattelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13010-13013
The small‐DNA human adenovirus encodes one of the most versatile molecular hubs, the E1A protein. This protein is essential for productive viral infection in human cells and a vast amount of biologically relevant data are available on its interactions with host proteins. Up to now, however, no high‐resolution structural and dynamic information on E1A is available despite its important biological role. Among the different spliced variants of E1A, two are expressed at high level in the early stage of infection. These are 243 and 289 residues isoforms. Herein, we present their NMR characterization, showing that they are both highly disordered, but also demonstrate a certain heterogeneous behavior in terms of structural and dynamic properties. Furthermore, we present the characterization of the isolated domain of the longer variant, known as CR3. This study opens the way to understanding at the molecular level how E1A functions. 相似文献
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Alfred Schmidpeter Angela Willhalm Jürgen Kroner Roberta O. Day Joan M. Holmes Robert R. Holmes 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):495-498
Abstract Phosphamethincyanines prepared in 1964 by Dimroth and Hoffmann were among the first compounds with two-coordinate phosphorus. They are special cases of 2-phospha-allylic cations. Simple representatives of this type become available from the reaction of imidoyl chlorides with tris(trimethylsily1)phosphane. 相似文献
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Dr. Roberta Pievo Brigitta Angerstein Dr. Alistair J. Fielding Dr. Christian Koch Prof. Dr. Ivo Feussner Prof. Dr. Marina Bennati 《Chemphyschem》2013,14(18):4094-4101
Electron paramagnetic resonance (EPR) spectroscopy in combination with the rapid freeze‐quench (RFQ) technique is a well‐established method to trap and characterize intermediates in chemical or enzymatic reactions at the millisecond or even shorter time scales. The method is particularly powerful for mechanistic studies of enzymatic reactions when combined with high‐frequency EPR (ν≥90 GHz), which permits the identification of substrate or protein radical intermediates by their electronic g values. In this work, we describe a new custom‐designed micro‐mix rapid freeze‐quench apparatus, for which reagent volumes for biological samples as small as 20 μL are required. The apparatus was implemented with homemade sample collectors appropriate for 9, 34, and 94 GHz EPR capillaries (4, 2, and 0.87 mm outer diameter, respectively) and the performance was evaluated. We demonstrate the application potential of the RFQ apparatus by following the enzymatic reaction of PpoA, a fungal dioxygenase producing hydro(pero)xylated fatty acids. The larger spectral resolution at 94 GHz allows the discernment of structural changes in the EPR spectra, which are not detectable in the same samples at the standard 9 GHz frequency. 相似文献
77.
Manuel Sergi Natalia Battista Camilla Montesano Roberta Curini Mauro Maccarrone Dario Compagnone 《Analytical and bioanalytical chemistry》2013,405(2-3):785-793
Endocannabinoids (ECs) are endogenous compounds that interact with type-1 and type-2 cannabinoid receptors (CB1 and CB2), as well as non-cannabinoid receptors. The multitude of roles attributed to ECs makes them an emerging target of pharmacotherapy for a number of disparate diseases. Here a high-throughput bioanalytical method based on micro SPE (μ-SPE) followed by LC-MS/MS analysis for the simultaneous determination of the two major endocannabinoids 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide, AEA) in human plasma is presented. The chromatographic conditions obtained with the fused-core column allowed a good separation in 10 min also of the AG isomers. A very simple and reliable extraction has been optimised by means of C18-modified tips: it requires only 100 μL of plasma and allows the use of minimal volumes of organic solvent. The present method allows a rapid and effective clean-up, which also minimises the isomerisation of 2-AG. The whole procedure has been validated following the FDA guidelines for bioanalytical methods validation: the satisfactory recovery values, the negligible matrix effect and the good values of accuracy and reproducibility make it a simple and high-throughput analytical tool for clinical and biochemical studies on endocannabinoid signaling in humans. Figure
Determination of the two major endocannabinoids in human plasma by μ-SPE followed by HPLC-MS/MS 相似文献
78.
Andrea Piazzalunga Vera Bernardoni Paola Fermo Roberta Vecchi 《Analytical and bioanalytical chemistry》2013,405(2-3):1123-1132
In the last decade, our research group set up and optimised analytical techniques for the characterisation of the major components of atmospheric aerosol (i.e. secondary inorganic ions and carbonaceous material) and source markers (e.g. levoglucosan, carbonates). In this study, we present a complete overview on the most problematic aspects that can be encountered during the quantification of the two main components of aerosol, i.e. the ionic and carbonaceous fractions. More in detail, different liquid chromatographic approaches were set up for main ions and anhydrosugars determination. Quality assurance procedures (i.e. tests on data reliability) were applied during the set-up phase and they are presented in this work. As regards the carbonaceous component characterisation, two evolved gas analysis techniques were set up and applied: the thermogravimetric technique coupled to the Fourier transformed infrared spectroscopy (TGA/FTIR) and the thermal–optical transmittance method (TOT). A suitable protocol for organic and elemental carbon separation was set up for the TGA/FTIR system and a comparison with the results obtained by the TOT method was carried out. Studies on the impact of filter load, field blanks, and sample composition on OC/EC quantification by the TOT method were performed. Moreover, approaches for carbonate carbon quantification on different kinds of filters were developed. It was demonstrated that this approach allows to reach the ionic balance in samples impacted by carbonate compounds. The optimised methods have been applied for the analysis of thousands of PM filters allowing the obtainment of reliable results. 相似文献
79.
Ernesto Mesto Fernando Scordari Maria Lacalamita Luisa De Cola Roberta Ragni Gianluca Maria Farinola 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):480-482
The title complex, [Ir2(C18H13FNO2S)4Cl2]·C7H8, was crystallized from dichloromethane solution under a toluene atmosphere. It is a dimeric complex in which each of the two IrIII centres is octahedrally coordinated by two bridging chloride ligands and by two chelating cyclometalated 2‐(4‐benzylsulfonyl‐2‐fluorophenyl)pyridine ligands. The crystal structure analysis unequivocally establishes the trans disposition of the two cyclometalated ligands bound to each IrIII centre, contrary to our previous hypothesis of a cis disposition. The latter was based on the 1H NMR spectra of a series of dimeric benzylsulfonyl‐functionalized dichloride‐bridged iridium complexes, including the compound described in the present work [Ragni et al. (2009). Chem. Eur. J. 15 , 136–148]. The toluene solvent molecules, embedded in cavities in the crystal structure, are highly disordered and could not be modelled successfully; their contribution was removed from the refinement using the SQUEEZE routine in the program PLATON [Spek (2009). Acta Cryst. D 65 , 148–155]. 相似文献
80.
Roberta A. Medeiros Roberto Matos Abdelkader Benchikh Boualem Saidani Catherine Debiemme-Chouvy Claude Deslouis Romeu C. Rocha-Filho Orlando Fatibello-Filho 《Analytica chimica acta》2013
Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CNx) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CNx electrode. Thus, an a-CNx film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L−1 KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CNx electrode were 0.0656 μmol L−1 for DA and 1.05 μmol L−1 for AA, whereas with the BDD electrode these values were 0.283 μmol L−1 and 0.968 μmol L−1, respectively. Furthermore, the results obtained in the analysis of the analytes in synthetic biological samples were satisfactory, attesting the potential application of the a-CNx electrode in electroanalysis. 相似文献