(Dimethylphosphoryl)methanaminium nitrate

In the crystal of the title salt, C3H11NOP+·NO3−, dicationic inversion dimers are head-to-tail connected by a pair of strong N—H...O hydrogen bonds. The resulting graph-set descriptor of this ring system is R22(10). The nitrate counter-anions connect the dicationic dimers via N—H...O hydrogen bonds, forming two-dimensional networks in the bc plane

The US Reaction to the 2009 Iranian Election: The End of ‘Regime Change’ Politics

International audienceA method that allows partial denaturation of protein ligands in Bi- and Zn-protein complexes, leaving the metal coordination centre intact, was developed. It was based on the reduction of the S-S bridges with tris(2-carboxyl)phosphine followed by derivatization with iodoacetamide. Consequently conditions that allow the separation of Bi- and Zn-protein complexes using SDS electrophoresis were found. The separation efficiency was much higher than that in non-denaturating blue native electrophoresis. The method allowed the detection of seven Bi-binding protein candidates in H. pylori treated with bismuth subcitrate, some of which - fructose-bisphosphate aldolase (33.6 kDa), urease alpha subunit (26.4 kDa), and the 16.8 kDa proteins: 30S ribosomal protein S6 and neutrophil activating protein (NapA) - were bio-induced during the treatment. The method also allowed the monitoring of the changes in the Zn-proteome during treatment of H. pylori with the Bi-drug, which was found to increase the concentration of the Zn-binding proteins with particularly strong expression of the urease, S-adenosylmethionine synthetase and the above 16.8 kDa proteins. © 2012 The Royal Society of Chemistry

Large-scale speciation of selenium in rice proteins using ICP-MS assisted electrospray MS/MS proteomics

International audienceA Se-targeted bottom-up proteomics approach was developed for the identification of Se-containing proteins in rice grown naturally on seleniferous soils. The proteins were separated by 2D gel electrophoresis. The position of Se-containing spots was tentatively identified by the correlation between the 1D isoelectrofocusing (IEF) and 1D SDS electropherograms of a sample aliquot and confirmed by 78Se imaging in the 2D gel. The method was complemented by the ICP-MS assisted shotgun proteomics approach. The proteins were identified by capHPLC with the dual ICP MS and electrospray Orbitrap MS detection. The first ever comprehensive study of rice selenoproteome revealed the presence of selenium, as both selenomethionine (SeMet) and selenocysteine (SeCys) residues, in a dozen proteins including a 19 kDa globulin, granule-bound starch synthase, and the family of glutelin-type seed storage proteins

Thermomorphic Multiphase Systems: Switchable Solvent Mixtures for the Recovery of Homogeneous Catalysts in Batch and Flow Processes

Over the past 20 years, thermomorphic multiphase systems (TMS) have been used as a versatile and elegant strategy for the recovery and recycling of homogeneous transition-metal catalysts, in both batch-scale experiments and continuously operated processes. TMS ensure a homogeneous reaction in a monophasic reaction mixture at reaction temperature and the recovery of the homogeneous transition-metal catalyst through liquid-liquid separation at a lower separation temperature. This is achieved by using at least two solvents, which have a highly temperature-sensitive miscibility gap. The suitability of commercially available solvents makes this approach highly interesting from an industrial point of view. For the first time, herein, all studies in the area of TMS are reviewed, with the aim of providing a concise and integral representation of this approach for homogeneous catalyst recovery. In addition to the discussion of examples from the literature, the thermodynamic fundamentals of the temperature-dependent miscibility of solvents are also presented. This review also gives key indicators to compare different TMS approaches, for instance. In this way, new solvent combinations and in-depth research, as well as improvements to existing approaches, can be addressed and promoted

A comparative study of the Se/S substitution in methionine and cysteine in Se-enriched yeast using an inductively coupled plasma mass spectrometry (ICP MS)-assisted proteomics approach

International audienceA proteomics approach based on 2D gel electrophoresis followed by HPLC-electrospray Orbitrap MS/MS was developed to investigate the replacement and the degree of the Se/S substitution in methionine and cysteine in Se-rich yeast. Capillary HPLC-inductively coupled plasma mass spectrometry (ICP-MS), employed in parallel to capHPLC-ESI MS, indicated the virtual independence of the ESI MS response of the peptide structure (in the elution range of 30-65% methanol), and hence, the use of ESI MS data to determine the SeCys/Cys and SeMet/Met substitution ratios. For the first time a considerable incorporation of selenocysteine (SeCys) in proteins of the yeast proteome despite the absence of the UGA codon was demonstrated. The SeMet/Met and SeCys/Cys ratios were determined in a large number of peptides (57 and 26, respectively) issued from the tryptic digestion of 19 Se-containing proteins located in the gel by laser ablation-ICP MS imaging. The average Se/S substitution in methionine was 42.9. ±. 35.0 and was protein dependent with ratios ranging from 5 to 160 for individual peptides. The substitution of sulphur in cysteine (14.1. ±. 4.8%) in the cysteine-containing peptides was relatively similar (ratios from 9 to 23). Taking into account that the cysteine/methionine average ratio (2:1) in the yeast protein fraction, the study allowed the conclusion that 10-15% of selenium present in Se-enriched yeast is in the form of selenocysteine making up the mass balance of selenium species. Biological significance: For the first time a considerable incorporation of selenocysteine (SeCys) in proteins of the yeast proteome despite the absence of the UGA codon was demonstrated. It was achieved using a proteomics approach based on 2D gel electrophoresis followed by HPLC-electrospray Orbitrap MS/MS in order to investigate the replacement and the degree of the Se/S substitution in methionine and cysteine in Se-rich yeast