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Dissociation Tandem Mass Spectrometry (dissociation + tandem_mass_spectrometry)
Selected AbstractsComplete sequences of small acid-soluble proteins from Bacillus globigiiJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2004Jeffrey R. Whiteaker Abstract Three abundant small acid-soluble proteins (SASPs) from spores of Bacillus globigii were sequenced using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with post-source decay and nanoelectrospray collision-induced dissociation tandem mass spectrometry. The proteins were extracted from spores with 1 M HCl. Scanning electron micrographs of spores before and after acid extraction show that the spores retain their overall structure but have a shriveled texture following the acid treatment. Extracted SASPs were purified by high-performance liquid chromatography and molecular masses of the SASPs were identified at 7068 (SASP-1), 7332 (SASP-2), and 8889 (,-SASP). De novo peptide sequencing was used to determine the protein sequences. The correct ordering of peptide sequences was aided by mapping overlapping enzymatic digests and by comparison with homologous SASPs from Bacillus stearothermophilus. B. globigii is used in many field tests as a surrogate for B. anthracis. Thus complete SASP sequences from B. globigii will facilitate the development of methods for rapid identification of bacteria based on mass spectrometry and the examination of taxonomic relationships between Bacillus species. Copyright © 2004 John Wiley & Sons, Ltd. [source] High mass accuracy in-source collision-induced dissociation tandem mass spectrometry and multi-step mass spectrometry as complementary tools for fragmentation studies of quaternary ammonium herbicidesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2004Oscar Núñez Abstract Fragmentation studies using both an ion-trap mass analyzer and a hybrid quadrupole time-of-flight (Q-TOF) mass spectrometer were performed in order to establish the fragmentation pathways of organic molecules. A general strategy combining MSn data (n = 1,4) in an ion-trap analyzer with tandem mass spectrometry and in-source collision-induced dissociation tandem mass spectrometry (CID MS/MS) in a Q-TOF instrument was applied. The MSn data were used to propose a tentative fragmentation pathway following genealogical relationships. When several assignments were possible, MS/MS and in-source CID MS/MS (Q-TOF) allowed the elemental compositions of the fragments to be confirmed. Quaternary ammonium herbicides (quats) were used as test compounds and their fragmentation pathways were established. The elemental composition of the fragments was confirmed using the TOF analyzer with relative errors <0.0023 Da. Some fragments previously reported in the literature were reassigned taking advantage of the high mass resolution and accuracy of the Q-TOF instrument, which made it possible to solve losses where nitrogen was involved. Copyright © 2004 John Wiley & Sons, Ltd. [source] Determining the topology of virus assembly intermediates using ion mobility spectrometry,mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2010Tom W. Knapman We have combined ion mobility spectrometry,mass spectrometry with tandem mass spectrometry to characterise large, non-covalently bound macromolecular complexes in terms of mass, shape (cross-sectional area) and stability (dissociation) in a single experiment. The results indicate that the quaternary architecture of a complex influences its residual shape following removal of a single subunit by collision-induced dissociation tandem mass spectrometry. Complexes whose subunits are bound to several neighbouring subunits to create a ring-like three-dimensional (3D) architecture undergo significant collapse upon dissociation. In contrast, subunits which have only a single neighbouring subunit within a complex retain much of their original shape upon complex dissociation. Specifically, we have determined the architecture of two transient, on-pathway intermediates observed during in vitro viral capsid assembly. Knowledge of the mass, stoichiometry and cross-sectional area of each viral assembly intermediate allowed us to model a range of potential structures based on the known X-ray structure of the coat protein building blocks. Comparing the cross-sectional areas of these potential architectures before and after dissociation provided tangible evidence for the assignment of the topologies of the complexes, which have been found to encompass both the 3-fold and the 5-fold symmetry axes of the final icosahedral viral shell. Such insights provide unique information about virus assembly pathways that could allow the design of anti-viral therapeutics directed at the assembly step. This methodology can be readily applied to the structural characterisation of many other non-covalently bound macromolecular complexes and their assembly pathways. Copyright © 2010 John Wiley & Sons, Ltd. [source] Comparative analysis of glycosylinositol phosphorylceramides from fungi by electrospray tandem mass spectrometry with low-energy collision-induced dissociation of Li+ adduct ionsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2001Steven B. Levery Glycosylinositol phosphorylceramides (GIPCs) are a class of acidic glycosphingolipids (GSLs) expressed by fungi, plants, and certain parasitic organisms, but not found in cells or tissues of mammals or other higher animals. Recent characterizations of fungal GIPCs point to an emerging diversity which could rival that already known for mammalian GSLs, and which can be expected to present a multitude of challenges for the analytical chemist. Previously, the use of Li+ cationization, in conjunction with electrospray ionization mass spectrometry (ESI-MS) and low-energy collision-induced dissociation tandem mass spectrometry (ESI-MS/CID-MS), was found to be particularly effective for detailed structural analysis of monohexosylceramides (cerebrosides) from a variety of sources, including fungi, especially minor components present in mixtures at extremely low abundance. In applying Li+ cationization to characterization of GIPCs, a substantial increase in both sensitivity and fragmentation was observed on collision-induced dissociation of [M,+,Li]+ versus [M,+,Na]+ for the same components analyzed under similar conditions, similar to results obtained previously with cerebrosides. Molecular adduct fragmentation patterns were found to be systematic and characteristic for both the glycosylinositol and ceramide moieties with or without phosphate. Interestingly, significant differences were observed in fragmentation patterns when comparing GIPCs having Man,1,,,2 versus Man,1,,,6Ins core linkages. In addition, it was useful to perform tandem product ion scans on primary fragments generated in the orifice region, equivalent to ESI-(CID-MS)2 mode. Finally, precursor ion scanning from appropriate glycosylinositol phosphate product ions yielded clean molecular ion profiles in the presence of obscuring impurity peaks. The methods were applied to detailed characterization of GIPC fractions of increasing structural complexity from a variety of fungi, including a non-pathogenic Basidiomycete (mushroom), Agaricus blazei, and pathogenic Euascomycete species such as Aspergillus fumigatus, Histoplasma capsulatum, and Sporothrix schenckii. The analysis confirmed a remarkable diversity of GIPC structures synthesized by the dimorphic S. schenckii, as well as differential expression of both glycosylinositol and ceramide structures in the mycelium and yeast forms of this mycopathogen. Mass spectrometry also established that the ceramides of some A. fumigatus GIPC fractions contain very little 2-hydroxylation of the long-chain fatty- N -acyl moiety, a feature that is not generally observed with fungal GIPCs. Copyright © 2001 John Wiley & Sons, Ltd. [source] Electrospray ionisation mass spectrometric study of degradation products of quercetin, quercetin-3-glucoside and quercetin-3-rhamnoglucoside, produced by in vitro fermentation with human faecal floraRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2001Ulla Justesen Eight phenolic compounds, obtained by in vitro fermentation of quercetin, quercetin-3-glucoside and quercetin-3-rhamnoglucoside were analysed by electrospray ionisation mass spectrometry (ESI-MS). Low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) was performed on the [M,,,H], precursor ions to obtain specific fragmentation. Typical fragmentation of the phenolic acids was loss of 44 (CO2) and 18 (H2O),u. Production of m/z 108 by loss of neutral radicals, e.g. HCO2, CH3 or HCO, was also favoured. Structures of the compounds, numbered 1,8, were suggested based on the fragmentation patterns. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||