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Full-Text Articles in Physical Sciences and Mathematics
Direct Detection Of Additives And Degradation Products From Polymers By Liquid Extraction Surface Analysis Employing Chip-Based Nanospray Mass Spectrometry, Martin Paine, Phillip Barker, Shane A. Maclaughlin, Todd W. Mitchell, Stephen J. Blanksby
Direct Detection Of Additives And Degradation Products From Polymers By Liquid Extraction Surface Analysis Employing Chip-Based Nanospray Mass Spectrometry, Martin Paine, Phillip Barker, Shane A. Maclaughlin, Todd W. Mitchell, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
Rationale: Polymer-based surface coatings in outdoor applications experience accelerated degradation due to exposure to solar radiation, oxygen and atmospheric pollutants. These deleterious agents cause undesirable changes to the polymers aesthetic and mechanical properties reducing its lifetime. The use of antioxidants such as hindered amine light stabilisers (HALS) retard these degradative processes, however, mechanisms for HALS action and polymer degradation are poorly understood. Methods: Detection of the hindered amine light stabiliser (HALS) TINUVIN®123 (bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate) and the polymer degradation products directly from a polyester-based coil coating was achieved by liquid extraction surface analysis (LESA) coupled to a triple quadrupole QTRAP® …
Nanoesi Mass Spectrometry Of Rubisco And Rubisco Activase Structures And Their Interactions With Nucleotides And Sugar Phosphates, Michelle Blayney, Spencer M. Whitney, Jennifer L. Beck
Nanoesi Mass Spectrometry Of Rubisco And Rubisco Activase Structures And Their Interactions With Nucleotides And Sugar Phosphates, Michelle Blayney, Spencer M. Whitney, Jennifer L. Beck
Faculty of Science - Papers (Archive)
Ribulose bisphosphate carboxylase/oxygenase (Rubisco) is the protein that is responsible for the fixation of carbon dioxide in photosynthesis. Inhibitory sugar phosphate molecules, which can include its substrate ribulose-1,5- bisphosphate (RuBP), can bind to Rubisco catalytic sites and inhibit catalysis. These are removed by interaction with Rubisco activase (RA) via an ATP hydrolytic reaction. Here we show the first nanoESI mass spectra of the hexadecameric Rubisco and of RA from a higher plant (tobacco). The spectra of recombinant, purified RA revealed polydispersity in its oligomeric forms (up to hexamer) and that ADP was bound. ADP was removed by dialysis against a …
Identification Of Phospholipids In Human Meibum By Nano-Electrospray Ionisation Tandem Mass Spectrometry, Jennifer T. Saville, Zhenjun Zhao, Mark Dp Willcox, Manjula A. Ariyavidana, Stephen J. Blanksby, Todd W. Mitchell
Identification Of Phospholipids In Human Meibum By Nano-Electrospray Ionisation Tandem Mass Spectrometry, Jennifer T. Saville, Zhenjun Zhao, Mark Dp Willcox, Manjula A. Ariyavidana, Stephen J. Blanksby, Todd W. Mitchell
Faculty of Science - Papers (Archive)
Meibum is believed to be the major source of tear !lm lipids, which are vital in the prevention of excessevaporation of the aqueous phase. The complete lipid composition of meibum has yet to be established.While earlier studies reported the presence of phospholipids in human meibum, recent mass spectrometricstudies have not detected them. In this study we use electrospray ionisation tandem massspectrometry to investigate the presence of phospholipids in meibum and provide comparison to thephospholipid pro!le of tears.Lipids were extracted from human meibum and tear samples using standard biphasic methods andanalysed by nano-electrospray ionisation tandem mass spectrometry using targeted ion scans. …
A Mass Spectrometric Investigation Of Novel Quadruplex Dna-Selective Berberine Derivatives, Karina Gornall, Siritron Samosorn, Bongkot Tanwirat, Apichart Suksamrarn, John B. Bremner, Michael J. Kelso, Jennifer L. Beck
A Mass Spectrometric Investigation Of Novel Quadruplex Dna-Selective Berberine Derivatives, Karina Gornall, Siritron Samosorn, Bongkot Tanwirat, Apichart Suksamrarn, John B. Bremner, Michael J. Kelso, Jennifer L. Beck
Faculty of Science - Papers (Archive)
ESI mass spectrometry was used to assess the binding of 13-substituted, 5-nitro-2-phenylindolyl- and 2-naphthalenyl-based berberine derivatives to inter- and intramolecular G-quadruplex DNA molecules. In contrast with the parent berberine, the compounds showed selectivity for quadruplex over duplex DNA and stabilised the quadruplex structure. They represent a new class of quadruplex DNA-selective ligands. © 2010 The Royal Society of Chemistry.
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Faculty of Science - Papers (Archive)
The analysis of complex volatile mixtures by gas chromatography-mass spectrometry (GC-MS) is a time-consuming process. It involves separation and identification of the components based on their retention times and fragmentation patterns, followed by determination of their relative percentages from integration of their peak areas. Herein we show that multivariate statistical analysis of the relative abundances of the m/z values obtained from the average mass scans (AMS) of the complex mixture is a faster and potentially more reliable method of assessing these mixtures. To achieve this, 15 model complex mixtures, were prepared comprising varying amounts of 10 different constituents. The AMS …
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Faculty of Science - Papers (Archive)
Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground …
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our …
Nmr Study Of Complexes Between Low Molecular Mass Inhibitors And The West Nile Virus Ns2b-Ns3 Protease, X Su, Kiyoshi Ozawa, Hiromasa Yagi, S P. Lim, D Wen, D Ekonomiuk, D Huang, T Keller, S Sonntag, A Caflisch, S G. Vasudevan, G Otting
Nmr Study Of Complexes Between Low Molecular Mass Inhibitors And The West Nile Virus Ns2b-Ns3 Protease, X Su, Kiyoshi Ozawa, Hiromasa Yagi, S P. Lim, D Wen, D Ekonomiuk, D Huang, T Keller, S Sonntag, A Caflisch, S G. Vasudevan, G Otting
Faculty of Science - Papers (Archive)
The two-component NS2B-NS3 protease of West Nile virus is essential for its replication and presents an attractive target for drug development. Here, we describe protocols for the high-yield expression of stable isotope-labelled samples in vivo and in vitro. We also describe the use of NMR spectroscopy to determine the binding mode of new low molecular mass inhibitors of the West Nile virus NS2B-NS3 protease which were discovered using high-throughput in vitro screening. Binding to the substrate-binding sites S1 and S3 is confirmed by intermolecular NOEs and comparison with the binding mode of a previously identified low molecular mass inhibitor. Our …
Comparison Of Mass Spectrometry And Other Techniques For Probing Interactions Between Metal Complexes And Dna, Thitima Urathamakul, Daniel J. Waller, Jennifer L. Beck, Janice Aldrich-Wright, Stephen F. Ralph
Comparison Of Mass Spectrometry And Other Techniques For Probing Interactions Between Metal Complexes And Dna, Thitima Urathamakul, Daniel J. Waller, Jennifer L. Beck, Janice Aldrich-Wright, Stephen F. Ralph
Faculty of Science - Papers (Archive)
Electrospray ionization mass spectrometry (ESI-MS) was used to study the binding interactions of two series of ruthenium complexes, [Ru(phen)2L]2+ and [RuL′2(dpqC)]2+, to a double stranded DNA hexadecamer, and derive orders of relative binding affinity. These were shown to be in good agreement with orders of relative binding affinity derived from absorption and circular dichroism (CD) spectroscopic examination of the same systems and from DNA melting curves. However, the extent of luminescence enhancement caused by the addition of DNA to solutions of the ruthenium complexes showed little correlation with orders of binding affinity derived from ESI-MS or any of the other …
Reactions Of The Hydroperoxide Anion With Dimethyl Methylphosphonate In An Ion Trap Mass Spectrometer: Evidence For A Gas Phase A-Effect, Andrew M Mcanoy, Martin Paine, Stephen J. Blanksby
Reactions Of The Hydroperoxide Anion With Dimethyl Methylphosphonate In An Ion Trap Mass Spectrometer: Evidence For A Gas Phase A-Effect, Andrew M Mcanoy, Martin Paine, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
The gas phase degradation reactions of the chemical warfare agent (CWA) simulant, dimethyl methylphosphonate (DMMP), with the hydroperoxide anion (HOO–) were investigated using a modified quadrupole ion trap mass spectrometer. The HOO– anion reacts readily with neutral DMMP forming two significant product ions at m/z 109 and m/z 123. The major reaction pathways correspond to (i) the nucleophilic substitution at carbon to form [CH3P(O)(OCH3)O]– (m/z 109) in a highly exothermic process and (ii) exothermic proton transfer. The branching ratios of the two reaction pathways, 89% and 11% respectively, indicate that the …
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
Ions formed from lipids during electrospray ionization of crude lipid extracts have been mass-selected within a quadrupole linear ion trap mass spectrometer and allowed to react with ozone vapor. Gas-phase ion−molecule reactions between unsaturated lipid ions and ozone are found to yield two primary product ions for each carbon−carbon double bond within the molecule. The mass-to-charge ratios of these chemically induced fragments are diagnostic of the position of unsaturation within the precursor ion. This novel analytical technique, dubbed ozone-induced dissociation (OzID), can be applied both in series and in parallel with conventional collision-induced dissociation (CID) to provide near-complete structural assignment …
Detection Of Al(Iii) And Ga(Iii) Complexes With Morin By Electrospray Ionization Mass Spectrometry, John B. Bremner, Larry A. Hick, Jody Morgan, Saowanee Rattanaphani, Vichitr Rattanaphani, C Septhum
Detection Of Al(Iii) And Ga(Iii) Complexes With Morin By Electrospray Ionization Mass Spectrometry, John B. Bremner, Larry A. Hick, Jody Morgan, Saowanee Rattanaphani, Vichitr Rattanaphani, C Septhum
Faculty of Science - Papers (Archive)
The Al(III) and Ga(III) complexes formed by morin (M) in aqueous solution were investigated by means of electrospray ionization mass spectrometry (ESI-MS). In the full scan mass spectra, Al:M showed 1:2 and 2:3 stoichiometric ratios. When (S)-N-acetylserine methyl ester (Ser), as a partial mimic of the serine residue in silk, was added to Al:M and Ga:M complexes in aqueous solution, the mass spectra of Ser:Al:M showed 1:1:1 and 1:1:2 stoichiometric ratios. The patterns of the mass spectra of Ga:M and Ser:Ga:M complexes were similar to those for the corresponding Al(III) complexes. Calculated heats of formation of potential structures of the …
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Faculty of Science - Papers (Archive)
Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. …
Recruitment Failure And Shifts In Community Structure Following Mass Mortality Limit Recovery Prospects Of Black Abalone, C. Melissa Miner, Jessica M. Altstatt, Peter T. Raimondi, Todd E. Minchinton
Recruitment Failure And Shifts In Community Structure Following Mass Mortality Limit Recovery Prospects Of Black Abalone, C. Melissa Miner, Jessica M. Altstatt, Peter T. Raimondi, Todd E. Minchinton
Faculty of Science - Papers (Archive)
Mass mortalities of species can fundamentally alter the structure of natural communities, which can in turn negatively impact species’ recovery. Beginning in 1994, some of the largest remaining populations of black abaloneHaliotis cracherodii on the mainland coast of California, experienced mass mortalities due to the fatal disease called ‘withering syndrome’, which led to its listing as a species of concern by the USA National Marine Fisheries Service. We have been monitoring black abalone populations along the coast of southern and central California since 1992, and detection of withering syndrome at our southernmost site prompted us to investigate how the …
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
Faculty of Science - Papers (Archive)
The application of mass spectrometry (MS) to the study of progressively larger and more complex macromolecular assemblies is proving increasingly useful for structural biologists. The scope of this approach has recently been widened through the application of a tandem MS procedure. This two-step technique involves the selection of specific assemblies in the gas phase, and inducing their dissociation through collisions with argon atoms. Here we investigate the mechanism of this process and show that dissociation of subunits from a macromolecular assembly follows a sequential pathway, with the partitioning of charge between the dissociation products governed primarily by their relative surface …
The Epididymal Soluble Prion Protein Forms A High-Molecular-Mass Complex In Association With Hydrophobic Proteins, Heath W. Ecroyd, Maya Belghazi, Jean-Louis Dacheux, Jean-Luc Gatti
The Epididymal Soluble Prion Protein Forms A High-Molecular-Mass Complex In Association With Hydrophobic Proteins, Heath W. Ecroyd, Maya Belghazi, Jean-Louis Dacheux, Jean-Luc Gatti
Faculty of Science - Papers (Archive)
We have shown previously that a 'soluble' form of PrP (prion protein), not associated with membranous vesicles, exists in the male reproductive fluid [Ecroyd, Sarradin, Dacheux and Gatti (2004) Biol. Reprod. 71, 993-1001]. Attempts to purify this 'soluble' PrP indicated that it behaves like a high-molecular-mass complex of more than 350 kDa and always co-purified with the same set of proteins. The main associated proteins were sequenced by MS and were found to match to clusterin (apolipoprotein J), BPI (bacterial permeability-increasing protein), carboxylesterase-like urinary excreted protein (cauxin), beta-mannosidase and beta-galactosidase. Immunoblotting and enzymatic assay confirmed the presence of clusterin and …
Probing Dna Selectivity Of Ruthenium Metallointercalators Using Esi Mass Spectrometry, Jennifer L. Beck, Rajesh Gupta, Thitima Urathamakul, Nyree L. Williamson, Margaret Sheil, Janice Aldrich-Wright, Stephen F. Ralph
Probing Dna Selectivity Of Ruthenium Metallointercalators Using Esi Mass Spectrometry, Jennifer L. Beck, Rajesh Gupta, Thitima Urathamakul, Nyree L. Williamson, Margaret Sheil, Janice Aldrich-Wright, Stephen F. Ralph
Faculty of Science - Papers (Archive)
ESI mass spectra show that up to five ruthenium molecules can bind non-covalently to double stranded 16mer DNA, and provide information on the relative affinity and DNA sequence selectivity of different ruthenium complexes.
Electrospray Ionisation Mass Spectrometry Of Ruthenium And Palladium Complexes With Oligonucleotides, Jennifer L. Beck, Amy Humphries, Margaret Sheil, Stephen F. Ralph
Electrospray Ionisation Mass Spectrometry Of Ruthenium And Palladium Complexes With Oligonucleotides, Jennifer L. Beck, Amy Humphries, Margaret Sheil, Stephen F. Ralph
Faculty of Science - Papers (Archive)
No abstract provided.