1
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Ucur B, Shiels OJ, Blanksby SJ, Trevitt AJ. Observation of Solvent-Dependence in the Mechanism of Neutral-Catalyzed Isomerization of para-Aminobenzoic Acid Protomers. J Am Soc Mass Spectrom 2024. [PMID: 38523556 DOI: 10.1021/jasms.3c00433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Proton-transfer reactions are commonplace during electrospray ionization (ESI) mass spectrometry experiments and are often responsible for imparting charge to analyte molecules. Multiple protonation-site isomers (protomers) can arise for polyfunctional molecules and these isomers can interconvert via solvent-mediated proton transfer reactions during various stages of the ESI process. Studying the populations and interconversion of protonation isomers provides key insight into the ESI process, ion-molecule interactions, and ion dissociation mechanisms. An archetype molecule to study protomer interconversion fundamentals in this context is para-aminobenzoic acid (pABA), where both the amino and carboxylic acid protomers are typically formed under ESI and the mechanisms for interconversion are still under refinement. Using ion-trap mass spectrometry reaction kinetics (2.5 mTorr, 300 K), this study examines gas-phase interconversion catalysis of pABA protomers by seven neutral species, which are commen solvents and additives used for ESI: water, formic acid, methanol, ethanol, propanol, ammonia, and acetonitrile. Three distinct reaction cases are reported: (i) formic acid, methanol, ethanol, propanol, and ammonia each catalyze the interconversion between the amino and carboxylic acid protomers via a n = 1 solvent-molecule vehicle mechanism; (ii) for water, however, a n = 6 adduct complex is detected and this suggests that the observed protomer interconversion occurs through a Grotthuss mechanism, in accord with literature reports; (iii) acetonitrile inhibits proton transfer by the formation of particularly stable n = 1 and 2 adduct complexes. The second-order rate constants for the protomer interconversion are observed to increase in the following order: H2O < HCO2H < MeOH < EtOH < PrOH < NH3. Potential energy schemes are reported for all neutral-catalyzed proton transfer reactions using the DSD-PBEP86-D3(BJ)/aug-cc-pVDZ level of theory. A central transition state, which connects the protonation site adducts, is shown to be the key rate-limiting step. The energy of this transition state is sensitive to the proton affinity of the neutral solvent, and this is supported by the correlation between the reaction rate and the solvent proton affinity.
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Affiliation(s)
- Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and the School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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2
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Michael JA, Young RSE, Balez R, Jekimovs LJ, Marshall DL, Poad BLJ, Mitchell TW, Blanksby SJ, Ejsing CS, Ellis SR. Deep Characterisation of the sn-Isomer Lipidome Using High-Throughput Data-Independent Acquisition and Ozone-Induced Dissociation. Angew Chem Int Ed Engl 2024; 63:e202316793. [PMID: 38165069 DOI: 10.1002/anie.202316793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/12/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
In recent years there has been a significant interest in the development of innovative lipidomics techniques capable of resolving lipid isomers. To date, methods applied to resolving sn-isomers have resolved only a limited number of species. We report a workflow based on ozone-induced dissociation for untargeted characterisation of hundreds of sn-resolved glycerophospholipid isomers from biological extracts in under 20 min, coupled with an automated data analysis pipeline. It provides an order of magnitude increase in the number of sn-isomer pairs identified as compared to previous reports and reveals that sn-isomer populations are tightly regulated and significantly different between cell lines. The sensitivity of this method and potential for de novo molecular discovery is further demonstrated by the identification of unexpected lipids containing ultra-long monounsaturated acyl chains at the sn-1 position.
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Affiliation(s)
- Jesse A Michael
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Reuben S E Young
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Rachelle Balez
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Lachlan J Jekimovs
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - David L Marshall
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Todd W Mitchell
- Molecular Horizons and School of Medical, Indigenous and Health Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Christer S Ejsing
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Shane R Ellis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
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3
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Shiels OJ, Marlton SJP, Poad BLJ, Blanksby SJ, da Silva G, Trevitt AJ. Gas-Phase Phenyl Radical + O 2 Reacts via a Submerged Transition State. J Phys Chem A 2024; 128:413-419. [PMID: 38174881 DOI: 10.1021/acs.jpca.3c06878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
In the gas-phase chemistry of the atmosphere and automotive fuel combustion, peroxyl radical intermediates are formed following O2 addition to carbon-centered radicals which then initiate a complex network of radical reactions that govern the oxidative processing of hydrocarbons. The rapid association of the phenyl radical-a fundamental radical related to benzene-with O2 has hitherto been modeled as a barrierless process, a common assumption for peroxyl radical formation. Here, we provide an alternate explanation for the kinetics of this reaction by deploying double-hybrid density functional theory (DFT), at the DSD-PBEP86-D3(BJ)/aug-cc-pVTZ level of theory, and locate a submerged adiabatic transition state connected to a prereaction complex along the reaction entrance pathway. Using this potential energy scheme, experimental rate coefficients k(T) for the addition of O2 to the phenyl radical are accurately reproduced within a microcanonical kinetic model. This work highlights that purportedly barrierless radical oxidation reactions may instead be modeled using stationary points, which in turn provides insight into pressure and temperature dependence.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, the University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
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4
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Van Meurs DP, Kong D, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 9-Azahomocubane. Chemistry 2024; 30:e202303133. [PMID: 37823679 DOI: 10.1002/chem.202303133] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/13/2023]
Abstract
Homocubane, a highly strained cage hydrocarbon, contains two very different positions for the introduction of a nitrogen atom into the skeleton, e. g., a position 1 exchange results in a tertiary amine whereas position 9 yields a secondary amine. Herein reported is the synthesis of 9-azahomocubane along with associated structural characterization, physical property analysis and chemical reactivity. Not only is 9-azahomocubane readily synthesized, and found to be stable as predicted, the basicity of the secondary amine was observed to be significantly lower than the structurally related azabicyclo[2.2.1]heptane, although similar to 1-azahomocubane.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Gregory K Pierens
- Centre for Advanced imaging, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Derek P Van Meurs
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria, Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
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5
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Poad BLJ, Jekimovs LJ, Young RSE, Wongsomboon P, Marshall DL, Hansen FKM, Fulloon T, Pfrunder MC, Dodgen T, Ritchie M, Wong SCC, Blanksby SJ. Revolutions in Lipid Isomer Resolution: Application of Ultrahigh-Resolution Ion Mobility to Reveal Lipid Diversity. Anal Chem 2023; 95:15917-15923. [PMID: 37847864 DOI: 10.1021/acs.analchem.3c02658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Many families of lipid isomers remain unresolved by contemporary liquid chromatography-mass spectrometry approaches, leading to a significant underestimation of the structural diversity within the lipidome. While ion mobility coupled to mass spectrometry has provided an additional dimension of lipid isomer resolution, some isomers require a resolving power beyond the capabilities of conventional platforms. Here, we present the application of high-resolution traveling-wave ion mobility for the separation of lipid isomers that differ in (i) the location of a single carbon-carbon double bond, (ii) the stereochemistry of the double bond (cis or trans), or, for glycerolipids, (iii) the relative substitution of acyl chains on the glycerol backbone (sn-position). Collisional activation following mobility separation allowed identification of the carbon-carbon double-bond position and sn-position, enabling confident interpretation of variations in mobility peak abundance. To demonstrate the applicability of this method, double-bond and sn-position isomers of an abundant phosphatidylcholine composition were resolved in extracts from a prostate cancer cell line and identified by comparison to pure isomer reference standards, revealing the presence of up to six isomers. These findings suggest that ultrahigh-resolution ion mobility has broad potential for isomer-resolved lipidomics and is attractive to consider for future integration with other modes of ion activation, thereby bringing together advanced orthogonal separations and structure elucidation to provide a more complete picture of the lipidome.
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Affiliation(s)
- Berwyck L J Poad
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane 4000, Australia
| | - Lachlan J Jekimovs
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
| | - Reuben S E Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
| | - Puttandon Wongsomboon
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
| | - David L Marshall
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane 4000, Australia
| | - Felicia K M Hansen
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
| | - Therese Fulloon
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane 4000, Australia
| | - Michael C Pfrunder
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane 4000, Australia
| | | | | | | | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane 4000, Australia
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6
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Claes BR, Bowman AP, Poad BLJ, Heeren RMA, Blanksby SJ, Ellis SR. Isomer-Resolved Mass Spectrometry Imaging of Acidic Phospholipids. J Am Soc Mass Spectrom 2023; 34:2269-2277. [PMID: 37581874 PMCID: PMC10557375 DOI: 10.1021/jasms.3c00192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/25/2023] [Accepted: 07/27/2023] [Indexed: 08/16/2023]
Abstract
The biological functions of lipids are entirely dependent on their molecular structures with even small changes in structure─such as different sites of unsaturation─providing critical markers for changes in the underlying metabolism. Conventional mass spectrometry imaging (MSI) approaches, however, face the twin challenges of mixture and structural complexity and are typically unable to differentiate lipid isomers that differ only in the position(s) of carbon-carbon double bonds. Recent coupling of ozone-induced dissociation (OzID) with matrix-assisted laser desorption/ionization (MALDI)-MSI has demonstrated the potential to map changes in individual double-bond isomers, thus enabling visualization of the modulation in lipid desaturation in adjacent tissue types. This has, to date, only been performed in positive-ion mode due to a generally higher abundance of phosphatidylcholines (PC) in mammalian tissues and the efficient desorption/ionization of this lipid subclass. Many other glycerophospholipids (GPLs), however, are better detected in negative-ion mode as deprotonated anions. Recently, OzID has been implemented on a traveling-wave ion-mobility mass spectrometer (Waters, SYNAPT G2-Si) that provides a 50-fold increase in the rate of the gas-phase reaction between ionized lipids and ozone and a commensurate increase in sensitivity for isomer-resolved mass spectrometry. These gains are exploited here to interrogate the distributions of anionic GPL isomers in biological tissues, covering the subclasses phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylglycerol (PG), and phosphatidic acid (PA). Exploiting both ozone- and collision-induced dissociation in a single acquisition simultaneously identifies sites of unsaturation and acyl chain composition from the same mass spectrum.
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Affiliation(s)
- Britt
S. R. Claes
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Andrew P. Bowman
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Berwyck L. J. Poad
- Central
Analytical Research Facility, Queensland
University of Technology, Brisbane, Queensland 4000, Australia
- School
of Chemistry and Physics, Queensland University
of Technology, Brisbane, Queensland 4000, Australia
| | - Ron M. A. Heeren
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Stephen J. Blanksby
- Central
Analytical Research Facility, Queensland
University of Technology, Brisbane, Queensland 4000, Australia
- School
of Chemistry and Physics, Queensland University
of Technology, Brisbane, Queensland 4000, Australia
| | - Shane R. Ellis
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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7
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Fan X, Young RSE, Sun AR, Hamilton BR, Nedunchezhiyan U, Crawford R, Blanksby SJ, Prasadam I. Functional mass spectrometry imaging maps phospholipase-A2 enzyme activity during osteoarthritis progression. Theranostics 2023; 13:4636-4649. [PMID: 37649605 PMCID: PMC10465221 DOI: 10.7150/thno.86623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Background: Enzymes are central components of many physiological processes, and changes in enzyme activity are linked to numerous disease states, including osteoarthritis (OA). Assessing changes in enzyme function can be challenging because of difficulties in separating affected tissue areas that result in the homogenisation of healthy and diseased cells. Direct correlation between spatially-resolved enzyme distribution(s) and diseased cells/tissues can thus lead to advances in our understanding of OA pathophysiology. Herein, we present a method that uses mass spectrometry imaging (MSI) to visualise the distribution of lipase enzymes and their downstream lipid products in fresh bone and cartilage tissue sections. Immunohistostaining of adjacent tissue sections was then used to identify OA cells/tissues, which were then statistically correlated with molecular-level images. Methods: MSI was used to image lipase enzymes, their substrates, and their metabolic products to validate enzymatic activity and correlate to OA regions determined by immunohistochemistry (IHC). Based on the modified Mankin score, six non-OA and OA patient-matched osteochondral samples were analysed by matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI). Due to the involvement of phospholipase A2 (PLA2) in inflammatory pathways, explant tissues were treated with IL-1β to mimic inflammation observed in OA. Bovine explant tissues were then subject to MSI methods to observe the spatial distribution of PLA2. Results: Compared with non-OA samples, OA samples showed an elevated level of multiple arachidonic acid (AA)-containing phospholipids (P < 0.001), in which the elevation in the surface and deep layer cartilage of OA tissues is correlated to elevated PLA2 activity (P < 0.001). Bovine explant tissues treated with IL-1β to mimic OA pathophysiology validated these results and displayed elevated PLA2 levels in OA mimic samples relative to the controls (P < 0.001). It was established that the PLA2G2A isoform specifically was responsible for PLA2 enzyme activity changes in OA tissues (P < 0.001). Conclusion: Our results present a reliable method for imaging enzyme dynamics in OA cartilage, which sets up the foundation for future spatial enzyme dynamics in the OA field. We demonstrated that OA patients exhibit increased expression of PLA2G2A at the superficial and deep cartilage zone that degrades cartilage differently at the spatial level. A tissue-specific PLA2G2A precision inhibition may be the potential target for OA.
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Affiliation(s)
- Xiwei Fan
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Australia
- School of Mechanical, Medical & Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Reuben S. E. Young
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, Australia
- Molecular Horizons and School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, Australia
| | - Antonia Rujia Sun
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Australia
- School of Mechanical, Medical & Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Brett R. Hamilton
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Udhaya Nedunchezhiyan
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Australia
- School of Mechanical, Medical & Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Ross Crawford
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Australia
- The Prince Charles Hospital, Orthopedic department, Brisbane, Australia
| | - Stephen J. Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, Australia
| | - Indira Prasadam
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Australia
- School of Mechanical, Medical & Process Engineering, Queensland University of Technology, Brisbane, Australia
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8
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Menzel JP, Young RSE, Benfield AH, Scott JS, Wongsomboon P, Cudlman L, Cvačka J, Butler LM, Henriques ST, Poad BLJ, Blanksby SJ. Ozone-enabled fatty acid discovery reveals unexpected diversity in the human lipidome. Nat Commun 2023; 14:3940. [PMID: 37402773 DOI: 10.1038/s41467-023-39617-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/15/2023] [Indexed: 07/06/2023] Open
Abstract
Fatty acid isomers are responsible for an under-reported lipidome diversity across all kingdoms of life. Isomers of unsaturated fatty acids are often masked in contemporary analysis by incomplete separation and the absence of sufficiently diagnostic methods for structure elucidation. Here, we introduce a comprehensive workflow, to discover unsaturated fatty acids through coupling liquid chromatography and mass spectrometry with gas-phase ozonolysis of double bonds. The workflow encompasses semi-automated data analysis and enables de novo identification in complex media including human plasma, cancer cell lines and vernix caseosa. The targeted analysis including ozonolysis enables structural assignment over a dynamic range of five orders of magnitude, even in instances of incomplete chromatographic separation. Thereby we expand the number of identified plasma fatty acids two-fold, including non-methylene-interrupted fatty acids. Detection, without prior knowledge, allows discovery of non-canonical double bond positions. Changes in relative isomer abundances reflect underlying perturbations in lipid metabolism.
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Affiliation(s)
- Jan Philipp Menzel
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre for Data Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, 3010, Bern, Switzerland
| | - Reuben S E Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Faculty of Science, Medicine and Health, School of Chemistry and Molecular Bioscience, Wollongong, NSW, Australia
| | - Aurélie H Benfield
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Brisbane, QLD, 4102, Australia
| | - Julia S Scott
- South Australian Immunogenomics Cancer Institute and Freemasons Centre for Male Health and Wellbeing, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Puttandon Wongsomboon
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Lukáš Cudlman
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 542/2, 16600, Prague, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague 2, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 542/2, 16600, Prague, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague 2, Czech Republic
| | - Lisa M Butler
- South Australian Immunogenomics Cancer Institute and Freemasons Centre for Male Health and Wellbeing, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Sónia T Henriques
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Brisbane, QLD, 4102, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
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9
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Ucur B, Shiels OJ, Blanksby SJ, Trevitt AJ. Gas-Phase Internal Proton-Transfer of Protonated para-Aminobenzoic Acid Catalyzed by One Methanol Molecule. J Am Soc Mass Spectrom 2023. [PMID: 37288560 DOI: 10.1021/jasms.3c00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Electrospray ionization (ESI) is used to deliver analytes for mass analysis across a huge range of mass spectrometry applications. Despite its ubiquitous application and many mechanistic investigations, it remains that a fundamental understanding of ESI processes is not complete. In particular, all the factors that influence the populations of protonation isomers are elusive such that it remains a challenge to optimize experimental conditions to favor one isomer over another. The molecule para-aminobenzoic acid has emerged as an archetype for the study of protonation isomers, with both amino and carboxylic acid protonation site isomers (protomers) typically formed upon ESI, with the isomer ratio shown to be sensitive to several physical and chemical parameters. Here we report an ion-trap mass spectrometry study of the time-resolved methanol-catalyzed proton transfer between the amine and carboxylic acid moieties of para-aminobenzoic acid. The experimental and computational results presented are consistent with a bimolecular mechanism where isomerization is mediated by a single methanol rather than a multimolecular Grotthuss proton transfer process. Pseudo-first-order rate constants for protomer specific product ions are reported and confirm the depletion of the amino protomer is correlated to the growth of the carboxylic acid protomer. Under the controlled conditions of a low-pressure ion-trap mass spectrometer (2.5 mTorr, 300 K), the number of methanol molecules required to isomerize para-aminobenzoic acid is determined to be one, and the second-order rate constant for methanol-catalyzed isomerization is (1.9 ± 0.1) × 10-11 cm3 molecule-1 s-1. The para-aminobenzoic acid vehicle mechanism is explored computationally at the DSD-PBEP86-D3BJ/aug-cc-pVDZ level of theory and reveals that the transition state for proton transfer is submerged (-10 kJ mol-1) relative to the separated reactant energies. The findings from this paper show that single-solvent catalyzed intramolecular proton transfer reactions are possible and must be considered during the late stages of ESI to predict the site(s) of protonation and the ion's stability in the presence of solvent molecules.
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Affiliation(s)
- Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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10
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Pfrunder MC, Marshall DL, Poad BLJ, Fulloon TM, Clegg JK, Blanksby SJ, McMurtrie JC, Mullen KM. Diastereomer Resolution of M₄L₆ Coordination Cages by Ultra-High-Resolution Ion Mobility-Mass Spectrometry. Angew Chem Int Ed Engl 2023:e202302229. [PMID: 37186056 DOI: 10.1002/anie.202302229] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/17/2023]
Abstract
Coordination cages can be used for enantio- and regioselective catalysis and for the selective sensing and separation of isomeric guest molecules. Here, stereoisomers of a family of coordination cages are resolved using high-resolution cyclic ion mobility-mass spectrometry (cIM-MS). The observed ratio of diastereomers is dependent on both the metal ion and counter ion. Moreover, the point groups can be assigned through complementary NMR experiments. This method enables the identification and interrogation of the individual isomers in complex mixtures of cages which cannot be performed in solution. Furthermore, these techniques allow the stability of individual isomers within the mixture to be probed, with the T-symmetric isomers in this case shown to be more robust than the C3 and S4 analogues.
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Affiliation(s)
- Michael C Pfrunder
- Queensland University of Technology, School of Chemistry and Physics, AUSTRALIA
| | - David L Marshall
- Queensland University of Technology, Central Analytical Research Facility (CARF), AUSTRALIA
| | - Berwyck L J Poad
- Queensland University of Technology, School of Chemistry and Physics, AUSTRALIA
| | - Therese M Fulloon
- Queensland University of Technology, School of Chemistry and Physics, AUSTRALIA
| | - Jack K Clegg
- University of Queensland - Saint Lucia Campus: The University of Queensland, School of Chemistry and Molecular Biosciences, AUSTRALIA
| | - Stephen J Blanksby
- Queensland University of Technology, School of Chemistry and Physics, AUSTRALIA
| | - John C McMurtrie
- Queensland University of Technology, School of Chemistry and Physics, AUSTRALIA
| | - Kathleen Mary Mullen
- Queensland University of Technology, School of Chemistry and Physics, Faculty of Science, QUT, 2 George St, 4001, Brisbane, AUSTRALIA
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11
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Hormann RE, Fisher AM, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 1-Azahomocubane. Chem Sci 2023; 14:2821-2825. [PMID: 36937576 PMCID: PMC10016339 DOI: 10.1039/d3sc00001j] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Highly strained cage hydrocarbons have long stood as fundamental molecules to explore the limits of chemical stability and reactivity, probe physical properties, and more recently as bioactive molecules and in materials discovery. Interestingly, the nitrogenous congeners have attracted much less attention. Previously absent from the literature, azahomocubanes, offer an opportunity to investigate the effects of a nitrogen atom when incorporated into a highly constrained polycyclic environment. Herein disclosed is the synthesis of 1-azahomocubane, accompanied by comprehensive structural characterization, physical property analysis and chemical reactivity. These data support the conclusion that nitrogen is remarkably well tolerated in a highly strained environment.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology Brisbane 4000 Queensland Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, University of Queensland Brisbane 4072 Queensland Australia
| | - Robert E Hormann
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Allison M Fisher
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology Brisbane 4000 Queensland Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory Melbourne 3168 Victoria Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
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12
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Kirschbaum C, Young RSE, Greis K, Menzel JP, Gewinner S, Schöllkopf W, Meijer G, von Helden G, Causon T, Narreddula VR, Poad BLJ, Blanksby SJ, Pagel K. Establishing carbon-carbon double bond position and configuration in unsaturated fatty acids by gas-phase infrared spectroscopy. Chem Sci 2023; 14:2518-2527. [PMID: 36908944 PMCID: PMC9993887 DOI: 10.1039/d2sc06487a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
Fatty acids are an abundant class of lipids that are characterised by wide structural variation including isomeric diversity arising from the position and configuration of functional groups. Traditional approaches to fatty acid characterisation have combined chromatography and mass spectrometry for a description of the composition of individual fatty acids while infrared (IR) spectroscopy has provided insights into the functional groups and bond configurations at the bulk level. Here we exploit universal 3-pyridylcarbinol ester derivatization of fatty acids to acquire IR spectra of individual lipids as mass-selected gas-phase ions. Intramolecular interactions between the protonated pyridine moiety and carbon-carbon double bonds present highly sensitive probes for regiochemistry and configuration through promotion of strong and predictable shifts in IR resonances. Gas-phase IR spectra obtained from unsaturated fatty acids are shown to discriminate between isomers and enable the first unambiguous structural assignment of 6Z-octadecenoic acid in human-derived cell lines. Compatibility of 3-pyridylcarbinol ester derivatization with conventional chromatography-mass spectrometry and now gas-phase IR spectroscopy paves the way for comprehensive structure elucidation of fatty acids that is sensitive to regio- and stereochemical variations and with the potential to uncover new pathways in lipid metabolism.
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Affiliation(s)
- Carla Kirschbaum
- Institut für Chemie und Biochemie, Freie Universität Berlin Altensteinstraße 23a 14195 Berlin Germany .,Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Reuben S E Young
- School of Chemistry and Physics, Queensland University of Technology Brisbane QLD 4000 Australia .,Central Analytical Research Facility, Queensland University of Technology Brisbane QLD 4000 Australia
| | - Kim Greis
- Institut für Chemie und Biochemie, Freie Universität Berlin Altensteinstraße 23a 14195 Berlin Germany .,Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Jan Philipp Menzel
- School of Chemistry and Physics, Queensland University of Technology Brisbane QLD 4000 Australia .,Centre for Materials Science, Queensland University of Technology Brisbane QLD 4000 Australia
| | - Sandy Gewinner
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Wieland Schöllkopf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Gert von Helden
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
| | - Tim Causon
- Institute of Analytical Chemistry, University of Natural Resources and Life Sciences Vienna 1190 Vienna Austria
| | - Venkateswara R Narreddula
- School of Chemistry and Physics, Queensland University of Technology Brisbane QLD 4000 Australia .,Centre for Materials Science, Queensland University of Technology Brisbane QLD 4000 Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics, Queensland University of Technology Brisbane QLD 4000 Australia .,Central Analytical Research Facility, Queensland University of Technology Brisbane QLD 4000 Australia.,Centre for Materials Science, Queensland University of Technology Brisbane QLD 4000 Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics, Queensland University of Technology Brisbane QLD 4000 Australia .,Central Analytical Research Facility, Queensland University of Technology Brisbane QLD 4000 Australia.,Centre for Materials Science, Queensland University of Technology Brisbane QLD 4000 Australia
| | - Kevin Pagel
- Institut für Chemie und Biochemie, Freie Universität Berlin Altensteinstraße 23a 14195 Berlin Germany .,Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 14195 Berlin Germany
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13
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Young RSE, Flakelar CL, Narreddula VR, Jekimovs LJ, Menzel JP, Poad BLJ, Blanksby SJ. Identification of Carbon-Carbon Double Bond Stereochemistry in Unsaturated Fatty Acids by Charge-Remote Fragmentation of Fixed-Charge Derivatives. Anal Chem 2022; 94:16180-16188. [DOI: 10.1021/acs.analchem.2c03625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Reuben S. E. Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Queensland, Australia
| | - Clare L. Flakelar
- School of Behavioural and Health Sciences, Australian Catholic University, Brisbane 4014, Queensland, Australia
| | - Venkateswara R. Narreddula
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
| | - Lachlan J. Jekimovs
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
| | - Jan P. Menzel
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
| | - Berwyck L. J. Poad
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Queensland, Australia
| | - Stephen J. Blanksby
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Queensland, Australia
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Queensland, Australia
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14
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Pfrunder MC, Marshall DL, Poad BLJ, Stovell EG, Loomans BI, Blinco JP, Blanksby SJ, McMurtrie JC, Mullen KM. Exploring the Gas-Phase Formation and Chemical Reactivity of Highly Reduced M 8 L 6 Coordination Cages. Angew Chem Int Ed Engl 2022; 61:e202212710. [PMID: 36102176 PMCID: PMC9827999 DOI: 10.1002/anie.202212710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Indexed: 01/12/2023]
Abstract
Coordination cages with well-defined cavities show great promise in the field of catalysis on account of their unique combination of molecular confinement effects and transition-metal redox chemistry. Here, three coordination cages are reduced from their native 16+ oxidation state to the 2+ state in the gas phase without observable structural degradation. Using this method, the reaction rate constants for each reduction step were determined, with no noticeable differences arising following either the incorporation of a C60 -fullerene guest or alteration of the cage chemical structure. The reactivity of highly reduced cage species toward molecular oxygen is "switched-on" after a threshold number of reduction steps, which is influenced by guest molecules and the structure of cage components. These new experimental approaches provide a unique window to explore the chemistry of highly-reduced cage species that can be modulated by altering their structures and encapsulated guest species.
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Affiliation(s)
- Michael C. Pfrunder
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - David L. Marshall
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,Central Analytical Research Facility (CARF)Queensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - Berwyck L. J. Poad
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia,Central Analytical Research Facility (CARF)Queensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - Ethan G. Stovell
- School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - Benjamin I. Loomans
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - James P. Blinco
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - Stephen J. Blanksby
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia,Central Analytical Research Facility (CARF)Queensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - John C. McMurtrie
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
| | - Kathleen M. Mullen
- Centre for Materials Science (CFMS)Queensland University of Technology (QUT)2 George StreetBrisbaneQueensland4000Australia,School of Chemistry and PhysicsQueensland University of Technology2 George StreetBrisbaneQueensland4000Australia
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15
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Randolph CE, Beveridge CH, Iyer S, Blanksby SJ, McLuckey SA, Chopra G. Identification of Monomethyl Branched-Chain Lipids by a Combination of Liquid Chromatography Tandem Mass Spectrometry and Charge-Switching Chemistries. J Am Soc Mass Spectrom 2022; 33:2156-2164. [PMID: 36218280 PMCID: PMC10173259 DOI: 10.1021/jasms.2c00225] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
While various mass spectrometric approaches have been applied to lipid analysis, unraveling the extensive structural diversity of lipids remains a significant challenge. Notably, these approaches often fail to differentiate between isomeric lipids─a challenge that is particularly acute for branched-chain fatty acids (FAs) that often share similar (or identical) mass spectra to their straight-chain isomers. Here, we utilize charge-switching strategies that combine ligated magnesium dications with deprotonated fatty acid anions. Subsequent activation of these charge inverted anions yields mass spectra that differentiate anteiso-branched- from straight-chain and iso-branched-chain FA isomers with the predictable fragmentation enabling de novo assignment of anteiso branch points. The application of these charge-inversion chemistries in both gas- and solution-phase modalities is demonstrated to assign the position of anteiso-methyl branch-points in FAs and, with the aid of liquid chromatography, can be extended to de novo assignment of additional branching sites via predictable fragmentation patterns as methyl branching site(s) move closer to the carboxyl carbon. The gas-phase approach is shown to be compatible with top-down structure elucidation of complex lipids such as phosphatidylcholines, while the integration of solution-phase charge-inversion with reversed phase liquid chromatography enables separation and unambiguous identification of FA structures within isomeric mixtures. Taken together, the presented charge-switching MS-based technique, in combination with liquid chromatography, enables the structural identification of branched-chain FA without the requirement of authentic methyl-branched FA reference standards.
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Affiliation(s)
- Caitlin E. Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Connor H. Beveridge
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Sanjay Iyer
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Stephen J. Blanksby
- Central Analytical Research Facility and the School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Gaurav Chopra
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
- Department of Computer Science (by courtesy), Purdue Institutes of Drug Discovery and Integrative Neuroscience, Purdue Center for Cancer Research, West Lafayette, Indiana, 47907, USA
- Address reprint requests to: Dr. Gaurav Chopra, 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA, Phone: (765) 496-6108, Fax: (765) 494-0239,
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16
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Liu X, Jiao B, Cao W, Ma X, Xia Y, Blanksby SJ, Zhang W, Ouyang Z. Development of a Miniature Mass Spectrometry System for Point-of-Care Analysis of Lipid Isomers Based on Ozone-Induced Dissociation. Anal Chem 2022; 94:13944-13950. [PMID: 36176011 DOI: 10.1021/acs.analchem.2c03112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Disorder of lipid homeostasis is closely associated with a variety of diseases. Although mass spectrometry (MS) approaches have been well developed for the characterization of lipids, it still lacks an integrated and compact MS system that is capable of rapid and detailed lipid structural characterization and can be conveniently transferred into different laboratories. In this work, we describe a novel miniature MS system with the capability of both ozone-induced dissociation (OzID) and collision-induced dissociation (CID) for the assignment of sites of unsaturation and sn-positions in glycerolipids. A miniature ozone generator was developed, which can be operated at a relatively high pressure. By maintaining high-concentration ozone inside the linear ion trap, OzID efficiency was significantly improved for the identification of C═C locations in unsaturated lipids, with reaction times as short as 10 ms. Finally, the miniature OzID MS system was applied to the analysis of C═C locations and sn-positions of lipids from biological samples. Direct sampling and fast detection of changes in phospholipid isomers were demonstrated for the rapid discrimination of breast cancer tissue samples, showing the potential of the miniature OzID MS system for point-of-care analysis of lipid isomer biomarkers in complex samples.
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Affiliation(s)
- Xinwei Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Bin Jiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Wenbo Cao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Xiaoxiao Ma
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Yu Xia
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4000, Australia
| | - Wenpeng Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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17
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Pfrunder MC, Marshall DL, Poad BLJ, Stovell EG, Loomans BI, Blinco JP, Blanksby SJ, McMurtrie JC, Mullen KM. Exploring the Gas Phase Formation and Chemical Reactivity of Highly Reduced M8L6 Coordination Cages. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202212710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael C. Pfrunder
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - David L. Marshall
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - Berwyck L. J. Poad
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - Ethan G. Stovell
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - Benjamin I. Loomans
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - James P. Blinco
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - Stephen J. Blanksby
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - John C. McMurtrie
- QUT: Queensland University of Technology School of Chemistry and Physics AUSTRALIA
| | - Kathleen Mary Mullen
- Queensland University of Technology School of Chemistry, Physics and Mechanical Engineering Faculty of Science and EngineeringQUT2 George St 4001 Brisbane AUSTRALIA
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18
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Poad BLJ, Young RSE, Marshall DL, Trevitt AJ, Blanksby SJ. Accelerating Ozonolysis Reactions Using Supplemental RF-Activation of Ions in a Linear Ion Trap Mass Spectrometer. Anal Chem 2022; 94:3897-3903. [PMID: 35201768 DOI: 10.1021/acs.analchem.1c04915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas-phase ion-molecule reactions provide structural insights across a range of analytical applications. A hindrance to the wider use of ion-molecule reactions is that they are relatively slow compared to other ion activation modalities and can thereby impose a bottleneck on the time required to analyze each sample. Here we describe a method for accelerating the rate of ion-molecule reactions involving ozone, implemented by supplementary RF-activation of mass-selected ions within a linear ion trap. Reaction rate accelerations between 15-fold (for ozonolysis of alkenes in ionised lipids) and 90-fold (for ozonation of halide anions) are observed compared to thermal conditions. These enhanced reaction rates with ozone increase sample throughput, aligning the reaction time with the overall duty cycle of the mass spectrometer. We demonstrate that the acceleration is due to the supplementary RF-activation surmounting the activation barrier energy of the entrance channel of the ion-molecule reaction. This rate acceleration is subsequently shown to aid identification of new, low abundance lipid isomers and enables an equivalent increase in the number of lipid species that can be analyzed.
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Affiliation(s)
- Berwyck L J Poad
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4001, Australia.,Central Analytical Research Facility, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Reuben S E Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - David L Marshall
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Adam J Trevitt
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2552, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4001, Australia.,Central Analytical Research Facility, Queensland University of Technology, Brisbane, Queensland 4001, Australia
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19
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Ucur B, Maccarone AT, Ellis SR, Blanksby SJ, Trevitt AJ. Solvent-Mediated Proton-Transfer Catalysis of the Gas-Phase Isomerization of Ciprofloxacin Protomers. J Am Soc Mass Spectrom 2022; 33:347-354. [PMID: 35014802 DOI: 10.1021/jasms.1c00331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding how neutral molecules become protonated during positive-ion electrospray ionization (ESI) mass spectrometry is critically important to ensure analytes can be efficiently ionized, detected, and unambiguously identified. The ESI solvent is one of several parameters that can alter the dominant site of protonation in polyfunctional molecules and thus, in turn, can significantly change the collision-induced dissociation (CID) mass spectra relied upon for compound identification. Ciprofloxacin─a common fluoroquinolone antibiotic─is one such example whereby positive-ion ESI can result in gas-phase [M + H]+ ions protonated at either the keto-oxygen or the piperazine-nitrogen. Here, we demonstrate that these protonation isomers (or protomers) of ciprofloxacin can be resolved by differential ion mobility spectrometry and give rise to distinctive CID mass spectra following both charge-directed and charge-remote mechanisms. Interaction of mobility-selected protomers with methanol vapor (added via the throttle gas supply) was found to irreversibly convert the piperazine N-protomer to the keto-O-protomer. This methanol-mediated proton-transport catalysis is driven by the overall exothermicity of the reaction, which is computed to favor the O-protomer by 93 kJ mol-1 (in the gas phase). Conversely, gas phase interactions of mobility-selected ions with acetonitrile vapor selectively depletes the N-protomer ion signal as formation of stable [M + H + CH3CN]+ cluster ions skews the apparent protomer population ratio, as the O-protomer is unaffected. These findings provide a mechanistic basis for tuning protomer populations to ensure faithful characterization of multifunctional molecules by tandem mass spectrometry.
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Affiliation(s)
- Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Alan T Maccarone
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Shane R Ellis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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20
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McKinnon BI, Marlton SJP, Ucur B, Bieske EJ, Poad BLJ, Blanksby SJ, Trevitt AJ. Actinic Wavelength Action Spectroscopy of the IO - Reaction Intermediate. J Phys Chem Lett 2021; 12:11939-11944. [PMID: 34878800 DOI: 10.1021/acs.jpclett.1c03456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Iodinate anions are important in the chemistry of the atmosphere where they are implicated in ozone depletion and particle formation. The atmospheric chemistry of iodine is a complex overlay of neutral-neutral, ion-neutral, and photochemical processes, where many of the reactions and intermediates remain poorly characterized. This study targets the visible spectroscopy and photostability of the gas-phase hypoiodite anion (IO-), the initial product of the I- + O3 reaction, by mass spectrometry equipped with resonance-enhanced photodissociation and total ion-loss action spectroscopies. It is shown that IO- undergoes photodissociation to I- + O (3P) over 637-459 nm (15700-21800 cm-1) because of excitation to the bound first singlet excited state. Electron photodetachment competes with photodissociation above the electron detachment threshold of IO- at 521 nm (19200 cm-1) with peaks corresponding to resonant autodetachment involving the singlet excited state and the ground state of neutral IO possibly mediated by a dipole-bound state.
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Affiliation(s)
- Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
- School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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21
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Berthias F, Poad BLJ, Thurman HA, Bowman AP, Blanksby SJ, Shvartsburg AA. Disentangling Lipid Isomers by High-Resolution Differential Ion Mobility Spectrometry/Ozone-Induced Dissociation of Metalated Species. J Am Soc Mass Spectrom 2021; 32:2827-2836. [PMID: 34751570 DOI: 10.1021/jasms.1c00251] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The preponderance and functional importance of isomeric biomolecules have become topical in biochemistry. Therefore, one must distinguish and identify all such forms across compound classes, over a wide dynamic range as minor species often have critical activities. With all the power of modern mass spectrometry for compositional assignments by accurate mass, the identical precursor and often fragment ion masses render this task a steep challenge. This is recognized in proteomics and epigenetics, where proteoforms are disentangled and characterized employing novel separations and non-ergodic dissociation mechanisms. This issue is equally pertinent to lipidomics, where the lack of isomeric depth has thwarted the deciphering of functional networks. Here we introduce a new platform, where the isomeric lipids separated by high-resolution differential ion mobility spectrometry (FAIMS) are identified using ozone-induced dissociation (OzID). Cationization by metals (here K+, Ag+, and especially Cu+) broadly improves the FAIMS resolution of isomers with alternative C═C double bond (DB) positions or stereochemistry, presumably via metal attaching to the DB and reshaping the ion around it. However, the OzID yield diminishes for Ag+ and vanishes for Cu+ adducts. Argentination still strikes the best compromise between efficient separation and diagnostic fragmentation for optimal FAIMS/OzID performance.
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Affiliation(s)
- Francis Berthias
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Berwyck L J Poad
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD 4000, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Hayden A Thurman
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Andrew P Bowman
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD 4000, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Alexandre A Shvartsburg
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
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22
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Young RSE, Claes BSR, Bowman AP, Williams ED, Shepherd B, Perren A, Poad BLJ, Ellis SR, Heeren RMA, Sadowski MC, Blanksby SJ. Isomer-Resolved Imaging of Prostate Cancer Tissues Reveals Specific Lipid Unsaturation Profiles Associated With Lymphocytes and Abnormal Prostate Epithelia. Front Endocrinol (Lausanne) 2021; 12:689600. [PMID: 34421820 PMCID: PMC8374165 DOI: 10.3389/fendo.2021.689600] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/29/2021] [Indexed: 01/12/2023] Open
Abstract
Prostate cancer is the fourth most common cancer worldwide with definitive diagnosis reliant on biopsy and human-graded histopathology. As with other pathologies, grading based on classical haematoxylin and eosin (H&E) staining of formalin fixed paraffin-embedded material can be prone to variation between pathologists, prompting investigation of biomolecular markers. Comprising around 50% of cellular mass, and with known metabolic variations in cancer, lipids provide a promising target for molecular pathology. Here we apply isomer-resolved lipidomics in combination with imaging mass spectrometry to interrogate tissue sections from radical prostatectomy specimens. Guided by the histopathological assessment of adjacent tissue sections, regions of interest are investigated for molecular signatures associated with lipid metabolism, especially desaturation and elongation pathways. Monitoring one of the most abundant cellular membrane lipids within these tissues, phosphatidylcholine (PC) 34:1, high positive correlation was observed between the n-9 isomer (site of unsaturation 9-carbons from the methyl terminus) and epithelial cells from potential pre-malignant lesions, while the n-7 isomer abundance was observed to correlate with immune cell infiltration and inflammation. The correlation of lipid isomer signatures with human disease states in tissue suggests a future role for isomer-resolved mass spectrometry imaging in assisting pathologists with prostate cancer diagnoses and patient stratification.
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Affiliation(s)
- Reuben S. E. Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia
| | - Britt S. R. Claes
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, Netherlands
| | - Andrew P. Bowman
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, Netherlands
| | - Elizabeth D. Williams
- Australian Prostate Cancer Research Centre - Queensland, Faculty of Health, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD, Australia
| | - Benjamin Shepherd
- Department of Pathology, Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Aurel Perren
- Institute of Pathology, University of Bern, Bern, Switzerland
| | - Berwyck L. J. Poad
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, Australia
| | - Shane R. Ellis
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, Netherlands
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Ron M. A. Heeren
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, Netherlands
| | - Martin C. Sadowski
- Australian Prostate Cancer Research Centre - Queensland, Faculty of Health, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD, Australia
- Institute of Pathology, University of Bern, Bern, Switzerland
| | - Stephen J. Blanksby
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, Australia
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23
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Nitsche T, Sheil MM, Blinco JP, Barner-Kowollik C, Blanksby SJ. Electrospray Ionization-Mass Spectrometry of Synthetic Polymers Functionalized with Carboxylic Acid End-Groups. J Am Soc Mass Spectrom 2021; 32:2123-2134. [PMID: 34242006 DOI: 10.1021/jasms.1c00085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Electrospray ionization-mass spectrometry (ESI-MS) of low-charging synthetic polymers typically produces mass spectra exhibiting a bias toward the low-mass region of the polymer mass distribution. To examine the origin(s) of this ionization bias, narrow dispersity polystyrene polymers (Đ < 1.10) were prepared with ionizable carboxylic acid end-groups at one or both chain termini. The mixture complexity was further reduced through preparative size-exclusion chromatography (SEC), and these well-defined polymers were subjected to negative ion ESI-MS on a high-resolution instrument with a mass-to-charge (m/z) range up to 8000. Incorporation of one carboxylic acid end-group facilitated the generation of singly charged [M - H]- ions across the entire range of the mass analyzer. The comparison of mass spectra with size-exclusion chromatograms of the same polymer revealed an ionization bias toward lower masses, which was partially overcome through fractionation, modification of electrospray solvent, and increased declustering potentials. Incorporation of a second ionizable moiety within polymers of equivalent size facilitated multiply charged [M - 2H]2- ion formation with significantly improved ionization efficiency, spectral coverage of the molar mass distribution, and minimal cluster ion formation. These findings indicate that increased charging of polymers through multiple, well-defined sites of ionization can enhance volatilization and ionization of higher-mass polymers. Generation of higher-molecular-weight polymers in low-charge states-while possible under ideal conditions-competes ineffectively with either nonspecific, multiple-charging of similar sized polymers or ionization of the smaller polymers in the distribution.
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Affiliation(s)
- Tobias Nitsche
- School of Chemistry and Physics, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
| | - Margaret M Sheil
- School of Chemistry and Physics, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
| | - James P Blinco
- School of Chemistry and Physics, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
| | - Stephen J Blanksby
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
- Central Analytical Research Facility, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
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24
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Claes BR, Bowman AP, Poad BLJ, Young RSE, Heeren RMA, Blanksby SJ, Ellis SR. Mass Spectrometry Imaging of Lipids with Isomer Resolution Using High-Pressure Ozone-Induced Dissociation. Anal Chem 2021; 93:9826-9834. [PMID: 34228922 PMCID: PMC8295983 DOI: 10.1021/acs.analchem.1c01377] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/21/2021] [Indexed: 12/12/2022]
Abstract
Mass spectrometry imaging (MSI) of lipids within tissues has significant potential for both biomolecular discovery and histopathological applications. Conventional MSI technologies are, however, challenged by the prevalence of phospholipid regioisomers that differ only in the location(s) of carbon-carbon double bonds and/or the relative position of fatty acyl attachment to the glycerol backbone (i.e., sn position). The inability to resolve isomeric lipids within imaging experiments masks underlying complexity, resulting in a critical loss of metabolic information. Herein, ozone-induced dissociation (OzID) is implemented on a mobility-enabled quadrupole time-of-flight (Q-TOF) mass spectrometer capable of matrix-assisted laser desorption/ionization (MALDI). Exploiting the ion mobility region in the Q-TOF, high number densities of ozone were accessed, leading to ∼1000-fold enhancement in the abundance of OzID product ions compared to earlier MALDI-OzID implementations. Translation of this uplift into imaging resulted in a 50-fold improvement in acquisition rate, facilitating large-area mapping with resolution of phospholipid isomers. Mapping isomer distributions across rat brain sections revealed distinct distributions of lipid isomer populations with region-specific associations of isomers differing in double bond and sn positions. Moreover, product ions arising from sequential ozone- and collision-induced dissociation enabled double bond assignments in unsaturated fatty acyl chains esterified at the noncanonical sn-1 position.
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Affiliation(s)
- Britt
S. R. Claes
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Andrew P. Bowman
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Berwyck L. J. Poad
- Central
Analytical Research Facility, Queensland
University of Technology, Brisbane, Queensland 4001, Australia
- School
of Chemistry and Physics, Queensland University
of Technology, Brisbane, Queensland 4001, Australia
| | - Reuben S. E. Young
- School
of Chemistry and Physics, Queensland University
of Technology, Brisbane, Queensland 4001, Australia
| | - Ron M. A. Heeren
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
| | - Stephen J. Blanksby
- Central
Analytical Research Facility, Queensland
University of Technology, Brisbane, Queensland 4001, Australia
- School
of Chemistry and Physics, Queensland University
of Technology, Brisbane, Queensland 4001, Australia
| | - Shane R. Ellis
- The
Maastricht MultiModal Molecular Imaging (M4I) institute, Division
of Imaging Mass Spectrometry (IMS), Maastricht
University, 6229 ER Maastricht, The Netherlands
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
- llawarra
Health and Medical Research Institute, Wollongong, NSW 2522, Australia
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25
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Marshall DL, Menzel JP, McKinnon BI, Blinco JP, Trevitt AJ, Barner-Kowollik C, Blanksby SJ. Laser Photodissociation Action Spectroscopy for the Wavelength-Dependent Evaluation of Photoligation Reactions. Anal Chem 2021; 93:8091-8098. [PMID: 34019383 DOI: 10.1021/acs.analchem.1c01584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nitrile imine-mediated tetrazole-ene cycloaddition is a widely used class of photoligation. Optimizing the reaction outcome requires detailed knowledge of the tetrazole photoactivation profile, which can only partially be ascertained from absorption spectroscopy, or otherwise involves laborious reaction monitoring in solution. Photodissociation action spectroscopy (PDAS) combines the advantages of optical spectroscopy and mass spectrometry in that only absorption events resulting in a mass change are recorded, thus revealing the desired wavelength dependence of product formation. Moreover, the sensitivity and selectivity afforded by the mass spectrometer enable reliable assessment of the photodissociation profile even on small amounts of crude material, thus accelerating the design and synthesis of next-generation substrates. Using this workflow, we demonstrate that the photodissociation onset for nitrile imine formation is red-shifted by ca. 50 nm with a novel N-ethylcarbazole derivative relative to a phenyl-substituted archetype. Benchmarked against solution-phase tunable laser experiments and supported by quantum chemical calculations, these discoveries demonstrate that PDAS is a powerful tool for rapidly screening the efficacy of new substrates in the quest toward efficient visible light-triggered ligation for biological applications.
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Affiliation(s)
- David L Marshall
- Central Analytical Research Facility, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.,Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Jan P Menzel
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.,School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - James P Blinco
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.,School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Christopher Barner-Kowollik
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.,School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.,Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
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26
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Luginbühl M, Young RSE, Stoeth F, Weinmann W, Blanksby SJ, Gaugler S. Variation in the Relative Isomer Abundance of Synthetic and Biologically Derived Phosphatidylethanols and Its Consequences for Reliable Quantification. J Anal Toxicol 2021; 45:76-83. [PMID: 32248226 DOI: 10.1093/jat/bkaa034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/21/2020] [Accepted: 03/11/2020] [Indexed: 12/21/2022] Open
Abstract
Phosphatidylethanol (PEth) in human blood samples is a marker for alcohol usage. Typically, PEth is detected by reversed-phase liquid chromatography coupled with negative ion tandem mass spectrometry, investigating the fatty acyl anions released from the precursor ion upon collision-induced dissociation (CID). It has been established that in other classes of asymmetric glycerophospholipids, the unimolecular fragmentation upon CID is biased depending on the relative position (known as sn-position) of each fatty acyl chain on the glycerol backbone. As such, the use of product ions in selected-reaction-monitoring (SRM) transitions could be prone to variability if more than one regioisomer is present in either the reference materials or the sample. Here, we have investigated the regioisomeric purity of three reference materials supplied by different vendors, labeled as PEth 16:0/18:1. Using CID coupled with ozone-induced dissociation, the regioisomeric purity (% 16:0 at sn-1) was determined to be 76, 80 and 99%. The parallel investigation of the negative ion CID mass spectra of standards revealed differences in product ion ratios for both fatty acyl chain product ions and ketene neutral loss product ions. Furthermore, investigation of the product ion abundances in CID spectra of PEth within authentic blood samples appears to indicate a limited natural variation in isomer populations between samples, with the cannonical, PEth 16:0/18:1 (16:0 at sn-1) predominant in all cases. Different reference material isomer distributions led to variation in fully automated quantification of PEth in 56 authentic dried blood spot (DBS) samples when a single quantifier ion was used. Our results suggest caution in ensuring that the regioisomeric compositions of reference materials are well-matched with those of the authentic blood samples.
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Affiliation(s)
| | - Reuben S E Young
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Frederike Stoeth
- Institute of Forensic Medicine Bern, Forensic Toxicology and Chemistry, University of Bern, Bern, Switzerland
| | - Wolfgang Weinmann
- Institute of Forensic Medicine Bern, Forensic Toxicology and Chemistry, University of Bern, Bern, Switzerland
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
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27
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Randolph CE, Shenault DM, Blanksby SJ, McLuckey SA. Localization of Carbon-Carbon Double Bond and Cyclopropane Sites in Cardiolipins via Gas-Phase Charge Inversion Reactions. J Am Soc Mass Spectrom 2021; 32:455-464. [PMID: 33370110 PMCID: PMC8557092 DOI: 10.1021/jasms.0c00348] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cardiolipins (CLs) are comprised of two phosphatic acid moieties bound to a central glycerol backbone and are substituted with four acyl chains. Consequently, a vast number of distinct CL structures are possible in different biological contexts, representing a significant analytical challenge. Electrospray ionization tandem mass spectrometry (ESI-MS/MS) has become a widely used approach for the detection, characterization, and quantitation of complex lipids, including CLs. Central to this approach is fragmentation of the [CLs - H]- or [CL - 2H]2- anions by collision-induced dissociation (CID). Product ions in the resulting tandem mass spectra confirm the CL subclass assignment and reveal the numbers of carbons and degrees of unsaturation in each of the acyl chains. Conventional CID, however, affords limited structural elucidation of the fatty acyl chains, failing to discriminate isomers arising from different site(s) of unsaturation or cyclopropanation and potentially obscuring their metabolic origins. Here, we report the application of charge inversion ion/ion chemistry in the gas phase to enhance the structural elucidation of CLs. Briefly, CID of [CL - H]2- anions generated via negative ion ESI allowed for the assignment of individual fatty acyl substituents and phosphatidic acid moieties. Next, gas-phase derivatization of the resulting CL product ions, including fatty acyl carboxylate anions, was effected with gas-phase ion/ion charge inversion reactions with tris-phenanthroline magnesium reagent dications. Subsequent isolation and activation of the charge-inverted fatty acyl complex cations permitted the localization of both carbon-carbon double bond and cyclopropane motifs within each of the four acyl chains of CLs. This approach was applied to the de novo elucidation of unknown CLs in a biological extract revealing distinct isomeric populations and regiochemical relationships between double bonds and carbocyles.
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Affiliation(s)
- Caitlin E. Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | | | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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28
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Shiels OJ, Kelly PD, Bright CC, Poad BLJ, Blanksby SJ, da Silva G, Trevitt AJ. Reactivity Trends in the Gas-Phase Addition of Acetylene to the N-Protonated Aryl Radical Cations of Pyridine, Aniline, and Benzonitrile. J Am Soc Mass Spectrom 2021; 32:537-547. [PMID: 33444019 DOI: 10.1021/jasms.0c00386] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N-containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl), and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta, and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios, and reaction efficiencies are measured. The rate coefficients increase from para to ortho positions. The second-order rate coefficients can be sorted into three groups: low, between 1 and 3 × 10-12 cm3 molecule-1 s-1 (3Anl and 4Anl); intermediate, between 5 and 15 × 10-12 cm3 molecule-1 s-1 (2Bzn, 3Bzn, and 4Bzn); and high, between 8 and 31 × 10-11 cm3 molecule-1 s-1 (2Anl, 2Pyr, 3Pyr, and 4Pyr); and 2Anl is the only radical cation with a rate coefficient distinctly different from its isomers. Quantum chemical calculations, using M06-2X-D3(0)/6-31++G(2df,p) geometries and DSD-PBEP86-NL/aug-cc-pVQZ energies, are deployed to rationalize reactivity trends based on the stability of prereactive complexes. The G3X-K method guides the assignment of product ions following adduct formation. The rate coefficient trend can be rationalized by a simple model based on the prereactive complex forward barrier height.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - P D Kelly
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Cameron C Bright
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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29
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Young RSE, Bowman AP, Williams ED, Tousignant KD, Bidgood CL, Narreddula VR, Gupta R, Marshall DL, Poad BLJ, Nelson CC, Ellis SR, Heeren RMA, Sadowski MC, Blanksby SJ. Apocryphal FADS2 activity promotes fatty acid diversification in cancer. Cell Rep 2021; 34:108738. [PMID: 33567271 DOI: 10.1016/j.celrep.2021.108738] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/18/2020] [Accepted: 01/19/2021] [Indexed: 12/21/2022] Open
Abstract
Canonical fatty acid metabolism describes specific enzyme-substrate interactions that result in products with well-defined chain lengths, degree(s), and positions of unsaturation. Deep profiling of lipids across a range of prostate cancer cell lines reveals a variety of fatty acids with unusual site(s) of unsaturation that are not described by canonical pathways. The structure and abundance of these unusual lipids correlate with changes in desaturase expression and are strong indicators of cellular phenotype. Gene silencing and stable isotope tracing demonstrate that direct Δ6 and Δ8 desaturation of 14:0 (myristic), 16:0 (palmitic), and 18:0 (stearic) acids by FADS2 generate new families of unsaturated fatty acids (including n-8, n-10, and n-12) that have rarely-if ever-been reported in human-derived cells. Isomer-resolved lipidomics reveals the selective incorporation of these unusual fatty acids into complex structural lipids and identifies their presence in cancer tissues, indicating functional roles in membrane structure and signaling.
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Affiliation(s)
- Reuben S E Young
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Andrew P Bowman
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Elizabeth D Williams
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD 4000, Australia
| | - Kaylyn D Tousignant
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD 4000, Australia
| | - Charles L Bidgood
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD 4000, Australia
| | | | - Rajesh Gupta
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St., Brisbane, QLD 4000, Australia
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St., Brisbane, QLD 4000, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4000, Australia; Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St., Brisbane, QLD 4000, Australia
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD 4000, Australia
| | - Shane R Ellis
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Ron M A Heeren
- M4I, The Maastricht MultiModal Molecular Imaging Institute, Division of Imaging Mass Spectrometry, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Martin C Sadowski
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, QLD 4000, Australia; Institute of Pathology, University of Bern, Murtenstrasse 31, 3008 Bern, Switzerland.
| | - Stephen J Blanksby
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4000, Australia; Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St., Brisbane, QLD 4000, Australia.
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Narreddula VR, McKinnon BI, Marlton SJP, Marshall DL, Boase NRB, Poad BLJ, Trevitt AJ, Mitchell TW, Blanksby SJ. Next-generation derivatization reagents optimized for enhanced product ion formation in photodissociation-mass spectrometry of fatty acids. Analyst 2021; 146:156-169. [DOI: 10.1039/d0an01840f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Next-generation derivatives for photodissociation-mass spectrometry for fatty acids generating photoproduct yields of up to 97% at 266 nm.
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Affiliation(s)
- Venkateswara R. Narreddula
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Benjamin I. McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - Samuel J. P. Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - David L. Marshall
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Brisbane
- Australia
| | - Nathan R. B. Boase
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Berwyck L. J. Poad
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Brisbane
- Australia
| | - Adam J. Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - Todd W. Mitchell
- School of Medicine
- University of Wollongong
- Wollongong
- Australia
- Illawarra Health and Medical Research Institute
| | - Stephen J. Blanksby
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
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Shiels OJ, Prendergast MB, Savee JD, Osborn DL, Taatjes CA, Blanksby SJ, da Silva G, Trevitt AJ. Five vs. six membered-ring PAH products from reaction of o-methylphenyl radical and two C 3H 4 isomers. Phys Chem Chem Phys 2021; 23:14913-14924. [PMID: 34223848 DOI: 10.1039/d1cp01764k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase reactions of the o-methylphenyl (o-CH3C6H4) radical with the C3H4 isomers allene (H2C[double bond, length as m-dash]C[double bond, length as m-dash]CH2) and propyne (HC[triple bond, length as m-dash]C-CH3) are studied at 600 K and 4 Torr (533 Pa) using VUV synchrotron photoionisation mass spectrometry, quantum chemical calculations and RRKM modelling. Two major dissociation product ions arise following C3H4 addition: m/z 116 (CH3 loss) and 130 (H loss). These products correspond to small polycyclic aromatic hydrocarbons (PAHs). The m/z 116 signal for both reactions is conclusively assigned to indene (C9H8) and is the dominant product for the propyne reaction. Signal at m/z 130 for the propyne case is attributed to isomers of bicyclic methylindene (C10H10) + H, which contains a newly-formed methylated five-membered ring. The m/z 130 signal for allene, however, is dominated by the 1,2-dihydronaphthalene isomer arising from a newly created six-membered ring. Our results show that new ring formation from C3H4 addition to the methylphenyl radical requires an ortho-CH3 group - similar to o-methylphenyl radical oxidation. These reactions characteristically lead to bicyclic aromatic products, but the structure of the C3H4 co-reactant dictates the structure of the PAH product, with allene preferentially leading to the formation of two six-membered ring bicyclics and propyne resulting in the formation of six and five-membered bicyclic structures.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, 2522, Australia.
| | - Matthew B Prendergast
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, 2522, Australia.
| | - John D Savee
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA
| | - Craig A Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, 2522, Australia.
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Marshall DL, Poad BLJ, Luis ET, Da Silva Rodrigues RA, Blanksby SJ, Mullen KM. Stepwise reduction of interlocked viologen-based complexes in the gas phase. Chem Commun (Camb) 2020; 56:13575-13578. [PMID: 33052365 DOI: 10.1039/d0cc05115b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We present the first application of electrochemical reduction in an ion trap mass spectrometer as a dual-function tool to synthesise and probe the reactivity of interlocked viologen-based complexes. Compared with non-complexed archetypes, electron-donating macrocyclic porphyrin ethers retard electron transfer reaction rates and stabilise intact structures in low oxidation states.
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Affiliation(s)
- David L Marshall
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Australia.
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Randolph CE, Blanksby SJ, McLuckey SA. Enhancing detection and characterization of lipids using charge manipulation in electrospray ionization-tandem mass spectrometry. Chem Phys Lipids 2020; 232:104970. [PMID: 32890498 PMCID: PMC7606777 DOI: 10.1016/j.chemphyslip.2020.104970] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/25/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022]
Abstract
Heightened awareness regarding the implication of disturbances in lipid metabolism with respect to prevalent human-related pathologies demands analytical techniques that provide unambiguous structural characterization and accurate quantitation of lipids in complex biological samples. The diversity in molecular structures of lipids along with their wide range of concentrations in biological matrices present formidable analytical challenges. Modern mass spectrometry (MS) offers an unprecedented level of analytical power in lipid analysis, as many advancements in the field of lipidomics have been facilitated through novel applications of and developments in electrospray ionization tandem mass spectrometry (ESI-MS/MS). ESI allows for the formation of intact lipid ions with little to no fragmentation and has become widely used in contemporary lipidomics experiments due to its sensitivity, reproducibility, and compatibility with condensed-phase modes of separation, such as liquid chromatography (LC). Owing to variations in lipid functional groups, ESI enables partial chemical separation of the lipidome, yet the preferred ion-type is not always formed, impacting lipid detection, characterization, and quantitation. Moreover, conventional ESI-MS/MS approaches often fail to expose diverse subtle structural features like the sites of unsaturation in fatty acyl constituents or acyl chain regiochemistry along the glycerol backbone, representing a significant challenge for ESI-MS/MS. To overcome these shortcomings, various charge manipulation strategies, including charge-switching, have been developed to transform ion-type and charge state, with aims of increasing sensitivity and selectivity of ESI-MS/MS approaches. Importantly, charge manipulation approaches afford enhanced ionization efficiency, improved mixture analysis performance, and access to informative fragmentation channels. Herein, we present a critical review of the current suite of solution-based and gas-phase strategies for the manipulation of lipid ion charge and type relevant to ESI-MS/MS.
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Affiliation(s)
- Caitlin E Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
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Randolph CE, Fabijanczuk KC, Blanksby SJ, McLuckey SA. Proton Transfer Reactions for the Gas-Phase Separation, Concentration, and Identification of Cardiolipins. Anal Chem 2020; 92:10847-10855. [PMID: 32639138 PMCID: PMC7490759 DOI: 10.1021/acs.analchem.0c02545] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cardiolipin (CL) analysis demands high specificity, due to the extensive diversity of CL structures, and high sensitivity, due to their low relative abundance within the lipidome. While electrospray ionization mass spectrometry (ESI-MS) is the most widely used technology in lipidomics, the potential for multiple charging presents unique challenges for CL identification and quantification. Depending on the conditions, ESI-MS of lipid extracts in negative ion mode can give rise to cardiolipins ionized as both singly and doubly deprotonated anions. This signal degeneracy diminishes the signal-to-noise ratio, while in addition (for direct infusion), the dianion population falls within a m/z range already heavily congested with monoanions from more abundant glycerophospholipid subclasses. Herein, we describe a direct infusion strategy for CL profiling from total lipid extracts utilizing gas-phase proton-transfer ion/ion reactions. In this approach, lipid extracts are ionized by negative ion ESI generating both singly deprotonated phospholipids and doubly deprotonated CL anions. Charge reduction of the negative ion population by ion/ion reactions leads to an enhancement in singly deprotonated [CL - H]- species via proton transfer to the corresponding [CL - 2H]2-̅ dianions. To concentrate the [CL - H]- anion signal, multiple iterations of ion accumulation and proton-transfer ion/ion reaction can be performed prior to subsequent interrogation. Mass selection and collisional activation of the enriched population of [CL - H]- anions facilitates the assignment of individual fatty acyl substituents and phosphatidic acid moieties. Demonstrated advantages of this new approach derive from the improved performance in complex mixture analysis affording detailed characterization of low abundant CLs directly from a total biological extract.
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Affiliation(s)
- Caitlin E. Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | | | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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Kirschbaum C, Saied EM, Greis K, Mucha E, Gewinner S, Schöllkopf W, Meijer G, Helden G, Poad BLJ, Blanksby SJ, Arenz C, Pagel K. Innentitelbild: Unterscheidung von isomeren Sphingolipiden mittels kryogener Infrarotspektroskopie (Angew. Chem. 32/2020). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Carla Kirschbaum
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Essa M. Saied
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
- Chemistry Department Faculty of Science Suez Canal University Ismailia Ägypten
| | - Kim Greis
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Eike Mucha
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Sandy Gewinner
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Wieland Schöllkopf
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Gerard Meijer
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Gert Helden
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Berwyck L. J. Poad
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australien
| | - Stephen J. Blanksby
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australien
| | - Christoph Arenz
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
| | - Kevin Pagel
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
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Kirschbaum C, Saied EM, Greis K, Mucha E, Gewinner S, Schöllkopf W, Meijer G, Helden G, Poad BLJ, Blanksby SJ, Arenz C, Pagel K. Unterscheidung von isomeren Sphingolipiden mittels kryogener Infrarotspektroskopie. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Carla Kirschbaum
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Essa M. Saied
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
- Chemistry Department Faculty of Science Suez Canal University Ismailia Ägypten
| | - Kim Greis
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Eike Mucha
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Sandy Gewinner
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Wieland Schöllkopf
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Gerard Meijer
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Gert Helden
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Berwyck L. J. Poad
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australien
| | - Stephen J. Blanksby
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australien
| | - Christoph Arenz
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
| | - Kevin Pagel
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Deutschland
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
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Martínez-Montañés F, Casanovas A, Sprenger RR, Topolska M, Marshall DL, Moreno-Torres M, Poad BL, Blanksby SJ, Hermansson M, Jensen ON, Ejsing CS. Phosphoproteomic Analysis across the Yeast Life Cycle Reveals Control of Fatty Acyl Chain Length by Phosphorylation of the Fatty Acid Synthase Complex. Cell Rep 2020; 32:108024. [DOI: 10.1016/j.celrep.2020.108024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/11/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
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Randolph CE, Marshall DL, Blanksby SJ, McLuckey SA. Charge-switch derivatization of fatty acid esters of hydroxy fatty acids via gas-phase ion/ion reactions. Anal Chim Acta 2020; 1129:31-39. [PMID: 32891388 DOI: 10.1016/j.aca.2020.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/25/2020] [Accepted: 07/01/2020] [Indexed: 01/30/2023]
Abstract
Branched fatty acid esters of hydroxy fatty acids (FAHFAs) are a recently discovered class of endogenous bioactive lipids with anti-diabetic and anti-inflammatory effects. Identification of FAHFAs is challenging due to both the relatively low abundance of these metabolites in most biological samples and the significant structural diversity arising from the co-occurrence of numerous regioisomers. Ultimately, development of sensitive analytical techniques that enable rapid and unambiguous identification of FAHFAs is integral to understanding their diverse physiological functions in health and disease. While a battery of mass spectrometry (MS) based methods for complex lipid analysis has been developed, FAHFA identification presents specific challenges to conventional approaches. Notably, while the MS2 product ion spectra of [FAHFA - H]¯ anions afford the assignment of fatty acid (FA) and hydroxy fatty acid (HFA) constituents, FAHFA regioisomers are usually indistinguishable by this approach. Here, we report the development of a novel MS-based technique employing charge inversion ion/ion reactions with tris-phenanthroline magnesium complex dications, Mg(Phen)32+, to selectively and efficiently derivatize [FAHFA - H]¯ anions in the gas phase, yielding fixed-charge cations. Subsequent activation of [FAHFA - H + MgPhen2]+ cations yield product ions that facilitate the assignment of FA and HFA constituents, pinpoints unsaturation sites within the FA moiety, and elucidates ester linkage regiochemistry. Collectively, the presented approach represents a rapid, entirely gas-phase method for near-complete FAHFA structural elucidation and confident isomer discrimination without the requirement for authentic FAHFA standards.
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Affiliation(s)
- Caitlin E Randolph
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Scott A McLuckey
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA.
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Kirschbaum C, Saied EM, Greis K, Mucha E, Gewinner S, Schöllkopf W, Meijer G, Helden G, Poad BLJ, Blanksby SJ, Arenz C, Pagel K. Inside Cover: Resolving Sphingolipid Isomers Using Cryogenic Infrared Spectroscopy (Angew. Chem. Int. Ed. 32/2020). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/anie.202007701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Carla Kirschbaum
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Essa M. Saied
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
- Chemistry Department Faculty of Science Suez Canal University Ismailia Egypt
| | - Kim Greis
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Eike Mucha
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Sandy Gewinner
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Wieland Schöllkopf
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Gerard Meijer
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Gert Helden
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Berwyck L. J. Poad
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australia
| | - Stephen J. Blanksby
- Central Analytical Research Facility Institute for Future Environments Queensland University of Technology Brisbane QLD 4000 Australia
| | - Christoph Arenz
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Kevin Pagel
- Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
- Abteilung Molekülphysik Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
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Tousignant KD, Rockstroh A, Poad BLJ, Talebi A, Young RSE, Taherian Fard A, Gupta R, Zang T, Wang C, Lehman ML, Swinnen JV, Blanksby SJ, Nelson CC, Sadowski MC. Therapy-induced lipid uptake and remodeling underpin ferroptosis hypersensitivity in prostate cancer. Cancer Metab 2020; 8:11. [PMID: 32577235 PMCID: PMC7304214 DOI: 10.1186/s40170-020-00217-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/08/2020] [Indexed: 12/13/2022] Open
Abstract
Background Metabolic reprograming, non-mutational epigenetic changes, increased cell plasticity, and multidrug tolerance are early hallmarks of therapy resistance in cancer. In this temporary, therapy-tolerant state, cancer cells are highly sensitive to ferroptosis, a form of regulated cell death that is caused by oxidative stress through excess levels of iron-dependent peroxidation of polyunsaturated fatty acids (PUFA). However, mechanisms underpinning therapy-induced ferroptosis hypersensitivity remain to be elucidated. Methods We used quantitative single-cell imaging of fluorescent metabolic probes, transcriptomics, proteomics, and lipidomics to perform a longitudinal analysis of the adaptive response to androgen receptor-targeted therapies (androgen deprivation and enzalutamide) in prostate cancer (PCa). Results We discovered that cessation of cell proliferation and a robust reduction in bioenergetic processes were associated with multidrug tolerance and a strong accumulation of lipids. The gain in lipid biomass was fueled by enhanced lipid uptake through cargo non-selective (macropinocytosis, tunneling nanotubes) and cargo-selective mechanisms (lipid transporters), whereas de novo lipid synthesis was strongly reduced. Enzalutamide induced extensive lipid remodeling of all major phospholipid classes at the expense of storage lipids, leading to increased desaturation and acyl chain length of membrane lipids. The rise in membrane PUFA levels enhanced membrane fluidity and lipid peroxidation, causing hypersensitivity to glutathione peroxidase (GPX4) inhibition and ferroptosis. Combination treatments against AR and fatty acid desaturation, lipase activities, or growth medium supplementation with antioxidants or PUFAs altered GPX4 dependence. Conclusions Our work provides mechanistic insight into processes of lipid metabolism that underpin the acquisition of therapy-induced GPX4 dependence and ferroptosis hypersensitivity to standard of care therapies in PCa. It demonstrates novel strategies to suppress the therapy-tolerant state that may have potential to delay and combat resistance to androgen receptor-targeted therapies, a currently unmet clinical challenge of advanced PCa. Since enhanced GPX4 dependence is an adaptive phenotype shared by several types of cancer in response to different therapies, our work might have universal implications for our understanding of metabolic events that underpin resistance to cancer therapies.
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Affiliation(s)
- Kaylyn D Tousignant
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Anja Rockstroh
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Australia
| | - Ali Talebi
- Department of Oncology, Laboratory of Lipid Metabolism and Cancer, LKI Leuven Cancer Institute, KU Leuven-University of Leuven, Leuven, Belgium
| | - Reuben S E Young
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Australia
| | - Atefeh Taherian Fard
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Rajesh Gupta
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Australia
| | - Tuo Zang
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Chenwei Wang
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Melanie L Lehman
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia.,Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, Canada
| | - Johan V Swinnen
- Department of Oncology, Laboratory of Lipid Metabolism and Cancer, LKI Leuven Cancer Institute, KU Leuven-University of Leuven, Leuven, Belgium
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Australia
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia
| | - Martin C Sadowski
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Princess Alexandra Hospital, Translational Research Institute, Brisbane, Australia.,Cancer & Ageing Research Program, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Translational Research Institute, Brisbane, Australia
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41
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Marlton SJP, McKinnon BI, Ucur B, Bezzina JP, Blanksby SJ, Trevitt AJ. Discrimination between Protonation Isomers of Quinazoline by Ion Mobility and UV-Photodissociation Action Spectroscopy. J Phys Chem Lett 2020; 11:4226-4231. [PMID: 32368922 DOI: 10.1021/acs.jpclett.0c01009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The influence of oriented electric fields on chemical reactivity and photochemistry is an area of increasing interest. Within a molecule, different protonation sites offer the opportunity to control the location of charge and thus orientation of electric fields. New techniques are thus needed to discriminate between protonation isomers in order to understand this effect. This investigation reports the UV-photodissociation action spectroscopy of two protonation isomers (protomers) of 1,3-diazanaphthalene (quinazoline) arising from protonation of a nitrogen at either the 1- or 3-position. It is shown that these protomers are separable by field-asymmetric ion mobility spectrometry (FAIMS) with confirmation provided by UV-photodissociation (PD) action spectroscopy. Vibronic features in the UVPD action spectra and computational input allow assignment of the origin transitions to the S1 and S5 states of both protomers. These experiments also provide vital benchmarks for protomer-specific calculations and examination of isomer-resolved reaction kinetics and thermodynamics.
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Affiliation(s)
- Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - James P Bezzina
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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42
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Kirschbaum C, Saied EM, Greis K, Mucha E, Gewinner S, Schöllkopf W, Meijer G, von Helden G, Poad BLJ, Blanksby SJ, Arenz C, Pagel K. Resolving Sphingolipid Isomers Using Cryogenic Infrared Spectroscopy. Angew Chem Int Ed Engl 2020; 59:13638-13642. [PMID: 32291895 PMCID: PMC7496694 DOI: 10.1002/anie.202002459] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/23/2020] [Indexed: 12/21/2022]
Abstract
1‐Deoxysphingolipids are a recently described class of sphingolipids that have been shown to be associated with several disease states including diabetic and hereditary neuropathy. The identification and characterization of 1‐deoxysphingolipids and their metabolites is therefore highly important. However, exact structure determination requires a combination of sophisticated analytical techniques due to the presence of various isomers, such as ketone/alkenol isomers, carbon–carbon double‐bond (C=C) isomers and hydroxylation regioisomers. Here we demonstrate that cryogenic gas‐phase infrared (IR) spectroscopy of ionized 1‐deoxysphingolipids enables the identification and differentiation of isomers by their unique spectroscopic fingerprints. In particular, C=C bond positions and stereochemical configurations can be distinguished by specific interactions between the charged amine and the double bond. The results demonstrate the power of gas‐phase IR spectroscopy to overcome the challenge of isomer resolution in conventional mass spectrometry and pave the way for deeper analysis of the lipidome.
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Affiliation(s)
- Carla Kirschbaum
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany.,Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Essa M Saied
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,Chemistry Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Kim Greis
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany.,Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Eike Mucha
- Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Sandy Gewinner
- Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Wieland Schöllkopf
- Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Gerard Meijer
- Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Gert von Helden
- Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Christoph Arenz
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Kevin Pagel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany.,Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
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43
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Narreddula VR, Sadowski P, Boase NRB, Marshall DL, Poad BLJ, Trevitt AJ, Mitchell TW, Blanksby SJ. Structural elucidation of hydroxy fatty acids by photodissociation mass spectrometry with photolabile derivatives. Rapid Commun Mass Spectrom 2020; 34:e8741. [PMID: 32012356 DOI: 10.1002/rcm.8741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 06/10/2023]
Abstract
RATIONALE Eicosanoids are short-lived bio-responsive lipids produced locally from oxidation of polyunsaturated fatty acids (FAs) via a cascade of enzymatic or free radical reactions. Alterations in the composition and concentration of eicosanoids are indicative of inflammation responses and there is strong interest in developing analytical methods for the sensitive and selective detection of these lipids in biological mixtures. Most eicosanoids are hydroxy FAs (HFAs), which present a particular analytical challenge due to the presence of regioisomers arising from differing locations of hydroxylation and unsaturation within their structures. METHODS In this study, the recently developed derivatization reagent 1-(3-(aminomethyl)-4-iodophenyl)pyridin-1-ium (4-I-AMPP+ ) was applied to a representative set of HFAs including bioactive eicosanoids. Photodissociation (PD) mass spectra obtained at 266 nm of 4-I-AMPP+ -modified HFAs exhibit abundant product ions arising from photolysis of the aryl-iodide bond within the derivative with subsequent migration of the radical to the hydroxyl group promoting fragmentation of the FA chain and facilitating structural assignment. RESULTS Representative polyunsaturated HFAs (from the hydroxyeicosatetraenoic acid and hydroxyeicosapentaenoic acid families) were derivatized with 4-I-AMPP+ and subjected to a reversed-phase liquid chromatography workflow that afforded chromatographic resolution of isomers in conjunction with structurally diagnostic PD mass spectra. CONCLUSIONS PD of these complex HFAs was found to be sensitive to the locations of hydroxyl groups and carbon-carbon double bonds, which are structural properties strongly associated with the biosynthetic origins of these lipid mediators.
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Affiliation(s)
- Venkateswara R Narreddula
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Pawel Sadowski
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Nathan R B Boase
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Adam J Trevitt
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Todd W Mitchell
- School of Medicine, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Stephen J Blanksby
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia
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44
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Bhujel M, Marshall DL, Maccarone AT, McKinnon BI, Trevitt AJ, da Silva G, Blanksby SJ, Poad BLJ. Gas phase reactions of iodide and bromide anions with ozone: evidence for stepwise and reversible reactions. Phys Chem Chem Phys 2020; 22:9982-9989. [PMID: 32363365 DOI: 10.1039/d0cp01498b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite the impacts - both positive and negative - of atmospheric ozone for life on Earth, there remain significant gaps in our knowledge of the products, mechanisms and rates of some of its most fundamental gas phase reactions. This incomplete understanding is largely due to the experimental challenges involved in the study of gas-phase reactions of ozone and, in particular, the identification of short-lived reaction intermediates. Here we report direct observation of the stepwise reaction of the halide anions iodide (I-) and bromide (Br-) with ozone to produce XO3- (where X = I and Br, respectively). These results substantially revise the rate constant for the I- + O3 reaction to 1.1 (± 0.5) × 10-12 cm3 molecule-1 s-1 (0.13% efficiency) and the Br- + O3 reaction to 6.2 (± 0.4) × 10-15 cm3 molecule-1 s-1 (0.001% efficiency). Exploiting five-orders of temporal dynamic range on a linear ion trap mass spectrometer enabled explicit measurement of the rate constants for the highly efficient intermediate, XO- + O3 and XO2- + O3, reactions thus confirming a stepwise addition of three oxygen atoms (i.e., X- + 3O3 → XO3- + 3O2) with the first addition representing the rate determining step. Evidence is also presented for (i) slow reverse reactions of XO- and XO2-, but not XO3-, with molecular oxygen and (ii) the photodissociation of IO-, IO2- and IO3- to release I-. Collectively, these results suggest relatively short lifetimes for Br- and I- in the tropospere with direct gas-phase oxidation by ozone playing a role in both the formation of atmospheric halogen oxides and, conversely, in the ozone depletion associated with springtime polar bromine explosion events.
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Affiliation(s)
- Mahendra Bhujel
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane QLD 4001, Australia.
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane QLD 4001, Australia.
| | - Alan T Maccarone
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Benjamin I McKinnon
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Adam J Trevitt
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane QLD 4001, Australia.
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane QLD 4001, Australia.
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45
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Randolph CE, Shenault DM, Blanksby SJ, McLuckey SA. Structural Elucidation of Ether Glycerophospholipids Using Gas-Phase Ion/Ion Charge Inversion Chemistry. J Am Soc Mass Spectrom 2020; 31:1093-1103. [PMID: 32251588 PMCID: PMC7328668 DOI: 10.1021/jasms.0c00025] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Ether lipids represent a unique subclass of glycerophospholipid (GPL) that possesses a 1-O-alkyl (i.e., plasmanyl subclass) or a 1-O-alk-1'-enyl (i.e., plasmenyl subclass) group linked at the sn-1 position of the glycerol backbone. As changes in ether GPL composition and abundance are associated with numerous human pathologies, analytical strategies capable of providing high-level structural detail are desirable. While mass spectrometry (MS) has emerged as a prominent tool for lipid structural elucidation in biological extracts, distinctions between the various isomeric forms of ether-linked GPLs have remained a significant challenge for tandem MS, principally due to similarities in the conventional tandem mass spectra obtained from the two ether-linked subclasses. To distinguish plasmanyl and plasmenyl GPLs, a multistage (i.e., MSn where n = 3 or 4) mass spectrometric approach reliant on low-energy collision-induced dissociation (CID) is required. While this method facilitates assignment of the sn-1 bond type (i.e., 1-O-alkyl versus 1-O-alk-1'-enyl), a composite distribution of isomers is left unresolved, as carbon-carbon double-bond (C=C) positions cannot be localized in the sn-2 fatty acyl substituent. In this study, we combine a systematic MSn approach with two unique gas-phase charge inversion ion/ion chemistries to elucidate ether GPL structures with high-level detail. Ultimately, we assign both the sn-1 bond type and sites of unsaturation in the sn-2 fatty acyl substituent using an entirely gas-phase MS-based workflow. Application of this workflow to human blood plasma extract permitted isomeric resolution and in-depth structural identification of major and, in some cases, minor isomeric contributors to ether GPLs that have been previously unresolved when examined via conventional methods.
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Affiliation(s)
- Caitlin E. Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | | | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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46
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Frisch H, Mundsinger K, Poad BLJ, Blanksby SJ, Barner-Kowollik C. Wavelength-gated photoreversible polymerization and topology control. Chem Sci 2020; 11:2834-2842. [PMID: 32206267 PMCID: PMC7069517 DOI: 10.1039/c9sc05381f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/10/2020] [Indexed: 01/01/2023] Open
Abstract
We exploit the wavelength dependence of [2 + 2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks. Blue light (λ max = 460 nm) initiates a catalyst-free polymerization yielding high molar mass polymers (M n = 60 000 g mol-1), which are stable at wavelengths exceeding 430 nm, yet highly responsive to shorter wavelengths. UVB irradiation (λ max = 330 nm) induces a rapid depolymerization affording linear oligomers, whereas violet light (λ max = 410 nm) generates cyclic entities. Thus, different colors of light allow switching between a depolymerization that either proceeds through cyclic or linear topologies. The light-controlled topology formation was evidenced by correlation of mass spectrometry (MS) with size exclusion chromatography (SEC) and ion mobility data. Critically, the color-guided topology control was also possible with ambient laboratory light affording cyclic oligomers, while sunlight activated the linear depolymerization pathway. These findings suggest that light not only induces polymerization and depolymerization but that its color can control the topological outcomes.
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Affiliation(s)
- Hendrik Frisch
- Centre for Materials Science , School of Chemistry and Physics , Queensland University of Technology (QUT) , 2 George Street , Brisbane , QLD 4000 , Australia .
| | - Kai Mundsinger
- Centre for Materials Science , School of Chemistry and Physics , Queensland University of Technology (QUT) , 2 George Street , Brisbane , QLD 4000 , Australia .
| | - Berwyck L J Poad
- Central Analytical Research Facility , Institute for Future Environments , Queensland University of Technology (QUT) , 2 George Street , Brisbane , QLD 4000 , Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility , Institute for Future Environments , Queensland University of Technology (QUT) , 2 George Street , Brisbane , QLD 4000 , Australia
| | - Christopher Barner-Kowollik
- Centre for Materials Science , School of Chemistry and Physics , Queensland University of Technology (QUT) , 2 George Street , Brisbane , QLD 4000 , Australia .
- Macromolecular Architectures , Institut für Technische Chemie und Polymerchemie , Karlsruhe Institute of Technology (KIT) , Engesserstrasse 18 , 76131 Karlsruhe , Germany
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47
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De Bruycker K, Welle A, Hirth S, Blanksby SJ, Barner-Kowollik C. Mass spectrometry as a tool to advance polymer science. Nat Rev Chem 2020; 4:257-268. [PMID: 37127980 DOI: 10.1038/s41570-020-0168-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2020] [Indexed: 12/12/2022]
Abstract
In contrast to natural polymers, which have existed for billions of years, the first well-understood synthetic polymers date back to just over one century ago. Nevertheless, this relatively short period has seen vast progress in synthetic polymer chemistry, which can now afford diverse macromolecules with varying structural complexities. To keep pace with this synthetic progress, there have been commensurate developments in analytical chemistry, where mass spectrometry has emerged as the pre-eminent technique for polymer analysis. This Perspective describes present challenges associated with the mass-spectrometric analysis of synthetic polymers, in particular the desorption, ionization and structural interrogation of high-molar-mass macromolecules, as well as strategies to lower spectral complexity. We critically evaluate recent advances in technology in the context of these challenges and suggest how to push the field beyond its current limitations. In this context, the increasingly important role of high-resolution mass spectrometry is emphasized because of its unrivalled ability to describe unique species within polymer ensembles, rather than to report the average properties of the ensemble.
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48
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Hamilton BR, Marshall DL, Casewell NR, Harrison RA, Blanksby SJ, Undheim EAB. Mapping Enzyme Activity on Tissue by Functional Mass Spectrometry Imaging. Angew Chem Int Ed Engl 2020; 59:3855-3858. [PMID: 31854493 PMCID: PMC7106485 DOI: 10.1002/anie.201911390] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/29/2019] [Indexed: 12/02/2022]
Abstract
Enzymes are central components of most physiological processes, and are consequently implicated in various pathologies. High‐resolution maps of enzyme activity within tissues therefore represent powerful tools for elucidating enzymatic functions in health and disease. Here, we present a novel mass spectrometry imaging (MSI) method for assaying the spatial distribution of enzymatic activity directly from tissue. MSI analysis of tissue sections exposed to phospholipid substrates produced high‐resolution maps of phospholipase activity and specificity, which could subsequently be compared to histological images of the same section. Functional MSI thus represents a new and generalisable method for imaging biological activity in situ.
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Affiliation(s)
- Brett R Hamilton
- Centre for Advanced Imaging, and Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4001, Australia
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Robert A Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4001, Australia
| | - Eivind A B Undheim
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway.,Centre for Ecological and Evolutionary Synthesis, Department of Bioscience, The University of Oslo, 0316, Oslo, Norway.,Centre for Advanced Imaging, and Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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49
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Hamilton BR, Marshall DL, Casewell NR, Harrison RA, Blanksby SJ, Undheim EAB. Mapping Enzyme Activity on Tissue by Functional Mass Spectrometry Imaging. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911390] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Brett R. Hamilton
- Centre for Advanced Imaging, and Centre for Microscopy and Microanalysis The University of Queensland Brisbane QLD 4072 Australia
| | - David L. Marshall
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology Brisbane QLD 4001 Australia
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions Liverpool School of Tropical Medicine Pembroke Place Liverpool L3 5QA UK
| | - Robert A. Harrison
- Centre for Snakebite Research & Interventions Liverpool School of Tropical Medicine Pembroke Place Liverpool L3 5QA UK
| | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology Brisbane QLD 4001 Australia
| | - Eivind A. B. Undheim
- Centre for Biodiversity Dynamics Department of Biology Norwegian University of Science and Technology 7491 Trondheim Norway
- Centre for Ecological and Evolutionary Synthesis Department of Bioscience The University of Oslo 0316 Oslo Norway
- Centre for Advanced Imaging, and Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
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50
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Randolph CE, Blanksby SJ, McLuckey SA. Toward Complete Structure Elucidation of Glycerophospholipids in the Gas Phase through Charge Inversion Ion/Ion Chemistry. Anal Chem 2020; 92:1219-1227. [PMID: 31763816 PMCID: PMC6949391 DOI: 10.1021/acs.analchem.9b04376] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Shotgun lipidomics has recently gained popularity for lipid analysis. Conventionally, shotgun analysis of glycerophospholipids via direct electrospray ionization tandem mass spectrometry (ESI-MS/MS) provides glycerophospholipid (GPL) class (i.e., headgroup composition) and fatty acyl composition. Reliant on low-energy collision-induced dissociation (CID), traditional ESI-MS/MS fails to define fatty acyl regiochemistry along the glycerol backbone or carbon-carbon double bond position(s) in unsaturated fatty acyl substituents. Therefore, isomeric GPLs are often unresolved, representing a significant challenge for shotgun-MS approaches. We developed a top-down shotgun-MS method utilizing gas-phase ion/ion charge inversion chemistry that provides near-complete GPL structural identification. First, in negative ion mode, CID of mass-selected GPL anions generates fatty acyl carboxylate anions via fragmentation of ester bonds linking the fatty acyl substituents at the sn-1 and sn-2 positions of the glycerol backbone. Product anions, including fatty acyl carboxylate ions, were then derivatized in the mass spectrometer via an ion/ion charge inversion reaction with tris-phenanthroline magnesium dications. Subsequent CID of charge-inverted fatty acyl complex cations yielded isomer-specific product ion spectra that permit (i) unambiguous assignment of carbon-carbon double bond position(s) and (ii) relative quantitation of isomeric fatty acyl substituents. The outlined strategy was applied to the analysis of targeted GPLs extracted from human plasma, including several proposed plasma biomarkers. A single experiment thus facilitates assignment of the GPL headgroup, fatty acyl composition, carbon-carbon double bond position(s) in unsaturated fatty acyl chains, and, in some cases, fatty acyl sn-position and relative abundances for isomeric fatty acyl substituents. Ultimately, this MSn platform paired with ion/ion chemistry permitted identification of major, and some minor, isomeric contributors that are unresolved using conventional ESI-MS/MS.
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Affiliation(s)
- Caitlin E. Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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