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Qi Y, Fu P, Volmer DA. Analysis of natural organic matter via fourier transform ion cyclotron resonance mass spectrometry: an overview of recent non-petroleum applications. MASS SPECTROMETRY REVIEWS 2022; 41:647-661. [PMID: 32412674 DOI: 10.1002/mas.21634] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/22/2019] [Indexed: 06/11/2023]
Abstract
Among the different techniques for mass analysis, ultra-high-resolution Fourier transform ion cyclotron resonance (FTICR) is the method of choice for highly complex samples, as it offers unrivaled mass accuracy and resolving power, combined with a high degree of flexibility in hybrid instruments as well as for ion activation techniques. FTICR instruments are readily embraced by the biological and biomedical research communities and applied over a wide range of applications for the analysis of biomolecules such as carbohydrates, lipids, nucleic acids, and proteins. In the field of natural organic matter (NOM) analysis, petroleum-related studies currently dominate FTICR-MS applications. Recently, however, there is a growing interest in developing high-performance MS methods for the characterization of NOM samples from natural aquatic and terrestrial environments. Here, we present an overview of FTICR-MS techniques for complex, non-petroleum NOM samples, including data analysis and novel tandem mass spectrometry (MS/MS) methods for structural classifications. © 2020 The Authors. Mass Spectrometry Reviews published by John Wiley & Sons Ltd.
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Affiliation(s)
- Yulin Qi
- Institute of Surface-Earth System Science, Tianjin University, Tianjin, China
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin, China
| | - Dietrich A Volmer
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
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Zhang R, Qi Y, Ma C, Ge J, Hu Q, Yue FJ, Li SL, Volmer DA. Characterization of Lignin Compounds at the Molecular Level: Mass Spectrometry Analysis and Raw Data Processing. Molecules 2021; 26:molecules26010178. [PMID: 33401378 PMCID: PMC7795929 DOI: 10.3390/molecules26010178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/07/2020] [Accepted: 09/07/2020] [Indexed: 12/16/2022] Open
Abstract
Lignin is the second most abundant natural biopolymer, which is a potential alternative to conventional fossil fuels. It is also a promising material for the recovery of valuable chemicals such as aromatic compounds as well as an important biomarker for terrestrial organic matter. Lignin is currently produced in large quantities as a by-product of chemical pulping and cellulosic ethanol processes. Consequently, analytical methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This review is devoted to the application of mass spectrometry, including data analysis strategies, for the elemental and structural elucidation of lignin products. We describe and critically evaluate how these methods have contributed to progress and trends in the utilization of lignin in chemical synthesis, materials, energy, and geochemistry.
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Affiliation(s)
- Ruochun Zhang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China
| | - Yulin Qi
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China
- Correspondence: ; Fax: +86-022-27405051
| | - Chao Ma
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
| | - Jinfeng Ge
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
| | - Qiaozhuan Hu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
| | - Fu-Jun Yue
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China
| | - Si-Liang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; (R.Z.); (C.M.); (J.G.); (Q.H.); (F.-J.Y.); (S.-L.L.)
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China
| | - Dietrich A. Volmer
- Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany;
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Novel Microcystins from Planktothrix prolifica NIVA-CYA 544 Identified by LC-MS/MS, Functional Group Derivatization and 15N-labeling. Mar Drugs 2019; 17:md17110643. [PMID: 31731697 PMCID: PMC6891653 DOI: 10.3390/md17110643] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/08/2019] [Accepted: 11/09/2019] [Indexed: 12/31/2022] Open
Abstract
Microcystins are cyclic heptapeptides from cyanobacteria that are potent inhibitors of protein phosphatases and are toxic to animals and humans. At present, more than 250 microcystin variants are known, with variants reported for all seven peptide moieties. While d-glutamic acid (d-Glu) is highly-conserved at position-6 of microcystins, there has been only one report of a cyanobacterium (Anabaena) producing microcystins containing l-Glu at the variable 2- and 4-positions. Liquid chromatography–mass spectrometry analyses of extracts from Planktothrix prolifica NIVA-CYA 544 led to the tentative identification of two new Glu-containing microcystins, [d-Asp3]MC-ER (12) and [d-Asp3]MC-EE (13). Structure determination was aided by thiol derivatization of the Mdha7-moiety and esterification of the carboxylic acid groups, while 15N-labeling of the culture and isotopic profile analysis assisted the determination of the number of nitrogen atoms present and the elemental composition of molecular and product-ions. The major microcystin analog in the extracts was [d-Asp3]MC-RR (1). A microcystin with an unprecedented high-molecular-mass (2116 Da) was also detected and tentatively identified as a sulfide-linked conjugate of [d-Asp3]MC-RR (15) by LC–HRMS/MS and sulfide oxidation, together with its sulfoxide (16) produced via autoxidation. Low levels of [d-Asp3]MC-RW (14), [d-Asp3]MC-LR (4), [d-Asp3,Mser7]MC-RR (11), [d-Asp3]MC-RY (17), [d-Asp3]MC-RF (18), [d-Asp3]MC-RR–glutathione conjugate (19), and [d-Asp3]MC-RCit (20), the first reported microcystin containing citrulline, were also identified in the extract, and an oxidized derivative of [d-Asp3]MC-RR and the cysteine conjugate of 1 were partially characterized.
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Qi Y, Volmer DA. Chemical diversity of lignin degradation products revealed by matrix-optimized MALDI mass spectrometry. Anal Bioanal Chem 2019; 411:6031-6037. [PMID: 31278551 DOI: 10.1007/s00216-019-01984-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/18/2022]
Abstract
Lignin is the most abundant natural resource of aromatic moieties and the second most abundant natural biopolymer. Analytical techniques that obtain as much information as possible on the exact structural content of lignin species are essential for developing efficient processes that transform highly complex lignin wastes into value chemicals and biofuels. For mass spectrometric analysis of lignin samples, usually electrospray ionization, atmospheric pressure chemical ionization, or atmospheric pressure photoionization are used as ionization techniques. Matrix-assisted laser desorption/ionization (MALDI) is less frequently applied but offers a much more rapid screening option for lignin mixtures. In this study, we compared several common MALDI matrices for analysis of alkali lignin and discovered that different chemical matrices exhibited very different ionization efficiencies and selectivity with respect to the structures of the lignin-related compounds as well as the presence of heteroatoms. Importantly, the results highlight that the choice of matrix strongly determines the analytical coverage of molecular species in the complex lignin degradation mixtures. Graphical abstract.
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Affiliation(s)
- Yulin Qi
- Institute of Surface-Earth System Science, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Dietrich A Volmer
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany.
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Andeden EE, Ozturk S, Aslim B. Antiproliferative, neurotoxic, genotoxic and mutagenic effects of toxic cyanobacterial extracts. Interdiscip Toxicol 2018; 11:267-274. [PMID: 31762678 PMCID: PMC6853012 DOI: 10.2478/intox-2018-0026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 01/13/2018] [Indexed: 01/08/2023] Open
Abstract
Cyanobacteria are the rich resource of various secondary metabolites including toxins with broad pharmaceutical significance. The aim of this work was to evaluate the antiproliferative, neurotoxic, genotoxic and mutagenic effects of cyanobacterial extracts containing Microcystin-LR (MCLR) in vitro. ELISA analysis results showed that MCLR contents of five cyanobacterial extracts were 2.07 ng/mL, 1.43 ng/mL, 1.41 ng/mL, 1.27 ng/mL, and 1.12 ng/mL for Leptolyngbya sp. SB1, Phormidium sp. SB4, Oscillatoria earlei SB5, Phormidium sp. SB2, Uncultured cyanobacterium, respectively. Phormidium sp. SB4 and Phormidium sp. SB2 extracts had the lowest neurotoxicity (86% and 79% cell viability, respectively) and Oscillatoria earlei SB5 extracts had the highest neurotoxicity (47% cell viability) on PC12 cell at 1000 µg/ml extract concentration. Leptolyngbya sp. SB1 and Phormidium sp. SB2 showed the highest antiproliferative effect (92% and 77% cell death) on HT29 cell. On the other hand, all concentrations of five toxic cyanobacterial extracts induced DNA damage between 3.0% and 1.3% of tail intensity and did not cause any direct mutagenic effect at the 1000 µg/plate cyanobacterial extracts. These results suggest that cyanobacteria-derived MCLR is a promising candidate for development of effective agents against colon cancer.
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Affiliation(s)
- Enver Ersoy Andeden
- Molecular biology and genetics, Life sciences, Nevsehir Hacı Bektas Veli, Nevsehir, Turkey
| | - Sahlan Ozturk
- Environmental Engineering, Faculty of Engineering-Architecture, Life sciences, Nevsehir Haci Bektas Veli, Nevsehir, Turkey
| | - Belma Aslim
- Biology, Faculty of Science, Life sciences, Gazi, Ankara, Turkey
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Chen X, Wang Z, Wong YLE, Wu R, Zhang F, Chan TWD. Electron-ion reaction-based dissociation: A powerful ion activation method for the elucidation of natural product structures. MASS SPECTROMETRY REVIEWS 2018; 37:793-810. [PMID: 29603345 DOI: 10.1002/mas.21563] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/12/2018] [Indexed: 05/16/2023]
Abstract
The structural elucidation of natural products (NPs) remains a challenge due to their structurally diversities and unpredictable functionalities, motifs, and scaffolds. Tandem mass spectrometry (MS/MS) is an effective method that assists the full elucidation of complicated NP structures. Ion activation methods play a key role in determining the fragmentation pathways and the structural information obtained from MS/MS. Electron-ion reaction-based dissociation (ExD) methods, including electron capture dissociation (ECD), electron transfer dissociation (ETD), electron-induced dissociation (EID), and electron detachment dissociation (EDD), can induce the breakage of specific chemical bonds and the generation of distinct fragment ions. This review article provides an overview of the mechanisms, instrumentation, and typical applications related to ExD MS/MS in the structural elucidation of NPs, primarly including lipids, oligosaccharides, glycoconjugates, metabolites, and pharmaceutical drugs. This work aims to reveal the capacity and potential of ExD mass spectrometry in analyzing NPs and consequently helping the NP communities to utilize the modern capabilities of MS/MS in the discovery and evaluation of novel NPs.
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Affiliation(s)
- Xiangfeng Chen
- Key Laboratory for Applied Technology of Sophisticated Analytical Instruments, Shandong Analysis and Test Centre, Qilu University of Technology (Shandong Academy of Science), Shandong, P.R. China
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Ze Wang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Y-L Elaine Wong
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Ri Wu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Feng Zhang
- Chinese Academy of Inspection and Quarantine, Beijing, P. R. China
| | - T-W Dominic Chan
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
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Stewart AK, Strangman WK, Percy A, Wright JLC. The biosynthesis of 15N-labeled microcystins and the comparative MS/MS fragmentation of natural abundance and their 15N-labeled congeners using LC-MS/MS. Toxicon 2018; 144:91-102. [PMID: 29427567 DOI: 10.1016/j.toxicon.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 10/25/2017] [Accepted: 01/30/2018] [Indexed: 10/18/2022]
Abstract
The global need for accurate and sensitive quantitation of microcystins (MCs) persists as incidents of cyanobacterial harmful algal blooms continue to rise and recent research reveals an underestimation of the human health implications of these toxins. An optimal approach for their accurate quantitation relies on the availability of stable isotope-labeled MC standards for use in stable isotope dilution analysis (SIDA) strategies involving liquid chromatography tandem mass spectrometry (LC-MS/MS). Due to the dearth of isotopically labeled MCs, ten different 15N-enriched MCs were biosynthesized from producing cultures and fully characterized. This involved the comparative MS/MS fragmentation of natural abundance or unlabeled metabolites with their 15N-labeled congeners for improved confidence in product ion annotation. These results revealed a series of incorrect annotations described previously in the literature. In this manuscript, the biosynthesis of labeled microcystin is detailed, and their complete analytical characterization for prospective use in targeted SIDA applications, such as routine water testing is described.
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Affiliation(s)
- Allison K Stewart
- MARBIONC, UNC- Wilmington, Center for Marine Science, 5600 Marvin K. Moss Lane, Wilmington, NC 28409, USA
| | - Wendy K Strangman
- MARBIONC, UNC- Wilmington, Center for Marine Science, 5600 Marvin K. Moss Lane, Wilmington, NC 28409, USA
| | - Andrew Percy
- Cambridge Isotope Laboratories, Department of Applications Development, 3 Highwood Drive, Tewksburg, MA 01876, USA
| | - Jeffrey L C Wright
- MARBIONC, UNC- Wilmington, Center for Marine Science, 5600 Marvin K. Moss Lane, Wilmington, NC 28409, USA; UNC-Wilmington, Department of Chemistry and Biochemistry, 601 S. College Road, Wilmington, NC 28403, USA.
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Bogialli S, Bortolini C, Di Gangi IM, Di Gregorio FN, Lucentini L, Favaro G, Pastore P. Liquid chromatography-high resolution mass spectrometric methods for the surveillance monitoring of cyanotoxins in freshwaters. Talanta 2017; 170:322-330. [DOI: 10.1016/j.talanta.2017.04.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 04/07/2017] [Accepted: 04/11/2017] [Indexed: 10/19/2022]
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Qi Y, Volmer DA. Electron-based fragmentation methods in mass spectrometry: An overview. MASS SPECTROMETRY REVIEWS 2017; 36:4-15. [PMID: 26445267 DOI: 10.1002/mas.21482] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/03/2015] [Accepted: 07/03/2015] [Indexed: 05/21/2023]
Abstract
Tandem mass spectrometry (MS/MS) provides detailed information for structural characterization of biomolecules. The combination of electron capture dissociation (ECD) techniques with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) often provides unique ion-electron reactions and fragmentation channels in MS/MS. ECD is often a complimentary, sometimes even a superior tool to conventional MS/MS techniques. This article is aimed at providing a short overview of ECD-based fragmentation techniques (ExD) and optimization of ECD experiments for FTICR mass analyzers. Most importantly, it is meant to pique the interest of potential users for this exciting research field. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:4-15, 2017.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, Saarbrücken, 66123, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, Saarbrücken, 66123, Germany
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Qi Y, Volmer DA. Structural analysis of small to medium-sized molecules by mass spectrometry after electron-ion fragmentation (ExD) reactions. Analyst 2016; 141:794-806. [PMID: 26725919 DOI: 10.1039/c5an02171e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron capture dissociation (ECD) is a tandem mass spectrometry (MS/MS) method that utilizes the interaction of ions and electrons. Its unique ability to preserve labile bonds distinguishes it from conventional threshold-based MS/MS methods, the most important of which is collision-induced dissociation (CID). During the last decade, ECD has opened up several new venues in protein analyses, for example top-down sequencing, identification of post-translational modifications, and characterization of protein-protein interactions. In recent years, a number of related dissociation techniques, so-called ExD techniques, particularly electron transfer dissociation (ETD), electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD), have emerged and have extended the application range of ion-electron dissociations further. Importantly, ExD techniques have been applied beyond protein analyses, which is the focus of the current paper. This short introduction describes the application of ExD to small and medium-sized molecules and reviews important applications to natural products, biomedical compounds, synthetic molecules, crude oils, and environmental toxins.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, 66123 Saarbrücken, Germany.
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Qi Y, Volmer DA. Electron-capture dissociation for investigating host/guest complexes of 18-crown-6-ether and peptides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:2316-2318. [PMID: 26522326 DOI: 10.1002/rcm.7399] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
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Qi Y, Hayen H, Volmer DA. Characterization of the iron-binding properties of pyoverdine using electron-capture dissociation-tandem mass spectrometry. Biometals 2015; 29:53-60. [PMID: 26596281 DOI: 10.1007/s10534-015-9895-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 11/11/2015] [Indexed: 11/29/2022]
Abstract
Pyoverdines (PVD) are a group of siderophores produced by fluorescent Pseudomonads. Identification of PVD variants mostly relies on liquid chromatography-tandem mass spectrometry (LC-MS/MS) using collision-induced dissociation (CID). Here, both CID and the novel dissociation technique electron-capture dissociation (ECD) were applied to characterize PVD succinamide and its Fe(III)-chelated complex. The results clearly showed that ECD produced diagnostic side chain fragmentation of the PVD peptide chain and preserved the labile Fe(III) binding to the chromophore in contrast to CID. The ECD technique is therefore expected to support the understanding of strain-specific Fe(III) transport processes of PVDs.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Heiko Hayen
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany.
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Qi Y, Geib T, Volmer DA. Determining the Binding Sites of β-Cyclodextrin and Peptides by Electron-Capture Dissociation High Resolution Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1143-1149. [PMID: 25862187 DOI: 10.1007/s13361-015-1118-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/25/2015] [Accepted: 02/25/2015] [Indexed: 06/04/2023]
Abstract
Cyclodextrins (CDs) are a group of cyclic oligosaccharides, which readily form inclusion complexes with hydrophobic compounds to increase bioavailability, thus making CDs ideal drug excipients. Recent studies have also shown that CDs exhibit a wide range of protective effects, preventing proteins from aggregation, degradation, and folding. These effects strongly depend on the binding sites on the protein surface. CDs only exhibit weak interactions with amino acids, however; conventional analytical techniques therefore usually fail to reveal the exact location of the binding sites. Moreover, some studies even suggest that CD inclusion complexes are merely electrostatic adducts. Here, electron capture dissociation (ECD) was applied in this proof-of-concept study to examine the exact nature of the CD/peptide complexes, and CD binding sites were unambiguously located for the first time via Fourier-transform ion cyclotron resonance (FTICR) tandem mass spectrometry.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
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Qi Y, Geib T, Huynh AM, Jung G, Volmer DA. Fragmentation patterns of boron-dipyrromethene (BODIPY) dyes by electrospray ionization high-resolution tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:885-890. [PMID: 26377017 DOI: 10.1002/rcm.7179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/24/2015] [Accepted: 02/21/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene derivatives (BODIPYs) are fluorescent organic dyes that are widely used as non-radioactive labels in biological analyses. The fragmentation behaviour of ten structurally related BODIPYs was studied using tandem mass spectrometry (MS/MS), to support the structural elucidation process during synthesis. METHODS The BODIPYs were investigated by electrospray ionization (ESI)-MS/MS, utilizing collision-induced dissociation (CID) data from triple quadrupole MS and high-resolution, accurate mass CID data from Fourier transform ion cyclotron resonance (FTICR) experiments. RESULTS Unusual radical molecular cations ([M](+•)) were formed directly during the ESI process. These radical species dissociated into a large range of product ions during the subsequent CID experiments. Superimposed dissociations originating from parallel [M](+•) and [M+H](+) decompositions significantly complicated the interpretation of the MS/MS spectra. CONCLUSIONS Detailed dissociation mechanisms were proposed in this study for BODIPY dyes. The elemental formulae of CID product ions were unambiguously assigned using FTICR-MS and unique fragment ions were discovered for the rapid identification of methyl, ethyl, butyl, tert-butyl, and phenyl substituents of individual dyes in BODIPY synthesis mixtures by low-resolution MS.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Timon Geib
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Anh-Minh Huynh
- Biophysical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Gregor Jung
- Biophysical Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
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Qi Y, Rosso L, Sedan D, Giannuzzi L, Andrinolo D, Volmer DA. Seven new microcystin variants discovered from a native Microcystis aeruginosa strain--unambiguous assignment of product ions by tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:220-224. [PMID: 25641497 DOI: 10.1002/rcm.7098] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/14/2014] [Accepted: 11/14/2014] [Indexed: 06/04/2023]
Abstract
RATIONALE High-resolution mass spectrometry was applied to the study of a Microcystis aeruginosa strain previously reported as a [D-Leu(1)]MC-LR producer. Detailed analysis revealed new microcystin (MC) variants produced from the strain, and seven of these were previously unreported variants. This work shows the importance of mass accuracy for the identification of unknown MCs. METHODS The M. aeruginosa strain was isolated from a bloom sample collected from Argentina and acclimated to lab conditions. The MC variants in the strain were separated by UV/Vis detection-guided high-performance liquid chromatography, and their structures were unambiguous determined by tandem mass spectrometry (MS/MS). RESULTS A simple strategy was developed for quickly locating the low-abundance MC precursors from complex samples. MS/MS anlysis revealed ten MC variants produced from the strain, of which seven have never been reported before. CONCLUSIONS This work shows the interference of isobarics and isomers in the study of unknown MCs, and, therefore, high mass accuracy is important to avoid false assignments. Moreover, the peak list provided here (30-50 fragments unambiguously assigned for ten MCs) can be used as a reference for the discovery of MCs from environmental samples.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany
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