1
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Graham KA, Grisolia VJ, Borotto NB. Mobility-Assisted Pseudo-MS 3 Sequencing of Protein Ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38920020 DOI: 10.1021/jasms.4c00148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
The sequencing of intact proteins within a mass spectrometer has many benefits but is frequently limited by the fact that tandem mass spectrometry (MS/MS) techniques often generate poor sequence coverages when applied to protein ions. To overcome this limitation, exotic MS/MS techniques that rely on lasers and radical chemistry have been developed. These techniques generate high sequence coverages, but they require specialized instrumentation, create products through multiple dissociation mechanisms, and often require long acquisition times. Recently, we demonstrated that protein ions can be dissociated in a trapped ion mobility spectrometry (TIMS) device prior to mobility separation in a commercial timsTOF. All generated product ions were distributed throughout the mobility dimension, and this separation enabled deconvolution of complex tandem mass spectra and could enable facile pseudo-MS3 interrogation of generated product ions with the downstream quadrupole and collision cell. A second activation step improves sequence coverage because the most labile bonds have been depleted during the first dissociation and subsequent dissociation events are more evenly distributed throughout the product ion backbone. In this work, we explore the potential of this mobility-assisted pseudo-MS3 (MAP) method on a commercial timsTOF and timsTOF Pro 2. We demonstrate that while MAP only generates 92% of the sequence coverage of the most effective MS/MS technique, it accomplished this feat in 1.5 min and could be facilely integrated with liquid chromatographic separations.
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Affiliation(s)
- Katherine A Graham
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Vincent J Grisolia
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Nicholas B Borotto
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, Nevada 89557, United States
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2
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van Tetering L, Spies S, Wildeman QDK, Houthuijs KJ, van Outersterp RE, Martens J, Wevers RA, Wishart DS, Berden G, Oomens J. A spectroscopic test suggests that fragment ion structure annotations in MS/MS libraries are frequently incorrect. Commun Chem 2024; 7:30. [PMID: 38355930 PMCID: PMC10867025 DOI: 10.1038/s42004-024-01112-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 01/22/2024] [Indexed: 02/16/2024] Open
Abstract
Modern untargeted mass spectrometry (MS) analyses quickly detect and resolve thousands of molecular compounds. Although features are readily annotated with a molecular formula in high-resolution small-molecule MS applications, the large majority of them remains unidentified in terms of their full molecular structure. Collision-induced dissociation tandem mass spectrometry (CID-MS2) provides a diagnostic molecular fingerprint to resolve the molecular structure through a library search. However, for de novo identifications, one must often rely on in silico generated MS2 spectra as reference. The ability of different in silico algorithms to correctly predict MS2 spectra and thus to retrieve correct molecular structures is a topic of lively debate, for instance in the CASMI contest. Underlying the predicted MS2 spectra are the in silico generated product ion structures, which are normally not used in de novo identification, but which can serve to critically assess the fragmentation algorithms. Here we evaluate in silico generated MSn product ion structures by comparison with structures established experimentally by infrared ion spectroscopy (IRIS). For a set of three dozen product ion structures from five precursor molecules, we find that virtually all fragment ion structure annotations in three major in silico MS2 libraries (HMDB, METLIN, mzCloud) are incorrect and caution the reader against their use for structure annotation of MS/MS ions.
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Affiliation(s)
- Lara van Tetering
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Sylvia Spies
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Quirine D K Wildeman
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Kas J Houthuijs
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Rianne E van Outersterp
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Jonathan Martens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Ron A Wevers
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, The Netherlands
| | - David S Wishart
- Departments of Computing Science and Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED, Nijmegen, The Netherlands.
- van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
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3
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Graham KA, Lawlor CF, Borotto NB. Characterizing the top-down sequencing of protein ions prior to mobility separation in a timsTOF. Analyst 2023; 148:1534-1542. [PMID: 36876327 PMCID: PMC10042122 DOI: 10.1039/d2an01682f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/28/2023] [Indexed: 03/07/2023]
Abstract
Mass spectrometry (MS)-based proteomics workflows of intact protein ions have increasingly been utilized to study biological systems. These workflows, however, frequently result in convoluted and difficult to analyze mass spectra. Ion mobility spectrometry (IMS) is a promising tool to overcome these limitations by separating ions by their mass- and size-to-charge ratios. In this work, we further characterize a newly developed method to collisionally dissociate intact protein ions in a trapped ion mobility spectrometry (TIMS) device. Dissociation occurs prior to ion mobility separation and thus, all product ions are distributed throughout the mobility dimension, enabling facile assignment of near isobaric product ions. We demonstrate that collisional activation within a TIMS device is capable of dissociating protein ions up to 66 kDa. We also demonstrate that the ion population size within the TIMS device significantly influences the efficiency of fragmentation. Lastly, we compare CIDtims to the other modes of collisional activation available on the Bruker timsTOF and demonstrate that the mobility resolution in CIDtims enables the annotation of overlapping fragment ions and improves sequence coverage.
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Affiliation(s)
- Katherine A Graham
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Charles F Lawlor
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Nicholas B Borotto
- Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, NV 89557, USA.
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4
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Chen J, Cao D, Fortmann SD, Curcio CA, Feist RM, Crosson JN. Transthyretin proteoforms of intraocular origin in human subretinal fluid. Exp Eye Res 2022; 222:109163. [PMID: 35760119 DOI: 10.1016/j.exer.2022.109163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/24/2022] [Accepted: 06/20/2022] [Indexed: 11/26/2022]
Abstract
Understanding the molecular composition of ocular tissues and fluids could inform new approaches to prevalent causes of blindness. Subretinal fluid accumulating between the photoreceptor outer segments and retinal pigment epithelium (RPE) is potentially a rich source of proteins and lipids normally cycling among outer retinal cells and choroid. Herein, intact post-translationally modified proteins (proteoforms) were extracted from subretinal fluids of five patients with rhegmatogenous retinal detachment (RRD), analyzed by tandem mass spectrometry, and compared to published data on these same proteins as synthesized by other organs. Single-nuclei transcriptomic data from non-diseased human retina/RPE were used to identify whether proteins in subretinal fluid were of potential ocular origin. Two human donor eyes with normal maculas were immunoprobed for transthyretin (TTR) with appropriate controls. The three most abundant proteins detected in subretinal fluid were albumin, TTR, and apolipoprotein A-I. Remarkably, TTR relative to the other proteins was more abundant than its serum counterpart, suggestive of TTR being synthesized predominantly locally. Six post-translationally modified protein forms (proteoforms) of TTR were detected, with the relative amount of glutathionylated TTR being much higher in the subretinal fluid (12-43%) than values reported for serum (<5%) and cerebrospinal fluid (0.4-13%). Moreover, a putative glycosylated TTR dimer of 32,428 Da was detected as the fourth most abundant protein. The high abundance of TTR and putative TTR dimer in subretinal fluid was supported by analysis of available single-nuclei transcriptomic data, which showed strong and specific signal for TTR in RPE. Immunohistochemistry further showed strong diffuse TTR immunoreactivity in choroidal stroma that contrasted with vertically aligned signal in the outer segment zone of the subretinal space and negligible signal in RPE cell bodies. These results suggest that TTR in the retina is synthesized intraocularly, and glutathionylation is crucial for its normal function. Further studies on the composition, function, and quantities of TTR and other proteoforms in subretinal fluid could inform mechanisms, diagnostic methods, and treatment strategies for age-related macular degeneration, familial amyloidosis, and other retinal diseases involving dysregulation of physiologic lipid transfer and oxidative stress.
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Affiliation(s)
- Jianzhong Chen
- Department of Optometry and Vision Science, The University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Seth D Fortmann
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Richard M Feist
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jason N Crosson
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
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5
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Profiling of Chlorogenic Acids from Bidens pilosa and Differentiation of Closely Related Positional Isomers with the Aid of UHPLC-QTOF-MS/MS-Based In-Source Collision-Induced Dissociation. Metabolites 2020; 10:metabo10050178. [PMID: 32365739 PMCID: PMC7281500 DOI: 10.3390/metabo10050178] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/14/2022] Open
Abstract
Bidens pilosa is an edible herb from the Asteraceae family which is traditionally consumed as a leafy vegetable. B. pilosa has many bioactivities owing to its diverse phytochemicals, which include aliphatics, terpenoids, tannins, alkaloids, hydroxycinnamic acid (HCA) derivatives and other phenylpropanoids. The later include compounds such as chlorogenic acids (CGAs), which are produced as either regio- or geometrical isomers. To profile the CGA composition of B. pilosa, methanol extracts from tissues, callus and cell suspensions were utilized for liquid chromatography coupled to mass spectrometric detection (UHPLC-QTOF-MS/MS). An optimized in-source collision-induced dissociation (ISCID) method capable of discriminating between closely related HCA derivatives of quinic acids, based on MS-based fragmentation patterns, was applied. Careful control of collision energies resulted in fragment patterns similar to MS2 and MS3 fragmentation, obtainable by a typical ion trap MSn approach. For the first time, an ISCID approach was shown to efficiently discriminate between positional isomers of chlorogenic acids containing two different cinnamoyl moieties, such as a mixed di-ester of feruloyl-caffeoylquinic acid (m/z 529) and coumaroyl-caffeoylquinic acid (m/z 499). The results indicate that tissues and cell cultures of B. pilosa contained a combined total of 30 mono-, di-, and tri-substituted chlorogenic acids with positional isomers dominating the composition thereof. In addition, the tartaric acid esters, caftaric- and chicoric acids were also identified. Profiling revealed that these HCA derivatives were differentially distributed across tissues types and cell culture lines derived from leaf and stem explants.
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6
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Chen J, Shiyanov P, Green KB. Top-down mass spectrometry of intact phosphorylated β-casein: Correlation between the precursor charge state and internal fragments. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:527-539. [PMID: 30997701 PMCID: PMC6779312 DOI: 10.1002/jms.4364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/25/2019] [Accepted: 04/11/2019] [Indexed: 05/12/2023]
Abstract
Phosphorylated proteins play essential roles in many cellular processes, and identification and characterization of the relevant phosphoproteins can help to understand underlying mechanisms. Herein, we report a collision-induced dissociation top-down approach for characterizing phosphoproteins on a quadrupole time-of-flight mass spectrometer. β-casein, a protein with two major isoforms and five phosphorylatable serine residues, was used as a model. Peaks corresponding to intact β-casein ions with charged states up to 36+ were detected. Tandem mass spectrometry was performed on β-casein ions of different charge states (12+ , and 15+ to 28+ ) in order to determine the effects of charge state on dissociation of this protein. Most of the abundant fragments corresponded to y, b ions, and internal fragments caused by cleavage of the N-terminal amide bond adjacent to proline residues (Xxx-Pro). The abundance of internal fragments increased with the charge state of the protein precursor ion; these internal fragments predominantly arose from one or two Xxx-Pro cleavage events and were difficult to accurately assign. The presence of abundant sodium adducts of β-casein further complicated the spectra. Our results suggest that when interpreting top-down mass spectra of phosphoproteins and other proteins, researchers should consider the potential formation of internal fragments and sodium adducts for reliable characterization.
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Affiliation(s)
- Jianzhong Chen
- Department of Optometry and Vision Science; University of Alabama at Birmingham; Birmingham, AL, 35294
- Applied Biotechnology Branch; Air Force Research Laboratory; Dayton, OH 45433, USA
- Mass Spectrometry and Proteomics Facility; The Ohio State University; Columbus, OH 43210, USA
- Corresponding author: Jianzhong Chen, Ph.D., Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, USA; ; Phone: 205.934.8230
| | - Pavel Shiyanov
- Applied Biotechnology Branch; Air Force Research Laboratory; Dayton, OH 45433, USA
| | - Kari B Green
- Mass Spectrometry and Proteomics Facility; The Ohio State University; Columbus, OH 43210, USA
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7
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Zhang P, Chan W, Ang IL, Wei R, Lam MMT, Lei KMK, Poon TCW. Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation. Sci Rep 2019; 9:6453. [PMID: 31015571 PMCID: PMC6478932 DOI: 10.1038/s41598-019-42777-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/08/2019] [Indexed: 12/23/2022] Open
Abstract
Fragmentation reactions of protonated α-amino acids (AAs) were studied previously using tandem mass spectrometry (MS/MS) of unit mass resolution. Isobaric fragmentation products and minor fragmentation products could have been overlooked or misannotated. In the present study, we examined the fragmentation patterns of 19 AAs using high-resolution electrospray ionization MS/MS (HR-ESI-MS/MS) with collision-induced dissociation (CID). Isobaric fragmentation products from protonated Met and Trp were resolved and identified for the first time. Previously unreported fragmentation products from protonated Met, Cys, Gln, Arg, and Lys were observed. Additionally, the chemical identity of a fragmentation product from protonated Trp that was incorrectly annotated in previous investigations was corrected. All previously unreported fragmentation products and reactions were verified by pseudo MS3 experiments and/or MS/MS analyses of deuterated AAs. Clearer pictures of the fragmentation reactions for Met, Cys, Trp, Gln, Arg and Lys were obtained in the present study.
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Affiliation(s)
- Pengwei Zhang
- Pilot Laboratory, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
| | - Wan Chan
- Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong, China
| | - Irene L Ang
- Pilot Laboratory, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
| | - Rui Wei
- Pilot Laboratory, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
| | - Melody M T Lam
- Proteomics Core, Faculty of Health Sciences, University of Macau, Macau, China
| | - Kate M K Lei
- Pilot Laboratory, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
| | - Terence C W Poon
- Pilot Laboratory, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China.
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8
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Terajima T, Uchida H, Abe N, Yasumoto T. Structure elucidation of ostreocin-A and ostreocin-E1, novel palytoxin analogs produced by the dinoflagellate Ostreopsis siamensis, using LC/Q-TOF MS. Biosci Biotechnol Biochem 2019; 83:381-390. [DOI: 10.1080/09168451.2018.1550356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
ABSTRACT
Palytoxin analogs are marine toxins with large complex polyol structures. A benthic dinoflagellate Ostreopsis siamensis produces more than ten palytoxins (ostreocins, OSTs). The limited sample availability of minor OSTs restricts the definition of their chemical structures. The present investigation characterizes structures of two minor OSTs, i.e., ostreocin-A (OSTA) and ostreocin-E1 (OSTE1), using ostreocin-D (OSTD) as a reference compound, by liquid chromatography/quadrupole-time-of-flight mass spectrometry. The molecular formulas of OSTA and OSTE1 were C127H219N3O54 and C127H217N3O52, respectively. Compared to OSTD, OSTA has an extra oxygen atom whereas OSTE1 lacks one oxygen atom and two hydrogen atoms. The MS/MS experiments (precursor ions: [M + H]+ and [M-H]−) suggested a hydroxyl substitution at C82 in OSTA and alteration(s) between C53 and C100 in OSTE1. Further analysis of structural details in OSTE1 was performed through a pseudo-MS3 experiment (precursor ion: m/z 1432.748). Accordingly, the planar structures of OSTA and OSTE1 were assigned to 42,82-dihydroxy-3,26-didemethyl-19,44-dideoxypalytoxin and 42-hydroxy-3,26-didemethyl-19,44,73-trideoxypalytoxin-72-ene, respectively.
Abbreviations:CID: collision induced dissociation; HR-LC/MS/MS: high-resolution liquid chromatography/tandem mass spectrometry; LC/ESI/Q-TOF MS: liquid chromatography/quadrupole time-of-flight mass spectrometry equipped with an electrospray ionization source; NMR: nuclear magnetic resonance; OSTs: ostreocins; OSTA: ostreocin-A; OSTB: ostreocin-B; OSTD: ostreocin-D; OSTE1: ostreocin-E1; OVTX-a: ovatoxin-a; OVTXs: ovatoxins; PLTX: palytoxin
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Affiliation(s)
- Takehito Terajima
- Department of Food and Nutrition Science, Graduate School of Agriculture, Tokyo University of Agriculture, Setagaya, Tokyo, Japan
| | - Hideaki Uchida
- Japan Customer Service Operation, Agilent Technologies Japan, Ltd, Hachioji, Tokyo, Japan
| | - Naoki Abe
- Department of Food and Nutrition Science, Graduate School of Agriculture, Tokyo University of Agriculture, Setagaya, Tokyo, Japan
| | - Takeshi Yasumoto
- Tama Laboratory, Japan Food Research Laboratories, Tama, Tokyo, Japan
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9
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Lakshmanan R, Loo JA. Top-Down Protein Identification using a Time-of-Flight Mass Spectrometer and Data Independent Acquisition. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2019; 435:136-144. [PMID: 31105465 PMCID: PMC6519736 DOI: 10.1016/j.ijms.2018.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Top-down mass spectrometry and direct dissociation of gas phase intact proteins have been demonstrated to be a powerful platform for identifying proteins from complex mixtures and for elucidating post-translational modifications (PTMs). Fragmentation of proteins in the atmospheric pressure/vacuum interface of the electrospray ionization mass spectrometer is an effective dissociation technique that can be utilized for on-line HPLC top-down analysis. We demonstrate the capability to perform intact protein identifications in a single-stage time-of- flight (TOF) mass spectrometer in a data independent (DIA) acquisition fashion by rapidly switching the in-source dissociation (ISD) energy during protein elution from a liquid chromatography (LC) column. The intact protein and product ion masses obtained at low and high ISD energies, respectively, were measured using a TOF mass analyzer. By coupling on-line protein separations to dissociation in the atmospheric pressure/vacuum interface region of the mass spectrometer, we identified proteins in simple complexity mixtures, including subunits from the human 20S proteasome complex, and PTMs such as phosphorylation and N-terminal acetylation events. This proof-of-principle study demonstrates that a data-independent pseudo- MS/MS method could be a relatively in-expensive platform for top-down MS.
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Affiliation(s)
- Rajeswari Lakshmanan
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Molecular Biology Institute, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA 90095
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10
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Baira SM, Gunupudi P, Abbaraju V, R. S, Talluri MVNK. Study of forced degradation behaviour of cobicistat and atazanavir using LC/ESI/QTOF/MS; a combination of in-sourced and collision-induced dissociation for evaluation of the fragmentation patterns of degradation products. NEW J CHEM 2018. [DOI: 10.1039/c8nj03418d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present study describes the LC/MS/MS characterization of degradation products of cobicistat and atazanavir.
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Affiliation(s)
- Shandilya Mahamuni Baira
- Department of Pharmaceutical Analysis
- National Institute of Pharmaceutical Education & Research
- Hyderabad
- India
| | - Padmini Gunupudi
- Department of Pharmaceutical Analysis
- National Institute of Pharmaceutical Education & Research
- Hyderabad
- India
| | - Vigjna Abbaraju
- Department of Pharmaceutical Analysis
- National Institute of Pharmaceutical Education & Research
- Hyderabad
- India
| | - Srinivas R.
- Analytical Department
- CSIR-Indian Institute of Chemical Technology
- Hyderabad
- India
| | - M. V. N. Kumar Talluri
- Department of Pharmaceutical Analysis
- National Institute of Pharmaceutical Education & Research
- Hyderabad
- India
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11
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Wang B, Liu J, Cao J, Wang H, Guan X, Wei Z, Guo X. Investigation of c ions formed by N-terminally charged peptides upon collision-induced dissociation. JOURNAL OF MASS SPECTROMETRY : JMS 2016; 51:989-997. [PMID: 27537939 DOI: 10.1002/jms.3841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 08/16/2016] [Indexed: 06/06/2023]
Abstract
Peptide fragments such as b and y sequence ions generated upon low-energy collision-induced dissociation have been routinely used for tandem mass spectrometry (MS/MS)-based peptide/protein identification. The underlying formation mechanisms have been studied extensively and described within the literature. As a result, the 'mobile proton model' and 'pathways in competition model' have been built to interpret a majority of peptide fragmentation behavior. However, unusual peptide fragments which involve unfamiliar fragmentation pathways or various rearrangement reactions occasionally appear in MS/MS spectra, resulting in confused MS/MS interpretations. In this work, a series of unfamiliar c ions are detected in MS/MS spectra of the model peptides having an N-terminal Arg or deuterohemin group upon low-energy collision-induced dissociation process. Both the protonated Arg and deuterohemin group play an important role in retention of a positive charge at the N-terminus that is remote from the cleavage sites. According to previous reports and our studies involving amino acid substitutions and hydrogen-deuterium exchange, we propose a McLafferty-type rearrangement via charge-remote fragmentation as the potential mechanism to explain the formation of c ions from precursor peptide ions or unconventional b ions. Density functional theory calculations are also employed in order to elucidate the proposed fragmentation mechanisms. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Bing Wang
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Jinrong Liu
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Jungang Cao
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Huixin Wang
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Xinshu Guan
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Zhonglin Wei
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Xinhua Guo
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
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12
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Chen J, Green KB, Nichols KK. Characterization of Wax Esters by Electrospray Ionization Tandem Mass Spectrometry: Double Bond Effect and Unusual Product Ions. Lipids 2015; 50:821-36. [PMID: 26178197 DOI: 10.1007/s11745-015-4044-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 06/22/2015] [Indexed: 11/26/2022]
Abstract
A series of different types of wax esters (represented by RCOOR') were systematically studied by using electrospray ionization (ESI) collision-induced dissociation tandem mass spectrometry (MS/MS) along with pseudo MS(3) (in-source dissociation combined with MS/MS) on a quadrupole time-of-flight (Q-TOF) mass spectrometer. The tandem mass spectra patterns resulting from dissociation of ammonium/proton adducts of these wax esters were influenced by the wax ester type and the collision energy applied. The product ions [RCOOH2](+), [RCO](+) and [RCO-H2O](+) that have been reported previously were detected; however, different primary product ions were demonstrated for the three wax ester types including: (1) [RCOOH2](+) for saturated wax esters, (2) [RCOOH2](+), [RCO](+) and [RCO-H2O](+) for unsaturated wax esters containing only one double bond in the fatty acid moiety or with one additional double bond in the fatty alcohol moiety, and (3) [RCOOH2](+) and [RCO](+) for unsaturated wax esters containing a double bond in the fatty alcohol moiety alone. Other fragments included [R'](+) and several series of product ions for all types of wax esters. Interestingly, unusual product ions were detected, such as neutral molecule (including water, methanol and ammonia) adducts of [RCOOH2](+) ions for all types of wax esters and [R'-2H](+) ions for unsaturated fatty acyl-containing wax esters. The patterns of tandem mass spectra for different types of wax esters will inform future identification and quantification approaches of wax esters in biological samples as supported by a preliminary study of quantification of isomeric wax esters in human meibomian gland secretions.
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Affiliation(s)
- Jianzhong Chen
- Applied Biotechnology Branch, Air Force Research Laboratory, Dayton, OH, 45433, USA,
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Rubino FM. Toxicity of Glutathione-Binding Metals: A Review of Targets and Mechanisms. TOXICS 2015; 3:20-62. [PMID: 29056650 PMCID: PMC5634692 DOI: 10.3390/toxics3010020] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/04/2014] [Accepted: 01/14/2015] [Indexed: 02/07/2023]
Abstract
Mercury, cadmium, arsenic and lead are among priority metals for toxicological studies due to the frequent human exposure and to the significant burden of disease following acute and chronic intoxication. Among their common characteristics is chemical affinity to proteins and non-protein thiols and their ability to generate cellular oxidative stress by the best-known Fenton mechanism. Their health effects are however diverse: kidney and liver damage, cancer at specific sites, irreversible neurological damages with metal-specific features. Mechanisms for the induction of oxidative stress by interaction with the cell thiolome will be presented, based on literature evidence and of experimental findings.
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Affiliation(s)
- Federico Maria Rubino
- LaTMA Laboratory for Analytical Toxicology and Metabonomics, Department of Health Sciences, Università degli Studi di Milano at "Ospedale San Paolo" v. A. di Rudinì 8, I-20142 Milano, Italy.
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14
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Panyala NR, Sturzbecher-Hoehne M, Abergel RJ. Identification of process related trace level impurities in the actinide decorporation agent 3,4,3-LI(1,2-HOPO): Nozzle-skimmer fragmentation via ESI LC-QTOFMS. J Pharm Biomed Anal 2014; 100:157-166. [PMID: 25165012 PMCID: PMC4179986 DOI: 10.1016/j.jpba.2014.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/29/2014] [Accepted: 08/01/2014] [Indexed: 10/24/2022]
Abstract
3,4,3-LI(1,2-HOPO) is a chelating ligand and decorporation agent that can remove radioactive lanthanides and actinides from the body. Identification of trace impurities in drug samples is gaining much interest due to their significant influence on drug activity. In this study, trace impurities were detected in manufactured lots of 3,4,3-LI(1,2-HOPO) by a developed method of liquid chromatography coupled with photo-diode array UV detection and electrospray ionization-quadrupole time of flight mass spectrometry (LC-QTOFMS), via induced-in-source or collision-induced mass fragmentation (nozzle-skimmer fragmentation). Molecular ions were fragmented within the nozzle-skimmer region of electrospray ionization (ESI) mass spectrometer equipped with a Time of Flight detector. Eight major (detected at levels higher than a 0.1% threshold) and seven minor trace impurities were identified. The respective structures of these impurities were elucidated via analysis of the generated fragment ions using mass fragmentation and elemental composition software. Proposed structures of impurities were further confirmed via isotopic modeling.
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Affiliation(s)
- Nagender R Panyala
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Rebecca J Abergel
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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15
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Reinwarth M, Avrutina O, Fabritz S, Kolmar H. Fragmentation follows structure: top-down mass spectrometry elucidates the topology of engineered cystine-knot miniproteins. PLoS One 2014; 9:e108626. [PMID: 25303319 PMCID: PMC4193770 DOI: 10.1371/journal.pone.0108626] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/02/2014] [Indexed: 12/21/2022] Open
Abstract
Over the last decades the field of pharmaceutically relevant peptides has enormously expanded. Among them, several peptide families exist that contain three or more disulfide bonds. In this context, elucidation of the disulfide patterns is extremely important as these motifs are often prerequisites for folding, stability, and activity. An example of this structure-determining pattern is a cystine knot which comprises three constrained disulfide bonds and represents a core element in a vast number of mechanically interlocked peptidic structures possessing different biological activities. Herein, we present our studies on disulfide pattern determination and structure elucidation of cystine-knot miniproteins derived from Momordica cochinchinensis peptide MCoTI-II, which act as potent inhibitors of human matriptase-1. A top-down mass spectrometric analysis of the oxidised and bioactive peptides is described. Following the detailed sequencing of the peptide backbone, interpretation of the MS(3) spectra allowed for the verification of the knotted topology of the examined miniproteins. Moreover, we found that the fragmentation pattern depends on the knottin's folding state, hence, tertiary structure, which to our knowledge has not been described for a top-down MS approach before.
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Affiliation(s)
- Michael Reinwarth
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
| | - Olga Avrutina
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
| | | | - Harald Kolmar
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
- * E-mail: (SF); (HK)
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16
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Helfer AG, Meyer MR, Michely JA, Maurer HH. Direct analysis of the mushroom poisons α- and β-amanitin in human urine using a novel on-line turbulent flow chromatography mode coupled to liquid chromatography–high resolution-mass spectrometry/mass spectrometry. J Chromatogr A 2014; 1325:92-8. [DOI: 10.1016/j.chroma.2013.11.054] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/24/2013] [Accepted: 11/27/2013] [Indexed: 11/30/2022]
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Glotzbach B, Reinwarth M, Weber N, Fabritz S, Tomaszowski M, Fittler H, Christmann A, Avrutina O, Kolmar H. Combinatorial optimization of cystine-knot peptides towards high-affinity inhibitors of human matriptase-1. PLoS One 2013; 8:e76956. [PMID: 24146945 PMCID: PMC3795654 DOI: 10.1371/journal.pone.0076956] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/27/2013] [Indexed: 12/02/2022] Open
Abstract
Cystine-knot miniproteins define a class of bioactive molecules with several thousand natural members. Their eponymous motif comprises a rigid structured core formed by six disulfide-connected cysteine residues, which accounts for its exceptional stability towards thermic or proteolytic degradation. Since they display a remarkable sequence tolerance within their disulfide-connected loops, these molecules are considered promising frameworks for peptide-based pharmaceuticals. Natural open-chain cystine-knot trypsin inhibitors of the MCoTI (Momordica cochinchinensis trypsin inhibitor) and SOTI (Spinacia oleracea trypsin inhibitor) families served as starting points for the generation of inhibitors of matriptase-1, a type II transmembrane serine protease with possible clinical relevance in cancer and arthritic therapy. Yeast surface-displayed libraries of miniproteins were used to select unique and potent matriptase-1 inhibitors. To this end, a knowledge-based library design was applied that makes use of detailed information on binding and folding behavior of cystine-knot peptides. Five inhibitor variants, four of the MCoTI family and one of the SOTI family, were identified, chemically synthesized and oxidatively folded towards the bioactive conformation. Enzyme assays revealed inhibition constants in the low nanomolar range for all candidates. One subnanomolar binder (Ki = 0.83 nM) with an inverted selectivity towards trypsin and matriptase-1 was identified.
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Affiliation(s)
- Bernhard Glotzbach
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Michael Reinwarth
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Niklas Weber
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | | | - Michael Tomaszowski
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Heiko Fittler
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Andreas Christmann
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Olga Avrutina
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Harald Kolmar
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
- * E-mail:
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Goyder MS, Rebeaud F, Pfeifer ME, Kálmán F. Strategies in mass spectrometry for the assignment of Cys-Cys disulfide connectivities in proteins. Expert Rev Proteomics 2013; 10:489-501. [PMID: 24087910 DOI: 10.1586/14789450.2013.837663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Elucidating disulfide linkage patterns is a crucial part of protein characterization, for which mass spectrometry (MS) is now an indispensable analytical tool. In many cases, MS-based disulfide connectivity assignment is straightforwardly achieved using one-step protein fragmentation in the unreduced form followed by mass measurement of bridged fragments. By contrast, venom proteins, which are receiving increasing interest as potential therapeutics, are a challenge for MS-based disulfide assignment due to their numerous closely spaced cysteines and knotted disulfide structure, requiring creative strategies to determine their connectivity. Today, these include the use of an array of reagents for enzymatic and/or chemical cleavage, partial reduction, differential cysteine labeling and tandem MS. This review aims to describe the toolkit of techniques available to MS users approaching both straightforward and complex disulfide bridge assignments, with a particular focus on strategies utilizing standard instrumentation found in a well-equipped analytical or proteomics laboratory.
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Affiliation(s)
- Miriam S Goyder
- Institute of Life Technologies, University of Applied Sciences Western Switzerland (HES-SO Valais/Wallis), 1950 Sion, Switzerland
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