1
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Vasileva ID, Samgina TY, Meng Z, Zubarev RA, Lebedev AT. EThcD Benefits for the Sequencing Inside Intramolecular Disulfide Cycles of Amphibian Intact Peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1979-1988. [PMID: 37525119 DOI: 10.1021/jasms.3c00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Disulfide bonds formed by a pair of cysteine residues in the peptides' backbone represent a certain problem for their sequencing by means of mass spectrometry. As a rule, in proteomics, disulfide bonds should be cleaved before the analysis followed by some sort of chemical derivatization. That step is time-consuming and may lead to losses of minor peptides of the analyzed mixtures due to incomplete reaction, adsorption on the walls of the vials, etc. Certain problems in the de novo top-down sequencing of amphibian skin peptides are caused by the C-terminal disulfide loop, called the Rana box. Its reduction with or without subsequent derivatization was considered to be an unavoidable step before mass spectrometry. In the present study, EThcD demonstrated its efficiency in sequencing intact disulfide-containing peptides without any preliminary derivatization. Applied to the secretion of three frog species, EThcD provided the full sequence inside the intramolecular disulfide cycle for all S-S-containing peptides found in the samples, with the only exception being diarginine species. Proteolytic fragments, which are shorter than the original peptides, were helpful in some cases. HCD should be mentioned as a complementary tool to the EThcD tool, being useful as a confirmation method for some sequence details.
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Affiliation(s)
- Irina D Vasileva
- Lomonosov Moscow State University, Department of Organic Chemistry, 119991 Moscow, Russia
| | - Tatiana Yu Samgina
- Lomonosov Moscow State University, Department of Organic Chemistry, 119991 Moscow, Russia
| | - Zhaowei Meng
- Department of Medicinal Biochemistry and Biophysics, Division of Molecular Biometry, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Roman A Zubarev
- Department of Medicinal Biochemistry and Biophysics, Division of Molecular Biometry, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Albert T Lebedev
- Lomonosov Moscow State University, Department of Organic Chemistry, 119991 Moscow, Russia
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2
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Wei B, Zenaidee MA, Lantz C, Williams BJ, Totten S, Ogorzalek Loo RR, Loo JA. Top-down mass spectrometry and assigning internal fragments for determining disulfide bond positions in proteins. Analyst 2022; 148:26-37. [PMID: 36399030 PMCID: PMC9772244 DOI: 10.1039/d2an01517j] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Disulfide bonds in proteins have a substantial impact on protein structure, stability, and biological activity. Localizing disulfide bonds is critical for understanding protein folding and higher-order structure. Conventional top-down mass spectrometry (TD-MS), where only terminal fragments are assigned for disulfide-intact proteins, can access disulfide information, but suffers from low fragmentation efficiency, thereby limiting sequence coverage. Here, we show that assigning internal fragments generated from TD-MS enhances the sequence coverage of disulfide-intact proteins by 20-60% by returning information from the interior of the protein sequence, which cannot be obtained by terminal fragments alone. The inclusion of internal fragments can extend the sequence information of disulfide-intact proteins to near complete sequence coverage. Importantly, the enhanced sequence information that arise from the assignment of internal fragments can be used to determine the relative position of disulfide bonds and the exact disulfide connectivity between cysteines. The data presented here demonstrates the benefits of incorporating internal fragment analysis into the TD-MS workflow for analyzing disulfide-intact proteins, which would be valuable for characterizing biotherapeutic proteins such as monoclonal antibodies and antibody-drug conjugates.
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Affiliation(s)
- Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | - Muhammad A Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | | | | | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
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3
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Baba T, Rajabi K, Liu S, Ryumin P, Zhang Z, Pohl K, Causon J, Le Blanc JCY, Kurogochi M. Electron Impact Excitation of Ions from Organics on Singly Protonated Peptides with and without Post-Translational Modifications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1723-1732. [PMID: 35948044 DOI: 10.1021/jasms.2c00146] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We report on the dissociation of singly protonated peptides by electrons using electron-activated dissociation (EAD), which comprises electron impact excitation of ions from organics (EIEIO), electronic-excitation dissociation (EED), and electron ionization dissociation (EIoD). Various singly protonated peptides were dissociated using a recently reported fast EAD device. The dissociation can be induced through two pathways: (i) vibrational dissociation similar to collision-activated dissociation (CAD, or collision-induced dissociation, CID) by relaxation from a molecular electronic excited state to high vibrational states; and (ii) radical-induced dissociation where molecular electronic excitation is followed by homolytic cleavage. EAD is complementary to CAD as additional molecular information can be obtained; e.g., fragile PTM moieties, such as glycosylation and sulfation, can be localized. Simultaneously, the energetic production of radical z• fragments enables Leu and Ile discrimination, like in a hot ECD process. Using the fast EAD device, LC-EIEIO-time-of-flight mass spectrometry was applied to a tryptic monoclonal antibody digest containing short singly protonated peptides.
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Affiliation(s)
- Takashi Baba
- SCIEX, 71 Four Valley Dr., Concord, Ontario L4K 4 V8, Canada
| | - Khadijeh Rajabi
- SCIEX, 71 Four Valley Dr., Concord, Ontario L4K 4 V8, Canada
| | - Suya Liu
- SCIEX, 71 Four Valley Dr., Concord, Ontario L4K 4 V8, Canada
| | - Pavel Ryumin
- SCIEX, 71 Four Valley Dr., Concord, Ontario L4K 4 V8, Canada
| | - Zoe Zhang
- SCIEX, 1201 Radio Rd, Redwood City, California 94065, United States
| | - Kerstin Pohl
- SCIEX, 500 Old Connecticut Path, Framingham, Massachusetts 01701, United States
| | - Jason Causon
- SCIEX, 71 Four Valley Dr., Concord, Ontario L4K 4 V8, Canada
| | | | - Masaki Kurogochi
- The Noguchi Institute, 1-9-7, Kaga, Itabashi-ku, Tokyo 173-0003, Japan
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4
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Watts E, Thyer R, Ellington AD, Brodbelt JS. Integrated Top-Down and Bottom-Up Mass Spectrometry for Characterization of Diselenide Bridging Patterns of Synthetic Selenoproteins. Anal Chem 2022; 94:11175-11184. [PMID: 35930618 DOI: 10.1021/acs.analchem.2c01433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With the rapid acceleration in the design and development of new biotherapeutics, ensuring consistent quality and understanding degradation pathways remain paramount, requiring an array of analytical methods including mass spectrometry. The incorporation of non-canonical amino acids, such as for synthetic selenoproteins, creates additional challenges. A comprehensive strategy to characterize selenoproteins should serve dual purposes of providing sequence confirmation and mapping of selenocysteine bridge locations and the identification of unanticipated side products. In the present study, a combined approach exploiting the benefits of both top-down and bottom-up mass spectrometry was developed. Both electron-transfer/higher-energy collision dissociation and 213 nm ultraviolet photodissociation were utilized to provide complementary information, allowing high quality characterization, localization of diselenide bridges for complex proteins, and the identification of previously unreported selenoprotein dimers.
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Affiliation(s)
- Eleanor Watts
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Ross Thyer
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Andrew D Ellington
- Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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5
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Macias LA, Brodbelt JS. Investigation of Product Ions Generated by 193 nm Ultraviolet Photodissociation of Peptides and Proteins Containing Disulfide Bonds. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1315-1324. [PMID: 35736955 DOI: 10.1021/jasms.2c00124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Disulfide bridges are unique post-translational modifications (PTM) that contribute to protein architecture and modulate function. This PTM, however, challenges top-down mass spectrometry by cyclizing stretches of the protein sequence. In order to produce and release detectable product ions that contribute to the assignment of proteoforms, regions of a protein encapsulated by disulfide bonds require two fragmentation events: cleavage of the protein backbone and cleavage of the disulfide bond. Traditional collisional activation methods do not cleave disulfide bonds efficiently, often leading to low sequence coverage of proteins that incorporate this feature. To address this challenge, we have evaluated the fragmentation pathways enabled by 193 nm ultraviolet photodissociation (UVPD) and UVPD coupled to electron transfer dissociation for the characterization of protein structures incorporating disulfide bonds. Cleavage of disulfide bonds by either approach results in S-S and C-S dissociation products that result from a combination of homolytic cleavage and hydrogen-transfer processes. Characterization of these product ions elevates interpretation of complex top-down spectra of proteins that incorporate disulfide bonds.
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Affiliation(s)
- Luis A Macias
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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6
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Du Y, May RC, Cooper HJ. Native ambient mass spectrometry of intact protein assemblies directly from Escherichia coli colonies. Chem Commun (Camb) 2022; 58:6857-6860. [PMID: 35617055 PMCID: PMC9196203 DOI: 10.1039/d2cc02085h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/19/2022] [Indexed: 11/30/2022]
Abstract
Here, we demonstrate that by combining electroporation with native ambient mass spectrometry, it is possible to detect intact non-covalent protein complexes directly from bacterial colonies growing on agar. Homodimers HdeA and HdeB were identified, together with the 50 kDa Mn-bound superoxide dismutase homodimer, in addition to some previously undetected monomeric proteins.
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Affiliation(s)
- Yuying Du
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Robin C May
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Helen J Cooper
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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7
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Zhao X, Zhang S, Ma Q, Zhang X, Ma X. Rapid Disulfide Mapping in Peptides and Proteins by meta-Chloroperoxybenzoic Acid ( mCPBA) Oxidation and Tandem Mass Spectrometry. Anal Chem 2021; 93:14618-14625. [PMID: 34704736 DOI: 10.1021/acs.analchem.1c02379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Disulfide bonds are a class of important post-translational modifications that play important roles in modulating the structures and functions of proteins. Therefore, the mapping of disulfide linkages in peptides and proteins is indispensable for complete structure characterization and functional studies. As disulfide bonds in protonated ions do not dissociate readily under low-energy collision-induced dissociation (CID), they are usually chemically cleaved or activated prior to mass spectrometry (MS) or tandem MS (MS/MS) analysis. In this study, we report a new method that allows the mapping of disulfide linkages in peptides and proteins through meta-chloroperoxybenzoic acid (mCPBA)-based disulfide oxidation and MS/MS. Upon oxidation, the disulfide bond is converted to a thiosulfinate group, i.e., S(═O)-S, in a rapid (>60% yield in 1 min) and highly specific approach in an aqueous phase. The thiosulfinate group is then preferentially cleaved by MS/MS. For interchain disulfide linkages, this leads to a facile peptide chain separation and the identification of disulfide-linked peptides. For intrachain disulfide linkages, collisional activation of the thiosulfinate leads to disulfide cleavage and fragmentation of the peptide backbone constrained by the disulfide loop, enabling a near-complete peptide sequencing. The mCPBA oxidation-based disulfide mapping strategy can be readily integrated with bottom-up or top-down protein analysis for comprehensive protein structure elucidation, e.g., digested lysozyme and intact human insulin.
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Affiliation(s)
- Xu Zhao
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Sichun Zhang
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qiang Ma
- Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Xinrong Zhang
- Department of Chemistry, 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
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8
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Gammelgaard SK, Petersen SB, Haselmann KF, Nielsen PK. Characterization of Insulin Dimers by Top-Down Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1910-1918. [PMID: 33084334 DOI: 10.1021/jasms.0c00257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
High-molecular weight products (HMWP) are an important critical quality attribute in research and development of insulin biopharmaceuticals. We here demonstrate on two case studies of covalent insulin dimers, induced by Fe2+ incubation or ultraviolet (UV) light stress, that de novo characterization in top-down mass spectrometry (MS) workflows can identify cross-link types and sites. On the MS2 level, electron-transfer/higher-energy collision dissociation (EThcD) efficiently cleaved the interchain disulfide bonds in the dimers to reveal cross-link connectivities between chains. The combined utilization of EThcD and 213 nm ultraviolet photodissociation (UVPD) facilitated identification of the chemical composition of the cross-links. Identification of cross-link sites between chains at residue level was achievable for both dimers with MS3 analysis of MS2 fragments cleaved at the cross-link or additionally the interchain disulfide bonds. UVPD provided identification of cross-link sites in the Fe2+-induced dimer without MS3, while cross-link site identification with MS2 was not possible for the UV light-induced dimer. Thus, using varied multistage approaches, it was discovered that in the UV light-induced dimer, Tyr14 of the A-chain participated in an -O-S- cross-link in which the sulfur was derived either from Cys7 or Cys19 of the B-chain. In the Fe2+-induced dimer, Phe1 from both B-chains were cross-linked through a -CH2-. The UV chromophoric side chain of Phe1 was indicated in the cross-link, explaining why UVPD-MS2 was effective in fragmenting the cross-link and nearby backbone bonds. Our results demonstrated that higher-energy collisional dissociation (HCD), EThcD, and UVPD combined with MS3 were powerful tools for direct de novo characterization of cross-linked insulin dimers.
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Affiliation(s)
- Simon K Gammelgaard
- Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, 2760 Måløv, Denmark
- Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, 9220 Aalborg, Denmark
| | - Steffen B Petersen
- Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, 9220 Aalborg, Denmark
| | - Kim F Haselmann
- Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, 2760 Måløv, Denmark
| | - Peter Kresten Nielsen
- Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, 2760 Måløv, Denmark
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9
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Exploring structural signatures of the lanthipeptide prochlorosin 2.8 using tandem mass spectrometry and trapped ion mobility-mass spectrometry. Anal Bioanal Chem 2021; 413:4815-4824. [PMID: 34105020 DOI: 10.1007/s00216-021-03437-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 10/21/2022]
Abstract
Lanthipeptides are a family of ribosomally synthesized and post-translationally modified peptides (RiPPs) characterized by intramolecular thioether cross-links formed between a dehydrated serine/threonine (dSer/dThr) and a cysteine residue. Prochlorosin 2.8 (Pcn2.8) is a class II lanthipeptide that exhibits a non-overlapping thioether ring pattern, for which no biological activity has been reported yet. The variant Pcn2.8[16RGD] has been shown to bind tightly to the αvβ3 integrin receptor. In the present work, tandem mass spectrometry, using collision-induced dissociation (CID) and electron capture dissociation (ECD), and trapped ion mobility spectrometry-mass spectrometry (TIMS-MS) were used to investigate structural signatures for the non-overlapping thioether ring pattern of Pcn2.8. CID experiments on Pcn2.8 yielded bi and yj fragments between the thioether cross-links, evidencing the presence of a non-overlapping thioether ring pattern. ECD experiments of Pcn2.8 showed a significant increase of hydrogen migration events near the residues involved in the thioether rings with a more pronounced effect at the dehydrated residues as compared to the cysteine residues. The high-resolution mobility analysis, aided by site-directed mutagenesis ([P8A], [P11A], [P12A], [P8A/P11A], [P8A/P12A], [P11A/P12A], and [P8A/P11A/P12A] variants), demonstrated that Pcn2.8 adopts cis/trans-conformations at Pro8, Pro11, and Pro12 residues. These observations were complementary to recent NMR findings, for which only the Pro8 residue was evidenced to adopt cis/trans-orientations. This study highlights the analytical power of the TIMS-MS/MS workflow for the structural characterization of lanthipeptides and could be a useful tool in our understanding of the biologically important structural elements that drive the thioether cyclization process.
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10
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Lodge JM, Schauer KL, Brademan DR, Riley NM, Shishkova E, Westphall MS, Coon JJ. Top-Down Characterization of an Intact Monoclonal Antibody Using Activated Ion Electron Transfer Dissociation. Anal Chem 2020; 92:10246-10251. [PMID: 32608969 DOI: 10.1021/acs.analchem.0c00705] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Monoclonal antibodies (mAbs) are important therapeutic glycoproteins, but their large size and structural complexity make them difficult to rapidly characterize. Top-down mass spectrometry (MS) has the potential to overcome challenges of other common approaches by minimizing sample preparation and preserving endogenous modifications. However, comprehensive mAb characterization requires generation of many, well-resolved fragments and remains challenging. While ETD retains modifications and cleaves disulfide bonds-making it attractive for mAb characterization-it can be less effective for precursors having high m/z values. Activated ion electron transfer dissociation (AI-ETD) uses concurrent infrared photoactivation to promote product ion generation and has proven effective in increasing sequence coverage of intact proteins. Here, we present the first application of AI-ETD to mAb sequencing. For the standard NIST mAb, we observe a high degree of complementarity between fragments generated using standard ETD with a short reaction time and AI-ETD with a long reaction time. Most importantly, AI-ETD reveals disulfide-bound regions that have been intractable, thus far, for sequencing with top-down MS. We conclude AI-ETD has the potential to rapidly and comprehensively analyze intact mAbs.
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11
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Recent advances in LC–MS based characterization of protein-based bio-therapeutics – mastering analytical challenges posed by the increasing format complexity. J Pharm Biomed Anal 2020; 186:113251. [DOI: 10.1016/j.jpba.2020.113251] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 12/25/2022]
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12
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Berghmans E, Jacobs J, Deben C, Hermans C, Broeckx G, Smits E, Maes E, Raskin J, Pauwels P, Baggerman G. Mass Spectrometry Imaging Reveals Neutrophil Defensins as Additional Biomarkers for Anti-PD-(L)1 Immunotherapy Response in NSCLC Patients. Cancers (Basel) 2020; 12:E863. [PMID: 32252405 PMCID: PMC7225984 DOI: 10.3390/cancers12040863] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 12/17/2022] Open
Abstract
(1) Background: Therapeutic blocking of the interaction between programmed death-1 (PD-1) with its ligand PD-L1, an immune checkpoint, is a promising approach to restore the antitumor immune response. Improved clinical outcomes have been shown in different human cancers, including non-small cell lung cancer (NSCLC). Unfortunately, still a high number of NSCLC patients are treated with immunotherapy without obtaining any clinical benefit, due to the limitations of PD-L1 protein expression as the currently sole predictive biomarker for clinical use; (2) Methods: In this study, we applied mass spectrometry imaging (MSI) to discover new protein biomarkers, and to assess the possible correlation between candidate biomarkers and a positive immunotherapy response by matrix-assisted laser desorption/ionization (MALDI) MSI in 25 formalin-fixed paraffin-embedded (FFPE) pretreatment tumor biopsies (Biobank@UZA); (3) Results: Using MALDI MSI, we revealed that the addition of neutrophil defensin 1, 2 and 3 as pretreatment biomarkers may more accurately predict the outcome of immunotherapy treatment in NSCLC. These results were verified and confirmed with immunohistochemical analyses. In addition, we provide in-vitro evidence of the immune stimulatory effect of neutrophil defensins towards cancer cells; and (4) Conclusions: With proteomic approaches, we have discovered neutrophil defensins as additional prospective biomarkers for an anti-PD-(L)1 immunotherapy response. Thereby, we also demonstrated that the neutrophil defensins contribute in the activation of the immune response towards cancer cells, which could provide a new lead towards an anticancer therapy.
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Affiliation(s)
- Eline Berghmans
- Centre for Proteomics, University of Antwerp, 2020 Antwerpen, Belgium;
- Health Unit, VITO, 2400 Mol, Belgium
| | - Julie Jacobs
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Pathology Department, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Christophe Deben
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Pathology Department, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Christophe Hermans
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Pathology Department, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Glenn Broeckx
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Pathology Department, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Evelien Smits
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Center for Cell Therapy and Regenerative Medicine, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Evelyne Maes
- Food & Bio-Based Products, AgResearch Ltd., Lincoln 7674, New Zealand;
| | - Jo Raskin
- Thoracic Oncology Department, Antwerp University Hospital, 2650 Edegem, Belgium;
| | - Patrick Pauwels
- Center for Oncological Research, University of Antwerp, 2610 Wilrijk, Belgium; (J.J.); (C.D.); (C.H.); (G.B.); (E.S.); (P.P.)
- Pathology Department, Antwerp University Hospital, 2650 Edegem, Belgium
| | - Geert Baggerman
- Centre for Proteomics, University of Antwerp, 2020 Antwerpen, Belgium;
- Health Unit, VITO, 2400 Mol, Belgium
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13
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Mukhopadhyay R, Chacón KN, Jarvis JM, Talipov MR, Yukl ET. Structural insights into the mechanism of oxidative activation of heme-free H-NOX from Vibrio cholerae. Biochem J 2020; 477:1123-1136. [PMID: 32141496 PMCID: PMC7108781 DOI: 10.1042/bcj20200124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023]
Abstract
Bacterial heme nitric oxide/oxygen (H-NOX) domains are nitric oxide (NO) or oxygen sensors. This activity is mediated through binding of the ligand to a heme cofactor. However, H-NOX from Vibrio cholerae (Vc H-NOX) can be easily purified in a heme-free state that is capable of reversibly responding to oxidation, suggesting a heme-independent function as a redox sensor. This occurs by oxidation of Cys residues at a zinc-binding site conserved in a subset of H-NOX homologs. Remarkably, zinc is not lost from the protein upon oxidation, although its ligation environment is significantly altered. Using a combination of computational and experimental approaches, we have characterized localized structural changes that accompany the formation of specific disulfide bonds between Cys residues upon oxidation. Furthermore, the larger-scale structural changes accompanying oxidation appear to mimic those changes observed upon NO binding to the heme-bound form. Thus, Vc H-NOX and its homologs may act as both redox and NO sensors by completely separate mechanisms.
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Affiliation(s)
- Roma Mukhopadhyay
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, U.S.A
| | - Kelly N. Chacón
- Department of Chemistry, Reed College, Portland, OR 97202, U.S.A
| | - Jacqueline M. Jarvis
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM 88003, U.S.A
| | - Marat R. Talipov
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, U.S.A
| | - Erik T. Yukl
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, U.S.A
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14
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Asakawa D, Takahashi H, Iwamoto S, Tanaka K. Hydrogen attachment dissociation of peptides containing disulfide bonds. Phys Chem Chem Phys 2019; 21:26049-26057. [PMID: 31746862 DOI: 10.1039/c9cp03923f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of tandem mass spectrometry (MS/MS) and hydrogen attachment dissociation (HAD) is a useful method for peptide sequence analysis. In this study, gas-phase fragmentation induced by the attachment of hydrogen to peptides containing disulfide bonds was investigated. Hydrogen attachment induced the cleavage of either the disulfide or N-Cα bond, which competitively occurred during HAD. The disulfide bond cleavage proceeded through an intermediate, which contains a thiyl radical (-S˙) and a thiol group (-SH). In contrast, N-Cα bond cleavage produced an intermediate containing an enol-imine group and α-carbon radical. The intermediate α-carbon radical then attacked the disulfide bond, resulting in a cyclic [z]+ fragment. The counterpart, [c + H]+˙ with a thiyl radical underwent further hydrogen attachment, producing [c + 2H]+. Because both disulfide and N-Cα bonds were cleaved by a single hydrogen attachment event, HAD-MS/MS can provide sequence information for the backbone region in the disulfide loop.
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Affiliation(s)
- Daiki Asakawa
- National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
| | - Hidenori Takahashi
- Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho Nakagyo-ku, Kyoto 604-8511, Japan
| | - Shinichi Iwamoto
- Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho Nakagyo-ku, Kyoto 604-8511, Japan
| | - Koichi Tanaka
- Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho Nakagyo-ku, Kyoto 604-8511, Japan
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15
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Adhikari S, Xia Y, McLuckey SA. Top-Down Analysis of Disulfide-Linked Proteins Using Photoinduced Radical Reactions and ET-DDC. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2019; 444:116173. [PMID: 31372092 PMCID: PMC6675022 DOI: 10.1016/j.ijms.2019.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Top-down characterization of proteins via tandem mass spectrometry (MS/MS) can be challenging due to the presence of multiple disulfide bond linkages; which significantly inhibit the backbone cleavage efficiency for the formation of structurally informative fragment ions. In this study, we present a strategy of pairing a solution-phase photoinitiating system with dipolar direct current induced collisional activation of electron transfer products (ET-DDC) of proteins for a top-down MS/MS approach. The photoinitiating system allows for a rapid scission of all the disulfide linkages in the protein (on the time scale of seconds) with high efficiency (near to complete reduction); while ET-DDC collisional activation improves the fragmentation efficiency for the protein via broadband activation of all the first-generation charge reduced precursor ions (e.g., electron transfer no-dissociation or ETnoD products) from electron transfer reactions over a wide mass-to-charge range. As a result, this approach enabled the generation of extensive sequence informative fragment ion yields for a rapid and enhanced structural characterization of disulfide-linked proteins.
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Affiliation(s)
- Sarju Adhikari
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Yu Xia
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
- Address reprint requests to: Dr. Scott A. McLuckey, 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA, Phone: (765) 494-5270, Fax: (765) 494-0239,
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16
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Zhao E, St-Jean F, Robinson SJ, Sirois LE, Pellett J, Al-Sayah MA. Identification of an acetonitrile addition impurity formed during peptide disulfide bond reduction using dithiothreitol and Tris(2-carboxyethyl)phosphine. J Pharm Biomed Anal 2019; 174:518-524. [DOI: 10.1016/j.jpba.2019.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023]
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17
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Li X, Yang X, Hoang V, Liu YH. Characterization of Protein Disulfide Linkages by MS In-Source Dissociation Comparing to CID and ETD Tandem MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:519-528. [PMID: 30478816 DOI: 10.1007/s13361-018-2103-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/18/2018] [Accepted: 11/01/2018] [Indexed: 05/19/2023]
Abstract
Direct characterization of disulfide linkages in proteins by mass spectrometry has been challenging. Here, we report analysis of disulfide linkages in insulin variant, endothelin 3, and relaxin 2 by in-source dissociation (ISD) during LC-MS. A duplet insulin peptide from Glu-C digestion that contains peptides p1 and p2 (from chains A and B, respectively) was selected as a model peptide. This duplet peptide has an inter-chain disulfide bond between p1 and p2, and an intra-chain disulfide bond in p1. To compare the gas-phase fragmentation, it was subjected to ISD MS and MS/MS methods, including collision-induced dissociation (CID) and electron transfer dissociation (ETD). The pattern and efficiency of peptide backbone and disulfide cleavage varied with these dissociation methods. ETD, CID, and ISD were able to generate single backbone, double backbone, and triple (double backbone and single disulfide bond) cleavages in this model peptide, respectively. Specifically, CID did not cleave disulfide bonds and ETD was able to only cleave the inter-chain disulfide bond at low efficiency, limiting their usage in this disulfide analysis. In contrast, ISD was able to cleave the intra-chain disulfide bond in addition to peptide backbone, creating multiple fragment ions that allow accurate assignment of both intra- and inter-chain disulfide linkages. ISD was also successfully applied to determine double disulfide linkages in endothelin 3 and relaxin 2 peptides. This study contributes to the fundamental understanding of disulfide bond cleavages in different gas-phase fragmentations and provides an efficient cleavage strategy for identification of disulfide bonds in proteins by ISD ESI-MS. Graphical Abstract.
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Affiliation(s)
- Xiaojuan Li
- Bioprocess Development, MRL, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA.
| | - Xiaoyu Yang
- Bioprocess Development, MRL, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA
| | - Van Hoang
- Bioprocess Development, MRL, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA
| | - Yan-Hui Liu
- Bioprocess Development, MRL, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA
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18
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Zhao X, Shen Y, Tong W, Wang G, Chen DDY. Deducing disulfide patterns of cysteine-rich proteins using signature fragments produced by top-down mass spectrometry. Analyst 2019; 143:817-823. [PMID: 29362732 DOI: 10.1039/c7an01625e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct mapping of protein disulfide patterns using top-down mass spectrometry (MS) is often hampered by inadequate fragmentation at the disulfide-enclosing region, and insufficient structural information provided by the fragments. Here we used electron-transfer/high energy collision dissociation (EThcD) to improve the fragmentation efficiency, and developed strategies that minimize the false positive identification of fragments and deconvolute the signals representing specific modifications made to the disulfide-cleavage-induced fragments. We observed clear correlations between unique modification (attachment or removal of H or SH) patterns and the number of disulfide bonds that enclose the corresponding region. Using the characteristic signature fragments, we in part localized the Cys-bridging sites in disulfide-scrambled lysozymes, and reduced the number of putative disulfide patterns from 104 to 6. The results demonstrated the feasibility of direct analysis of complex disulfide patterns using top-down MS.
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Affiliation(s)
- Xiuxiu Zhao
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, and School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu 210023, China.
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19
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Bonner J, Talbert LE, Akkawi N, Julian RR. Simplified identification of disulfide, trisulfide, and thioether pairs with 213 nm UVPD. Analyst 2018; 143:5176-5184. [PMID: 30264084 PMCID: PMC6197924 DOI: 10.1039/c8an01582a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Disulfide heterogeneity and other non-native crosslinks introduced during therapeutic antibody production and storage could have considerable negative effects on clinical efficacy, but tracking these modifications remains challenging. Analysis must also be carried out cautiously to avoid introduction of disulfide scrambling or reduction, necessitating the use of low pH digestion with less specific proteases. Herein we demonstrate that 213 nm ultraviolet photodissociation streamlines disulfide elucidation through bond-selective dissociation of sulfur-sulfur and carbon-sulfur bonds in combination with less specific backbone dissociation. Importantly, both types of fragmentation can be initiated in a single MS/MS activation stage. In addition to disulfide mapping, it is also shown that thioethers and trisulfides can be identified by characteristic fragmentation patterns. The photochemistry resulting from 213 nm excitation facilitates a simplified, two-tiered data processing approach that allows observation of all native disulfide bonds, scrambled disulfide bonds, and non-native sulfur-based linkages in a pepsin digest of Rituximab. Native disulfides represented the majority of bonds according to ion count, but the highly solvent-exposed heavy/light interchain disulfides were found to be most prone to modification. Production and storage methods that facilitate non-native links are discussed. Due to the importance of heavy and light chain connectivity for antibody structure and function, this region likely requires particular attention in terms of its influence on maintaining structural fidelity.
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Affiliation(s)
- James Bonner
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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20
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Srzentić K, Nagornov KO, Fornelli L, Lobas AA, Ayoub D, Kozhinov AN, Gasilova N, Menin L, Beck A, Gorshkov MV, Aizikov K, Tsybin YO. Multiplexed Middle-Down Mass Spectrometry as a Method for Revealing Light and Heavy Chain Connectivity in a Monoclonal Antibody. Anal Chem 2018; 90:12527-12535. [DOI: 10.1021/acs.analchem.8b02398] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Kristina Srzentić
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | - Luca Fornelli
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Anna A. Lobas
- Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Daniel Ayoub
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | - Natalia Gasilova
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Laure Menin
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Alain Beck
- Centre d’Immunologie Pierre Fabre, 74160 St. Julien-en-Genevois, France
| | - Mikhail V. Gorshkov
- Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology State University, 141707 Dolgoprudny, Moscow Region, Russia
| | | | - Yury O. Tsybin
- Spectroswiss, EPFL Innovation Park, 1015 Lausanne, Switzerland
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21
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Dumont S, Bykova NV, Khaou A, Besserour Y, Dorval M, Rivoal J. Arabidopsis thaliana alcohol dehydrogenase is differently affected by several redox modifications. PLoS One 2018; 13:e0204530. [PMID: 30252897 PMCID: PMC6155552 DOI: 10.1371/journal.pone.0204530] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/10/2018] [Indexed: 11/19/2022] Open
Abstract
In plant cells, many stresses, including low oxygen availability, result in a higher production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These molecules can lead to redox-dependent post-translational modification of proteins Cys residues. Here, we studied the effect of different redox modifications on alcohol dehydrogenase (ADH) from Arabidopsis thaliana. ADH catalyzes the last step of the ethanol fermentation pathway used by plants to cope with energy deficiency during hypoxic stress. Arabidopsis suspension cell cultures showed decreased ADH activity upon exposure to H2O2, but not to the thiol oxidizing agent diamide. We purified recombinant ADH and observed a significant decrease in the enzyme activity by treatments with H2O2 and diethylamine NONOate (DEA/NO). Treatments leading to the formation of a disulfide bond between ADH and glutathione (protein S-glutathionylation) had no negative effect on the enzyme activity. LC-MS/MS analysis showed that Cys47 and Cys243 could make a stable disulfide bond with glutathione, suggesting redox sensitivity of these residues. Mutation of ADH Cys47 to Ser caused an almost complete loss of the enzyme activity while the Cys243 to Ser mutant had increased specific activity. Incubation of ADH with NAD+ or NADH prevented inhibition of the enzyme by H2O2 or DEA/NO. These results suggest that binding of ADH with its cofactors may limit availability of Cys residues to redox modifications. Our study demonstrates that ADH from A. thaliana is subject to different redox modifications. Implications of ADH sensitivity to ROS and RNS during hypoxic stress conditions are discussed.
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Affiliation(s)
- Sébastien Dumont
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
| | - Natalia V. Bykova
- Morden Research and Development Centre, Agriculture and Agri-Food Canada, Morden, Manitoba, Canada
| | - Alexia Khaou
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
| | - Yasmine Besserour
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
| | - Maude Dorval
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
| | - Jean Rivoal
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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22
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Quick MM, Crittenden CM, Rosenberg JA, Brodbelt JS. Characterization of Disulfide Linkages in Proteins by 193 nm Ultraviolet Photodissociation (UVPD) Mass Spectrometry. Anal Chem 2018; 90:8523-8530. [PMID: 29902373 PMCID: PMC6050148 DOI: 10.1021/acs.analchem.8b01556] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Deciphering disulfide bond patterns in proteins remains a significant challenge. In the present study, interlinked disulfide bonds connecting peptide chains are homolytically cleaved with 193 nm ultraviolet photodissociation (UVPD). Analysis of insulin showcased the ability of UVPD to cleave multiple disulfide bonds and provide sequence coverage of the peptide chains in the same MS/MS event. For proteins containing more complex disulfide bonding patterns, an approach combining partial reduction and alkylation mitigated disulfide scrambling and allowed assignment of the array of disulfide bonds. The 4 disulfide bonds of lysozyme and the 19 disulfide bonds of serotransferrin were characterized through LC/UVPD-MS analysis of nonreduced and partially reduced protein digests.
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23
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Rathore D, Faustino A, Schiel J, Pang E, Boyne M, Rogstad S. The role of mass spectrometry in the characterization of biologic protein products. Expert Rev Proteomics 2018; 15:431-449. [DOI: 10.1080/14789450.2018.1469982] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Deepali Rathore
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
- Center for Biomedical Mass Spectrometry Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Anneliese Faustino
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - John Schiel
- Biomolecular Measurement Division, National Institute of Standards and Technology, Institute for Bioscience and Biotechnology Research, Rockville, MD, USA
| | - Eric Pang
- Office of Lifecycle Drug Products, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Michael Boyne
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
- COUR Pharmaceuticals Development Company, Northbrook, IL, USA
| | - Sarah Rogstad
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
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24
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Abstract
Disulfide linkage is critical to protein folding and structural stability. The location of disulfide linkages for antibodies is routinely discovered by comparing the chromatograms of the reduced and non-reduced peptide mapping with location identification confirmed by collision-induced dissociation (CID) mass spectrometry (MS)/MS. However, CID product spectra of disulfide-linked peptides can be difficult to interpret, and provide limited information on the backbone region within the disulfide loop. Here, we applied an electron-transfer dissociation (ETD)/CID combined fragmentation method that identifies the disulfide linkage without intensive LC comparison, and yet maps the disulfide location accurately. The native protein samples were digested using trypsin for proteolysis. The method uses RapiGest SF Surfactant and obviates the need for reduction/alkylation and extensive sample manipulation. An aliquot of the digest was loaded onto a C4 analytical column. Peptides were gradient-eluted and analyzed using a Thermo Scientific LTQ Orbitrap Elite mass spectrometer for the ETD-triggered CID MS3 experiment. Survey MS scans were followed by data-dependent scans consisting of ETD MS2 scans on the most intense ion in the survey scan, followed by 5 MS3 CID scans on the 5 most intense ions in the ETD MS2 scan. We were able to identify the disulfide-mediated structural variants A and A/B forms and their corresponding disulfide linkages in an immunoglobulin G2 monoclonal antibody with λ light chain (IgG2λ), where the location of cysteine linkages were unambiguously determined.
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Affiliation(s)
- Xiaoyan Guan
- a Process Development, Amgen Inc. , Thousand Oaks , CA , United States
| | - Le Zhang
- a Process Development, Amgen Inc. , Thousand Oaks , CA , United States
| | - Jette Wypych
- a Process Development, Amgen Inc. , Thousand Oaks , CA , United States
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25
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Li P, Kreft I, Jackson GP. Top-Down Charge Transfer Dissociation (CTD) of Gas-Phase Insulin: Evidence of a One-Step, Two-Electron Oxidation Mechanism. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:284-296. [PMID: 28786096 PMCID: PMC5803485 DOI: 10.1007/s13361-017-1700-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/24/2017] [Accepted: 04/27/2017] [Indexed: 05/03/2023]
Abstract
Top-down analyses of protonated insulin cations of charge states of 4+, 5+, or 6+ were performed by exposing the isolated precursor ions to a beam of helium cations with kinetic energy of more than 6 keV, in a technique termed charge transfer dissociation (CTD). The ~100 ms charge transfer reaction resulted in approximately 20% conversion efficiency to other intact charge exchange products (CTnoD), and a range of low abundance fragment ions. To increase backbone and sulfide cleavages, and to provide better structural information than straightforward MS2 CTD, the CTnoD oxidized products were isolated and subjected to collisional activation at the MS3 level. The MS3 CTD/CID reaction effectively broke the disulfide linkages, separated the two chains, and yielded more structurally informative fragment ions within the inter-chain cyclic region. CTD also provided doubly oxidized intact product ions at the MS2 level, and resonance ejection of the singly oxidized product ion revealed that the doubly oxidized product originates directly from the isolated precursor ion and not from consecutive CTD reactions of a singly oxidized intermediate. MS4 experiments were employed to help identify potential radical cations and diradical cations, but the results were negative or inconclusive. Nonetheless, the two-electron oxidation process is a demonstration of the very large potential energy (>20 eV) available through CTD, and is a notable capability for a 3D ion trap platform. Graphical Abstract ᅟ.
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Affiliation(s)
- Pengfei Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Iris Kreft
- Department of Forensic and Investigative Science, West Virginia University, Morgantown, WV, 26506-6121, USA
| | - Glen P Jackson
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Forensic and Investigative Science, West Virginia University, Morgantown, WV, 26506-6121, USA.
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26
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Lakbub JC, Shipman JT, Desaire H. Recent mass spectrometry-based techniques and considerations for disulfide bond characterization in proteins. Anal Bioanal Chem 2017; 410:2467-2484. [PMID: 29256076 DOI: 10.1007/s00216-017-0772-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/09/2017] [Accepted: 11/17/2017] [Indexed: 12/21/2022]
Abstract
Disulfide bonds are important structural moieties of proteins: they ensure proper folding, provide stability, and ensure proper function. With the increasing use of proteins for biotherapeutics, particularly monoclonal antibodies, which are highly disulfide bonded, it is now important to confirm the correct disulfide bond connectivity and to verify the presence, or absence, of disulfide bond variants in the protein therapeutics. These studies help to ensure safety and efficacy. Hence, disulfide bonds are among the critical quality attributes of proteins that have to be monitored closely during the development of biotherapeutics. However, disulfide bond analysis is challenging because of the complexity of the biomolecules. Mass spectrometry (MS) has been the go-to analytical tool for the characterization of such complex biomolecules, and several methods have been reported to meet the challenging task of mapping disulfide bonds in proteins. In this review, we describe the relevant, recent MS-based techniques and provide important considerations needed for efficient disulfide bond analysis in proteins. The review focuses on methods for proper sample preparation, fragmentation techniques for disulfide bond analysis, recent disulfide bond mapping methods based on the fragmentation techniques, and automated algorithms designed for rapid analysis of disulfide bonds from liquid chromatography-MS/MS data. Researchers involved in method development for protein characterization can use the information herein to facilitate development of new MS-based methods for protein disulfide bond analysis. In addition, individuals characterizing biotherapeutics, especially by disulfide bond mapping in antibodies, can use this review to choose the best strategies for disulfide bond assignment of their biologic products. Graphical Abstract This review, describing characterization methods for disulfide bonds in proteins, focuses on three critical components: sample preparation, mass spectrometry data, and software tools.
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Affiliation(s)
- Jude C Lakbub
- Ralph N. Adams Institute for Bioanalytical Chemistry, Department of Chemistry, University of Kansas, 1251 Wescoe Hall Dr, Lawrence, KS, 66045, USA
| | - Joshua T Shipman
- Ralph N. Adams Institute for Bioanalytical Chemistry, Department of Chemistry, University of Kansas, 1251 Wescoe Hall Dr, Lawrence, KS, 66045, USA
| | - Heather Desaire
- Ralph N. Adams Institute for Bioanalytical Chemistry, Department of Chemistry, University of Kansas, 1251 Wescoe Hall Dr, Lawrence, KS, 66045, USA.
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27
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Hayakawa S. Study of Ion Dynamics by Electron Transfer Dissociation: Alkali Metals as Targets. Mass Spectrom (Tokyo) 2017; 6:A0062. [PMID: 28966899 DOI: 10.5702/massspectrometry.a0062] [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: 05/15/2017] [Accepted: 08/14/2017] [Indexed: 11/23/2022] Open
Abstract
High energy collision processes for singly charged positive ions using an alkali metal target are confirmed, as a charge inversion mass spectrometry, to occur by electron transfers in successive collisions and the dissociation processes involve the formation of energy-selected neutral species from near-resonant neutralization with alkali metal targets. A doubly charged thermometer molecule was made to collide with alkali metal targets to give singly and doubly charged positive ions. The internal energy resulting from the electron transfer with the alkali metal target was very narrow and centered at a particular energy. This narrow internal energy distribution can be attributed to electron transfer by Landau-Zener potential crossing between the precursor ion and an alkali metal atom, and the coulombic repulsion between singly charged ions in the exit channel. A large cross section of more than 10-14 cm2 was estimated for high-energy electron transfer dissociation (HE-ETD). Doubly protonated phosphorylated peptides obtained by electrospray ionization were collided with Xe and Cs targets to give singly and doubly charged positive ions. Whereas doubly charged fragment ions resulting from CAD were dominant in the case of the Xe target, singly charged fragment ions resulting from ETD were dominant with the Cs target. HE-ETD using the Cs target provided all of the z-type ions by N-Cα bond cleavage without the loss of the phosphate groups. The results demonstrate that HE-ETD with an alkali metal target allowed the position of phosphorylation and the amino acid sequence of peptides with post translational modifications (PTM) to be determined.
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28
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Mu X, Song T, Siu CK, Chu IK. Tautomerization and Dissociation of Molecular Peptide Radical Cations. CHEM REC 2017. [DOI: 10.1002/tcr.201700013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Xiaoyan Mu
- Department of Chemistry; University of Hong Kong; Pokfulam, Hong Kong SAR P. R. China
| | - Tao Song
- Department of Chemistry; University of Hong Kong; Pokfulam, Hong Kong SAR P. R. China
| | - Chi-Kit Siu
- Department of Biology and Chemistry; City University of Hong Kong; 83 Tat Chee Avenue Kowloon Tong, Hong Kong SAR P. R. China
| | - Ivan K. Chu
- Department of Chemistry; University of Hong Kong; Pokfulam, Hong Kong SAR P. R. China
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29
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Durand KL, Tan L, Stinson CA, Love-Nkansah CB, Ma X, Xia Y. Assigning Peptide Disulfide Linkage Pattern Among Regio-Isomers via Methoxy Addition to Disulfide and Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1099-1108. [PMID: 28194735 DOI: 10.1007/s13361-017-1595-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
Pinpointing disulfide linkage pattern is critical in the characterization of proteins and peptides consisting of multiple disulfide bonds. Herein, we report a method based on coupling online disulfide modification and tandem mass spectrometry (MS/MS) to distinguish peptide disulfide regio-isomers. Such a method relies on a new disulfide bond cleavage reaction in solution, involving methanol as a reactant and 254 nm ultraviolet (UV) irradiation. This reaction leads to selective cleavage of a disulfide bond and formation of sulfenic methyl ester (-SOCH3) at one cysteine residue and a thiol (-SH) at the other. Under low energy collision-induced dissociation (CID), cysteine sulfenic methyl ester motif produces a signature methanol loss (-32 Da), allowing its identification from other possible isomeric structures such as S-hydroxylmethyl (-SCH2OH) and methyl sulfoxide (-S(O)-CH3). Since disulfide bond can be selectively cleaved and modified upon methoxy addition, subsequent MS2 CID of the methoxy addition product provides enhanced sequence coverage as demonstrated by the analysis of bovine insulin. More importantly, this reaction does not induce disulfide scrambling, likely due to the fact that radical intermediates are not involved in the process. An approach based on methoxy addition followed by MS3 CID has been developed for assigning disulfide linkage patterns in peptide disulfide regio-isomers. This methodology was successfully applied to characterizing peptide systems having two disulfide bonds and three disulfide linkage isomers: side-by-side, overlapped, and looped-within-a-loop configurations. Graphical Abstract ᅟ.
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Affiliation(s)
- Kirt L Durand
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA
| | - Lei Tan
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA
| | - Craig A Stinson
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA
| | | | - Xiaoxiao Ma
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA
| | - Yu Xia
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907-2084, USA.
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30
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Zheng Q, Chen H. Development and Applications of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:411-448. [PMID: 27145689 DOI: 10.1146/annurev-anchem-071015-041620] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Desorption electrospray ionization mass spectrometry (DESI-MS) is a recent advance in the field of analytical chemistry. This review surveys the development of liquid sample DESI-MS (LS-DESI-MS), a variant form of DESI-MS that focuses on fast analysis of liquid samples, and its novel analy-tical applications in bioanalysis, proteomics, and reaction kinetics. Due to the capability of directly ionizing liquid samples, liquid sample DESI (LS-DESI) has been successfully used to couple MS with various analytical techniques, such as microfluidics, microextraction, electrochemistry, and chromatography. This review also covers these hyphenated techniques. In addition, several closely related ionization methods, including transmission mode DESI, thermally assisted DESI, and continuous flow-extractive DESI, are briefly discussed. The capabilities of LS-DESI extend and/or complement the utilities of traditional DESI and electrospray ionization and will find extensive and valuable analytical application in the future.
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Affiliation(s)
- Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, and Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701;
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, and Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701;
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The N-Terminus of the Floral Arabidopsis TGA Transcription Factor PERIANTHIA Mediates Redox-Sensitive DNA-Binding. PLoS One 2016; 11:e0153810. [PMID: 27128442 PMCID: PMC4851370 DOI: 10.1371/journal.pone.0153810] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/04/2016] [Indexed: 12/19/2022] Open
Abstract
The Arabidopsis TGA transcription factor (TF) PERIANTHIA (PAN) regulates the formation of the floral organ primordia as revealed by the pan mutant forming an abnormal pentamerous arrangement of the outer three floral whorls. The Arabidopsis TGA bZIP TF family comprises 10 members, of which PAN and TGA9/10 control flower developmental processes and TGA1/2/5/6 participate in stress-responses. For the TGA1 protein it was shown that several cysteines can be redox-dependently modified. TGA proteins interact in the nucleus with land plant-specific glutaredoxins, which may alter their activities posttranslationally. Here, we investigated the DNA-binding of PAN to the AAGAAT motif under different redox-conditions. The AAGAAT motif is localized in the second intron of the floral homeotic regulator AGAMOUS (AG), which controls stamen and carpel development as well as floral determinacy. Whereas PAN protein binds to this regulatory cis-element under reducing conditions, the interaction is strongly reduced under oxidizing conditions in EMSA studies. The redox-sensitive DNA-binding is mediated via a special PAN N-terminus, which is not present in other Arabidopsis TGA TFs and comprises five cysteines. Two N-terminal PAN cysteines, Cys68 and Cys87, were shown to form a disulfide bridge and Cys340, localized in a C-terminal putative transactivation domain, can be S-glutathionylated. Comparative land plant analyses revealed that the AAGAAT motif exists in asterid and rosid plant species. TGA TFs with N-terminal extensions of variable length were identified in all analyzed seed plants. However, a PAN-like N-terminus exists only in the rosids and exclusively Brassicaceae homologs comprise four to five of the PAN N-terminal cysteines. Redox-dependent modifications of TGA cysteines are known to regulate the activity of stress-related TGA TFs. Here, we show that the N-terminal PAN cysteines participate in a redox-dependent control of the PAN interaction with a highly conserved regulatory AG cis-element, emphasizing the importance of redox-modifications in the regulation of flower developmental processes.
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Yu X, Khani A, Ye X, Petruzziello F, Gao H, Zhang X, Rainer G. High-Efficiency Recognition and Identification of Disulfide Bonded Peptides in Rat Neuropeptidome Using Targeted Electron Transfer Dissociation Tandem Mass Spectrometry. Anal Chem 2015; 87:11646-51. [PMID: 26531061 DOI: 10.1021/ac504872z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The main goal of the present study is to develop a method to recognize and identify endogenous intrachain disulfide bonded peptide, which are rarely sequenced in current peptidomics studies. In order to achieve highly efficient detection of these peptides in a neuropeptidome analysis, we alkylated the peptides, mined the raw mass spectrometry data, and then recognized the candidates of untreated disulfide bonded peptides from unalkylated peptide extracts. After removing more than 90% features, targeted electron transfer dissociation fragmentation was performed for detecting and fragmenting disulfide bonded peptides, and even most of them were present in low abundance in the original sample. Diverse endogenous disulfide bonded peptides were then detected and sequenced, opening up new perspectives for comprehensively understanding the response of a neuropeptidome.
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Affiliation(s)
- Xi Yu
- Division of Biological Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Zhongshan Road 457, Dalian, China
| | - Abbas Khani
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg , Chemin de Musee 5, Fribourg, CH-1700, Switzerland
| | - Xueting Ye
- Shenyang Pharmaceutical University , Wenhua Road 103, Shenyang, China
| | - Filomena Petruzziello
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg , Chemin de Musee 5, Fribourg, CH-1700, Switzerland
| | - Huiyuan Gao
- Shenyang Pharmaceutical University , Wenhua Road 103, Shenyang, China
| | - Xiaozhe Zhang
- Division of Biological Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Zhongshan Road 457, Dalian, China
| | - Gregor Rainer
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg , Chemin de Musee 5, Fribourg, CH-1700, Switzerland
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Wongkongkathep P, Li H, Zhang X, Loo RRO, Julian RR, Loo JA. Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2015; 390:137-145. [PMID: 26644781 PMCID: PMC4669582 DOI: 10.1016/j.ijms.2015.07.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in combination with ECD allowed the three disulfide bonds of insulin to be cleaved and the overall sequence coverage to be increased. For the larger sized ribonuclease A with four disulfide bonds, irradiation from an infrared laser (10.6 µm) to disrupt non-covalent interactions was combined with UV-activation to facilitate the cleavage of up to three disulfide bonds. Preferences for disulfide bond cleavage are dependent on protein structure and sequence. Disulfide bonds can reform if the generated radicals remain in close proximity. By varying the time delay between the UV-activation and the ECD events, it was determined that disulfide bonds reform within 10-100 msec after their UV-homolytic cleavage.
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Affiliation(s)
- Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Huilin Li
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Xing Zhang
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Ryan R. Julian
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles Los Angeles, CA 90095
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
- UCLA/DOE Institute of Genomics and Proteomics, University of California-Los Angeles Los Angeles, CA 90095
- Corresponding author at: University of California-Los Angeles, Department of Chemistry and Biochemistry, 402 Boyer Hall, Molecular Biology Institute, Los Angeles, CA, United States, Tel.: +1 310 794 7023; fax: +1 310 206 4038, (J.A. Loo)
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Rombouts I, Lagrain B, Scherf KA, Koehler P, Delcour JA. Formation and reshuffling of disulfide bonds in bovine serum albumin demonstrated using tandem mass spectrometry with collision-induced and electron-transfer dissociation. Sci Rep 2015; 5:12210. [PMID: 26193081 PMCID: PMC4507448 DOI: 10.1038/srep12210] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/18/2015] [Indexed: 12/28/2022] Open
Abstract
Thermolysin hydrolyzates of freshly isolated, extensively stored (6 years, 6 °C, dry) and heated (60 min, 90 °C, in excess water) bovine serum albumin (BSA) samples were analyzed with liquid chromatography (LC) electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using alternating electron-transfer dissociation (ETD) and collision-induced dissociation (CID). The positions of disulfide bonds and free thiol groups in the different samples were compared to those deduced from the crystal structure of native BSA. Results revealed non-enzymatic posttranslational modifications of cysteine during isolation, extensive dry storage, and heating. Heat-induced extractability loss of BSA was linked to the impact of protein unfolding on the involvement of specific cysteine residues in intermolecular and intramolecular thiol-disulfide interchange and thiol oxidation reactions. The here developed approach holds promise for exploring disulfide bond formation and reshuffling in various proteins under conditions relevant for chemical, biochemical, pharmaceutical and food processing.
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Affiliation(s)
- Ine Rombouts
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
| | - Bert Lagrain
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
| | - Katharina A. Scherf
- Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straβe 34, D-85354 Freising, Germany
| | - Peter Koehler
- Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straβe 34, D-85354 Freising, Germany
| | - Jan A. Delcour
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
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Levy MJ, Gucinski AC, Boyne MT. Primary Sequence Confirmation of a Protein Therapeutic Using Top Down MS/MS and MS3. Anal Chem 2015; 87:6995-9. [DOI: 10.1021/acs.analchem.5b01113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Michaella J. Levy
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of
Testing and Research, Division of Pharmaceutical Analysis, 645 S. Newstead Ave., St. Louis, Missouri 63110, United States
| | - Ashley C. Gucinski
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of
Testing and Research, Division of Pharmaceutical Analysis, 645 S. Newstead Ave., St. Louis, Missouri 63110, United States
| | - Michael T. Boyne
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of
Testing and Research, Division of Pharmaceutical Analysis, 645 S. Newstead Ave., St. Louis, Missouri 63110, United States
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Sohn CH, Gao J, Thomas DA, Kim TY, Goddard WA, Beauchamp JL. Mechanisms and energetics of free radical initiated disulfide bond cleavage in model peptides and insulin by mass spectrometry. Chem Sci 2015; 6:4550-4560. [PMID: 29142703 PMCID: PMC5666513 DOI: 10.1039/c5sc01305d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/20/2015] [Indexed: 11/21/2022] Open
Abstract
Direct radical substitution at sulfur initiates disulfide bond cleavage by hydrogen-deficient radicals in peptides and proteins.
We investigate the mechanism of disulfide bond cleavage in gaseous peptide and protein ions initiated by a covalently-attached regiospecific acetyl radical using mass spectrometry (MS). Highly selective S–S bond cleavages with some minor C–S bond cleavages are observed by a single step of collisional activation. We show that even multiple disulfide bonds in intact bovine insulin are fragmented in the MS2 stage, releasing the A- and B-chains with a high yield, which has been challenging to achieve by other ion activation methods. Yet, regardless of the previous reaction mechanism studies, it has remained unclear why (1) disulfide bond cleavage is preferred to peptide backbone fragmentation, and why (2) the S–S bond that requires the higher activation energy conjectured in previously suggested mechanisms is more prone to be cleaved than the C–S bond by hydrogen-deficient radicals. To probe the mechanism of these processes, model peptides possessing deuterated β-carbon(s) at the disulfide bond are employed. It is suggested that the favored pathway of S–S bond cleavage is triggered by direct acetyl radical attack at sulfur with concomitant cleavage of the S–S bond (SH2). The activation energy for this process is substantially lower by ∼9–10 kcal mol–1 than those of peptide backbone cleavage processes determined by density functional quantum chemical calculations. Minor reaction pathways are initiated by hydrogen abstraction from the α-carbon or the β-carbon of a disulfide, followed by β-cleavages yielding C–S or S–S bond scissions. The current mechanistic findings should be generally applicable to other radical-driven disulfide bond cleavages with different radical species such as the benzyl and methyl pyridyl radicals.
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Affiliation(s)
- Chang Ho Sohn
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA .
| | - Jinshan Gao
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA .
| | - Daniel A Thomas
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA .
| | - Tae-Young Kim
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA .
| | - William A Goddard
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA . .,Materials and Process Simulation Center , Beckman Institute , California Institute of Technology , Pasadena , CA 91125 , USA
| | - J L Beauchamp
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , CA 91125 , USA .
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Massonnet P, Upert G, Smargiasso N, Gilles N, Quinton L, De Pauw E. Combined Use of Ion Mobility and Collision-Induced Dissociation To Investigate the Opening of Disulfide Bridges by Electron-Transfer Dissociation in Peptides Bearing Two Disulfide Bonds. Anal Chem 2015; 87:5240-6. [DOI: 10.1021/acs.analchem.5b00245] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Philippe Massonnet
- Laboratory of
Mass Spectrometry, Department of Chemistry, GIGA-R, University of Liege, Allée de la Chimie 3, B-4000 Liege, Belgium
| | - Gregory Upert
- Commissariat
à
l’Energie Atomique, DSV/iBiTec-S/SIMOPRO, F91191 Gif-sur-Yvette, France
| | - Nicolas Smargiasso
- Laboratory of
Mass Spectrometry, Department of Chemistry, GIGA-R, University of Liege, Allée de la Chimie 3, B-4000 Liege, Belgium
| | - Nicolas Gilles
- Commissariat
à
l’Energie Atomique, DSV/iBiTec-S/SIMOPRO, F91191 Gif-sur-Yvette, France
| | - Loïc Quinton
- Laboratory of
Mass Spectrometry, Department of Chemistry, GIGA-R, University of Liege, Allée de la Chimie 3, B-4000 Liege, Belgium
| | - Edwin De Pauw
- Laboratory of
Mass Spectrometry, Department of Chemistry, GIGA-R, University of Liege, Allée de la Chimie 3, B-4000 Liege, Belgium
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38
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Oh HB, Moon B. Radical-driven peptide backbone dissociation tandem mass spectrometry. MASS SPECTROMETRY REVIEWS 2015; 34:116-132. [PMID: 24863492 DOI: 10.1002/mas.21426] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 05/06/2013] [Accepted: 11/20/2013] [Indexed: 06/03/2023]
Abstract
In recent years, a number of novel tandem mass spectrometry approaches utilizing radical-driven peptide gas-phase fragmentation chemistry have been developed. These approaches show a peptide fragmentation pattern quite different from that of collision-induced dissociation (CID). The peptide fragmentation features of these approaches share some in common with electron capture dissociation (ECD) or electron transfer dissociation (ETD) without the use of sophisticated equipment such as a Fourier-transform mass spectrometer. For example, Siu and coworkers showed that CID of transition metal (ligand)-peptide ternary complexes led to the formation of peptide radical ions through dissociative electron transfer (Chu et al., 2000. J Phys Chem B 104:3393-3397). The subsequent collisional activation of the generated radical ions resulted in a number of characteristic product ions, including a, c, x, z-type fragments and notable side-chain losses. Another example is the free radical initiated peptide sequencing (FRIPS) approach, in which Porter et al. and Beauchamp et al. independently introduced a free radical initiator to the primary amine group of the lysine side chain or N-terminus of peptides (Masterson et al., 2004. J Am Chem Soc 126:720-721; Hodyss et al., 2005 J Am Chem Soc 127: 12436-12437). Photodetachment of gaseous multiply charged peptide anions (Joly et al., 2008. J Am Chem Soc 130:13832-13833) and UV photodissociation of photolabile radical precursors including a C-I bond (Ly & Julian, 2008. J Am Chem Soc 130:351-358; Ly & Julian, 2009. J Am Soc Mass Spectrom 20:1148-1158) also provide another route to generate radical ions. In this review, we provide a brief summary of recent results obtained through the radical-driven peptide backbone dissociation tandem mass spectrometry approach.
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Affiliation(s)
- Han Bin Oh
- Department of Chemistry, Sogang University, Seoul, 121-742, Republic of Korea
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Wiesner J, Resemann A, Evans C, Suckau D, Jabs W. Advanced mass spectrometry workflows for analyzing disulfide bonds in biologics. Expert Rev Proteomics 2015; 12:115-23. [DOI: 10.1586/14789450.2015.1018896] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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40
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Zhang J, Ogorzalek Loo RR, Loo JA. Increasing Fragmentation of Disulfide-Bonded Proteins for Top-Down Mass Spectrometry by Supercharging. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2015; 377:546-556. [PMID: 26028988 PMCID: PMC4448141 DOI: 10.1016/j.ijms.2014.07.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The disulfide bond is an important post-translational modification to form and maintain the native structure and biological functions of proteins. Characterization of disulfide bond linkages is therefore of essential interest in the structural elucidation of proteins. Top-down mass spectrometry (MS) of disulfide-bonded proteins has been hindered by relatively low sequence coverage due to disulfide cross-linking. In this study, we employed top-down ESI-MS with Fourier-transform ion cyclotron resonance (FT-ICR) MS with electron capture dissociation (ECD) and collisionally activated dissociation (CAD) to study the fragmentation of supercharged proteins with multiple intramolecular disulfide bonds. With charge enhancement upon the addition of sulfolane to the analyte solution, improved protein fragmentation and disulfide bond cleavage efficiency was observed for proteins including bovine β-lactoglobulin, soybean trypsin inhibitor, human proinsulin, and chicken lysozyme. Both the number and relative abundances of product ions representing disulfide cleavage increase with increasing charge states for the proteins studied. Our studies suggest supercharging ESI-MS is a promising tool to aid in the top-down MS analysis of disulfide-bonded proteins, providing potentially useful information for the determination of disulfide bond linkages.
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Affiliation(s)
- Jiang Zhang
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, 90095, United States
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, California, 90095, United States
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California, 90095, United States
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, 90095, United States
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, California, 90095, United States
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California, 90095, United States
- Corresponding author. Tel.: +1 310 794 7023; fax: +1 310 206 4038. (J.A. Loo)
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Cai Y, Zheng Q, Liu Y, Helmy R, Loo JA, Chen H. Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:341-51. [PMID: 26307715 PMCID: PMC4552337 DOI: 10.1255/ejms.1318] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.
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Affiliation(s)
- Yi Cai
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
| | - Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
| | - Yong Liu
- Department of Analytical Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, NJ 07065, USA.
| | - Roy Helmy
- Department of Analytical Chemistry, Merck Research Laboratories, Merck & Co., Inc., Rahway, NJ 07065, USA.
| | - Joseph A Loo
- Dep artment of Chemistry and Biochemistry, Department of Biological Chemistry, David Geffen School of Medicine at UCLA, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA 90095, USA.
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701 USA.
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Abstract
Numerous oxidative modifications to proteins and amino acids have been identified with most susceptible, to varying degrees, of some form of oxidative modification. The consequence of oxidation on protein structure and function reveals that some of these modifications are functionally important. The discovery and accurate characterization/description of existing and new modifications requires modern instrumentation, great care, and attention to detail, especially if the modifications are present in low stoichiometric quantities or they only exist transiently. The focus of this brief review is on the use of mass spectrometry, protein chemistry, and proteomics methods and tools to identify oxidatively modified proteins and peptides along with the characterization of specific sites. Many of the specialized mass spectrometry technologies and techniques are becoming more widely available in research laboratories with mass spectrometry or proteomics facilities allowing even non-expert researchers in the field to accurately determine modifications. Illustrative examples of some approaches are provided from the author's work, collaborative research projects, and elsewhere.
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Jia C, Wu Z, Lietz CB, Liang Z, Cui Q, Li L. Gas-phase ion isomer analysis reveals the mechanism of peptide sequence scrambling. Anal Chem 2013; 86:2917-24. [PMID: 24313304 DOI: 10.1021/ac401578p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Peptide sequence scrambling during mass spectrometry-based gas-phase fragmentation analysis causes misidentification of peptides and proteins. Thus, there is a need to develop an efficient approach to probing the gas-phase fragment ion isomers related to sequence scrambling and the underlying fragmentation mechanism, which will facilitate the development of bioinformatics algorithm for proteomics research. Herein, we report on the first use of electron transfer dissociation (ETD)-produced diagnostic fragment ions to probe the components of gas-phase peptide fragment ion isomers. In combination with ion mobility spectrometry (IMS) and formaldehyde labeling, this novel strategy enables qualitative and quantitative analysis of b-type fragment ion isomers. ETD fragmentation produced diagnostic fragment ions indicative of the precursor ion isomer components, and subsequent IMS analysis of b ion isomers provided their quantitative and structural information. The isomer components of three representative b ions (b9, b10, and b33 from three different peptides) were accurately profiled by this method. IMS analysis of the b9 ion isomers exhibited dynamic conversion among these structures. Furthermore, molecular dynamics simulation predicted theoretical drift time values, which were in good agreement with experimentally measured values. Our results strongly support the mechanism of peptide sequence scrambling via b ion cyclization, and provide the first experimental evidence to support that the conversion from molecular precursor ion to cyclic b ion (M → (c)b) pathway is less energetically (or kinetically) favored.
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Affiliation(s)
- Chenxi Jia
- School of Pharmacy and ‡Department of Chemistry, University of Wisconsin-Madison , 777 Highland Avenue, Madison, Wisconsin 53705, United States
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Zheng Q, Zhang H, Chen H. Integration of online digestion and electrolytic reduction with mass spectrometry for rapid disulfide-containing protein structural analysis. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2013; 353:84-92. [PMID: 25419170 PMCID: PMC4240030 DOI: 10.1016/j.ijms.2013.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Bottom-up structural analysis of disulfide-bond containing proteins usually involves time-consuming offline enzymatic digestion, chemical reduction and thiol protection prior to mass spectrometric detection, which takes many hours. This paper presents an expedited bottom-up approach, employing desorption electrospray ionization-mass spectrometry (DESI-MS) coupled with online pepsin digestion and online electrochemical reduction of disulfide bonds. Peptides are generated in high digestion yield as its precursor protein in acidic aqueous solution flows through a pepsin column, which can undergo direct electrolysis. The electrolytic behaviors of peptides, as online monitored by DESI-MS, suggest the presence or absence of disulfide bonds in the peptides, and also provide information to relate disulfide bond-containing peptide precursors to their corresponding reduced products. Furthermore, selective electrolysis simply using different reduction potentials can be adopted to generate either partially or fully reduced peptides to assist disulfide bond mapping. In addition, it turns out that DESI is suitable for ionizing peptides in water without organic solvent additives (organic solvent additives would not be compatible with the use of pepsin column). The feasibility of this method was demonstrated using insulin, a protein carrying three pairs of disulfide-bonds as an example, in which all disulfide bond linkages and most of the protein sequence were successfully determined. Strikingly, this method shortens the sample digestion, reduction and MS detection from hours to less than 7 min, which could be of high value in high-throughput proteomics research.
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Affiliation(s)
- Qiuling Zheng
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Hao Zhang
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
- Corresponding author. Tel.: +1 314 935 7486
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
- Corresponding author. Tel.: +1 740 593 0719; fax: +1 740 597 3157
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45
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Kraj A, Brouwer HJ, Reinhoud N, Chervet JP. A novel electrochemical method for efficient reduction of disulfide bonds in peptides and proteins prior to MS detection. Anal Bioanal Chem 2013; 405:9311-20. [PMID: 24077854 PMCID: PMC3826059 DOI: 10.1007/s00216-013-7374-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/10/2013] [Accepted: 09/13/2013] [Indexed: 01/16/2023]
Abstract
A novel electrochemical (EC) method for fast and efficient reduction of the disulfide bonds in proteins and peptides is presented. The method does not use any chemical agents and is purely instrumental. To demonstrate the performance of the EC reactor cell online with electrospray mass spectrometry, insulin and somatostatin were used as model compounds. Efficient reduction is achieved in continuous infusion mode using an EC reactor cell with a titanium-based working electrode. Under optimized conditions, the presented method shows almost complete reduction of insulin and somatostatin. The method does not require any special sample preparation, and the EC reactor cell makes it suitable for automation. Online EC reduction followed by collision-induced dissociation fragmentation of somatostatin showed more backbone cleavages and improved sequence coverage. By adjusting the settings, the EC reaction efficiency was gradually changed from partial to full disulfide bonds reduction in α-lactalbumin, and the expected shift in charge state distribution has been demonstrated. The reduction can be controlled by adjusting the square-wave pulse, flow rate or mobile phase composition. We have shown the successful use of an EC reactor cell for fast and efficient reduction of disulfide bonds for online mass spectrometry of proteins and peptides. The possibility of online and gradual disulfide bond reduction adds a unique dimension to characterization of disulfide bonds in mid-and top-down proteomics applications.
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Affiliation(s)
- Agnieszka Kraj
- Antec, Industrieweg 12, 2382NV Zoeterwoude, The Netherlands
| | | | - Nico Reinhoud
- Antec, Industrieweg 12, 2382NV Zoeterwoude, The Netherlands
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46
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Samgina TY, Vorontsov EA, Gorshkov VA, Artemenko KA, Zubarev RA, Ytterberg JA, Lebedev AT. Collision-induced dissociation fragmentation inside disulfide C-terminal loops of natural non-tryptic peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1037-1044. [PMID: 23633018 DOI: 10.1007/s13361-013-0632-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/27/2013] [Accepted: 03/27/2013] [Indexed: 06/02/2023]
Abstract
Collision-induced dissociation (CID) spectra of long non-tryptic peptides are usually quite complicated and rather difficult to interpret. Disulfide bond formed by two cysteine residues at C-terminus of frog skin peptides precludes one to determine sequence inside the forming loop. Thereby, chemical modification of S-S bonds is often used in "bottom up" sequencing approach. However, low-energy CID spectra of natural non-tryptic peptides with C-terminal disulfide cycle demonstrate an unusual fragmentation route, which may be used to elucidate the "hidden" C-terminal sequence. Low charge state protonated molecules experience peptide bond cleavage at the N-terminus of C-terminal cysteine. The forming isomeric acyclic ions serve as precursors for a series of b-type ions revealing sequence inside former disulfide cycle. The reaction is preferable for peptides with basic lysine residues inside the cycle. It may also be activated by acidic protons of Asp and Glu residues neighboring the loop. The observed cleavages may be quite competitive, revealing the sequence inside disulfide cycle, although S-S bond rupture does not occur in this case.
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Affiliation(s)
- Tatiana Y Samgina
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russian Federation
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47
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Affiliation(s)
- František Tureček
- Department of Chemistry, Bagley Hall, University of Washington , Seattle, Washington 98195-1700, United States
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48
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Echterbille J, Quinton L, Gilles N, De Pauw E. Ion Mobility Mass Spectrometry as a Potential Tool To Assign Disulfide Bonds Arrangements in Peptides with Multiple Disulfide Bridges. Anal Chem 2013; 85:4405-13. [DOI: 10.1021/ac303686w] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Julien Echterbille
- Laboratory of Mass Spectrometry,
GIGA-R, Department of Chemistry, University of Liege, Liege, Belgium
| | - Loïc Quinton
- Laboratory of Mass Spectrometry,
GIGA-R, Department of Chemistry, University of Liege, Liege, Belgium
| | - Nicolas Gilles
- iBiTec-S,
SIMOPRO, Commissariat à l’Energie Atomique, Gif-sur-Yvette,
France
| | - Edwin De Pauw
- Laboratory of Mass Spectrometry,
GIGA-R, Department of Chemistry, University of Liege, Liege, Belgium
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49
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Tan L, Xia Y. Gas-phase reactivity of peptide thiyl (RS•), perthiyl (RSS•), and sulfinyl (RSO•) radical ions formed from atmospheric pressure ion/radical reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:534-542. [PMID: 23354473 DOI: 10.1007/s13361-012-0548-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/20/2012] [Accepted: 11/26/2012] [Indexed: 06/01/2023]
Abstract
In this study, we demonstrated the formation of gas-phase peptide perthiyl (RSS•) and thiyl (RS•) radical ions besides sulfinyl radical (RSO•) ions from atmospheric pressure (AP) ion/radical reactions of peptides containing inter-chain disulfide bonds. The identity of perthiyl radical was verified from characteristic 65 Da (•SSH) loss in collision-induced dissociation (CID). This signature loss was further used to assess the purity of peptide perthiyl radical ions formed from AP ion/radical reactions. Ion/molecule reactions combined with CID were carried out to confirm the formation of thiyl radical. Transmission mode ion/molecule reactions in collision cell (q2) were developed as a fast means to estimate the population of peptide thiyl radical ions. The reactivity of peptide thiyl, perthiyl, and sulfinyl radical ions was evaluated based on ion/molecule reactions toward organic disulfides, allyl iodide, organic thiol, and oxygen, which followed in order of thiyl (RS•) > perthiyl (RSS•) > sulfinyl (RSO•). The gas-phase reactivity of these three types of sulfur-based radicals is consistent with literature reports from solution studies.
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Affiliation(s)
- Lei Tan
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
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50
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Asakawa D, Smargiasso N, Quinton L, De Pauw E. Peptide backbone fragmentation initiated by side-chain loss at cysteine residue in matrix-assisted laser desorption/ionization in-source decay mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2013; 48:352-360. [PMID: 23494792 DOI: 10.1002/jms.3182] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 06/01/2023]
Abstract
Matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) is initiated by hydrogen transfer from matrix molecules to the carbonyl oxygen of peptide backbone with subsequent radical-induced cleavage leading to c'/z• fragments pair. MALDI-ISD is a very powerful method to obtain long sequence tags from proteins or to do de novo sequencing of peptides. Besides classical fragmentation, MALDI-ISD also shows specific fragments for which the mechanism of formation enlightened the MALDI-ISD process. In this study, the MALDI-ISD mechanism is reviewed, and a specific mechanism is studied in details: the N-terminal side of Cys residue (Xxx-Cys) is described to promote the generation of c' and w fragments in MALDI-ISD. Our data suggest that for sequences containing Xxx-Cys motifs, the N-Cα bond cleavage occurs following the hydrogen attachment to the thiol group of Cys side-chain. The c•/w fragments pair is formed by side-chain loss of the Cys residue with subsequent radical-induced cleavage at the N-Cα bond located at the left side (N-terminal direction) of the Cys residue. This fragmentation pathway preferentially occurs at free Cys residue and is suppressed when the cysteines are involved in disulfide bonds. Hydrogen attachment to alkylated Cys residues using iodoacetamide gives free Cys residue by the loss of •CH2CONH2 radical. The presence of alkylated Cys residue also suppress the formation of c•/w fragments pair via the (Cβ)-centered radical, whereas w fragment is still observed as intense signal. In this case, the z• fragment formed by hydrogen attachment of carbonyl oxygen followed side-chain loss at alkylated Cys leads to a w fragment. Hydrogen attachment on peptide backbone and side-chain of Cys residue occurs therefore competitively during MALDI-ISD process.
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Affiliation(s)
- Daiki Asakawa
- Chemistry Department and GIGA-R, Mass Spectrometry Laboratory, University of Liège, Belgium.
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