1
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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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2
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Brodbelt JS. Deciphering combinatorial post-translational modifications by top-down mass spectrometry. Curr Opin Chem Biol 2022; 70:102180. [PMID: 35779351 PMCID: PMC9489649 DOI: 10.1016/j.cbpa.2022.102180] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 12/15/2022]
Abstract
Post-translational modifications (PTMs) create vast structural and functional diversity of proteins, ultimately modulating protein function and degradation, influencing cellular signaling, and regulating transcription. The combinatorial patterns of PTMs increase the heterogeneity of proteins and further mediates their interactions. Advances in mass spectrometry-based proteomics have resulted in identification of thousands of proteins and allowed characterization of numerous types and sites of PTMs. Examination of intact proteins, termed the top-down approach, offers the potential to map protein sequences and localize multiple PTMs on each protein, providing the most comprehensive cataloging of proteoforms. This review describes some of the dividends of using mass spectrometry to analyze intact proteins and showcases innovative strategies that have enhanced the promise of top-down proteomics for exploring the impact of combinatorial PTMs in unsurpassed detail.
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
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3
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Blevins MS, Juetten KJ, James VK, Butalewicz JP, Escobar EE, Lanzillotti MB, Sanders JD, Fort KL, Brodbelt JS. Nanohydrophobic Interaction Chromatography Coupled to Ultraviolet Photodissociation Mass Spectrometry for the Analysis of Intact Proteins in Low Charge States. J Proteome Res 2022; 21:2493-2503. [PMID: 36043517 DOI: 10.1021/acs.jproteome.2c00450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The direct correlation between proteoforms and biological phenotype necessitates the exploration of mass spectrometry (MS)-based methods more suitable for proteoform detection and characterization. Here, we couple nano-hydrophobic interaction chromatography (nano-HIC) to ultraviolet photodissociation MS (UVPD-MS) for separation and characterization of intact proteins and proteoforms. High linearity, sensitivity, and sequence coverage are obtained with this method for a variety of proteins. Investigation of collisional cross sections of intact proteins during nano-HIC indicates semifolded conformations in low charge states, enabling a different dimension of separation in comparison to traditional, fully denaturing reversed-phase separations. This method is demonstrated for a mixture of intact proteins from Escherichia coli ribosomes; high sequence coverage is obtained for a variety of modified and unmodified proteoforms.
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Affiliation(s)
- Molly S Blevins
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyle J Juetten
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Virginia K James
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jamie P Butalewicz
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Edwin E Escobar
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Michael B Lanzillotti
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - James D Sanders
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyle L Fort
- Thermo Fisher Scientific, Bremen 28199, Germany
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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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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Liu R, Xia S, Li H. Native top-down mass spectrometry for higher-order structural characterization of proteins and complexes. MASS SPECTROMETRY REVIEWS 2022:e21793. [PMID: 35757976 DOI: 10.1002/mas.21793] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Progress in structural biology research has led to a high demand for powerful and yet complementary analytical tools for structural characterization of proteins and protein complexes. This demand has significantly increased interest in native mass spectrometry (nMS), particularly native top-down mass spectrometry (nTDMS) in the past decade. This review highlights recent advances in nTDMS for structural research of biological assemblies, with a particular focus on the extra multi-layers of information enabled by TDMS. We include a short introduction of sample preparation and ionization to nMS, tandem fragmentation techniques as well as mass analyzers and software/analysis pipelines used for nTDMS. We highlight unique structural information offered by nTDMS and examples of its broad range of applications in proteins, protein-ligand interactions (metal, cofactor/drug, DNA/RNA, and protein), therapeutic antibodies and antigen-antibody complexes, membrane proteins, macromolecular machineries (ribosome, nucleosome, proteosome, and viruses), to endogenous protein complexes. The challenges, potential, along with perspectives of nTDMS methods for the analysis of proteins and protein assemblies in recombinant and biological samples are discussed.
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Affiliation(s)
- Ruijie Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shujun Xia
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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7
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Olsen C, Wiborg E, Lundanes E, Abadpour S, Scholz H, Wilson SR. On‐line reduction of insulin disulfide bonds with photoinduced radical reactions, upstream to nano liquid chromatography‐mass spectrometry. SEPARATION SCIENCE PLUS 2022. [DOI: 10.1002/sscp.202200022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Christine Olsen
- Department of Chemistry University of Oslo Blindern Oslo Norway
| | - Elisa Wiborg
- Department of Chemistry University of Oslo Blindern Oslo Norway
| | - Elsa Lundanes
- Department of Chemistry University of Oslo Blindern Oslo Norway
| | - Shadab Abadpour
- Hybrid Technology Hub‐Centre of Excellence Faculty of Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
- Department of Transplant Medicine and Institute for Surgical Research Oslo University Hospital, Oslo, Norway
| | - Hanne Scholz
- Hybrid Technology Hub‐Centre of Excellence Faculty of Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
- Department of Transplant Medicine and Institute for Surgical Research Oslo University Hospital, Oslo, Norway
| | - Steven Ray Wilson
- Department of Chemistry University of Oslo Blindern Oslo Norway
- Hybrid Technology Hub‐Centre of Excellence Faculty of Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
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8
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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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9
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Blevins MS, Walker JN, Schaub JM, Finkelstein IJ, Brodbelt JS. Characterization of the T4 gp32-ssDNA complex by native, cross-linking, and ultraviolet photodissociation mass spectrometry. Chem Sci 2021; 12:13764-13776. [PMID: 34760161 PMCID: PMC8549804 DOI: 10.1039/d1sc02861h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022] Open
Abstract
Protein-DNA interactions play crucial roles in DNA replication across all living organisms. Here, we apply a suite of mass spectrometry (MS) tools to characterize a protein-ssDNA complex, T4 gp32·ssDNA, with results that both support previous studies and simultaneously uncover novel insight into this non-covalent biological complex. Native mass spectrometry of the protein reveals the co-occurrence of Zn-bound monomers and homodimers, while addition of differing lengths of ssDNA generates a variety of protein:ssDNA complex stoichiometries (1 : 1, 2 : 1, 3 : 1), indicating sequential association of gp32 monomers with ssDNA. Ultraviolet photodissociation (UVPD) mass spectrometry allows characterization of the binding site of the ssDNA within the protein monomer via analysis of holo ions, i.e. ssDNA-containing protein fragments, enabling interrogation of disordered regions of the protein which are inaccessible via traditional crystallographic techniques. Finally, two complementary cross-linking (XL) approaches, bottom-up analysis of the crosslinked complexes as well as MS1 analysis of the intact complexes, are used to showcase the absence of ssDNA binding with the intact cross-linked homodimer and to generate two homodimer gp32 model structures which highlight that the homodimer interface overlaps with the monomer ssDNA-binding site. These models suggest that the homodimer may function in a regulatory capacity by controlling the extent of ssDNA binding of the protein monomer. In sum, this work underscores the utility of a multi-faceted mass spectrometry approach for detailed investigation of non-covalent protein-DNA complexes.
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Affiliation(s)
- Molly S Blevins
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jada N Walker
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
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10
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Gutierrez-Reyes CD, Jiang P, Atashi M, Bennett A, Yu A, Peng W, Zhong J, Mechref Y. Advances in mass spectrometry-based glycoproteomics: An update covering the period 2017-2021. Electrophoresis 2021; 43:370-387. [PMID: 34614238 DOI: 10.1002/elps.202100188] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/30/2021] [Accepted: 09/25/2021] [Indexed: 12/23/2022]
Abstract
Protein glycosylation is one of the most common posttranslational modifications, and plays an essential role in a wide range of biological processes such as immune response, intercellular signaling, inflammation, host-pathogen interaction, and protein stability. Glycoproteomics is a proteomics subfield dedicated to identifying and characterizing the glycans and glycoproteins in a given cell or tissue. Aberrant glycosylation has been associated with various diseases such as Alzheimer's disease, viral infections, inflammation, immune deficiencies, congenital disorders, and cancers. However, glycoproteomic analysis remains challenging because of the low abundance, site-specific heterogeneity, and poor ionization efficiency of glycopeptides during LC-MS analyses. Therefore, the development of sensitive and accurate approaches to efficiently characterize protein glycosylation is crucial. Methods such as metabolic labeling, enrichment, and derivatization of glycopeptides, coupled with different mass spectrometry techniques and bioinformatics tools, have been developed to achieve sophisticated levels of quantitative and qualitative analyses of glycoproteins. This review attempts to update the recent developments in the field of glycoproteomics reported between 2017 and 2021.
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Affiliation(s)
| | - Peilin Jiang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Mojgan Atashi
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Andrew Bennett
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Aiying Yu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Wenjing Peng
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Jieqiang Zhong
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
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11
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Schmitt ND, Berger JM, Conway JB, Agar JN. Increasing Top-Down Mass Spectrometry Sequence Coverage by an Order of Magnitude through Optimized Internal Fragment Generation and Assignment. Anal Chem 2021; 93:6355-6362. [DOI: 10.1021/acs.analchem.0c04670] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Nicholas D. Schmitt
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Joshua M. Berger
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Jeremy B. Conway
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Jeffrey N. Agar
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
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12
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Greisch JF, van der Laarse SA, Heck AJ. Enhancing Top-Down Analysis Using Chromophore-Assisted Infrared Multiphoton Dissociation from (Phospho)peptides to Protein Assemblies. Anal Chem 2020; 92:15506-15516. [PMID: 33180479 PMCID: PMC7711774 DOI: 10.1021/acs.analchem.0c03412] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/23/2020] [Indexed: 12/21/2022]
Abstract
Infrared multiphoton dissociation (IRMPD) has been used in mass spectrometry to fragment peptides and proteins, providing fragments mostly similar to collisional activation. Using the 10.6 μm wavelength of a CO2 laser, IRMPD suffers from the relative low absorption cross-section of peptides and small proteins. Focusing on top-down analysis, we investigate different means to tackle this issue. We first reassess efficient sorting of phosphopeptides from nonphosphopeptides based on IR-absorption cross-sectional enhancement by phosphate moieties. We subsequently demonstrate that a myo-inositol hexakisphosphate (IP6) noncovalent adduct can substantially enhance IRMPD for nonphosphopeptides and that this strategy can be extended to proteins. As a natural next step, we show that native phospho-proteoforms of proteins display a distinct and enhanced fragmentation, compared to their unmodified counterparts, facilitating phospho-group site localization. We then evaluate the impact of size on the IRMPD of proteins and their complexes. When applied to protein complexes ranging from a 365 kDa CRISPR-Cas Csy ribonucleoprotein hetero-decamer, a 800 kDa GroEL homo-tetradecamer in its apo-form or loaded with its ATP cofactor, to a 1 MDa capsid-like homo-hexacontamer, we conclude that while phosphate moieties present in crRNA and ATP molecules enhance IRMPD, an increase in the IR cross-section with the size of the protein assembly also favorably accrues dissociation yields. Overall, our work showcases the versatility of IRMPD in the top-down analysis of peptides, phosphopeptides, proteins, phosphoproteins, ribonucleoprotein assemblies, and large protein complexes.
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Affiliation(s)
- Jean-François Greisch
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, 3584CH Utrecht, The Netherlands
| | - Saar A.M. van der Laarse
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, 3584CH Utrecht, The Netherlands
| | - Albert J.R. Heck
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, 3584CH Utrecht, The Netherlands
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13
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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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14
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Affiliation(s)
| | | | - Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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15
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McCool EN, Lodge JM, Basharat AR, Liu X, Coon JJ, Sun L. Capillary Zone Electrophoresis-Tandem Mass Spectrometry with Activated Ion Electron Transfer Dissociation for Large-scale Top-down Proteomics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2470-2479. [PMID: 31073891 PMCID: PMC6527361 DOI: 10.1007/s13361-019-02206-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 05/21/2023]
Abstract
Capillary zone electrophoresis (CZE)-tandem mass spectrometry (MS/MS) has been recognized as an efficient approach for top-down proteomics recently for its high-capacity separation and highly sensitive detection of proteoforms. However, the commonly used collision-based dissociation methods often cannot provide extensive fragmentation of proteoforms for thorough characterization. Activated ion electron transfer dissociation (AI-ETD), that combines infrared photoactivation concurrent with ETD, has shown better performance for proteoform fragmentation than higher energy-collisional dissociation (HCD) and standard ETD. Here, we present the first application of CZE-AI-ETD on an Orbitrap Fusion Lumos mass spectrometer for large-scale top-down proteomics of Escherichia coli (E. coli) cells. CZE-AI-ETD outperformed CZE-ETD regarding proteoform and protein identifications (IDs). CZE-AI-ETD reached comparable proteoform and protein IDs with CZE-HCD. CZE-AI-ETD tended to generate better expectation values (E values) of proteoforms than CZE-HCD and CZE-ETD, indicating a higher quality of MS/MS spectra from AI-ETD respecting the number of sequence-informative fragment ions generated. CZE-AI-ETD showed great reproducibility regarding the proteoform and protein IDs with relative standard deviations less than 4% and 2% (n = 3). Coupling size exclusion chromatography (SEC) to CZE-AI-ETD identified 3028 proteoforms and 387 proteins from E. coli cells with 1% spectrum level and 5% proteoform-level false discovery rates. The data represents the largest top-down proteomics dataset using the AI-ETD method so far. Single-shot CZE-AI-ETD of one SEC fraction identified 957 proteoforms and 253 proteins. N-terminal truncations, signal peptide cleavage, N-terminal methionine removal, and various post-translational modifications including protein N-terminal acetylation, methylation, S-thiolation, disulfide bonds, and lysine succinylation were detected.
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Affiliation(s)
- Elijah N McCool
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI, 48824, USA
| | - Jean M Lodge
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Abdul Rehman Basharat
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, 719 Avenue, Indianapolis, IN, 46202, USA
| | - Xiaowen Liu
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, 719 Avenue, Indianapolis, IN, 46202, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, 410 West 10th Street, Indianapolis, IN, 46202, USA
| | - Joshua J Coon
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI, 48824, USA.
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Shen X, Yang Z, McCool EN, Lubeckyj RA, Chen D, Sun L. Capillary zone electrophoresis-mass spectrometry for top-down proteomics. Trends Analyt Chem 2019; 120:115644. [PMID: 31537953 PMCID: PMC6752746 DOI: 10.1016/j.trac.2019.115644] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mass spectrometry (MS)-based top-down proteomics characterizes complex proteomes at the intact proteoform level and provides an accurate picture of protein isoforms and protein post-translational modifications in the cell. The progress of top-down proteomics requires novel analytical tools with high peak capacity for proteoform separation and high sensitivity for proteoform detection. The requirements have made capillary zone electrophoresis (CZE)-MS an attractive approach for advancing large-scale top-down proteomics. CZE has achieved a peak capacity of 300 for separation of complex proteoform mixtures. CZE-MS has shown drastically better sensitivity than commonly used reversed-phase liquid chromatography (RPLC)-MS for proteoform detection. The advanced CZE-MS identified 6,000 proteoforms of nearly 1,000 proteoform families from a complex proteome sample, which represents one of the largest top-down proteomic datasets so far. In this review, we focus on the recent progress in CZE-MS-based top-down proteomics and provide our perspectives about its future directions.
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Affiliation(s)
- Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Zhichang Yang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Elijah N. McCool
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Rachele A. Lubeckyj
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Daoyang Chen
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
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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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18
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Chen B, Lin Z, Zhu Y, Jin Y, Larson E, Xu Q, Fu C, Zhang Z, Zhang Q, Pritts WA, Ge Y. Middle-Down Multi-Attribute Analysis of Antibody-Drug Conjugates with Electron Transfer Dissociation. Anal Chem 2019; 91:11661-11669. [PMID: 31442030 DOI: 10.1021/acs.analchem.9b02194] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Antibody-drug conjugates (ADCs) are designed to combine the target specificity of monoclonal antibodies and potent cytotoxin drugs to achieve better therapeutic outcomes. Comprehensive evaluation of the quality attributes of ADCs is critical for drug development but remains challenging due to heterogeneity of the construct. Currently, peptide mapping with reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the predominant approach to characterize ADCs. However, it is suboptimal for sequence characterization and quantification of ADCs because it lacks a comprehensive view of coexisting variants and suffers from varying ionization effects of drug-conjugated peptides compared to unconjugated counterparts. Here, we present the first middle-down RPLC-MS analysis of both cysteine (Adcetris; BV) and lysine (Kadcyla; T-DM1) conjugated ADCs at the subunit level (∼25 kDa) with electron transfer dissociation (ETD). We successfully achieved high-resolution separation of subunit isomers arising from different drug conjugation and subsequently localized the conjugation sites. Moreover, we obtained a comprehensive overview of the microvariants associated with each subunits and characterized them such as oxidized variants with different sites. Furthermore, we observed relatively high levels of conjugation near complementarity-determining regions (CDRs) from the heavy chain but no drug conjugation near CDRs of light chain (Lc) from lysine conjugated T-DM1. Based on the extracted ion chromatograms, we accurately measured average drug to antibody ratio (DAR) values and relative occupancy of drug-conjugated subunits. Overall, the middle-down MS approach enables the evaluation of multiple quality attributes including DAR, positional isomers, conjugation sites, occupancy, and microvariants, which potentially opens up a new avenue to characterize ADCs.
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Affiliation(s)
- Bifan Chen
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Ziqing Lin
- Department of Cell and Regenerative Biology , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States.,Human Proteomics Program, School of Medicine and Public Health , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Yanlong Zhu
- Department of Cell and Regenerative Biology , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States.,Human Proteomics Program, School of Medicine and Public Health , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Yutong Jin
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Eli Larson
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Qingge Xu
- Department of Cell and Regenerative Biology , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States.,Human Proteomics Program, School of Medicine and Public Health , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Cexiong Fu
- Process Analytical , AbbVie Inc. , North Chicago , Illinois 60064 , United States
| | - Zhaorui Zhang
- Process Analytical , AbbVie Inc. , North Chicago , Illinois 60064 , United States
| | - Qunying Zhang
- Process Analytical , AbbVie Inc. , North Chicago , Illinois 60064 , United States
| | - Wayne A Pritts
- Process Analytical , AbbVie Inc. , North Chicago , Illinois 60064 , United States
| | - Ying Ge
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States.,Department of Cell and Regenerative Biology , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States.,Human Proteomics Program, School of Medicine and Public Health , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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19
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Capturing site-specific heterogeneity with large-scale N-glycoproteome analysis. Nat Commun 2019; 10:1311. [PMID: 30899004 PMCID: PMC6428843 DOI: 10.1038/s41467-019-09222-w] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 02/19/2019] [Indexed: 11/08/2022] Open
Abstract
Protein glycosylation is a highly important, yet poorly understood protein post-translational modification. Thousands of possible glycan structures and compositions create potential for tremendous site heterogeneity. A lack of suitable analytical methods for large-scale analyses of intact glycopeptides has limited our abilities both to address the degree of heterogeneity across the glycoproteome and to understand how this contributes biologically to complex systems. Here we show that N-glycoproteome site-specific microheterogeneity can be captured via large-scale glycopeptide profiling methods enabled by activated ion electron transfer dissociation (AI-ETD), ultimately characterizing 1,545 N-glycosites (>5,600 unique N-glycopeptides) from mouse brain tissue. Our data reveal that N-glycosylation profiles can differ between subcellular regions and structural domains and that N-glycosite heterogeneity manifests in several different forms, including dramatic differences in glycosites on the same protein. Moreover, we use this large-scale glycoproteomic dataset to develop several visualizations that will prove useful for analyzing intact glycopeptides in future studies. Mass spectrometry facilitates large-scale glycosylation profiling but in-depth analysis of intact glycopeptides is still challenging. Here, the authors show that activated ion electron transfer dissociation is suitable for glycopeptide fragmentation and improves glycoproteome coverage.
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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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