1
|
Zhao Z, Guo Y, Chowdhury T, Anjum S, Li J, Huang L, Cupp-Sutton KA, Burgett A, Shi D, Wu S. Top-Down Proteomics Analysis of Picogram-Level Complex Samples Using Spray-Capillary-Based Capillary Electrophoresis-Mass Spectrometry. Anal Chem 2024; 96:8763-8771. [PMID: 38722793 DOI: 10.1021/acs.analchem.4c01119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Proteomics analysis of mass-limited samples has become increasingly important for understanding biological systems in physiologically relevant contexts such as patient samples, multicellular organoids, spheroids, and single cells. However, relatively low sensitivity in top-down proteomics methods makes their application to mass-limited samples challenging. Capillary electrophoresis (CE) has emerged as an ideal separation method for mass-limited samples due to its high separation resolution, ultralow detection limit, and minimal sample volume requirements. Recently, we developed "spray-capillary", an electrospray ionization (ESI)-assisted device, that is capable of quantitative ultralow-volume sampling (e.g., pL-nL level). Here, we developed a spray-capillary-CE-MS platform for ultrasensitive top-down proteomics analysis of intact proteins in mass-limited complex biological samples. Specifically, to improve the sensitivity of the spray-capillary platform, we incorporated a polyethylenimine (PEI)-coated capillary and optimized the spray-capillary inner diameter. Under optimized conditions, we successfully detected over 200 proteoforms from 50 pg of E. coli lysate. To our knowledge, the spray-capillary CE-MS platform developed here represents one of the most sensitive detection methods for top-down proteomics. Furthermore, in a proof-of-principle experiment, we detected 261 ± 65 and 174 ± 45 intact proteoforms from fewer than 50 HeLa and OVCAR-8 cells, respectively, by coupling nanodroplet-based sample preparation with our optimized CE-MS platform. Overall, our results demonstrate the capability of the modified spray-capillary CE-MS platform to perform top-down proteomics analysis on picogram amounts of samples. This advancement presents the possibility of meaningful top-down proteomics analysis of mass-limited samples down to the level of single mammalian cells.
Collapse
Affiliation(s)
- Zhitao Zhao
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Yanting Guo
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Trishika Chowdhury
- Department of Chemistry and Biochemistry, University of Alabama, 250 Hackberry Ln, Tuscaloosa, Alabama 35487, United States
| | - Samin Anjum
- Department of Chemistry and Biochemistry, University of Alabama, 250 Hackberry Ln, Tuscaloosa, Alabama 35487, United States
| | - Jiaxue Li
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Lushuang Huang
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Kellye A Cupp-Sutton
- Department of Chemistry and Biochemistry, University of Alabama, 250 Hackberry Ln, Tuscaloosa, Alabama 35487, United States
| | - Anthony Burgett
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences, 1110 N. Stonewall Ave., Oklahoma City, Oklahoma 73117, United States
| | - Dingjing Shi
- Department of Psychology, University of Oklahoma, 455 W Lindsey Street, Norman, Oklahoma 73069, United States
| | - Si Wu
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
- Department of Chemistry and Biochemistry, University of Alabama, 250 Hackberry Ln, Tuscaloosa, Alabama 35487, United States
| |
Collapse
|
2
|
Chen D, McCool EN, Yang Z, Shen X, Lubeckyj RA, Xu T, Wang Q, Sun L. Recent advances (2019-2021) of capillary electrophoresis-mass spectrometry for multilevel proteomics. MASS SPECTROMETRY REVIEWS 2023; 42:617-642. [PMID: 34128246 PMCID: PMC8671558 DOI: 10.1002/mas.21714] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 05/06/2023]
Abstract
Multilevel proteomics aims to delineate proteins at the peptide (bottom-up proteomics), proteoform (top-down proteomics), and protein complex (native proteomics) levels. Capillary electrophoresis-mass spectrometry (CE-MS) can achieve highly efficient separation and highly sensitive detection of complex mixtures of peptides, proteoforms, and even protein complexes because of its substantial technical progress. CE-MS has become a valuable alternative to the routinely used liquid chromatography-mass spectrometry for multilevel proteomics. This review summarizes the most recent (2019-2021) advances of CE-MS for multilevel proteomics regarding technological progress and biological applications. We also provide brief perspectives on CE-MS for multilevel proteomics at the end, highlighting some future directions and potential challenges.
Collapse
Affiliation(s)
| | | | | | - Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Rachele A. Lubeckyj
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Tian Xu
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Qianjie Wang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| |
Collapse
|
3
|
Guo Y, Chowdhury T, Seshadri M, Cupp-Sutton KA, Wang Q, Yu D, Wu S. Optimization of Higher-Energy Collisional Dissociation Fragmentation Energy for Intact Protein-Level Tandem Mass Tag Labeling. J Proteome Res 2023; 22:1406-1418. [PMID: 36603205 PMCID: PMC10164041 DOI: 10.1021/acs.jproteome.2c00549] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Isobaric chemical tag labeling (e.g., TMT) is a commonly used approach in quantitative proteomics, and quantification is enabled through detection of low-mass reporter ions generated after MS2 fragmentation. Recently, we have introduced and optimized an intact protein-level TMT labeling platform that demonstrated >90% labeling efficiency in complex samples with top-down proteomics. Higher-energy collisional dissociation (HCD) is commonly utilized for isobaric tag-labeled peptide fragmentation because it produces accurate reporter ion intensities and avoids loss of low mass ions. HCD energies have been optimized for isobaric tag labeled-peptides but have not been systematically evaluated for isobaric tag-labeled intact proteins. In this study, we report a systematic evaluation of normalized HCD fragmentation energies (NCEs) on TMT-labeled HeLa cell lysate using top-down proteomics. Our results suggested that reporter ions often result in higher ion intensities at higher NCEs. Optimal fragmentation of intact proteins for identification, however, required relatively lower NCE. We further demonstrated that a stepped NCE scheme with energies from 30% to 50% resulted in optimal quantification and identification of TMT-labeled HeLa proteins. These parameters resulted in an average reporter ion intensity of ∼4E4 and average proteoform spectrum matches (PrSMs) of >1000 per RPLC-MS/MS run with a 1% false discovery rate (FDR) cutoff.
Collapse
Affiliation(s)
- Yanting Guo
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Trishika Chowdhury
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Meena Seshadri
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Kellye A Cupp-Sutton
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Qingyu Wang
- School of Meteorology, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Dahang Yu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Si Wu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| |
Collapse
|
4
|
Seeing the complete picture: proteins in top-down mass spectrometry. Essays Biochem 2022; 67:283-300. [PMID: 36468679 DOI: 10.1042/ebc20220098] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022]
Abstract
Abstract
Top-down protein mass spectrometry can provide unique insights into protein sequence and structure, including precise proteoform identification and study of protein–ligand and protein–protein interactions. In contrast with the commonly applied bottom-up approach, top-down approaches do not include digestion of the protein of interest into small peptides, but instead rely on the ionization and subsequent fragmentation of intact proteins. As such, it is fundamentally the only way to fully characterize the composition of a proteoform. Here, we provide an overview of how a top-down protein mass spectrometry experiment is performed and point out recent applications from the literature to the reader. While some parts of the top-down workflow are broadly applicable, different research questions are best addressed with specific experimental designs. The most important divide is between studies that prioritize sequence information (i.e., proteoform identification) versus structural information (e.g., conformational studies, or mapping protein–protein or protein–ligand interactions). Another important consideration is whether to work under native or denaturing solution conditions, and the overall complexity of the sample also needs to be taken into account, as it determines whether (chromatographic) separation is required prior to MS analysis. In this review, we aim to provide enough information to support both newcomers and more experienced readers in the decision process of how to answer a potential research question most efficiently and to provide an overview of the methods that exist to answer these questions.
Collapse
|
5
|
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.
Collapse
Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| |
Collapse
|
6
|
McCool EN, Lubeckyj RA, Chen D, Sun L. Top-Down Proteomics by Capillary Zone Electrophoresis-Tandem Mass Spectrometry for Large-Scale Characterization of Proteoforms in Complex Samples. Methods Mol Biol 2022; 2531:107-124. [PMID: 35941482 DOI: 10.1007/978-1-0716-2493-7_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Capillary zone electrophoresis (CZE) is a fundamentally simple and highly efficient separation technique based on differences in electrophoretic mobilities of analytes. CZE-mass spectrometry (MS) has become an important analytical tool in top-down proteomics which aims to delineate proteoforms in cells comprehensively, because of the improvement of capillary coatings, sample stacking methods, and CE-MS interfaces. Here, we present a CZE-MS/MS-based top-down proteomics procedure for the characterization of a standard protein mixture and an Escherichia coli (E. coli) cell lysate using linear polyacrylamide-coated capillaries, a dynamic pH junction sample stacking method, a commercialized electro-kinetically pumped sheath flow CE-MS interface and an Orbitrap mass spectrometer. CZE-MS/MS can identify hundreds of proteoforms routinely from the E. coli sample with a 1% proteoform-level false discovery rate (FDR).
Collapse
Affiliation(s)
- Elijah N McCool
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Rachele A Lubeckyj
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Daoyang Chen
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
7
|
Shen X, Xu T, Hakkila B, Hare M, Wang Q, Wang Q, Beckman JS, Sun L. Capillary Zone Electrophoresis-Electron-Capture Collision-Induced Dissociation on a Quadrupole Time-of-Flight Mass Spectrometer for Top-Down Characterization of Intact Proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1361-1369. [PMID: 33749270 PMCID: PMC8576897 DOI: 10.1021/jasms.0c00484] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mass spectrometry (MS)-based denaturing top-down proteomics (dTDP) requires high-capacity separation and extensive gas-phase fragmentation of proteoforms. Herein, we coupled capillary zone electrophoresis (CZE) to electron-capture collision-induced dissociation (ECciD) on an Agilent 6545 XT quadrupole time-of-flight (Q-TOF) mass spectrometer for dTDP for the first time. During ECciD, the protein ions were first fragmented using ECD, followed by further activation and fragmentation by applying a CID potential. In this pilot study, we optimized the CZE-ECciD method for small proteins (lower than 20 kDa) regarding the charge state of protein parent ions for fragmentation and the CID potential applied to maximize the protein backbone cleavage coverage and the number of sequence-informative fragment ions. The CZE-ECciD Q-TOF platform provided extensive backbone cleavage coverage for three standard proteins lower than 20 kDa from only single charge states in a single CZE-MS/MS run in the targeted MS/MS mode, including ubiquitin (97%, +7, 8.6 kDa), superoxide dismutase (SOD, 87%, +17, 16 kDa), and myoglobin (90%, +16, 17 kDa). The CZE-ECciD method produced comparable cleavage coverage of small proteins (i.e., myoglobin) with direct-infusion MS studies using electron transfer dissociation (ETD), activated ion-ETD, and combinations of ETD and collision-based fragmentation on high-end orbitrap mass spectrometers. The results render CZE-ECciD a new tool for dTDP to enhance both separation and gas-phase fragmentation of proteoforms.
Collapse
Affiliation(s)
- Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Tian Xu
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Blake Hakkila
- e-MSion, Inc., 2121 NE Jack London Drive, Corvallis, Oregon 97330, United States
| | - Mike Hare
- e-MSion, Inc., 2121 NE Jack London Drive, Corvallis, Oregon 97330, United States
| | - Qianjie Wang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Qianyi Wang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Joseph S Beckman
- e-MSion, Inc., 2121 NE Jack London Drive, Corvallis, Oregon 97330, United States
- Linus Pauling Institute and the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| |
Collapse
|
8
|
Buch-Larsen SC, Hendriks IA, Lodge JM, Rykær M, Furtwängler B, Shishkova E, Westphall MS, Coon JJ, Nielsen ML. Mapping Physiological ADP-Ribosylation Using Activated Ion Electron Transfer Dissociation. Cell Rep 2021; 32:108176. [PMID: 32966781 PMCID: PMC7508052 DOI: 10.1016/j.celrep.2020.108176] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/25/2020] [Accepted: 08/31/2020] [Indexed: 11/26/2022] Open
Abstract
ADP-ribosylation (ADPr) is a post-translational modification that plays pivotal roles in a wide range of cellular processes. Mass spectrometry (MS)-based analysis of ADPr under physiological conditions, without relying on genetic or chemical perturbation, has been hindered by technical limitations. Here, we describe the applicability of activated ion electron transfer dissociation (AI-ETD) for MS-based proteomics analysis of physiological ADPr using our unbiased Af1521 enrichment strategy. To benchmark AI-ETD, we profile 9,000 ADPr peptides mapping to >5,000 unique ADPr sites from a limited number of cells exposed to oxidative stress and identify 120% and 28% more ADPr peptides compared to contemporary strategies using ETD and electron-transfer higher-energy collisional dissociation (EThcD), respectively. Under physiological conditions, AI-ETD identifies 450 ADPr sites on low-abundant proteins, including in vivo cysteine modifications on poly(ADP-ribosyl)polymerase (PARP) 8 and tyrosine modifications on PARP14, hinting at specialist enzymatic functions for these enzymes. Collectively, our data provide insights into the physiological regulation of ADPr.
Collapse
Affiliation(s)
- Sara C Buch-Larsen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Ivo A Hendriks
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jean M Lodge
- University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Martin Rykær
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Benjamin Furtwängler
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | | | - Joshua J Coon
- University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael L Nielsen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| |
Collapse
|
9
|
Mehaffey MR, Xia Q, Brodbelt JS. Uniting Native Capillary Electrophoresis and Multistage Ultraviolet Photodissociation Mass Spectrometry for Online Separation and Characterization of Escherichia coli Ribosomal Proteins and Protein Complexes. Anal Chem 2020; 92:15202-15211. [PMID: 33156608 PMCID: PMC7788560 DOI: 10.1021/acs.analchem.0c03784] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
With an overarching goal of characterizing the structure of every protein within a cell, identifying its interacting partners, and quantifying the dynamics of the states in which it exists, key developments are still necessary to achieve comprehensive native proteomics by mass spectrometry (MS). In practice, much work remains to optimize reliable online separation methods that are compatible with native MS and improve tandem MS (MS/MS) approaches with respect to when and how energy is deposited into proteins of interest. Herein, we utilize native capillary zone electrophoresis coupled with MS to characterize the proteoforms in the Escherichia coli 70S ribosome. The capabilities of 193 nm ultraviolet photodissociation (UVPD) to yield informative backbone sequence ions are compared to those of higher-energy collisional dissociation (HCD). To further improve sequence coverage values, a multistage MS/MS approach is implemented involving front-end collisional activation to disassemble protein complexes into constituent subunits that are subsequently individually isolated and activated by HCD or UVPD. In total, 48 of the 55 known E. coli ribosomal proteins are identified as 84 unique proteoforms, including 22 protein-metal complexes and 10 protein-protein complexes. Additionally, mapping metal-bound holo fragment ions resulting from UVPD of protein-metal complexes offers insight into the metal-binding sites.
Collapse
Affiliation(s)
- M Rachel Mehaffey
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Qiangwei Xia
- CMP Scientific Corporation, Brooklyn, New York, New York 11226, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
10
|
Chen D, Lubeckyj RA, Yang Z, McCool EN, Shen X, Wang Q, Xu T, Sun L. Predicting Electrophoretic Mobility of Proteoforms for Large-Scale Top-Down Proteomics. Anal Chem 2020; 92:3503-3507. [PMID: 32043875 PMCID: PMC7543059 DOI: 10.1021/acs.analchem.9b05578] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Large-scale top-down proteomics characterizes proteoforms in cells globally with high confidence and high throughput using reversed-phase liquid chromatography (RPLC)-tandem mass spectrometry (MS/MS) or capillary zone electrophoresis (CZE)-MS/MS. The false discovery rate (FDR) from the target-decoy database search is typically deployed to filter identified proteoforms to ensure high-confidence identifications (IDs). It has been demonstrated that the FDRs in top-down proteomics can be drastically underestimated. An alternative approach to the FDR can be useful for further evaluating the confidence of proteoform IDs after the database search. We argue that predicting retention/migration time of proteoforms from the RPLC/CZE separation accurately and comparing their predicted and experimental separation time could be a useful and practical approach. Based on our knowledge, there is still no report in the literature about predicting separation time of proteoforms using large top-down proteomics data sets. In this pilot study, for the first time, we evaluated various semiempirical models for predicting proteoforms' electrophoretic mobility (μef) using large-scale top-down proteomics data sets from CZE-MS/MS. We achieved a linear correlation between experimental and predicted μef of E. coli proteoforms (R2 = 0.98) with a simple semiempirical model, which utilizes the number of charges and molecular mass of each proteoform as the parameters. Our modeling data suggest that the complete unfolding of proteoforms during CZE separation benefits the prediction of their μef. Our results also indicate that N-terminal acetylation and phosphorylation both decrease the proteoforms' charge by roughly one charge unit.
Collapse
Affiliation(s)
- Daoyang Chen
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Rachele A Lubeckyj
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Zhichang Yang
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Elijah N McCool
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Qianjie Wang
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Tian Xu
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| |
Collapse
|
11
|
Affiliation(s)
| | | | - Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Gomes FP, Yates JR. Recent trends of capillary electrophoresis-mass spectrometry in proteomics research. MASS SPECTROMETRY REVIEWS 2019; 38:445-460. [PMID: 31407381 PMCID: PMC6800771 DOI: 10.1002/mas.21599] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Progress in proteomics research has led to a demand for powerful analytical tools with high separation efficiency and sensitivity for confident identification and quantification of proteins, posttranslational modifications, and protein complexes expressed in cells and tissues. This demand has significantly increased interest in capillary electrophoresis-mass spectrometry (CE-MS) in the past few years. This review provides highlights of recent advances in CE-MS for proteomics research, including a short introduction to top-down mass spectrometry and native mass spectrometry (native MS), as well as a detailed overview of CE methods. Both the potential and limitations of these methods for the analysis of proteins and peptides in synthetic and biological samples and the challenges of CE methods are discussed, along with perspectives about the future direction of CE-MS. @ 2019 Wiley Periodicals, Inc. Mass Spec Rev 00:1-16, 2019.
Collapse
Affiliation(s)
| | - John R. Yates
- Correspondent author: , Phone number: (858) 784-8862, Departments of Molecular Medicine and Neurobiology, 10550 North Torrey Pines Road, SR302B, The Scripps Research Institute, La Jolla, CA 92037
| |
Collapse
|