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Lu G, Ying G, He Y, Li Y, Zhang Z. Integrated MICROFASP Method with CZE-Based Fractionation Technique and NanoRPLC-ESI-MS/MS for a Comprehensive Proteomics Analysis of a Submicrogram Sample. J Proteome Res 2024; 23:3696-3703. [PMID: 39013029 DOI: 10.1021/acs.jproteome.4c00396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
We report a loss-less two-dimensional (2D) separation platform that integrated capillary zone electrophoresis (CZE) fractionation and nanoRPLC-ESI-MS/MS for a comprehensive proteomics analysis of a submicrogram sample. Protein digest was injected into the linear polyacrylamide-coated capillary, followed by CZE separation. The schemes for collecting the fractions were carefully optimized to maximize the protein coverage. The peptide fractions were directly eluted into the autosampler insert vials, followed by the nanoRPLC-ESI-MS/MS analysis without lyophilization and redissolution, thus dramatically minimizing sample loss and potential contamination. The integrated platform generated 30,845 unique peptides and 5231 protein groups from 500 ng of a HeLa protein digest within 11.5 h (90 min CZE fractionation plus 10 h LC-MS analysis). Finally, the developed platform was used to analyze the protein digest prepared by the MICROFASP method with 1 μg of cell lysate as the starting material. Three thousand seven hundred ninety-six (N = 2, RSD = 4.95%) protein groups and 20,577 (N = 2, RSD = 7.89%) peptides were identified from only 200 ng of the resulted tryptic digest within 5.5 h. The results indicated that the combination of the MICROFASP method and the developed CZE/nanoRPLC-MS/MS 2D separation platform enabled comprehensive proteome profiling of a submicrogram biological sample. Data are available via ProteomeXchange with the identifier PXD052735.
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Affiliation(s)
- Gang Lu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Guojin Ying
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Yu He
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Yang Li
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Zhenbin Zhang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
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Colón Rosado J, Sun L. Solid-Phase Microextraction-Aided Capillary Zone Electrophoresis-Mass Spectrometry: Toward Bottom-Up Proteomics of Single Human Cells. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1120-1127. [PMID: 38514245 PMCID: PMC11157658 DOI: 10.1021/jasms.3c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/02/2024] [Accepted: 03/13/2024] [Indexed: 03/23/2024]
Abstract
Capillary zone electrophoresis-mass spectrometry (CZE-MS) has been recognized as a valuable technique for the proteomics of mass-limited biological samples (i.e., single cells). However, its broad adoption for single cell proteomics (SCP) of human cells has been impeded by the low sample loading capacity of CZE, only allowing us to use less than 5% of the available peptide material for each measurement. Here we present a reversed-phase-based solid-phase microextraction (RP-SPME)-CZE-MS platform to solve the issue, paving the way for SCP of human cells using CZE-MS. The RP-SPME-CZE system was constructed in one fused silica capillary with zero dead volume for connection via in situ synthesis of a frit, followed by packing C8 beads into the capillary to form a roughly 2 mm long SPME section. Peptides captured by SPME were eluted with a buffer containing 30% (v/v) acetonitrile and 50 mM ammonium acetate (pH 6.5), followed by dynamic pH junction-based CZE-MS. The SPME-CZE-MS enabled the injection of nearly 40% of the available peptide sample for each measurement. The system identified 257 ± 24 proteins and 523 ± 69 peptides (N = 2) using a Q-Exactive HF mass spectrometer when only 0.25 ng of a commercial HeLa cell digest was available in the sample vial and 0.1 ng of the sample was injected. The amount of available peptide is equivalent to the protein mass of one HeLa cell. The data indicate that SPME-CZE-MS is ready for SCP of human cells.
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Affiliation(s)
- Jorge
A. Colón Rosado
- 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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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] [Grants] [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.
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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
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Opetová M, Tomašovský R, Mikuš P, Maráková K. Transient isotachophoresis-Capillary zone electrophoresis-Mass spectrometry method with off-line microscale solid phase extraction pretreatment for quantitation of intact low molecular mass proteins in various biological fluids. J Chromatogr A 2024; 1718:464697. [PMID: 38341901 DOI: 10.1016/j.chroma.2024.464697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/13/2024]
Abstract
Quantification of proteins is still predominantly done by the traditional bottom-up approach. Targeting of intact proteins in complex biological matrices is connected with multiple challenges during the sample pretreatment, separation, and detection step of the analytical workflow. In this work, we focused on the development of an on-line hyphenated capillary zone electrophoresis-mass spectrometry method employing off-line microscale solid-phase extraction based on hydrophilic lipophilic balance (HLB) sorbent as a sample pretreatment step for the analysis of low molecular mass intact proteins (<20 kDa) spiked in various biological fluids (human serum, plasma, urine, and saliva). A detailed optimization process involved the selection of a suitable capillary surface, background electrolyte (BGE), and comparison of two in-capillary preconcentration methods, namely transient isotachophoresis (tITP) and dynamic pH junction (DPJ), to enhance the sensitivity of the method. Optimum separation of the analytes was achieved using uncoated bare fused silica capillary employing 500 mM formic acid (pH 1.96) + 5 % (v/v) acetonitrile as BGE. tITP was utilized as an optimum preconcentration technique, achieving a 19- to 127-fold increase in the signal intensity when using 200 mM ammonium formate (adjusted to pH 4.00) as the leading electrolyte and BGE as the terminating electrolyte. Off-line microscale solid-phase extraction with various eluate treatment procedures was evaluated to ensure the compatibility of the sample pretreatment method with the selected in-capillary preconcentration, separation, and detection process. Achieved extraction recoveries of spiked proteins were in the range of 76-100 % for urine, 12-54 % for serum, 21-106 % for plasma, and 25-98 % for saliva when the eluate was evaporated and reconstituted in the solution of the leading electrolyte to achieve the tITP process. The optimum method was validated across different biological matrices, offering good linearity, accuracy, and precision, and making it suitable for proteomic studies (e.g., therapeutic drug monitoring, biomarker research) in different biological samples.
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Affiliation(s)
- Martina Opetová
- Faculty of Pharmacy, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia; Faculty of Pharmacy, Toxicological and Antidoping Center, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia
| | - Radovan Tomašovský
- Faculty of Pharmacy, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia; Faculty of Pharmacy, Toxicological and Antidoping Center, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia
| | - Peter Mikuš
- Faculty of Pharmacy, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia; Faculty of Pharmacy, Toxicological and Antidoping Center, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia
| | - Katarína Maráková
- Faculty of Pharmacy, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia; Faculty of Pharmacy, Toxicological and Antidoping Center, Department of Pharmaceutical Analysis and Nuclear Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32, Bratislava, Slovakia.
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Nagy C, Andrasi M, Szabo R, Gaspar A. CZE-MS peptide mapping: To desalt or not to desalt? Anal Chim Acta 2024; 1288:342162. [PMID: 38220294 DOI: 10.1016/j.aca.2023.342162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/10/2023] [Accepted: 12/16/2023] [Indexed: 01/16/2024]
Abstract
BACKGROUND In "shotgun" approaches involving high-performance liquid chromatography or capillary zone electrophoresis (CZE), matrix removal prior to sample analysis is considered as an indispensable tool. Despite the fact that CZE offers a high tolerance towards salts, most publications reported on the use of desalting. There seems to be no clear consensus on the utilization of desalting in the CZE-MS community, most probably due to the absence of works addressing the comparison of desalted and non-desalted digests. Our aim was to fill this research gap using protein samples of varying complexity in different sample matrices. RESULTS First, standard protein digests were analyzed to build the knowledge on the effect of sample clean-up by solid-phase extraction (SPE) pipette tips and the possible stacking phenomena induced by different sample matrices. Desalting led to a somewhat altered peptide profile, the procedure affected mostly the hydrophilic peptides (although not to a devastating extent). Nevertheless, desalting samples allowed remarkable stacking efficiency owing to their low-conductivity sample background, enabling a so-called field-amplified sample stacking phenomenon. Non-desalted samples also produced a stacking event, the mechanism of which is based on transient-isotachophoresis due to the presence of high-mobility ions in the digestion buffer itself. Adding either extra ammonium ions or acetonitrile into the non-desalted digests enhanced the stacking efficiency. A complex sample (yeast cell lysate) was also analyzed with the optimal conditions, which yielded similar tendencies. SIGNIFICANCE Based on these results, we propose that sample clean-up in the bottom-up sample preparation process prior to CZE-MS analysis can be omitted. The preclusion of desalting can even enhance detection sensitivity, separation efficiency or sequence coverage.
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Affiliation(s)
- Cynthia Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary
| | - Melinda Andrasi
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary
| | - Ruben Szabo
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary
| | - Attila Gaspar
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary.
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Guo Y, Cupp‐Sutton KA, Zhao Z, Anjum S, Wu S. Multidimensional Separations in Top-Down Proteomics. ANALYTICAL SCIENCE ADVANCES 2023; 4:181-203. [PMID: 38188188 PMCID: PMC10769458 DOI: 10.1002/ansa.202300016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/21/2023] [Accepted: 05/01/2023] [Indexed: 01/09/2024]
Abstract
Top-down proteomics (TDP) identifies, quantifies, and characterizes proteins at the intact proteoform level in complex biological samples to understand proteoform function and cellular mechanisms. However, analyzing complex biological samples using TDP is still challenging due to high sample complexity and wide dynamic range. High-resolution separation methods are often applied prior to mass spectrometry (MS) analysis to decrease sample complexity and increase proteomics throughput. These separation methods, however, may not be efficient enough to characterize low abundance intact proteins in complex samples. As such, multidimensional separation techniques (combination of two or more separation methods with high orthogonality) have been developed and applied that demonstrate improved separation resolution and more comprehensive identification in TDP. A suite of multidimensional separation methods that couple various types of liquid chromatography (LC), capillary electrophoresis (CE), and/or gel electrophoresis-based separation approaches have been developed and applied in TDP to analyze complex biological samples. Here, we reviewed multidimensional separation strategies employed for TDP, summarized current applications, and discussed the gaps that may be addressed in the future.
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Affiliation(s)
- Yanting Guo
- Department of Chemistry and BiochemistryUniversity of OklahomaOklahomaNormanUSA
| | | | - Zhitao Zhao
- Department of Chemistry and BiochemistryUniversity of OklahomaOklahomaNormanUSA
| | - Samin Anjum
- Department of Chemistry and BiochemistryUniversity of OklahomaOklahomaNormanUSA
| | - Si Wu
- Department of Chemistry and BiochemistryUniversity of OklahomaOklahomaNormanUSA
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7
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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.
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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
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8
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Cupp-Sutton KA, Fang M, Wu S. Separation methods in single-cell proteomics: RPLC or CE? INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2022; 481:116920. [PMID: 36211475 PMCID: PMC9542495 DOI: 10.1016/j.ijms.2022.116920] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cellular heterogeneity is commonly investigated using single-cell genomics and transcriptomics to investigate biological questions such as disease mechanism, therapeutic screening, and genomic and transcriptomic diversity between cellular populations and subpopulations at the cellular level. Single-cell mass spectrometry (MS)-based proteomics enables the high-throughput examination of protein expression at the single-cell level with wide applicability, and with spatial and temporal resolution, applicable to the study of cellular development, disease, effect of treatment, etc. The study of single-cell proteomics has lagged behind genomics and transcriptomics largely because proteins from single-cell samples cannot be amplified as DNA and RNA can using well established techniques such as PCR. Therefore, analytical methods must be robust, reproducible, and sensitive enough to detect the very small amount of protein within a single cell. To this end, nearly every step of the proteomics process has been extensively altered and improved to facilitate the proteomics analysis of single cells including cell counting and sorting, lysis, protein digestion, sample cleanup, separation, MS data acquisition, and data analysis. Here, we have reviewed recent advances in single-cell protein separation using nano reversed phase liquid chromatography (nRPLC) and capillary electrophoresis (CE) to inform application driven selection of separation techniques in the laboratory setting.
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Affiliation(s)
| | - Mulin Fang
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019
| | - Si Wu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019
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9
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Using Solid-Phase Microextraction Coupled with Reactive Carbon Fiber Ionization-Mass Spectrometry for the Detection of Aflatoxin B1 from Complex Samples. SEPARATIONS 2022. [DOI: 10.3390/separations9080199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aflatoxin B1 (AFB1) is a common mycotoxin present in agricultural and food products. Therefore, rapid screening methods must be developed for AFB1 detection with high sensitivity and good selectivity. In this study, we developed an analytical method based on the combination of solid-phase microextraction (SPME) with carbon fiber ionization (CFI)-mass spectrometry (MS) to detect the presence of trace AFB1 from complex samples. A pencil lead (type 2B, length: ~2.5 cm) with a sharp end (diameter: ~150 μm) was used as the SPME fiber and the ionization emitter in CFI-MS analysis. Owing to the graphite structure of the pencil lead, AFB1 can be trapped on the pencil lead through π–π interactions. After adsorbing AFB1, the pencil lead was directly introduced in a pipette tip (length: ~0.7 cm; tip inner diameter: ~0.6 mm), placed close (~1 mm) to the inlet of the mass spectrometer, and applied with a high voltage (−4.5 kV) for in situ AFB1 elution and CFI-MS analysis. A direct electric contact on the SPME-CFI setup was not required. Followed by the introduction of an elution solvent (10 μL) (acetonitrile/ethanol/deionized water, 2:2:1 (v/v/v)) to the pipette tip, electrospray ionization was generated from the elution solvent containing AFB1 for CFI-MS analysis. A reactive SPME-CFI-MS strategy was employed to further identify AFB1 and improve elution capacity using our approach. Butylamine was added to the elution solvent, which was then introduced to the pipette tip inserted with the SPME fiber. Butylamine-derivatized AFB1 was readily generated and appeared in the resultant SPME-CFI mass spectrum. The lowest detectable concentration against AFB1 using our approach was ~1.25 nM. Our method can distinguish AFB1 from AFG1 in a mixture and can be used for the detection of trace AFB1 in complex peanut extract samples.
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Weaver SD, Schuster-Little N, Whelan RJ. Preparative capillary electrophoresis (CE) fractionation of protein digests improves protein and peptide identification in bottom-up proteomics. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:1103-1110. [PMID: 35175250 PMCID: PMC9210495 DOI: 10.1039/d1ay02145a] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Reversed-phase liquid chromatography (RPLC) is widely used to reduce sample complexity prior to mass spectrometry (MS) analysis in bottom-up proteomics. Improving peptide separation in complex samples enables lower-abundance proteins to be identified. Multidimensional separations that combine orthogonal separation modes improve protein and peptide identifications over RPLC alone. Here we report a preparative capillary electrophoresis (CE) fractionation method that combines CE and RPLC separations. Using this method, we demonstrate improved protein and peptide identification in a tryptic digest of E. coli cell lysate, with 132 ± 33% more protein identifications and 185 ± 65% more peptide identifications over non-fractionated samples. Fractionation enables detection of lower-abundance proteins in this complex sample. We demonstrate improved coverage of ovarian cancer biomarker MUC16 isolated from conditioned cell media, with 6.73% sequence coverage using CE fractionation compared to 2.74% coverage without preparative fractionation. This new method will allow researchers performing bottom-up proteomics to harness the advantages of CE separations while using widely available LC-MS/MS instrumentation.
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Affiliation(s)
- Simon D Weaver
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA.
| | - Naviya Schuster-Little
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA.
| | - Rebecca J Whelan
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA.
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11
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Choi SB, Muñoz-LLancao P, Manzini MC, Nemes P. Data-Dependent Acquisition Ladder for Capillary Electrophoresis Mass Spectrometry-Based Ultrasensitive (Neuro)Proteomics. Anal Chem 2021; 93:15964-15972. [PMID: 34812615 DOI: 10.1021/acs.analchem.1c03327] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Measurement of broad types of proteins from a small number of cells to single cells would help to better understand the nervous system but requires significant leaps in sensitivity in high-resolution mass spectrometry (HRMS). Microanalytical capillary electrophoresis electrospray ionization (CE-ESI) offers a path to ultrasensitive proteomics by integrating scalability with sensitivity. Here, we systematically evaluate performance limitations in this technology to develop a data acquisition strategy with deeper coverage of the neuroproteome from trace amounts of starting materials than traditional dynamic exclusion. During standard data-dependent acquisition (DDA), compact migration challenged the duty cycle of second-stage transitions and redundant targeting of abundant peptide signals lowered their identification success rate. DDA was programmed to progressively exclude a static set of high-intensity peptide signals throughout replicate measurements, essentially forming rungs of a "DDA ladder." The method was tested for ∼500 pg portions of a protein digest from cultured hippocampal (primary) neurons (mouse), which estimated the total amount of protein from a single neuron. The analysis of ∼5 ng of protein digest over all replicates, approximating ∼10 neurons, identified 428 nonredundant proteins (415 quantified), an ∼35% increase over traditional DDA. The identified proteins were enriched in neuronal marker genes and molecular pathways of neurobiological importance. The DDA ladder enhances CE-HRMS sensitivity to single-neuron equivalent amounts of proteins, thus expanding the analytical toolbox of neuroscience.
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Affiliation(s)
- Sam B Choi
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
| | - Pablo Muñoz-LLancao
- Department of Neuroscience & Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, United States
| | - M Chiara Manzini
- Department of Neuroscience & Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901, United States
| | - Peter Nemes
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
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12
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Technique development of high-throughput and high-sensitivity sample preparation and separation for proteomics. Bioanalysis 2021; 14:101-111. [PMID: 34854341 DOI: 10.4155/bio-2021-0202] [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: 11/17/2022] Open
Abstract
Sample preparation and separation methods determine the sensitivity and the quantification accuracy of the proteomics analysis. This article covers a comprehensive review of the recent technique development of high-throughput and high-sensitivity sample preparation and separation methods in proteomics research.
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13
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Guzman NA, Guzman DE. Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression. Biomolecules 2021; 11:1443. [PMID: 34680076 PMCID: PMC8533156 DOI: 10.3390/biom11101443] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 01/08/2023] Open
Abstract
Over the years, multiple biomarkers have been used to aid in disease screening, diagnosis, prognosis, and response to therapy. As of late, protein biomarkers are gaining strength in their role for early disease diagnosis and prognosis in part due to the advancements in identification and characterization of a distinct functional pool of proteins known as proteoforms. Proteoforms are defined as all of the different molecular forms of a protein derived from a single gene caused by genetic variations, alternative spliced RNA transcripts and post-translational modifications. Monitoring the structural changes of each proteoform of a particular protein is essential to elucidate the complex molecular mechanisms that guide the course of disease. Clinical proteomics therefore holds the potential to offer further insight into disease pathology, progression, and prevention. Nevertheless, more technologically advanced diagnostic methods are needed to improve the reliability and clinical applicability of proteomics in preventive medicine. In this manuscript, we review the use of immunoaffinity capillary electrophoresis (IACE) as an emerging powerful diagnostic tool to isolate, separate, detect and characterize proteoform biomarkers obtained from liquid biopsy. IACE is an affinity capture-separation technology capable of isolating, concentrating and analyzing a wide range of biomarkers present in biological fluids. Isolation and concentration of target analytes is accomplished through binding to one or more biorecognition affinity ligands immobilized to a solid support, while separation and analysis are achieved by high-resolution capillary electrophoresis (CE) coupled to one or more detectors. IACE has the potential to generate rapid results with significant accuracy, leading to reliability and reproducibility in diagnosing and monitoring disease. Additionally, IACE has the capability of monitoring the efficacy of therapeutic agents by quantifying companion and complementary protein biomarkers. With advancements in telemedicine and artificial intelligence, the implementation of proteoform biomarker detection and analysis may significantly improve our capacity to identify medical conditions early and intervene in ways that improve health outcomes for individuals and populations.
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Affiliation(s)
| | - Daniel E. Guzman
- Princeton Biochemicals, Inc., Princeton, NJ 08543, USA;
- Division of Hospital Medicine, Department of Medicine, University of California at San Francisco, San Francisco, CA 94143, USA
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Yang Z, Zhang Z, Chen D, Xu T, Wang Y, Sun L. Nanoparticle-Aided Nanoreactor for Nanoproteomics. Anal Chem 2021; 93:10568-10576. [PMID: 34297524 DOI: 10.1021/acs.analchem.1c01704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Large-scale bottom-up proteomics of few even single cells is crucial for a better understanding of the roles played by cell-to-cell heterogeneity in disease and development. Novel proteomic methodologies with extremely high sensitivity are required for few even single-cell proteomics. Sample processing with high recovery and no contaminants is one key step. Here we developed a nanoparticle-aided nanoreactor for nanoproteomics (Nano3) technique for processing low-nanograms of mammalian cell proteins for proteome profiling. The Nano3 technique employed nanoparticles packed in a capillary channel to form a nanoreactor (≤30 nL) for concentrating, cleaning, and digesting proteins originally in a lysis buffer containing sodium dodecyl sulfate (SDS), followed by nanoRPLC-MS/MS analysis. The Nano3 method identified a 40-times higher number of proteins based on MS/MS from 2-ng mouse brain protein samples compared to the SP3 (single-pot solid-phase-enhanced sample preparation) method, which performed the sample processing using the nanoparticles in a 10 μL solution in an Eppendorf tube. The data indicates a drastically higher sample recovery of the Nano3 compared to the SP3 method for processing mass-limited proteome samples. In this pilot study, the Nano3 method was further applied in processing 10-1000 HeLa cells for bottom-up proteomics, producing 441 ± 263 (n = 4) (MS/MS) and 983 ± 292 (n = 4) [match between runs (MBR)+MS/MS] protein identifications from only 10 HeLa cells using a Q-Exactive HF mass spectrometer. The preliminary results render the Nano3 method a useful approach for processing few mammalian cells for proteome profiling.
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Affiliation(s)
- Zhichang Yang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824 United States
| | - Zhaoran Zhang
- Department of Animal Sciences, Michigan State University, 766 Service Road, East Lansing, Michigan 48824 United States
| | - Daoyang Chen
- 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
| | - Yuan Wang
- Department of Animal Sciences, Michigan State University, 766 Service Road, 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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Zhang L, Xu T, Zhang J, Wong SCC, Ritchie M, Hou HW, Wang Y. Single Cell Metabolite Detection Using Inertial Microfluidics-Assisted Ion Mobility Mass Spectrometry. Anal Chem 2021; 93:10462-10468. [PMID: 34289696 DOI: 10.1021/acs.analchem.1c00106] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Single-cell metabolite measurement remains highly challenging due to difficulties related to single cell isolation, metabolite detection, and identification of low levels of metabolites. Here, as a first step of the technological development, we propose a novel strategy integrating spiral inertial microfluidics and ion mobility mass spectrometry (IM-MS) for single-cell metabolite detection and identification. Cells in methanol suspension are inertially focused into a single stream in the spiral microchannel. This stream of separated cells is delivered to the nanoelectrospray needle to be lysed and ionized and subsequently analyzed in real time by IM-MS. This analytical system enables six to eight single-cell metabolic fingerprints to be collected per minute, including gas-phase collisional cross section (CCS) measurements as an additional molecular descriptor, giving increased confidence in metabolite identification. As a proof of concept, the metabolic profiles of three types of cancer cells (U2OS, HepG2, and HepG2.215) were successfully screened, and 19 distinct lipids species were identified with CCS value filtering. Furthermore, principal component analysis (PCA) showed differentiation of the three cancer cell lines, mainly due to cellular surface phospholipids. Taken together, our technology platform offers a simple and efficient method for single-cell lipid profiling, with additional ion mobility separation of lipids significantly improving the confidence toward identification of metabolites.
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Affiliation(s)
- Leicheng Zhang
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore
| | - Tengfei Xu
- School of Civil and Environmental Engineering, Nanyang Technological University, 639798 Singapore
| | - Jingtao Zhang
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore
| | | | - Mark Ritchie
- Waters Pacific Pte Ltd, Science Park 2, 117528 Singapore
| | - Han Wei Hou
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore.,School of Mechanical & Aerospace Engineering, Nanyang Technological University, 639798 Singapore
| | - Yulan Wang
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore
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Yang Z, Sun L. Recent technical progress in sample preparation and liquid-phase separation-mass spectrometry for proteomic analysis of mass-limited samples. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:1214-1225. [PMID: 33629703 DOI: 10.1039/d1ay00171j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Mass spectrometry (MS)-based proteomics has enabled the identification and quantification of thousands of proteins from complex proteomes in a single experiment. However, its performance for mass-limited proteome samples (e.g., single cells and tissue samples from laser capture microdissection) is still not satisfying. The development of novel proteomic methodologies with better overall sensitivity is vital. During the last several years, substantial technical progress has been achieved for the preparation and liquid-phase separation-MS characterization of mass-limited proteome samples. In this review, we summarize recent technological progress of sample preparation, liquid chromatography (LC)-MS, capillary zone electrophoresis (CZE)-MS and MS instrumentation for bottom-up proteomics of trace biological samples, highlight some exciting applications of the novel techniques for single-cell proteomics, and provide a very brief perspective about the field at the end.
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Affiliation(s)
- Zhichang Yang
- 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.
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Kumar R, Shah RL, Ahmad S, Rathore AS. Harnessing the power of electrophoresis and chromatography: Offline coupling of reverse phase liquid chromatography-capillary zone electrophoresis-tandem mass spectrometry for analysis of host cell proteins in monoclonal antibody producing CHO cell line. Electrophoresis 2021; 42:735-741. [PMID: 33348443 DOI: 10.1002/elps.202000252] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/04/2020] [Accepted: 12/14/2020] [Indexed: 11/05/2022]
Abstract
Host cell proteins (HCPs) are widely regarded as a critical quality attribute for a biotherapeutic product. Bottom up MS is the present gold standard for HCP analysis but suffers from incomplete protein identification due to complex nature of the HCP mixture and limited separation efficiency of the preceding LC-based systems. In this paper, we present for the first time an application involving use of LC-CE-MS/MS platform for analysis of HCPs. It has been demonstrated that the proposed platform has been able to successfully identify 397 HCPs from the supernatants of recombinant Chinese hamster ovary cells, twice and thrice the number of proteins identified by the state-of-the-art LC-MS/MS (189 HCPs) and CE-MS/MS (128 HCPs) analyses, respectively. Of these, 225 HCPs were unique to the LC-CE-MS/MS approach and were not identified by either LC-MS/MS or CE-MS/MS. It is observed that the LC-CE-MS/MS platform combines the benefits of LC-MS/MS and CE-MS/MS techniques and identifies peptides in a wider range of size, pI, and hydrophobicity. Additionally, LC-CE-MS/MS also identified more HCPs associated with cellular components, molecular functions, biological processes, peptidases, and secretory proteins. The proposed approach would thus be a useful addition in HCP analysis and secretome studies of mAb-producing Chinese hamster ovary cells.
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Affiliation(s)
- Ramesh Kumar
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Rohan L Shah
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | | | - Anurag S Rathore
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
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Wang Z, Yu D, Cupp-Sutton KA, Liu X, Smith K, Wu S. Development of an Online 2D Ultrahigh-Pressure Nano-LC System for High-pH and Low-pH Reversed Phase Separation in Top-Down Proteomics. Anal Chem 2020; 92:12774-12777. [PMID: 32857493 PMCID: PMC7544661 DOI: 10.1021/acs.analchem.0c03395] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of novel high-resolution separation techniques is crucial for advancing the complex sample analysis necessary for high-throughput top-down proteomics. Recently, our group developed an offline 2D high-pH RPLC/low-pH RPLC separation method and demonstrated good orthogonality between these two RPLC formats. Specifically, ultrahigh-pressure long capillary column RPLC separation has been applied as the second dimensional low-pH RPLC separation for the improvement of separation resolution. To further improve the throughput and sensitivity of the offline approach, we developed an online 2D ultrahigh-pressure nano-LC system for high-pH and low-pH RPLC separations in top-down proteomics. An online microtrap column with a dilution setup was used to collect eluted proteins from the first dimension high-pH separation and inject the fractions for ultrahigh-pressure long capillary column low-pH RPLC separation in the second dimension. This automatic platform enables the characterization of 1000+ intact proteoforms from 5 μg of intact E. coli cell lysate in 10 online-collected fractions. Here, we have demonstrated that our online 2D pH RP/RPLC system coupled with top-down proteomics holds the potential for deep proteome characterization of mass-limited samples because it allows the identification of hundreds of intact proteoforms from complex biological samples at low microgram sample amounts.
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Affiliation(s)
- Zhe Wang
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Dahang Yu
- 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 Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Xiaowen Liu
- School of Informatics and Computing, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Kenneth Smith
- Arthritis & Clinical Immunology Research Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Si Wu
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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Zheng Y, Liu Z, Xing J, Zheng Z, Pi Z, Song F, Liu S. In situ analysis of single cell and biological samples with rGO-Cu functional probe ESI-MS spectrometry. Talanta 2020; 211:120751. [DOI: 10.1016/j.talanta.2020.120751] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/12/2020] [Accepted: 01/14/2020] [Indexed: 01/17/2023]
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20
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Melzer T, Wimmer B, Bock S, Posch TN, Huhn C. Challenges and applications of isotachophoresis coupled to mass spectrometry: A review. Electrophoresis 2020; 41:1045-1059. [DOI: 10.1002/elps.201900454] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/30/2022]
Affiliation(s)
- Tanja Melzer
- Institute of Physical and Theoretical ChemistryEberhard Karls Universität Tübingen Germany
| | - Benedikt Wimmer
- Institute of Physical and Theoretical ChemistryEberhard Karls Universität Tübingen Germany
| | - Stephanie Bock
- Institute of Physical and Theoretical ChemistryEberhard Karls Universität Tübingen Germany
| | | | - Carolin Huhn
- Institute of Physical and Theoretical ChemistryEberhard Karls Universität Tübingen Germany
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21
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Application of CE-MS for the analysis of histones and histone modifications. Methods 2020; 184:125-134. [PMID: 32014606 DOI: 10.1016/j.ymeth.2020.01.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/02/2019] [Accepted: 01/26/2020] [Indexed: 02/02/2023] Open
Abstract
The analysis, identification and quantification of histones and their post-translational modifications plays a central role in chromatin research and in studying epigenetic regulations during physiological processes. In the last decade analytical strategies based on mass spectrometry have been greatly improved for providing a global view of single modification abundances or to determine combinatorial patterns of modifications. Presented here is a newly developed strategy for histone protein analysis and a number of applications are illustrated with an emphasis on PTM characterization. Capillary electrophoresis is coupled to mass spectrometry (CE-MS) and has proven to be a very promising concept as it enables to study intact histones (top-down proteomics) as well as the analysis of enzymatically digested proteins (bottom-up proteomics). This technology combines highly efficient low-flow CE separations with ionization in a single device and offers an orthogonal separation principle to conventional LC-MS analysis, thus expanding the existing analytical repertoire in a perfect manner.
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22
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Practical sample pretreatment techniques coupled with capillary electrophoresis for real samples in complex matrices. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.115702] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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DeLaney K, Li L. Capillary electrophoresis coupled to MALDI mass spectrometry imaging with large volume sample stacking injection for improved coverage of C. borealis neuropeptidome. Analyst 2019; 145:61-69. [PMID: 31723949 PMCID: PMC6917920 DOI: 10.1039/c9an01883b] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuropeptides are important signaling molecules responsible for a wide range of functions within the nervous and neuroendocrine system. However, they are difficult to study due to numerous challenges, most notably their large degree of variability and low abundance in vivo. As a result, effective separation methods with sensitive detection capabilities are necessary for profiling neuropeptides in tissue samples, particularly those of simplified model organisms such as crustaceans. In order to address these challenges, this study utilized a capillary electrophoresis (CE)-matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry imaging (MSI) platform, building upon our previous design for improved neuropeptidomic coverage. The capillary was coated with polyethylenimine (PEI) to reduce peptide adsorption and reverse the electroosmotic flow, and large volume sample stacking (LVSS) was used to load and pre-concentrate 1 μL of sample. The method demonstrated good reproducibility, with lower than 5% relative standard deviation for standards, and a limit of detection of approximately 100 pM for an allatostatin III peptide standard. The method was tested on brain and sinus gland (SG) tissue extracts and enabled detection of over 200 neuropeptides per run. When comparing the number detected in brain extracts in a direct spot, 60-second fractions, and 30-second fractions, the continuous trace collection afforded by the CE-MALDI-MSI platform yielded the largest number of detected neuropeptides. The method was compared to conventional LC-ESI-MS, and though the number of neuropeptides detected by LC-ESI-MS was slightly larger, the two methods were highly complementary, indicating the potential for the CE-MALDI-MSI method to uncover previously undetected neuropeptides in the crustacean nervous system. These results indicate the potential of CE-MALDI-MSI for routine use in neuropeptide research.
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Affiliation(s)
- Kellen DeLaney
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705-2222
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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.
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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
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Yang Z, Shen X, Chen D, Sun L. Improved Nanoflow RPLC-CZE-MS/MS System with High Peak Capacity and Sensitivity for Nanogram Bottom-up Proteomics. J Proteome Res 2019; 18:4046-4054. [PMID: 31610113 DOI: 10.1021/acs.jproteome.9b00545] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Novel mass spectrometry (MS)-based proteomic tools with extremely high sensitivity and high peak capacity are required for comprehensive characterization of protein molecules in mass-limited samples. We reported a nanoRPLC-CZE-MS/MS system for deep bottom-up proteomics of low micrograms of human cell samples in previous work. In this work, we improved the sensitivity of the nanoRPLC-CZE-MS/MS system drastically via employing bovine serum albumin (BSA)-treated sample vials, improving the nanoRPLC fraction collection procedure, and using a short capillary for fast CZE separation. The improved nanoRPLC-CZE produced a peak capacity of 8500 for peptide separation. The improved system identified 6500 proteins from a MCF7 proteome digest starting with only 500 ng of peptides using a Q-Exactive HF mass spectrometer. The system produced a comparable number of protein identifications (IDs) to our previous system and the two-dimensional (2D) nanoRPLC-MS/MS system developed by Mann's group with 10-fold and 4-fold less sample consumption, respectively. We coupled the single-spot solid phase sample preparation (SP3) method to the improved nanoRPLC-CZE-MS/MS for bottom-up proteomics of 5000 HEK293T cells, resulting in 3689 protein IDs with the consumption of a peptide amount that corresponded to only roughly 1000 cells.
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Affiliation(s)
- Zhichang Yang
- Department of Chemistry , Michigan State University , 578 S Shaw Lane , East Lansing , Michigan 48824 , United States
| | - Xiaojing Shen
- 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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Zhang Z, Hebert AS, Westphall MS, Coon JJ, Dovichi NJ. Single-Shot Capillary Zone Electrophoresis-Tandem Mass Spectrometry Produces over 4400 Phosphopeptide Identifications from a 220 ng Sample. J Proteome Res 2019; 18:3166-3173. [PMID: 31180221 DOI: 10.1021/acs.jproteome.9b00244] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The dependence of capillary zone electrophoresis (CZE) separations on the charge state of the analyte is useful for the analysis of many post-translational modifications in proteins. In this work, we coupled CZE to an Orbitrap Fusion Lumos Tribrid platform with an advanced peak determination algorithm for phosphoproteomics analysis. A linear-polyacrylamide-coated capillary with very low electroosmotic flow was used for the separation. The optimal injection volume was between 100 and 150 nL of a solution of phosphopeptides in 30 mM ammonium bicarbonate (pH 8.2) buffer, which produces a dynamic pH junction sample injection. Larger injection volumes resulted in serious peak broadening and decreased numbers of phosphopeptide identifications. The optimized system identified 4405 phosphopeptides from 220 ng of enriched phosphopeptides from mouse brain, which represents the state-of-the-art result for single-shot CZE-ESI-MS/MS-based phosphoproteome analysis. We found that the migration time for phosphopeptides is much longer than that for non-phosphopeptides and increased along with the number of phosphorylation sites on the peptides, as expected for the additional negative charges associated with the phosphate groups. We also investigated the phosphorylation site motifs; a number of motifs appeared in the CZE-ESI-MS/MS data but not in LC-ESI-MS/MS data, which suggested the complementary performance of the techniques. The data are available via ProteomeXchange with identifier PXD012888.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Alexander S Hebert
- Genome Center of Wisconsin and Departments of Chemistry and Biomolecular Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Michael S Westphall
- Genome Center of Wisconsin and Departments of Chemistry and Biomolecular Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Joshua J Coon
- Genome Center of Wisconsin and Departments of Chemistry and Biomolecular Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
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A critical retrospective and prospective review of designs and materials in in-line solid-phase extraction capillary electrophoresis. Anal Chim Acta 2019; 1079:1-19. [PMID: 31387699 DOI: 10.1016/j.aca.2019.05.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/08/2019] [Accepted: 05/10/2019] [Indexed: 11/20/2022]
Abstract
Several strategies have been developed to decrease the concentration limits of detection (LODs) in capillary electrophoresis (CE). Nowadays, chromatographic-based preconcentration using a microcartridge integrated in the separation capillary for in-line solid-phase extraction capillary electrophoresis (SPE-CE) is one of the best alternatives for high throughput and reproducible sample clean-up and analyte preconcentration. This review covers different designs (geometrical configurations, with frits or fritless, capillary types, compatibility with commercial instrumentation, etc.) and materials (sorbents, supports, affinity ligands, etc.) applied for almost 30 years to prepare in-line SPE-CE microcartridges (i.e. analyte concentrators), with emphasis on the conventional unidirectional configuration in capillary format. Advantages, disadvantages and future perspectives are analyzed in detail to provide the reader a wide overview about the great potential of this technique to enhance sensitivity and address trace analysis.
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Gahoual R, Leize-Wagner E, Houzé P, François YN. Revealing the potential of capillary electrophoresis/mass spectrometry: the tipping point. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 1:11-19. [PMID: 30022554 DOI: 10.1002/rcm.8238] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/04/2018] [Accepted: 07/11/2018] [Indexed: 06/08/2023]
Abstract
The hyphenation of capillary electrophoresis and mass spectrometry (CE/MS) remains a minor technique compared with liquid chromatography/mass spectrometry (LC/MS), which represents nowadays the standard instrumentation, regardless of its introduction thirty years ago. However, from a theoretical point of view, CE coupling should be quite favorable especially with electrospray ionization mass spectrometry (ESI-MS). At the time, the sensitivity provided by CE/MS was often limited, due to hyphenation requirements, which at some point appeared to disqualify CE/MS from benefiting from the performance gain driving the evolution of MS instruments. However, this context has been significantly modified in a matter of a few years. The development of innovative CE/MS interfacing systems has enabled an important improvement regarding sensitivity and reinforced robustness in order to provide an instrumentation accessible to the largest scientific community. Because of the unique selectivity delivered by the electrophoretic separation, CE/MS has proved to be particularly relevant for the analysis of biological molecules. The conjunction of these aspects is motivating the interest in CE/MS analysis and shows that CE/MS is mature enough to enrich the toolbox of analytical techniques for the analysis of complex biological samples. Here we discuss the characteristics of the major types of high-sensitivity CE/ESI-MS instrumentation and emphasize the late evolution and future positioning of CE/MS analysis for the characterization of biological molecules like peptides and proteins, through some pertinent applications.
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Affiliation(s)
- Rabah Gahoual
- Unité de Technologies Biologiques et Chimiques pour la Santé (UTCBS), Paris 5-CNRS UMR8258 Inserm U1022, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Emmanuelle Leize-Wagner
- Laboratoire de spectrométrie de masse des interactions et des systèmes (LSMIS), Unistra-CNRS UMR7140, Université de Strasbourg, Strasbourg, France
| | - Pascal Houzé
- Unité de Technologies Biologiques et Chimiques pour la Santé (UTCBS), Paris 5-CNRS UMR8258 Inserm U1022, Faculté de Pharmacie, Université Paris Descartes, Paris, France
- Laboratoire de Biochimie, Hôpital Universitaire Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Yannis-Nicolas François
- Laboratoire de spectrométrie de masse des interactions et des systèmes (LSMIS), Unistra-CNRS UMR7140, Université de Strasbourg, Strasbourg, France
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30
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Štěpánová S, Kašička V. Recent developments and applications of capillary and microchip electrophoresis in proteomics and peptidomics (2015-mid 2018). J Sep Sci 2018; 42:398-414. [DOI: 10.1002/jssc.201801090] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Sille Štěpánová
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague 6 Czechia
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague 6 Czechia
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31
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32
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McCool EN, Lubeckyj R, Shen X, Kou Q, Liu X, Sun L. Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry. J Vis Exp 2018. [PMID: 30417888 DOI: 10.3791/58644] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.
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Affiliation(s)
| | | | | | - Qiang Kou
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis
| | - Xiaowen Liu
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine
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33
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Zhang Z, Hebert AS, Westphall MS, Qu Y, Coon JJ, Dovichi NJ. Production of Over 27 000 Peptide and Nearly 4400 Protein Identifications by Single-Shot Capillary-Zone Electrophoresis-Mass Spectrometry via Combination of a Very-Low-Electroosmosis Coated Capillary, a Third-Generation Electrokinetically-Pumped Sheath-Flow Nanospray Interface, an Orbitrap Fusion Lumos Tribrid Mass Spectrometer, and an Advanced-Peak-Determination Algorithm. Anal Chem 2018; 90:12090-12093. [PMID: 30179504 DOI: 10.1021/acs.analchem.8b02991] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We show that capillary-zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) generates very large numbers of peptide and protein identifications (IDs) by combining four technologies: a separation capillary coated to generate very low electroosmosis, an electrokinetically pumped sheath-flow nanoelectrospray interface to produce high-sensitivity ionization, an Orbitrap Fusion Lumos Tribrid platform to provide high-speed analysis, and an advanced-peak-determination (APD) algorithm to take advantage of the mass spectrometer's data-acquisition speed. The use of the APD algorithm resulted in 2 times more identifications than the standard peak algorithm. We also investigated the effect of the isolation window, injection time, and loading amount. Optimization of these parameters produced over 27 000 peptide identifications and nearly 4400 protein-group identifications from 220 ng of K562-cell digest in a single 120 min run, which is 2.7 times more IDs produced by CZE-ESI-MS/MS than by the previous state-of-the-art technique.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Alexander S Hebert
- Department of Biomolecular Chemistry, Genome Center of Wisconsin, and Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Michael S Westphall
- Department of Biomolecular Chemistry, Genome Center of Wisconsin, and Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Yanyan Qu
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Joshua J Coon
- Department of Biomolecular Chemistry, Genome Center of Wisconsin, and Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
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34
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Yang Z, Shen X, Chen D, Sun L. Microscale Reversed-Phase Liquid Chromatography/Capillary Zone Electrophoresis-Tandem Mass Spectrometry for Deep and Highly Sensitive Bottom-Up Proteomics: Identification of 7500 Proteins with Five Micrograms of an MCF7 Proteome Digest. Anal Chem 2018; 90:10479-10486. [PMID: 30102516 PMCID: PMC6156779 DOI: 10.1021/acs.analchem.8b02466] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) has been well recognized for bottom-up proteomics. It has approached 4000-8000 protein identifications (IDs) from a human cell line, mouse brains, or Xenopus embryos via coupling with liquid chromatography (LC) prefractionation. However, at least 500 μg of complex proteome digests were required for the LC/CZE-MS/MS studies. This requirement of a large amount of initial peptide material impedes the application of CZE-MS/MS for deep bottom-up proteomics of mass-limited samples. In this work, we coupled microscale reversed-phase LC (μRPLC)-based peptide prefractionation to dynamic pH-junction-based CZE-MS/MS for deep bottom-up proteomics of the MCF7 breast cancer cell proteome starting with only 5 μg of peptides. The dynamic pH-junction-based CZE enabled a 500 nL sample injection from as low as a 1.5 μL peptide sample, using up to 33% of the available peptide material for an analysis. Two kinds of μRPLC prefractionation were investigated, C18 ZipTip and nanoflow RPLC. C18 ZipTip/CZE-MS/MS identified 4453 proteins from 5 μg of the MCF7 proteome digest and showed good qualitative and quantitative reproducibility. Nanoflow RPLC/CZE-MS/MS produced over 7500 protein IDs and nearly 60 000 peptide IDs from the 5 μg of MCF7 proteome digest. The nanoflow RPLC/CZE-MS/MS platform reduced the required amount of complex proteome digests for LC/CZE-MS/MS-based deep bottom-up proteomics by 2 orders of magnitude. Our work provides the proteomics community with a powerful tool for deep and highly sensitive proteomics.
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Affiliation(s)
- Zhichang Yang
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824 USA
| | - Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824 USA
| | - Daoyang Chen
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824 USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824 USA
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35
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Choi SB, Lombard-Banek C, Muñoz-LLancao P, Manzini MC, Nemes P. Enhanced Peptide Detection Toward Single-Neuron Proteomics by Reversed-Phase Fractionation Capillary Electrophoresis Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:913-922. [PMID: 29147852 DOI: 10.1007/s13361-017-1838-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/12/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
The ability to detect peptides and proteins in single cells is vital for understanding cell heterogeneity in the nervous system. Capillary electrophoresis (CE) nanoelectrospray ionization (nanoESI) provides high-resolution mass spectrometry (HRMS) with trace-level sensitivity, but compressed separation during CE challenges protein identification by tandem HRMS with limited MS/MS duty cycle. Here, we supplemented ultrasensitive CE-nanoESI-HRMS with reversed-phase (RP) fractionation to enhance identifications from protein digest amounts that approximate to a few mammalian neurons. An ~1 to 20 μg neuronal protein digest was fractionated on a RP column (ZipTip), and 1 ng to 500 pg of peptides were analyzed by a custom-built CE-HRMS system. Compared with the control (no fractionation), RP fractionation improved CE separation (theoretical plates ~274,000 versus 412,000 maximum, resp.), which enhanced detection sensitivity (2.5-fold higher signal-to-noise ratio), minimized co-isolation spectral interferences during MS/MS, and increased the temporal rate of peptide identification by up to ~57%. From 1 ng of protein digest (<5 neurons), CE with RP fractionation identified 737 protein groups (1,753 peptides), or ~480 protein groups (~1,650 peptides) on average per analysis. The approach was scalable to 500 pg of protein digest (~a single neuron), identifying 225 protein groups (623 peptides) in technical triplicates, or 141 protein groups on average per analysis. Among identified proteins, 101 proteins were products of genes that are known to be transcriptionally active in single neurons during early development of the brain, including those involved in synaptic transmission and plasticity and cytoskeletal organization. Graphical abstract ᅟ.
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Affiliation(s)
- Sam B Choi
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Camille Lombard-Banek
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Pablo Muñoz-LLancao
- Institute for Neuroscience, Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20052, USA
| | - M Chiara Manzini
- Institute for Neuroscience, Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20052, USA
| | - Peter Nemes
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA.
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA.
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36
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Chen H, Shi P, Fan F, Tu M, Xu Z, Xu X, Du M. Complementation of UPLC-Q-TOF-MS and CESI-Q-TOF-MS on identification and determination of peptides from bovine lactoferrin. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1084:150-157. [DOI: 10.1016/j.jchromb.2018.03.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/05/2018] [Accepted: 03/10/2018] [Indexed: 12/27/2022]
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37
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Faserl K, Sarg B, Gruber P, Lindner HH. Investigating capillary electrophoresis-mass spectrometry for the analysis of common post-translational modifications. Electrophoresis 2018; 39:1208-1215. [PMID: 29389038 PMCID: PMC6001557 DOI: 10.1002/elps.201700437] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/24/2018] [Accepted: 01/24/2018] [Indexed: 12/26/2022]
Abstract
Capillary electrophoresis coupled to mass spectrometry is a very efficient analytical method for the analysis of post-translational modifications because of its high separation efficiency and high detection sensitivity. Here we applied CE-MS using three differently coated separation capillaries for in-depth analysis of a set of 70 synthetic post-translationally modified peptides (including phosphorylation, acetylation, methylation, and nitration). We evaluated the results in terms of peptide detection and separation characteristics and found that the use of a neutrally coated capillary resulted in highest overall signal intensity of singly modified peptides. In contrast, the use of a bare-fused silica capillary was superior in the identification of multi-phosphorylated peptides (12 out of 15 were identified). Fast separations of approximately 12 min could be achieved using a positively coated capillary, however, at the cost of separation efficiency. A comparison to nanoLC-MS revealed that multi-phosphorylated peptides interact with the RP material very poorly so that these peptides were either washed out or elute as very broad peaks from the nano column which results in a reduced peptide identification rate (7 out of 15). Moreover, the methods applied were found to be very well suited for the analysis of the acetylated, nitrated and methylated peptides. All 36 synthetic peptides, which exhibit one of those modifications, could be identified regardless of the method applied. As a final step in this study and as a proof of principle, the phosphoproteome enriched from PC-12 pheochromocytoma cells was analyzed by CE-MS resulting in 5686 identified and 4088 quantified phosphopeptides. We compared the characterized analytes to those identified by a nanoLC-MS proteomics study and found that less than one third of the phosphopeptides were identical, which demonstrates the benefit by combining different approaches quite impressively.
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Affiliation(s)
- Klaus Faserl
- Division of Clinical BiochemistryBiocenterInnsbruck Medical UniversityInnsbruckTirolAustria
| | - Bettina Sarg
- Division of Clinical BiochemistryBiocenterInnsbruck Medical UniversityInnsbruckTirolAustria
| | - Peter Gruber
- Division of Medical BiochemistryBiocenterInnsbruck Medical UniversityInnsbruckTirolAustria
| | - Herbert H. Lindner
- Division of Clinical BiochemistryBiocenterInnsbruck Medical UniversityInnsbruckTirolAustria
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38
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Chen D, Shen X, Sun L. Strong cation exchange-reversed phase liquid chromatography-capillary zone electrophoresis-tandem mass spectrometry platform with high peak capacity for deep bottom-up proteomics. Anal Chim Acta 2018; 1012:1-9. [PMID: 29475469 DOI: 10.1016/j.aca.2018.01.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/19/2018] [Accepted: 01/22/2018] [Indexed: 11/29/2022]
Abstract
Two-dimensional (2D) liquid chromatography (LC)-tandem mass spectrometry (MS/MS) are typically employed for deep bottom-up proteomics, and the state-of-the-art 2D-LC-MS/MS has approached over 8000 protein identifications (IDs) from mammalian cell lines or tissues in 1-3 days of mass spectrometer time. Capillary zone electrophoresis (CZE)-MS/MS has been suggested as an alternative to LC-MS/MS for bottom-up proteomics. CZE-MS/MS and LC-MS/MS are complementary in protein/peptide ID from complex proteome digests because CZE and LC are orthogonal for peptide separation. In addition, the migration time of peptides from CZE-MS can be predicted accurately, which is invaluable for evaluating the confidence of peptide ID from the database search and even guiding the database search. However, the number of protein IDs from complex proteomes using CZE-MS/MS is still much lower than the state of the art using 2D-LC-MS/MS. In this work, for the first time, we established a strong cation exchange (SCX)-reversed phase LC (RPLC)-CZE-MS/MS platform for deep bottom-up proteomics. The platform identified around 8200 protein groups and 65,000 unique peptides from a mouse brain proteome digest in 70 h. The data represents the largest bottom-up proteomics dataset using CZE-MS/MS and provides a valuable resource for further improving the tool for prediction of peptide migration time in CZE. The peak capacity of the orthogonal SCX-RPLC-CZE platform was estimated to be around 7000. SCX-RPLC-CZE-MS/MS produced comparable numbers of protein and peptide IDs with 2D-LC-MS/MS (8200 vs. 8900 protein groups, 65,000 vs. 70,000 unique peptides) from the mouse brain proteome digest using comparable instrument time. This is the first time that CZE-MS/MS showed its capability to approach comparable performance to the state-of-the-art 2D-LC-MS/MS for deep proteomic sequencing. SCX-RPLC-CZE-MS/MS and 2D-LC-MS/MS showed good complementarity in protein and peptide IDs and combining those two methods improved the number of protein group and unique peptide IDs by nearly 10% and over 40%, respectively, compared with 2D-LC-MS/MS alone.
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Affiliation(s)
- Daoyang Chen
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824, USA
| | - Xiaojing Shen
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, MI 48824, USA.
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39
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Huang Q, Mao S, Khan M, Zhou L, Lin JM. Dean flow assisted cell ordering system for lipid profiling in single-cells using mass spectrometry. Chem Commun (Camb) 2018; 54:2595-2598. [DOI: 10.1039/c7cc09608a] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A Dean flow assisted ordering system connected to an ESI-MS to identify single-cells in a subpopulation by lipid profiling.
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Affiliation(s)
- Qiushi Huang
- Department of Chemistry, Beijing Key Laboratory of Micronalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University
- Beijing 100084
- China
| | - Sifeng Mao
- Department of Chemistry, Beijing Key Laboratory of Micronalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University
- Beijing 100084
- China
| | - Mashooq Khan
- Department of Chemistry, Beijing Key Laboratory of Micronalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University
- Beijing 100084
- China
| | - Lin Zhou
- Department of Chemistry, Beijing Key Laboratory of Micronalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University
- Beijing 100084
- China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Micronalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University
- Beijing 100084
- China
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40
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Quirino JP, Grochocki W, Markuszewski MJ. Sample Concentration of Charged Small Molecules and Peptides in Capillary Electrophoresis by Micelle to Cyclodextrin Stacking. Anal Chem 2017; 89:13422-13428. [DOI: 10.1021/acs.analchem.7b03700] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Joselito P. Quirino
- Australian
Centre for Research on Separation Science (ACROSS), School of Physical
Sciences-Chemistry, University of Tasmania, Hobart 7001, Australia
| | - Wojciech Grochocki
- Australian
Centre for Research on Separation Science (ACROSS), School of Physical
Sciences-Chemistry, University of Tasmania, Hobart 7001, Australia
- Department
of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gdansk, Poland
| | - Michał J. Markuszewski
- Department
of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gdansk, Poland
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41
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Zhang Z, Dovichi NJ. Optimization of mass spectrometric parameters improve the identification performance of capillary zone electrophoresis for single-shot bottom-up proteomics analysis. Anal Chim Acta 2017; 1001:93-99. [PMID: 29291811 DOI: 10.1016/j.aca.2017.11.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 11/02/2017] [Accepted: 11/07/2017] [Indexed: 12/23/2022]
Abstract
The effects of MS1 injection time, MS2 injection time, dynamic exclusion time, intensity threshold, and isolation width were investigated on the numbers of peptide and protein identifications for single-shot bottom-up proteomics analysis using CZE-MS/MS analysis of a Xenopus laevis tryptic digest. An electrokinetically pumped nanospray interface was used to couple a linear-polyacrylamide coated capillary to a Q Exactive HF mass spectrometer. A sensitive method that used a 1.4 Th isolation width, 60,000 MS2 resolution, 110 ms MS2 injection time, and a top 7 fragmentation produced the largest number of identifications when the CZE loading amount was less than 100 ng. A programmable autogain control method (pAGC) that used a 1.4 Th isolation width, 15,000 MS2 resolution, 110 ms MS2 injection time, and top 10 fragmentation produced the largest number of identifications for CZE loading amounts greater than 100 ng; 7218 unique peptides and 1653 protein groups were identified from 200 ng by using the pAGC method. The effect of mass spectrometer conditions on the performance of UPLC-MS/MS was also investigated. A fast method that used a 1.4 Th isolation width, 30,000 MS2 resolution, 45 ms MS2 injection time, and top 12 fragmentation produced the largest number of identifications for 200 ng UPLC loading amount (6025 unique peptides and 1501 protein groups). This is the first report where the identification number for CZE surpasses that of the UPLC at the 200 ng loading level. However, more peptides (11476) and protein groups (2378) were identified by using UPLC-MS/MS when the sample loading amount was increased to 2 μg with the fast method. To exploit the fast scan speed of the Q-Exactive HF mass spectrometer, higher sample loading amounts are required for single-shot bottom-up proteomics analysis using CZE-MS/MS.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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42
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Yi L, Piehowski PD, Shi T, Smith RD, Qian WJ. Advances in microscale separations towards nanoproteomics applications. J Chromatogr A 2017; 1523:40-48. [PMID: 28765000 PMCID: PMC6042839 DOI: 10.1016/j.chroma.2017.07.055] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 01/22/2023]
Abstract
Microscale separation (e.g., liquid chromatography or capillary electrophoresis) coupled with mass spectrometry (MS) has become the primary tool for advanced proteomics, an indispensable technology for gaining understanding of complex biological processes. In recent decades significant advances have been achieved in MS-based proteomics. However, the current proteomics platforms still face an analytical challenge in overall sensitivity towards nanoproteomics applications for starting materials of less than 1μg total proteins (e.g., cellular heterogeneity in tissue pathologies). Herein, we review recent advances in microscale separation techniques and integrated sample processing strategies that improve the overall sensitivity and proteome coverage of the proteomics workflow, and their contributions towards nanoproteomics applications.
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Affiliation(s)
- Lian Yi
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, United States
| | - Paul D Piehowski
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, United States
| | - Tujin Shi
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, United States
| | - Richard D Smith
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, United States
| | - Wei-Jun Qian
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, United States.
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43
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Lubeckyj RA, McCool EN, Shen X, Kou Q, Liu X, Sun L. Single-Shot Top-Down Proteomics with Capillary Zone Electrophoresis-Electrospray Ionization-Tandem Mass Spectrometry for Identification of Nearly 600 Escherichia coli Proteoforms. Anal Chem 2017; 89:12059-12067. [PMID: 29064224 DOI: 10.1021/acs.analchem.7b02532] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as an invaluable platform for top-down proteomics. However, the scale of top-down proteomics using CZE-MS/MS is still limited due to the low loading capacity and narrow separation window of CZE. In this work, for the first time we systematically evaluated the dynamic pH junction method for focusing of intact proteins during CZE-MS. The optimized dynamic pH junction-based CZE-MS/MS approached a 1 μL loading capacity, 90 min separation window, and high peak capacity (∼280) for characterization of an Escherichia coli proteome. The results represent the largest loading capacity and the highest peak capacity of CZE for top-down characterization of complex proteomes. Single-shot CZE-MS/MS identified about 2800 proteoform-spectrum matches, nearly 600 proteoforms, and 200 proteins from the Escherichia coli proteome with spectrum-level false discovery rate (FDR) less than 1%. The number of identified proteoforms in this work is over three times higher than that in previous single-shot CZE-MS/MS studies. Truncations, N-terminal methionine excision, signal peptide removal, and some post-translational modifications including oxidation and acetylation were detected.
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Affiliation(s)
- Rachele A Lubeckyj
- 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
| | - Xiaojing Shen
- Department of Chemistry, Michigan State University , 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Qiang Kou
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis , 719 Indiana Avenue, Indianapolis, Indiana 46202, United States
| | - Xiaowen Liu
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis , 719 Indiana Avenue, Indianapolis, Indiana 46202, United States.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine , 410 W. 10th Street, Indianapolis, Indiana 46202, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University , 578 S Shaw Lane, East Lansing, Michigan 48824, United States
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44
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Moreno-González D, Haselberg R, Gámiz-Gracia L, García-Campaña AM, de Jong GJ, Somsen GW. Fully compatible and ultra-sensitive micellar electrokinetic chromatography-tandem mass spectrometry using sheathless porous-tip interfacing. J Chromatogr A 2017; 1524:283-289. [PMID: 28992989 DOI: 10.1016/j.chroma.2017.09.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/26/2017] [Accepted: 09/30/2017] [Indexed: 11/26/2022]
Abstract
The on-line coupling of micellar electrokinetic chromatography and mass spectrometry (MEKC-MS) is often hampered by incompatibility problems leading to reduced separation performance and unfavorable limits of detection (LODs). Here we propose a new selective and highly sensitive MEKC-MS/MS method employing a sheathless porous-tip interface in combination with a micellar phase comprised of semi-volatile surfactant molecules. Carbamate pesticides (CRBs) were selected as representative model compounds being neutral toxic pollutants potentially present at trace levels in environmental water samples. A background electrolyte of 75mM perfluorooctanoic acid adjusted to pH 9.0 with ammonium hydroxide allowed efficient separation of 15 CRBs and appeared fully compatible with electrospray ionization (ESI)-MS. Interfacing parameters, such as the distance between the capillary tip and mass-spectrometer inlet, ESI voltage, and dry gas temperature and flow were optimized in order to attain good spray stability and high analyte signal-to-noise ratios. For CRBs the LODs ranged from 0.2 to 3.9ngL-1 (13nL injected, i.e., 2% of capillary volume), representing an improvement for certain CRBs of more than 300-fold when compared with conventional sheath-liquid interfacing. Good linearity (R2>0.99) and satisfactory reproducibility were obtained for all CRBs with interday RSD values for peak area and migration time of 4.0-11.3% and below 1.5%, respectively. Analysis of spiked mineral water showed that the new MEKC-MS/MS method allows selective and quantitative determination of CRB concentrations below the maximum residue limit of 100ngL-1 without the need for sample preconcentration.
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Affiliation(s)
- David Moreno-González
- Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva, E-18071 Granada, Spain
| | - Rob Haselberg
- Division of BioAnalytical Chemistry, AIMMS research group BioMolecular Analysis, Faculty of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
| | - Laura Gámiz-Gracia
- Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva, E-18071 Granada, Spain
| | - Ana M García-Campaña
- Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva, E-18071 Granada, Spain
| | - Gerhardus J de Jong
- Biomolecular Analysis, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Govert W Somsen
- Division of BioAnalytical Chemistry, AIMMS research group BioMolecular Analysis, Faculty of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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45
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Yan X, Sun L, Zhu G, Cox OF, Dovichi NJ. Over 4100 protein identifications from a Xenopus laevis fertilized egg digest using reversed-phase chromatographic prefractionation followed by capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry analysis. Proteomics 2017; 16:2945-2952. [PMID: 27723263 DOI: 10.1002/pmic.201600262] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 09/14/2016] [Accepted: 10/07/2016] [Indexed: 12/25/2022]
Abstract
A tryptic digest generated from Xenopus laevis fertilized embryos was fractionated by RPLC. One set of 30 fractions was analyzed by 100-min CZE-ESI-MS/MS separations (50 h total instrument time), and a second set of 15 fractions was analyzed by 3-h UPLC-ESI-MS/MS separations (45 h total instrument time). CZE-MS/MS produced 70% as many protein IDs (4134 versus 5787) and 60% as many peptide IDs (22 535 versus 36 848) as UPLC-MS/MS with similar instrument time (50 h versus 45 h) but with 50 times smaller total consumed sample amount (1.5 μg versus 75 μg). Surprisingly, CZE generated peaks that were 25% more intense than UPLC for peptides that were identified by both techniques, despite the 50-fold lower loading amount; this high sensitivity reflects the efficient ionization produced by the electrokinetically pumped nanospray interface used in CZE. This report is the first comparison of CZE-MS/MS and UPLC-MS/MS for large-scale eukaryotic proteomic analysis. The numbers of protein and peptide identifications produced by CZE-ESI-MS/MS approach those produced by UPLC-MS/MS, but with nearly two orders of magnitude lower sample amounts.
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Affiliation(s)
- Xiaojing Yan
- Department of Chemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Liangliang Sun
- Department of Chemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Guijie Zhu
- Department of Chemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Olivia F Cox
- Department of Chemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Norman J Dovichi
- Department of Chemistry, University of Notre Dame, Notre Dame, IN, USA
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46
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Boley DA, Zhang Z, Dovichi NJ. Multisegment injections improve peptide identification rates in capillary zone electrophoresis-based bottom-up proteomics. J Chromatogr A 2017; 1523:123-126. [PMID: 28732593 DOI: 10.1016/j.chroma.2017.07.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 02/03/2023]
Abstract
While capillary zone electrophoresis (CZE) provides dramatically improved numbers of peptide identifications compared with reversed-phase chromatography for bottom-up proteomics of mass limited samples, CZE inevitably produces lower numbers of peptide identifications than RPLC for larger samples. One reason for this poorer performance is the dead time between injection of samples and subsequent appearance of the fastest moving component. This dead time is typically 25% of the separation window in CZE, but is only 5% of the separation window in gradient elution RPLC. This dead time can be eliminated in CZE by use of a multisegment injection mode where a series of samples is analyzed by injecting each sample while the preceding sample is still being separated. In this paper, we demonstrate that capillary zone electrophoresis employing sequential injections can produce a doubling in peptide identification rate with no degradation in separation efficiency.
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Affiliation(s)
- Danielle A Boley
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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47
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Zhang Z, Peuchen EH, Dovichi NJ. Surface-Confined Aqueous Reversible Addition-Fragmentation Chain Transfer (SCARAFT) Polymerization Method for Preparation of Coated Capillary Leads to over 10 000 Peptides Identified from 25 ng HeLa Digest by Using Capillary Zone Electrophoresis-Tandem Mass Spectrometry. Anal Chem 2017; 89:6774-6780. [PMID: 28540730 DOI: 10.1021/acs.analchem.7b01147] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A surface-confined aqueous reversible addition-fragmentation chain transfer (SCARAFT) polymerization method was developed to coat capillaries for use in capillary zone electrophoresis (CZE). SCARAFT polymerization primarily takes place on the inner surface of the capillary instead of in solution, which greatly improves the homogeneity of the coating. Capillaries treated with this coating produced an electroosmotic mobility of 2.8 ± 0.2 × 10-6 cm2·V-1·s-1 (N = 3), which is roughly an order of magnitude lower than that of commercial linear polyacrylamide (LPA)-coated capillaries. Coated capillaries were evaluated for bottom-up proteomic analysis using CZE. The very low electroosmotic mobility results in a 200 min separation and improved single-shot analysis. An average of 977 protein groups and 5605 unique peptides were identified from 50 ng of an E. coli digest, and 2158 protein groups and 10 005 peptides were identified from 25 ng of a HeLa digest using single-shot analysis with a SCARAFT-acrylamide capillary coupled to a Q Exactive HF mass spectrometer. The coating is stable. A single capillary was used for over 200 h (8.4 days) of continuous operation. RSD in migration time was between 2 and 3% for selected ion electropherograms (SIEs) generated for six ions; median theoretical plate counts ranged from 240 000 to 600 000 for these SIEs. Various types of coatings could be prepared by simply changing the functional vinyl monomers in the polymerization mixture. Positively charged coatings using direct attachment and formation of a block copolymer were prepared and demonstrated for the separation of mixtures of intact proteins.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Elizabeth H Peuchen
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
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48
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Sarver SA, Schiavone NM, Arceo J, Peuchen EH, Zhang Z, Sun L, Dovichi NJ. Capillary electrophoresis coupled to negative mode electrospray ionization-mass spectrometry using an electrokinetically-pumped nanospray interface with primary amines grafted to the interior of a glass emitter. Talanta 2017; 165:522-525. [PMID: 28153293 PMCID: PMC5651131 DOI: 10.1016/j.talanta.2017.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 01/11/2023]
Abstract
We demonstrate an electrokinetically pumped sheath flow nanospray interface for capillary electrophoresis coupled to negative mode electrospray mass spectrometry. In this interface, application of an electric field generates electro-osmotic flow at the interior of a glass emitter that is pulled to a 10-20µm inner diameter orifice. Electro-osmotic flow pumps liquid around the distal tip of the separation capillary, ensheathing analyte into the electrospray electrolyte. In negative ion mode, negative potential applied to an untreated glass emitter drives sheath flow away from the emitter orifice, decreasing the stability and efficiency of the spray. In this manuscript, we treat a portion of the interior of the electrospray emitter with 3-aminopropyltrimethoxysilane, which grafts primary amines to the interior. The amines take on a positive charge, which reverses electro-osmosis and generates stable sheath flow to the emitter orifice under negative potential. Negative mode operation is demonstrated by analyzing a metabolite extract from stage 1 Xenopus laevis embryos. Production of the treated emitters was quite reproducible. We evaluated the performance of three emitters using a set of amino acids; the relative standard deviation in peak intensity was 7% for the most intense component.
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Affiliation(s)
- Scott A Sarver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Nicole M Schiavone
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jennifer Arceo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Elizabeth H Peuchen
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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49
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Choi SB, Zamarbide M, Manzini MC, Nemes P. Tapered-Tip Capillary Electrophoresis Nano-Electrospray Ionization Mass Spectrometry for Ultrasensitive Proteomics: the Mouse Cortex. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:597-607. [PMID: 27853976 DOI: 10.1007/s13361-016-1532-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
Ultrasensitive characterization of the proteome raises the potential to understand how differential gene expression orchestrates cell heterogeneity in the brain. Here, we report a microanalytical capillary electrophoresis nano-flow electrospray ionization (CE-nanoESI) interface for mass spectrometry to enable the measurement of limited amounts of proteins in the mouse cortex. Our design integrates a custom-built CE system to a tapered-tip metal emitter in a co-axial sheath-flow configuration. This interface can be constructed in <15 min using readily available components, facilitating broad adaptation. Tapered-tip CE-nanoESI generates stable electrospray by reproducibly anchoring the Taylor cone, minimizes sample dilution in the ion source, and ensures efficient ion generation by sustaining the cone-jet spraying regime. Parallel reaction monitoring provided a 260-zmol lower limit of detection for angiotensin II (156,000 copies). CE was able to resolve a complex mixture of peptides in ~330,000 theoretical plates and identify ~15 amol (~1 pg) of BSA or cytochrome c. Over 30 min of separation, 1 ng protein digest from the mouse cortex yielded 217 nonredundant proteins encompassing a ~3-log-order concentration range using a quadrupole time-of-flight mass spectrometer. Identified proteins included many products from genes that are traditionally used to mark oligodendrocytes, astrocytes, and microglia. Finally, key proteins involved in neurodegenerative disorders were detected (e.g., parkinsonism and spastic paraplegia). CE-nanoESI-HRMS delivers sufficient sensitivity to detect proteins in limited amounts of tissues and cell populations to help understand how gene expression differences maintain cell heterogeneity in the brain. Graphical Abstract ᅟ.
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Affiliation(s)
- Sam B Choi
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Marta Zamarbide
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20037, USA
| | - M Chiara Manzini
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20037, USA
| | - Peter Nemes
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA.
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50
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Development and application of a new in-line coupling of a miniaturized boronate affinity monolithic column with capillary zone electrophoresis for the selective enrichment and analysis of cis-diol-containing compounds. J Chromatogr A 2017; 1494:65-76. [DOI: 10.1016/j.chroma.2017.03.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/06/2017] [Accepted: 03/08/2017] [Indexed: 11/22/2022]
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