1
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Sadeghi S, Chen W, Wang Q, Wang Q, Fang F, Liu X, Sun L. Pilot Evaluation of the Long-Term Reproducibility of Capillary Zone Electrophoresis-Tandem Mass Spectrometry for Top-Down Proteomics of a Complex Proteome Sample. J Proteome Res 2024; 23:1399-1407. [PMID: 38417052 PMCID: PMC11002928 DOI: 10.1021/acs.jproteome.3c00872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 03/01/2024]
Abstract
Mass spectrometry (MS)-based top-down proteomics (TDP) has revolutionized biological research by measuring intact proteoforms in cells, tissues, and biofluids. Capillary zone electrophoresis-tandem MS (CZE-MS/MS) is a valuable technique for TDP, offering a high peak capacity and sensitivity for proteoform separation and detection. However, the long-term reproducibility of CZE-MS/MS in TDP remains unstudied, which is a crucial aspect for large-scale studies. This work investigated the long-term qualitative and quantitative reproducibility of CZE-MS/MS for TDP for the first time, focusing on a yeast cell lysate. Over 1000 proteoforms were identified per run across 62 runs using one linear polyacrylamide (LPA)-coated separation capillary, highlighting the robustness of the CZE-MS/MS technique. However, substantial decreases in proteoform intensity and identification were observed after some initial runs due to proteoform adsorption onto the capillary inner wall. To address this issue, we developed an efficient capillary cleanup procedure using diluted ammonium hydroxide, achieving high qualitative and quantitative reproducibility for the yeast sample across at least 23 runs. The data underscore the capability of CZE-MS/MS for large-scale quantitative TDP of complex samples, signaling its readiness for deployment in broad biological applications. The MS RAW files were deposited in ProteomeXchange Consortium with the data set identifier of PXD046651.
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Affiliation(s)
- Seyed
Amirhossein Sadeghi
- Department
of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Wenrong Chen
- Department
of BioHealth Informatics, Indiana University-Purdue
University Indianapolis, 535 W Michigan Street, Indianapolis, Indiana 46202, United States
| | - Qianyi Wang
- Department
of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Qianjie Wang
- Department
of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Fei Fang
- Department
of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Xiaowen Liu
- Deming
Department of Medicine, School of Medicine, Tulane University, 1441 Canal Street, New Orleans, Louisiana 70112, United States
| | - Liangliang Sun
- Department
of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
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2
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Huang CF, Kline JT, Negrão F, Robey MT, Toby TK, Durbin KR, Fellers RT, Friedewald JJ, Levitsky J, Abecassis MMI, Melani RD, Kelleher NL, Fornelli L. Targeted Quantification of Proteoforms in Complex Samples by Proteoform Reaction Monitoring. Anal Chem 2024; 96:3578-3586. [PMID: 38354049 PMCID: PMC11008684 DOI: 10.1021/acs.analchem.3c05578] [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: 02/28/2024]
Abstract
Existing mass spectrometric assays used for sensitive and specific measurements of target proteins across multiple samples, such as selected/multiple reaction monitoring (SRM/MRM) or parallel reaction monitoring (PRM), are peptide-based methods for bottom-up proteomics. Here, we describe an approach based on the principle of PRM for the measurement of intact proteoforms by targeted top-down proteomics, termed proteoform reaction monitoring (PfRM). We explore the ability of our method to circumvent traditional limitations of top-down proteomics, such as sensitivity and reproducibility. We also introduce a new software program, Proteoform Finder (part of ProSight Native), specifically designed for the easy analysis of PfRM data. PfRM was initially benchmarked by quantifying three standard proteins. The linearity of the assay was shown over almost 3 orders of magnitude in the femtomole range, with limits of detection and quantification in the low femtomolar range. We later applied our multiplexed PfRM assay to complex samples to quantify biomarker candidates in peripheral blood mononuclear cells (PBMCs) from liver-transplanted patients, suggesting their possible translational applications. These results demonstrate that PfRM has the potential to contribute to the accurate quantification of protein biomarkers for diagnostic purposes and to improve our understanding of disease etiology at the proteoform level.
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Affiliation(s)
- Che-Fan Huang
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Jake T Kline
- School of Biological Sciences, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Fernanda Negrão
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Matthew T Robey
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
- Proteinaceous, Inc., Evanston, Illinois 60201, United States
| | - Timothy K Toby
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Kenneth R Durbin
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
- Proteinaceous, Inc., Evanston, Illinois 60201, United States
| | - Ryan T Fellers
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
- Proteinaceous, Inc., Evanston, Illinois 60201, United States
| | - John J Friedewald
- Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Josh Levitsky
- Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Michael M I Abecassis
- Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Rafael D Melani
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Neil L Kelleher
- Departments of Molecular Biosciences, Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Luca Fornelli
- School of Biological Sciences, University of Oklahoma, Norman, Oklahoma 73019, United States
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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3
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Marx V. Inside the chase after those elusive proteoforms. Nat Methods 2024; 21:158-163. [PMID: 38308015 DOI: 10.1038/s41592-024-02170-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
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4
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D'Ippolito RA, Scheidemantle GM, Smith BP, Powell K, Eury S, Neish A, Mehalko J, Beaumont L, Fer N, Wall V, Burgan W, Maciag AE, Esposito D, DeHart CJ. FLAG-KRAS4B as a Model System for KRAS4B Proteoform and PTM Evaluation by Mass Spectrometry. Methods Mol Biol 2024; 2797:299-322. [PMID: 38570469 DOI: 10.1007/978-1-0716-3822-4_22] [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: 04/05/2024]
Abstract
Prior analysis of intact and modified protein forms (proteoforms) of KRAS4B isolated from cell lines and tumor samples by top-down mass spectrometry revealed the presence of novel posttranslational modifications (PTMs) and potential evidence of context-specific KRAS4B modifications. However, low endogenous proteoform signal resulted in ineffective characterization, making it difficult to visualize less abundant PTMs or perform follow-up PTM validation using standard proteomic workflows. The NCI RAS Initiative has developed a model system, whereby KRAS4B bearing an N-terminal FLAG tag can be stably expressed within a panel of cancer cell lines. Herein, we present a method for combining immunoprecipitation with complementary proteomic methods to directly analyze N-terminally FLAG-tagged KRAS4B proteoforms and PTMs. We provide detailed protocols for FLAG-KRAS4B purification, proteoform analysis by targeted top-down LC-MS/MS, and validation of abundant PTMs by bottom-up LC-MS/MS with example results.
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Affiliation(s)
- Robert A D'Ippolito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Grace M Scheidemantle
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Brian P Smith
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Katie Powell
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Scott Eury
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Abigail Neish
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jennifer Mehalko
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Lauren Beaumont
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Nicole Fer
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Vanessa Wall
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - William Burgan
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Anna E Maciag
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dominic Esposito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Caroline J DeHart
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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5
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Po A, Eyers CE. Top-Down Proteomics and the Challenges of True Proteoform Characterization. J Proteome Res 2023; 22:3663-3675. [PMID: 37937372 PMCID: PMC10696603 DOI: 10.1021/acs.jproteome.3c00416] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 11/09/2023]
Abstract
Top-down proteomics (TDP) aims to identify and profile intact protein forms (proteoforms) extracted from biological samples. True proteoform characterization requires that both the base protein sequence be defined and any mass shifts identified, ideally localizing their positions within the protein sequence. Being able to fully elucidate proteoform profiles lends insight into characterizing proteoform-unique roles, and is a crucial aspect of defining protein structure-function relationships and the specific roles of different (combinations of) protein modifications. However, defining and pinpointing protein post-translational modifications (PTMs) on intact proteins remains a challenge. Characterization of (heavily) modified proteins (>∼30 kDa) remains problematic, especially when they exist in a population of similarly modified, or kindred, proteoforms. This issue is compounded as the number of modifications increases, and thus the number of theoretical combinations. Here, we present our perspective on the challenges of analyzing kindred proteoform populations, focusing on annotation of protein modifications on an "average" protein. Furthermore, we discuss the technical requirements to obtain high quality fragmentation spectral data to robustly define site-specific PTMs, and the fact that this is tempered by the time requirements necessary to separate proteoforms in advance of mass spectrometry analysis.
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Affiliation(s)
- Allen Po
- Centre
for Proteome Research, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L69 7ZB, U.K.
- Department
of Biochemistry, Cell & Systems Biology, Institute of Systems,
Molecular & Integrative Biology, Faculty of Health & Life
Sciences, University of Liverpool, Liverpool L69 7ZB, U.K.
| | - Claire E. Eyers
- Centre
for Proteome Research, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L69 7ZB, U.K.
- Department
of Biochemistry, Cell & Systems Biology, Institute of Systems,
Molecular & Integrative Biology, Faculty of Health & Life
Sciences, University of Liverpool, Liverpool L69 7ZB, U.K.
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6
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Leonard B, Danna V, Gorham L, Davison M, Chrisler W, Kim DN, Gerbasi VR. Shaping Nanobodies and Intrabodies against Proteoforms. Anal Chem 2023; 95:8747-8751. [PMID: 37235478 PMCID: PMC10269583 DOI: 10.1021/acs.analchem.3c00958] [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] [Received: 03/03/2023] [Accepted: 05/23/2023] [Indexed: 05/28/2023]
Abstract
Proteoforms expand genomic diversity and direct developmental processes. While high-resolution mass spectrometry has accelerated characterization of proteoforms, molecular techniques working to bind and disrupt the function of specific proteoforms have lagged behind. In this study, we worked to develop intrabodies capable of binding specific proteoforms. We employed a synthetic camelid nanobody library expressed in yeast to identify nanobody binders of different SARS-CoV-2 receptor binding domain (RBD) proteoforms. Importantly, employment of the positive and negative selection mechanisms inherent to the synthetic system allowed for amplification of nanobody-expressing yeast that bind to the original (Wuhan strain RBD) but not the E484 K (Beta variant) mutation. Nanobodies raised against specific RBD proteoforms were validated by yeast-2-hybrid analysis and sequence comparisons. These results provide a framework for development of nanobodies and intrabodies that target proteoforms.
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Affiliation(s)
- Bojana Leonard
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Vincent Danna
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Leo Gorham
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Michelle Davison
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - William Chrisler
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Doo Nam Kim
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Vincent R. Gerbasi
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
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