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Wang L, Wu H, Cao T, Li H, Shen P, Lu L, Zhang Z. Identification of structural origins of complex charge heterogeneity in therapeutic ACE2Fc fusion protein facilitated by free-flow isoelectric focusing. Eur J Pharm Biopharm 2024; 198:114248. [PMID: 38467335 DOI: 10.1016/j.ejpb.2024.114248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/26/2024] [Accepted: 03/06/2024] [Indexed: 03/13/2024]
Abstract
Fc Fusion protein represents a versatile molecular platform with considerable potential as protein therapeutics of which the charge heterogeneity should be well characterized according to regulatory guidelines. Angiotensin-converting enzyme 2 Fc fusion protein (ACE2Fc) has been investigated as a potential neutralizing agent to various coronaviruses, including the lingering SARS-CoV-2, as this coronavirus must bind to ACE2 to allow for its entry into host cells. ACE2Fc, an investigational new drug developed by Henlius (Shanghai China), has passed the Phase I clinical trial, but its huge amount of charge isoforms and complicated charge heterogeneity posed a challenge to charge variant investigation in pharmaceutical development. We employed offline free-flow isoelectric focusing (FF-IEF) fractionation, followed by detailed characterization of enriched ACE2Fc fractions, to unveil the structural origins of charge heterogeneity in ACE2Fc expressed by recombinant CHO cells. We adopted a well-tuned 3-component separation medium for ACE2Fc fractionation, the highest allowable voltage to maximize the FF-IEF separation window and a mild Protein A elution method for preservation of protein structural integrity. Through peptide mapping and other characterizations, we revealed that the intricate profiles of ACE2Fc charge heterogeneity are mainly caused by highly sialylated multi-antenna N-glycosylation. In addition, based on fraction characterization and in silico glycoprotein model analysis, we discovered that the large acidic glycans at N36, N73, and N305 of ACE2Fc were able to decrease the binding activity towards Spike (S) protein of SARS-CoV-2. Our study exemplifies the value of FF-IEF in highly complex fusion protein characterization and revealed a quantitative sialylation-activity relationship in ACE2Fc.
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Affiliation(s)
- Lingyu Wang
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Hai Wu
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Ting Cao
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Hongyang Li
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Pengcheng Shen
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Lihong Lu
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China
| | - Zhongli Zhang
- Department of Analytical Science and Development, Shanghai Henlius Biologics Co., Ltd., Shanghai 201600, China.
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May C, Brosseron F, Pfeiffer K, Fuchs K, Meyer HE, Sitek B, Marcus K. Proteome Analysis with Classical 2D-PAGE. Methods Mol Biol 2021; 2228:53-62. [PMID: 33950483 DOI: 10.1007/978-1-0716-1024-4_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) is based on the combination of two orthogonal separation techniques. In the first dimension, proteins are separated by their isoelectric point, a technique known as isoelectric focusing (IEF). There are two important variants of IEF, which are carrier-ampholine (CA)-based IEF and immobilized pH-gradient (IPG)-based IEF. In the second dimension, proteins are further separated by their electrophoretic mobility using SDS-PAGE. Finally, proteins can be visualized and quantified by different staining procedures such as Coomassie, silver staining, or fluorescence labeling. This article gives detailed protocols for 2D-PAGE, using both CA- and IPG-based separation in the first dimension.
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Affiliation(s)
- Caroline May
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
- Medical Proteome Analysis, Center for Proteindiagnostics (PRODI) Ruhr-University Bochum, Bochum, Germany
| | - Frederic Brosseron
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Kathy Pfeiffer
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
- Medical Proteome Analysis, Center for Proteindiagnostics (PRODI) Ruhr-University Bochum, Bochum, Germany
| | - Kristin Fuchs
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
- Medical Proteome Analysis, Center for Proteindiagnostics (PRODI) Ruhr-University Bochum, Bochum, Germany
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Knappschaftskrankenhaus Bochum, Bochum, Germany
| | - Helmut E Meyer
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Barbara Sitek
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany
- Medical Proteome Analysis, Center for Proteindiagnostics (PRODI) Ruhr-University Bochum, Bochum, Germany
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Knappschaftskrankenhaus Bochum, Bochum, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center (MPC), Medical Faculty, Ruhr-University Bochum, Bochum, Germany.
- Medical Proteome Analysis, Center for Proteindiagnostics (PRODI) Ruhr-University Bochum, Bochum, Germany.
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Lohnes K, Quebbemann NR, Liu K, Kobzeff F, Loo JA, Ogorzalek Loo RR. Combining high-throughput MALDI-TOF mass spectrometry and isoelectric focusing gel electrophoresis for virtual 2D gel-based proteomics. Methods 2016; 104:163-9. [PMID: 26826592 PMCID: PMC4930893 DOI: 10.1016/j.ymeth.2016.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/13/2016] [Accepted: 01/25/2016] [Indexed: 01/07/2023] Open
Abstract
The virtual two-dimensional gel electrophoresis/mass spectrometry (virtual 2D gel/MS) technology combines the premier, high-resolution capabilities of 2D gel electrophoresis with the sensitivity and high mass accuracy of mass spectrometry (MS). Intact proteins separated by isoelectric focusing (IEF) gel electrophoresis are imaged from immobilized pH gradient (IPG) polyacrylamide gels (the first dimension of classic 2D-PAGE) by matrix-assisted laser desorption/ionization (MALDI) MS. Obtaining accurate intact masses from sub-picomole-level proteins embedded in 2D-PAGE gels or in IPG strips is desirable to elucidate how the protein of one spot identified as protein 'A' on a 2D gel differs from the protein of another spot identified as the same protein, whenever tryptic peptide maps fail to resolve the issue. This task, however, has been extremely challenging. Virtual 2D gel/MS provides access to these intact masses. Modifications to our matrix deposition procedure improve the reliability with which IPG gels can be prepared; the new procedure is described. Development of this MALDI MS imaging (MSI) method for high-throughput MS with integrated 'top-down' MS to elucidate protein isoforms from complex biological samples is described and it is demonstrated that a 4-cm IPG gel segment can now be imaged in approximately 5min. Gel-wide chemical and enzymatic methods with further interrogation by MALDI MS/MS provide identifications, sequence-related information, and post-translational/transcriptional modification information. The MSI-based virtual 2D gel/MS platform may potentially link the benefits of 'top-down' and 'bottom-up' proteomics.
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Affiliation(s)
- Karen Lohnes
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Neil R Quebbemann
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kate Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Fred Kobzeff
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Joseph A Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; DOE/UCLA Institute of Genomics and Proteomics and UCLA Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; DOE/UCLA Institute of Genomics and Proteomics and UCLA Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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