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Vos GM, Hooijschuur KC, Li Z, Fjeldsted J, Klein C, de Vries RP, Toraño JS, Boons GJ. Sialic acid O-acetylation patterns and glycosidic linkage type determination by ion mobility-mass spectrometry. Nat Commun 2023; 14:6795. [PMID: 37880209 PMCID: PMC10600165 DOI: 10.1038/s41467-023-42575-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 03/07/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023] Open
Abstract
O-acetylation is a common modification of sialic acids that has been implicated in a multitude of biological and disease processes. A lack of analytical methods that can determine exact structures of sialic acid variants is a hurdle to determine roles of distinct O-acetylated sialosides. Here, we describe a drift tube ion mobility-mass spectrometry approach that can elucidate exact O-acetylation patterns as well as glycosidic linkage types of sialosides isolated from complex biological samples. It is based on the use of a library of synthetic O-acetylated sialosides to establish intrinsic collision cross section (CCS) values of diagnostic fragment ions. The CCS values were used to characterize O-acetylated sialosides from mucins and N-linked glycans from biologicals as well as equine tracheal and nasal tissues. It uncovered contrasting sialic acid linkage types of acetylated and non-acetylated sialic acids and provided a rationale for sialic acid binding preferences of equine H7 influenza A viruses.
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Affiliation(s)
- Gaёl M Vos
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Kevin C Hooijschuur
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Zeshi Li
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | | | | | - Robert P de Vries
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Javier Sastre Toraño
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands.
| | - Geert-Jan Boons
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands.
- Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG, Utrecht, The Netherlands.
- Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, GA, 30602, USA.
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Vos GM, Weber J, Sweet IR, Hooijschuur KC, Sastre Toraño J, Boons GJ. Oxidative Release of O-Glycans under Neutral Conditions for Analysis of Glycoconjugates Having Base-Sensitive Substituents. Anal Chem 2023. [PMID: 37259796 DOI: 10.1021/acs.analchem.3c00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Protein O-glycosylation is one of the most diverse post-translational modifications. A critical step in the analysis of O-glycomes is the release of glycans from glycoconjugates. Current release methods rely mainly on β-elimination, which can result in peeling reactions and loss of base-sensitive functionalities leading to misidentification of glycans. To address this challenge, well-defined synthetic glycopeptides were used to establish a robust workflow for the oxidative release of O-glycans suitable for glycomics. Treatment of O-glycopeptides with neutralized hypochlorite resulted in the selective formation of lactic/glycolic acid glycosides, thereby retaining unique information of the parent amino acid (serine/threonine) that is lost by β-elimination. It locks the glycan in a closed ring configuration, thereby preventing peeling, and furthermore, the carboxylate of the anomeric tag promotes ionization in negative ion mode mass spectrometry, thereby increasing signal intensities. Labile modifications such as sialic acids, sulfates, and acetyl esters are maintained during the release procedure. The promise of the approach was demonstrated by the analysis of O-glycans from bovine submaxillary mucin, which identified mono- and di-O-acetylated sialoglycans as well as previously undetected tri-O-acetylated and sulfated glycans. The use of well-defined glycopeptide standards made it also possible to identify reaction intermediates, which in turn allowed us to postulate a reaction mechanism for oxidative O-glycan release under neutral conditions.
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Affiliation(s)
- Gaël M Vos
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Julia Weber
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Igor R Sweet
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Kevin C Hooijschuur
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Javier Sastre Toraño
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Geert-Jan Boons
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
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