Identification of the High Mannose N-Glycan Isomers Undescribed by Conventional Multicellular Eukaryotic Biosynthetic Pathways

Chia Yen Liew; Hong-Sheng Luo; Ting-Yi Yang; An-Ti Hung; Bryan John Abel Magoling; Charles Pin-Kuang Lai; Chi-Kung Ni

doi:10.1021/acs.analchem.2c05599

Identification of the High Mannose N-Glycan Isomers Undescribed by Conventional Multicellular Eukaryotic Biosynthetic Pathways

Anal Chem. 2023 Jun 13;95(23):8789-8797. doi: 10.1021/acs.analchem.2c05599. Epub 2023 May 26.

Authors

Chia Yen Liew^{1

2

3}, Hong-Sheng Luo^{1

4}, Ting-Yi Yang^{1

4}, An-Ti Hung^{1

5}, Bryan John Abel Magoling^{1

6

7}, Charles Pin-Kuang Lai^{1

7

8}, Chi-Kung Ni^{1

3

5}

Affiliations

¹ Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
² International Graduate Program of Molecular Science and Technology, National Taiwan University (NTU-MST), Taipei 10617, Taiwan.
³ Molecular Science and Technology (MST), Taiwan International Graduate Program (TIGP), Academia Sinica, Taipei 10617, Taiwan.
⁴ Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan.
⁵ Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
⁶ Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei 10617, Taiwan.
⁷ Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan.
⁸ Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan.

Abstract

N-linked glycosylation is one of the most important post-translational modifications of proteins. Current knowledge of multicellular eukaryote N-glycan biosynthesis suggests high mannose N-glycans are generated in the endoplasmic reticulum and Golgi apparatus through conserved biosynthetic pathways. According to conventional biosynthetic pathways, four Man₇GlcNAc₂ isomers, three Man₆GlcNAc₂ isomers, and one Man₅GlcNAc₂ isomer are generated during this process. In this study, we applied our latest mass spectrometry method, logically derived sequence tandem mass spectrometry (LODES/MSⁿ), to re-examine high mannose N-glycans extracted from various multicellular eukaryotes which are not glycosylation mutants. LODES/MSⁿ identified many high mannose N-glycan isomers previously unreported in plantae, animalia, cancer cells, and fungi. A database consisting of retention time and CID MSⁿ mass spectra was constructed for all possible Man_nGlcNAc₂ (n = 5, 6, 7) isomers that include the isomers by removing arbitrary numbers and positions of mannose from canonical N-glycan, Man₉GlcNAc₂. Many N-glycans in this database are not found in current N-glycan mass spectrum libraries. The database is useful for rapid high mannose N-glycan isomeric identification.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biosynthetic Pathways
Eukaryota* / metabolism
Humans
Mannose* / chemistry
Polysaccharides / chemistry
Tandem Mass Spectrometry / methods

Substances

Mannose
Polysaccharides