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.

中文翻译：

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传统多细胞真核生物合成途径未描述的高甘露糖 N-聚糖异构体的鉴定

N-连接糖基化是蛋白质最重要的翻译后修饰之一。多细胞真核生物N-聚糖生物合成的当前知识表明，高甘露糖N-聚糖是通过保守的生物合成途径在内质网和高尔基体中产生的。根据常规生物合成途径，在此过程中产生了4种Man ₇ GlcNAc ₂异构体、3种Man ₆ GlcNAc ₂异构体和1种Man ₅ GlcNAc _{2异构体。}在这项研究中，我们应用了我们最新的质谱法，逻辑衍生序列串联质谱法 (LODES/MS ⁿ), 重新检查从非糖基化突变体的各种多细胞真核生物中提取的高甘露糖N-聚糖。LODES/MS ⁿ鉴定了许多以前未在植物、动物、癌细胞和真菌中报道过的高甘露糖N-聚糖异构体。_{为所有可能的 Man n} GlcNAc ₂ ( n = 5, 6, 7) 异构体构建了一个由保留时间和 CID MS ⁿ质谱组成的数据库，这些异构体包括通过从规范N -聚糖中去除任意数量和位置的甘露糖的异构体，Man ₉葡萄糖酸₂。该数据库中的许多N-聚糖在当前N-聚糖质谱库。该数据库可用于快速鉴定高甘露糖N-聚糖异构体。