Mass Spectrometric Analysis of Neutral and Anionic N-Glycans from a Dictyostelium discoideum Model for Human Congenital Disorder of Glycosylation CDG IL
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- 作者：Alba Hykollari ; Crina I. A. Balog ; Dubravko Rendi膰 ; Thomas Braulke ; Iain B. H. Wilson ; Katharina Paschinger
- 刊名：Journal of Proteome Research
- 出版年：2013
- 出版时间：March 1, 2013
- 年：2013
- 卷：12
- 期：3
- 页码：1173-1187
- 全文大小：682K
- 年卷期：v.12,no.3(March 1, 2013)
- ISSN：1535-3907
文摘
The HL241 mutant strain of the cellular slime mold Dictyostelium discoideum is a potential model for human congenital disorder of glycosylation type IL (ALG9-CDG) and has been previously predicted to possess a lower degree of modification of its N-glycans with anionic moieties than the parental wild-type. In this study, we first showed that this strain has a premature stop codon in its alg9 mannosyltransferase gene compatible with the occurrence of truncated N-glycans. These were subject to an optimized analytical workflow, considering that the mass spectrometry of acidic glycans often presents challenges due to neutral loss and suppression effects. Therefore, the protein-bound N-glycans were first fractionated, after serial enzymatic release, by solid phase extraction. Then primarily single glycan species were isolated by mixed hydrophilic-interaction/anion-exchange or reversed-phase HPLC and analyzed using chemical and enzymatic treatments and MS/MS. We show that protein-linked N-glycans of the mutant are of reduced size as compared to those of wild-type AX3, but still contain core 伪1,3-fucose, intersecting N-acetylglucosamine, bisecting N-acetylglucosamine, methylphosphate, phosphate, and sulfate residues. We observe that a single N-glycan can carry up to four of these six possible modifications. Due to the improved analytical procedures, we reveal fuller details regarding the N-glycomic potential of this fascinating model organism.