Facile synthesis of hydrophilic magnetic graphene nanocomposites via dopamine self-polymerization and Michael addition for selective enrichment of N-linked glycopeptides

Changfen Bi,Yukui Zhang,Xiwen He,Ye Yuan,Langxing Chen,Yulu Liang,Jiahui Wu,Yiliang Li,Yuran Tu

doi:10.1038/s41598-019-56944-4

Abstract

The development of methods to effectively capture N-glycopeptides from the complex biological samples is crucial to N-glycoproteome profiling. Herein, the hydrophilic chitosan–functionalized magnetic graphene nanocomposites (denoted as Fe3O4-GO@PDA-Chitosan) were designed and synthesized via a simple two-step modification (dopamine self-polymerization and Michael addition). The Fe3O4-GO@PDA-Chitosan nanocomposites exhibited good performances with low detection limit (0.4 fmol·μL−1), good selectivity (mixture of bovine serum albumin and horseradish peroxidase tryptic digests at a molar ration of 10:1), good repeatability (4 times), high binding capacity (75 mg·g−1). Moreover, Fe3O4-GO@PDA-Chitosan nanocomposites were further utilized to selectively enrich glycopeptides from human renal mesangial cell (HRMC, 200 μg) tryptic digest, and 393 N-linked glycopeptides, representing 195 different glycoproteins and 458 glycosylation sites were identified. This study provides a feasible strategy for the surface functionalized novel materials for isolation and enrichment of N-glycopeptides.

Highlights

Protein N-glycosylation, as one of the most prevalent post-translational modifications (PTMs), can significantly change the structure, increase stability and subsequently endow new functions of protein[1,2,3]
The morphology of Fe3O4-Graphene oxide (GO), Fe3O4-GO@PDA, Fe3O4-GO@PDA-Chitosan nanocomposites and the thickness of the grafted PDA layer were revealed by transmission electron microscopy (TEM) at the 200 or 10 nanometer scale
The results indicated that Fe3O4-GO@PDA-Chitosan nanocomposites have the great potential in N-glycopeptides enrichment from complex biological sample

Summary

Introduction

Protein N-glycosylation, as one of the most prevalent post-translational modifications (PTMs), can significantly change the structure, increase stability and subsequently endow new functions of protein[1,2,3]. H2O, 0.1% TFA; 89% ACN/H2O, 0.5% TFA; 89% ACN/H2O, 1% TFA) were utilized for investigate the effect of capturing glycopeptides from HRP digestion by Fe3O4-GO@PDA-Chitosan nanocomposites and the results were displayed in Fig. S3 (Electronical Supporting Materials). The performance of Fe3O4-GO@PDA-Chitosan nanocomposites for enrichment of N-glycopeptides was the best in the loading buffer (89% ACN/H2O, 0.5% TFA).

Results

Conclusion