Mohamed Adly Gab-Allah (Chungnam National University)

Mohamed Adly Gab-Allah (Chungnam National University)

Mohamed Adly Gab-Allah (Chungnam National University)

Jeongkwon Kim (Chungnam National University)

As an important and widespread post-translational modification of proteins, glycosylation plays a key role in regulating a variety of complicated biological reactions. Owing to the fact that glycopeptides are low abundant and the ionization efficiency could be suppressed in mass spectroscopic detection, highly efficient and selective enrichment methods are essential to identify protein glycosylation by mass spectrometry. Boronate affinity materials, as unique sorbents, have emerged as important media for the selective separation and molecular recognition of cis-diol-containing biomolecules including glycopeptides. In this study, we propose a new enrichment strategy using a boronic acid (BA)-functionalized mesoporous nanomaterial for isolating intact glycopeptides from human serum. The material was prepared by using a two-step post-grafting method. Firstly, the 3-glycidyloxypropyltrimethoxysilane (GLYMO) and 3-aminophenylboronic acid monohydrate (APB) were reacted to prepare boronic-acid bonded GLYMO (denoted as GLYMO-APB). Secondly, the nanocomposite was added into the prepared GLYMO-APB solution to prepare the final product. This as-prepared material was characterized by FT-IR and the results showed that the boronic acid groups were successfully grafted to the nanocomposite material. The attractive features of this composite, including high surface area, hydrophilic interaction of silica, and the reversible covalent binding with BA enable the effective and specific enrichment of glycopeptides. In total, 123 deglycosylated peptides corresponding to 55 glycoproteins were enriched from merely 2 µL serum using this material. The experimental conditions will be optimized further to enhance the number enriched glycopeptides. Moreover, the results from the enrichment performance of the strategy will be evaluated through the analysis of standard glycoproteins. This research would open up a promising idea to utilize new nanocomposite materials with specific enrichment capacity, revealing their great potential for precise glycoproteomic analysis.