Application Of Supramolecular Assemblies Based On ?-cyclodextrin In Glycopeptide And Phosphopeptide Analysis

As one of the most star macrocyclic compounds,?-cyclodextrin(?-CD)is a cyclic oligosaccharide composed of seven D-glucopyranose units.?-CD has not only the hydrophobic interior cavity can include non-polar guest molecules through host-guest interaction,but also the hydrophilic exterior possesses a large number of polar hydroxyl groups.Therefore,?-CD is an ideal building block for supramolecular systems as well as a good hydrophilic compound.Supramolecular assemblies based on?-CD have attracted attention in many research fields,especially in the field of biochemistry.?-CD-based supramolecular assemblies have excellent biocompatibility and low toxicity.In addition,supramolecular assemblies generally outperform individual building units with more complex structures and functions.?-CD-based supramolecular assemblies have been widely used in biochemical studies such as drug delivery&release,cell imaging,and in vitro therapy.Protein glycosylation and phosphorylation are the two vital types of protein post-translational modifications(PTM)and play crucial roles in living organisms,regulating almost all cellular activities.The occurrence and development of many major diseases are related to abnormal protein glycosylation and phosphorylation.Therefore,the analysis of glycopeptides and phosphopeptides are helpful for the discovery of biomarkers and the prediction and diagnosis of clinical diseases.Mass spectrometry(MS)detection for protein glycosylated and phosphorylated peptides generally suffers from low ionization efficiency and strong interference from unmodified peptides,resulting in extremely low feasibility of direct detection.Therefore,it is crucial to efficient enrichment of glycopeptides and phosphopeptides prior to MS.In recent years,the application of?-CD-based supramolecular assemblies in glycopeptide and phosphopeptide enrichment has been attracted more attentions.In this paper,we constructed novel supramolecular assemblies based on?-CD host-guest chemistry.The preparation process is simple and mild.The obtained supramolecular assemblies have good specificity,excellent biocompatibility,and fast magnetic responsiveness,which are applied to the enrichment and detection of low-abundance glycopeptides and phosphopeptides in complex biological samples by coupling with matrix-assisted ionization time-of-flight mass spectrometry(MALDI-TOF MS).The detailed contents are divided into the following two parts:1.A novel magnetic?-CD host-guest hydrophilic material(denoted as MCDC)was prepared for enrichment and detection of glycopeptides in combination with MALDI-TOF MS.The MCDC prepared through a simple self-assembly process not only possesses excellent hydrophilicity because the L-cysteine(L-Cys)modified adamantane was included with the interior cavity of?-CD,but also exhibits rapid separation efficiency due to the presence of the magnetic substrate.The glycopeptide analysis method based on MCDC has the characteristics of low detection limit,high selectivity and reusability.And it has been successfully used to efficiently separate and enrich glycopeptides from standard and real samples.2.A novel?-CD-based enriched material,the magnetic?-CD-based host-guest metal-polyphenol network(abbreviated as mTiCD@AG)was designed.mTiCD@AG prepared via host-guest interaction exploits the hydrophilic interaction between glutathione(GSH)and glycopeptides and the strong coordination between Ti⁴⁺and phosphopeptides,which possesses excellent simultaneous enrichment ability of both glycopeptides and phosphopeptides.Combining with MALDI-TOF MS,the as-prepared mTiCD@AG exhibits excellent selectivity,great sensitivity and stability.mTiCD@AG has been successfully applied to the simultaneous and efficient enrichment of glycopeptides and phosphopeptides in human serum,which proves that the method based on mTiCD@AG has good practical application ability.