Complementary multiple hydrogen-bond-based magnetic composite microspheres for high coverage and efficient phosphopeptide enrichment in bio-samples

Facile preparation of nitrogen/titanium-rich porous organic polymers for specific enrichment of N-glycopeptides and phosphopeptides

The comprehensive investigation of protein phosphorylation and glycosylation aids in the discovery of novel biomarkers as well as the understanding of the pathophysiology of illness. In this work, a nitrogen/titanium-rich porous organic polymer was developed by copolymerizing carbohydrazide (CH) and 2,3-dihydroxyterephthalaldehyde (2,3-Dha) and modifying with Ti4+ (CH-Dha-Ti4+). The adequate nitrogen contributes to the enrichment of glycopeptides via HILIC, while titanium benefits from capturing phosphopeptides through IMAC. The proposed method exhibits excellent selectivity (1 : 1000, both for glycopeptides and phosphopeptides), LOD (for glycopeptides: 0.05 fmol μL-1, for phosphopeptides: 0.2 fmol), loading capacity (for glycopeptides: 100 mg g-1, for phosphopeptides: 125 mg g-1) and size-exclusion effect (1 : 10 000, both for glycopeptides and phosphopeptides). Furthermore, CH-Dha-Ti4+ was applied to capture glycopeptides and phosphopeptides from human serum; 205 glycopeptides and 45 phosphopeptides were detected in the serum of normal controls; and 294 glycopeptides and 63 phosphopeptides were found in the serum of uremia patients after being analyzed by nano LC-MS/MS. The discovered glycopeptides and phosphopeptides were involved in several molecular biological processes and activities, according to a gene ontology study.

Tailoring multifunctional magnetic cationic metal-organic framework composite for synchronous enrichment of phosphopeptides/glycopeptides

Herein, for the first time, a multifunctional magnetic cationic MOF composite (Fe3O4@ILI-01@Ti4+) was successfully prepared for the synchronous enrichment of phosphopeptides/glycopeptides. The as-prepared Fe3O4@ILI-01@Ti4+ bears attractive properties like abundant surface...

Bifunctional magnetic covalent organic framework for simultaneous enrichment of phosphopeptides and glycopeptides

Protein phosphorylation and glycosylation, which are closely related to various diseases, have been extensively studied recently. Mass spectrometry (MS) based phosphoproteomics and glycoproteomics analysis rely heavily on the pre-treatment. Due to the differences in enrichment conditions, there are still huge challenges in designing and preparing a single affinity material to achieve efficient simultaneous capture and elution of phosphopeptides and glycopeptides. Herein, a novel magnetic covalent organic framework, which was modified with functional molecule 4-(3-(2-(methacryloyloxy)ethyl)-ureido)benzoic acid (MUBA), was designed as a bifunctional enrichment platform for glycopeptides and phosphopeptides. Thanks to the multiple hydrogen bonding interactions between MUBA and hydrogen phosphates, the material possessed excellent enrichment performance for phosphopeptides. In addition, the hydrophilicity of the COF structure and modified molecules endowed this material recognition capability towards glycopeptides based on hydrophilic interaction chromatography. Combining with the inherent properties of COF structure, the established platform achieved simultaneous enrichment of phosphopeptides and glycopeptides with excellent selectivity (1:1:1000 M ratio of α-casein/IgG/BSA), high sensitivity (0.05 fmol/μL α-casein; 0.05 fmol/μL IgG), and good size-exclusion effect (α-casein digests/IgG digests/BSA, 1:1:500). More excitingly, the method was used for the identification of glycopeptides and phosphopeptides from rat liver tissue and the exosomes extracted from liver cancer patients' plasma, proving its specific phosphoproteomics and glycoproteomics study in complex biosamples.