Preparation of high-efficiency titanium ion immobilized magnetic graphite nitride nanocomposite for phosphopeptide enrichment

Dandan Jiang; Ruixue Qi; Siqi Lv; Siyu Wu; Yangyang Li; Jinghai Liu

doi:10.1016/j.aca.2023.341974

Preparation of high-efficiency titanium ion immobilized magnetic graphite nitride nanocomposite for phosphopeptide enrichment

Anal Chim Acta. 2023 Dec 1:1283:341974. doi: 10.1016/j.aca.2023.341974. Epub 2023 Oct 27.

Authors

Dandan Jiang¹, Ruixue Qi², Siqi Lv², Siyu Wu², Yangyang Li², Jinghai Liu²

Affiliations

¹ College of Chemistry and Materials Science, Inner Mongolia Key Laboratory of Carbon Nanomaterials, Nano Innovation Institute (NII), Inner Mongolia Minzu University, Tongliao, 028000, PR China. Electronic address: ddjiang@imun.edu.cn.
² College of Chemistry and Materials Science, Inner Mongolia Key Laboratory of Carbon Nanomaterials, Nano Innovation Institute (NII), Inner Mongolia Minzu University, Tongliao, 028000, PR China.

PMID: 37977792
DOI: 10.1016/j.aca.2023.341974

Abstract

Background: Protein phosphorylation has been implicated in life processes including molecular interaction, protein structure transformation, and malignant disease. An in-depth study of protein phosphorylation may provide vital information for the discovery of early biomarkers. Mass spectrometry (MS)-based techniques have become an important method for phosphopeptide identification. Nevertheless, direct detection remains challenging because of the low ionization efficiency of phosphopeptides and serious interference from non-phosphopeptides. There is a great need for an efficient enrichment strategy to analyze protein phosphorylation prior to MS analysis.

Results: In this study, a novel nanocomposite was prepared by introducing titanium ions into two-dimensional magnetic graphite nitride. The nanocomposite was combined with immobilized metal ion affinity chromatography (IMAC) and anion-exchange chromatography mechanisms for phosphoproteome research. The nanocomposite had the advantages of a large specific surface (412.9 m² g^-1), positive electricity (175.44 mV), and excellent magnetic property (35.7 emu g^-1). Moreover, it presented satisfactory selectivity (α-casein:β-casein:bovine serum albumin = 1:1:5000), a low detection limit (0.02 fmol), great recyclability (10 cycles), and high recovery (92.8%). The nanocomposite demonstrated great practicability for phosphopeptides from non-fat milk, human serum, and saliva. Further, the nanocomposite was applied to enrich phosphopeptides from a more complicated specimen, A549 cell lysate. A total of 890 phosphopeptides mapping to 564 phosphoproteins were successfully detected with nano LC-MS.

Significance: We successfully designed and developed an efficient analysis platform for phosphopeptides, which includes protein digestion, phosphopeptide enrichment, and MS detection. The MS-based enrichment platform was further used to analyze phosphopeptides from complicated bio-samples. This work paves the way for the design and preparation of graphite nitride-based IMAC materials for phosphoproteome analysis.

Keywords: Graphite nitride; Magnetic; Mass spectrum; Phosphopeptide enrichment; Titanium ion.

MeSH terms

Caseins / chemistry
Chromatography, Affinity / methods
Graphite* / chemistry
Humans
Ions
Magnetic Phenomena
Phosphopeptides / analysis
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Titanium* / chemistry

Substances

Titanium
Phosphopeptides
Graphite
Caseins
Ions