Hydrophilic Carboxyl Cotton Chelator for Titanium(IV) Immobilization and Its Application as Novel Fibrous Sorbent for Rapid Enrichment of Phosphopeptides

Abstract

Sample preparation methods with high selectivity, efficiency, and matrix resistance are essential for phosphoproteomic analysis. In this study, carboxyl cotton chelator-titanium(IV) (CCC-Ti4+) fibers, a novel CCC-based fibrous sorbent with excellent biocompatibility, were successfully synthesized on the basis of the coordination effect between double carboxyl groups on CCC and Ti4+. The synthesis of CCC-Ti4+ fibers was easy, and the incorporated titanium content was high. On the basis of immobilized metal ion affinity chromatography (IMAC), CCC-Ti4+ fibers were used for specific capture of phosphopeptides using a lab-in-syringe solid-phase extraction (SPE) from multiple biological samples, including standard protein digests, nonfat milk digests, human serum, and animal tissue. The proposed sorbent exhibited high selectivity (β-casein/BSA=1:1000) and good sensitivity (10 fmol) in phosphopeptides analysis. Meanwhile, the lab-in-syringe SPE greatly simplified the entire process of enrichment. Thanks to the good biocompatibility of CCC-based material, CCC-Ti4+ fibers showed excellent performance in phosphopeptide enrichment from protein-rich human serum. Finally, CCC-Ti4+ fibers were applied for selective capture of phosphopeptides from tryptic digests of rat brain lysate followed by LC-MS/MS analysis. Using the proposed method, we identified 3950 unique phosphosites from 1 mg of rat brain in a single experiment, which is much better than previously reported IMAC-based strategies. Taken together, this efficient method will find broad application in large-scale phosphoproteomics analysis because of the rapid (3 min) convenient procedure and excellent performance.

Facile Preparation of Bright‐Fluorescent Soft Materials from Small Organic Molecules

“…However, in previous report, the synthesis of the bicyclic 2‐pyridone derivatives is somehow complicated . As illustrated in Scheme , in this study, the supposed formation processes for the formation of the nonaromatic molecule involved five steps: amidation, nucleophilic addition, dehydroxylation, cyclization reaction, and dehydroxylation, resulting in the nonaromatic structure of 5‐oxo‐2,3‐dihydro‐5 H ‐(1,3)thiazolo(3,2‐a)pyridine‐3,7‐dicarboxylic acid (noted as TPA), as similar to the mechanism reported by Kasprzyk and co‐workers . In their pioneering work, the solvent of water was removed from the CA+Cys aqueous mixture under vacuum and then the mixture was heated at high temperature (180 °C), resulting in a crude product that contains TPA .…”

Metal–organic framework based in‐syringe solid‐phase extraction for the on‐site sampling of polycyclic aromatic hydrocarbons from environmental water samples

“…Experimental results showed that the developed lab‐in‐syringe SPE approach allowed rapid and effective enrichment in less than 3 min without any electrical device. Subsequently, Feng and co‐workers applied the lab‐in‐syringe SPE technology with various adsorbents for proteomics researches, further verifying the simplified procedure and short extraction time of the proposed method .…”

“…In the extraction process, the sample solution and eluent are repeatedly passed through the adsorbent through pulling and pushing the plunger of syringe for several cycles, and in this way the extraction procedures including loading, washing, and eluting can be easily performed. The in‐syringe SPE technology has realized its own value in biological analysis . Feng synthesized the silica fiber with highly ordered mesoporous structure and continuously long fibrous property, and developed a lab‐in‐syringe SPE system using the prepared silica fiber as adsorbent for the enrichment of endogenous peptides from biological samples .…”

Modified cysteine S-phosphopeptide standards for mass spectrometry-based proteomics

“…Such direct detection of S-linked phosphorylation seems suitable for less complex analytes, such as in the case of offline fractionation (Ruprecht et al 2017) or affinity enrichment procedures. In preliminary experiments, S-phosphopeptides from a sample of Digest 1 were enriched using a hydrophilic Ti-IMAC (He et al 2015) prepared in-house from cotton-wool. The enriched analyte was subjected to a series of tandem MS applying complementary fragmentation methods CID, HCD, ETD, ETciD, and EThcD [S12].…”