Designed synthesis of fluorous-functionalized magnetic mesoporous microspheres for specific enrichment of phosphopeptides with fluorous derivatization

FAT-switch-based quantitative S-nitrosoproteomics reveals a key role of GSNOR1 in regulating ER functions

Reversible protein S-nitrosylation regulates a wide range of biological functions and physiological activities in plants. However, it is challenging to quantitively determine the S-nitrosylation targets and dynamics in vivo. In this study, we develop a highly sensitive and efficient fluorous affinity tag-switch (FAT-switch) chemical proteomics approach for S-nitrosylation peptide enrichment and detection. We quantitatively compare the global S-nitrosylation profiles in wild-type Arabidopsis and gsnor1/hot5/par2 mutant using this approach, and identify 2,121 S-nitrosylation peptides in 1,595 protein groups, including many previously unrevealed S-nitrosylated proteins. These are 408 S-nitrosylated sites in 360 protein groups showing an accumulation in hot5-4 mutant when compared to wild type. Biochemical and genetic validation reveal that S-nitrosylation at Cys337 in ER OXIDOREDUCTASE 1 (ERO1) causes the rearrangement of disulfide, resulting in enhanced ERO1 activity. This study offers a powerful and applicable tool for S-nitrosylation research, which provides valuable resources for studies on S-nitrosylation-regulated ER functions in plants.

Fabrication of a Magnetic Fluorinated Covalent Organic Framework for the Selective Capture of Benzoylurea Insecticide Residue in Beverages

Efficient capture of benzoylurea insecticide (BU) residue in food is a vital procedure for food safe monitoring. Herein, a core-shell structured magnetic fluorinated covalent organic framework with good magnetic responsiveness and abundant fluorine affinity sites was successfully synthesized, suitable for magnetic solid-phase extraction (MSPE) of BUs. Using a room-temperature synthesis strategy, the magnetic fluorinated covalent organic framework was fabricated by in situ polymerization of 1,3,5-tris(4-aminophenyl) triazine (TAPT) and 2,3,5,6-tetrafluoroterephthaldehyde (TFTA) on the surface of carboxylated Fe₃O₄ nanoparticles. The competitive adsorption experiment and molecular simulation verified that this magnetic fluorinated covalent organic framework possesses favorable adsorption affinity for BUs. This magnetic fluorinated covalent organic framework could be easily regenerated and reused at least eight times with no reduction of enrichment performance. Combining this magnetic fluorinated covalent organic framework-based MSPE with high-performance liquid chromatography-tandem mass spectrometry, a novel sensitive method for the analysis of BUs was developed. In yellow wine and fruit juice samples, good linear correlations were obtained for BUs in the range of 10-2000 and 20-4000 ng·L^-1, respectively. The limit of quantitation of the BUs ranged from 1.4 to 13.3 ng·L^-1 in the two beverage matrices. Desirable precision was achieved, with intraday and interday relative standard deviations lower than 11%.

Perfluorinated Probes for Noncovalent Protein Recognition and Isolation

Perfluorinated organic compounds (PFCs) are nontoxic, biocompatible, bioavailable, and bioorthogonal species which possess the unique ability to segregate away from both polar and nonpolar solvents producing a compact fluorophilic phase. Traditional techniques of fluorous chemical proteomics are generally applied to enrich biological samples in target protein(s) exploiting this property of PFCs to build fluorinated probes able to covalently bind to protein ensembles and being selectively extracted by fluorophilic solvents. Aiming at building a strategy able to avoid irreversible modification of the analyzed biosystem, a novel fully noncovalent probe is presented as an enabling tool for the recognition and isolation of biological protein(s). In our strategy, both the fluorophilic extraction and the biorecognition of a selected protein successfully occur via the establishment of reversible but selective interactions.

One-step separation of the recombinant protein by using the amine-functionalized magnetic mesoporous silica nanoparticles; an efficient and facile approach

The separation process is the main stage of recombinant production. With the advancement of nanotechnology and the development of magnetic nanoparticles, these structures are increasingly used in different applications. In the present study, we produced the recombinant human growth hormone from Pichia pastoris and for protein separation provided the surfaces similar to chromatographic columns on the surface of magnetic nanoparticles. For this purpose, using a co-precipitation method, the core of Fe₃O₄ was prepared and coated by silica. To increase the protein availability, silica mesoporous formation and its amine functionalization were performed. The specific surface area and the pore size were determined 78.3189 m²/g and 7.44 nm. After the magnetic separation, the sample loading in SDS gel shows a reduction in protein band and the protein absorption at a wavelength of 280 nm. Finally, we evaluate the ability of amine functionalized nanoparticles for protein separation that demonstrate the adsorption capacity significantly increased compare with silica-coated nanoparticles. The amine functionalized nanoparticles provide the maximum adsorption capacity of 235.21 μg/mg and after the elution, protein concentration determined 476 mg/L. This work indicates the functionalized magnetic mesoporous silica nanoparticles can be used as the best candidate for the separation of different biological macromolecules.

Palladium modified porous silicon as multi-functional MALDI chip for serum peptide detection

Interest in using mesoporous materials for peptidomic research has increased recently.

Fluorous modified magnetic mesoporous silica composites-incorporated fluorous solid-phase extraction for the specific enrichment of N-linked glycans with simultaneous exclusion of proteins

Taking advantage of fluorine-fluorine interactions, fluorous solid-phase extraction (FSPE) is emerging as a novel approach in proteomics research. Notably, silica gel bound with perfluoroalkyl groups was applied to the FSPE of N-linked glycans. Based on previous studies, mesoporous silica coated magnetic nanoparticles bound with perfluoroalkyl groups were synthesized for the specific enrichment of N-linked glycans in this study. The magnetic nanoparticles-incorporated FSPE strategy successfully identified 22 N-linked glycans from the OVA digest with a concentration of 0.5μg/μL, and achieved a detection limit of 5ng/μL (with 16 N-linked glycans identified). It also showed good day-to-day reproducibility. Its selectivity towards BSA protein is 1:200 (molar ratio), showing excellent size-exclusion effect. In addition, the present method proved to be effective for the analysis of the human serum digest, opening up new prospect for the identification of glycans and proteins with other post-translational modifications in biological environment.