Characterizations of Protein Arginine Deiminase 1 as a Substrate of NTMT1: Implications of Nα-Methylation in Protein Stability and Interaction.

α-N-Methylation (Nα-methylation), catalyzed by protein N-terminal methyltransferases (NTMTs), constitutes a crucial post-translational modification involving the transfer of a methyl group from -adenosyl-l-methionine (SAM) to the Nα-terminal amino group of substrate proteins. NTMT1/2 are known to methylate canonical Nα sequences, such as X-P-K/R. With over 300 potential human protein substrates, only a small fraction has been validated, and even less is known about the functions of Nα-methylation.

Global profiling of arginine dimethylation in regulating protein phase separation by a steric effect-based chemical-enrichment method.

Protein arginine methylation plays an important role in regulating protein functions in different cellular processes, and its dysregulation may lead to a variety of human diseases. Recently, arginine methylation was found to be involved in modulating protein liquid-liquid phase separation (LLPS), which drives the formation of different membraneless organelles (MLOs). Here, we developed a steric effect-based chemical-enrichment method (SECEM) coupled with liquid chromatography-tandem mass spectrometry to analyze arginine dimethylation (DMA) at the proteome level.

An antibody-free enrichment approach enabled by reductive glutaraldehydation for monomethyllysine proteome analysis.

Protein lysine monomethylation is an important post-translational modification participated in regulating many biological processes. There is growing interest in identifying these methylation events. However, the introduction of one methyl group on lysine residues has negligible effect on changing the physical and chemical properties of proteins or peptides, making enriching and identifying monomethylated lysine (Kme1) proteins or peptides extraordinarily challenging.

Proteome-Wide Deconvolution of Drug Targets and Binding Sites by Lysine Reactivity Profiling.

Recently, numerous efforts have been devoted to identifying drug targets and binding sites in complex proteomes, which is of great importance in modern drug discovery. In this study, we developed a robust lysine reactivity profiling method to systematically study drug-binding targets and binding sites at the proteome level. This method is based on the principle that binding of a drug to a specific region of target proteins will change the reactivity of lysine residues that are located at this region, and these changes can be detected with an enrichable and lysine reactive probe.

An efficient approach based on basic strong cation exchange chromatography for enriching methylated peptides with high specificity for methylproteomics analysis.

Protein methylation as one of the most important post-translational modifications has been under the spotlight due to its essential role in many biological processes. Development of methods for large-scale analysis of protein methylation greatly accelerates the related researches. To date, antibody-based enrichment strategy is the most common approach for methylproteomics analysis.

Selective enrichment of N-terminal proline peptides via hydrazide chemistry for proteomics analysis.

A challenge for shotgun proteomics is the identification of low abundance proteins, which is always hampered owing to the extreme complexity of protein digests and highly dynamic concentration range of proteins. To reduce the complexity of the peptide mixture, we developed a novel method to selectively enrich N-terminal proline peptides via hydrazide chemistry. This method consisted of ortho-phthalaldehyde (OPA) blocking of primary amines in peptides, reductive glutaraldehydation of N-terminal proline and solid phase hydrazide chemistry enrichment of aldehyde-modified N-terminal proline peptide.

In situ growth of COF-rLZU1 on the surface of silica sphere as stationary phase for high performance liquid chromatography.

The composite materials consist of Covalent Organic Frameworks (COFs) and silica have been regarded as a kind of promising stationary phases due to combination of the large specific surface area and good mechanical strength of porous silica microspheres and the porous structure and the excellent stability of COFs. Herein, a novel COFs-silica composite (SiO@rLZU1, reduced Lan Zhou University-1) was prepared via an in-situ growth strategy with a 32 nm-thick COFs layer on the surface of silica and a 2.2 nm-thick COFs layer on the inner surface of the mesopores of spherical silica (5 μm, 120 Å).