Customized synthesis of phosphoprotein bearing phosphoserine or its nonhydrolyzable analog.

Studies on the mechanism of protein phosphorylation and therapeutic interventions of its related molecular processes are limited by the difficulty in the production of purpose-built phosphoproteins harboring site-specific phosphorylated amino acids or their nonhydrolyzable analogs. Here we address this limitation by customizing the cell-free protein synthesis (CFPS) machinery via chassis strain selection and orthogonal translation system (OTS) reconfiguration screening. The suited chassis strains and reconfigured OTS combinations with high orthogonality were consequently picked out for individualized phosphoprotein synthesis.

Genetically Encoded Phosphine Ligand for Metalloprotein Design.

Phosphine ligands are the most important class of ligands for cross-coupling reactions due to their unique electronic and steric properties. However, metalloproteins generally rely on nitrogen, sulfur, or oxygen ligands. Here, we report the genetic incorporation of P3BF, which contains a biocompatible borane-protected phosphine, into proteins.

Intrinsically Disordered Protein Condensate-Modified Surface for Mitigation of Biofouling and Foreign Body Response.

Mitigation of biofouling and the host's foreign body response (FBR) is a critical challenge with biomedical implants. The surface coating with various anti-fouling materials provides a solution to overcome it, but limited options in clinic and their potential immunogenicity drive the development of more alternative coating materials. Herein, inspired by liquid-liquid phase separation of intrinsically disordered proteins (IDPs) to form separated condensates in physiological conditions, we develop a new type of low-fouling biomaterial based on flexible IDP of FUS protein containing rich hydrophilic residues.

Unremitting progresses for phosphoprotein synthesis.

Phosphorylation, one of the important protein post-translational modifications, is involved in many essential cellular processes. Site-specifical and homogeneous phosphoproteins can be used as probes for elucidating the protein phosphorylation network and as potential therapeutics for interfering their involved biological events. However, the generation of phosphoproteins has been challenging owing to the limitation of chemical synthesis and protein expression systems.

Metal ion and light sequentially induced sol-gel-sol transition of a responsive peptide-hydrogel.

We developed a new responsive peptide hydrogel FmocFFpSC(oNB)-PEG, which could achieve gel formation induced by calcium ions and sequential dissolution stimulated by light. It provides a potential delivery system for the efficient encapsulation of drugs and their controlled release in a spatial and temporal way.

SERS-based chip for discrimination of formaldehyde and acetaldehyde in aqueous solution using silver reduction.

A method is described for surface-enhanced Raman scattering (SERS) discrimination of formaldehyde (FA) and acetaldehyde (AA) in aqueous sample solutions. It is based on the use of a paper strip containing 4-aminothiophenol (Atp)-modified reduced graphene oxide (rGO)/[Ag(NH)] (rGO/[Ag(NH)]/Atp). The addition of FA or AA induces the conversion of [Ag(NH)] complex to silver nanoparticles (AgNPs) because of aldehyde-induced silver reduction reaction.

Stereoselective synthesis of a phosphonate pThr mimetic via palladium-catalyzed γ-C(sp)-H activation for peptide preparation.

We report a facile synthetic strategy toward CH2-substituted phosphothreonine mimetics. Herein, inexpensive valine with a directing group was converted into homothreonine via palladium-catalyzed γ-methyl C(sp3)-H bond activation, followed by construction of a phosphorus-carbon bond via the well-developed Appel reaction and Michaelis-Becker reaction with a total yield of 30%. Furthermore, the derived mimetic was applied for solid-phase synthesis of two phosphopeptide inhibitors.

Fluorescent/SERS dual-sensing and imaging of intracellular Zn.

A fluorescent and surface-enhanced Raman spectroscopy (SERS) dual-mode probe is developed for imaging of intracellular Zn based on N-(2-(bis(pyridine-2-ylmethyl)amino)ethyl)-2-mercaptoacetamide (MDPA) modified gold nanoparticles (MDPA-GNPs). Benefiting from the chelation-enhanced fluorescence (CHEF) between MDPA-GNPs and Zn, the fluorescent intensities of MDPA-GNPs are substantially enhanced with the increment of Zn concentrations, which can be clearly observed by the naked eye. Under physiological conditions, the probe exhibits a stable response for Zn from 1 μM to 120 μM, with a detection limit of 0.

Facile synthesis of highly active fluorinated ultrathin graphitic carbon nitride for photocatalytic H evolution using a novel NaF etching strategy.

Although graphitic carbon nitride (GCN) has been intensively studied in photocatalytic research, its performance is still hindered by its inherently low photo-absorption and inefficient charge separation. Herein, we report a simple NaF solution treating method to produce fluorinated and alkaline metal intercalated ultrathin GCN with abundant in-plane pores and exposed active edges, and therefore an enhanced number of actives sites. Compared to bulk GCN, NaF treated GCN has a larger specific surface area of 81.

Synthesis of α,α-Difluorinated Phosphonate pSer/pThr Mimetics via Rhodium-Catalyzed Asymmetric Hydrogenation of β-Difluorophosphonomethyl α-(Acylamino)acrylates.

A novel and facile synthetic strategy for α,α-difluorinated phosphonate mimetics of phosphoserine/phosphothreonine utilizing rhodium-catalyzed asymmetric hydrogenation was developed. The dehydrogenated substrate β-difluorophosphonomethyl α-(acylamino)acrylates were first prepared from protected serine/threonine followed by asymmetric hydrogenation using the rhodium-DuPhos catalytic system to generate the chiral center(s). These important phosphonate building blocks were successfully incorporated into phosphatase-resistant peptides, which displayed similar inhibition to the 14-3-3 ζ protein as the parent pSer/pThr peptides.

Headspace-Sampling Paper-Based Analytical Device for Colorimetric/Surface-Enhanced Raman Scattering Dual Sensing of Sulfur Dioxide in Wine.

This study demonstrates a novel strategy for colorimetric/surface-enhanced Raman scattering (SERS) dual-mode sensing of sulfur dioxide (SO) by coupling headspace sampling (HS) with paper-based analytical device (PAD). The smart and multifunctional PAD is fabricated with a vacuum filtration method in which 4-mercaptopyridine (Mpy)-modified gold nanorods (GNRs)-reduced graphene oxide (rGO) hybrids (rGO/MPy-GNRs), anhydrous methanol, and starch-iodine complex are immobilized into cellulose-based filter papers. The resultant PAD exhibits a deep-blue color with a strong absorption peak at 600 nm due to the formation of an intermolecular charge-transfer complex between starch and iodine.

On-site preconcentration of pesticide residues in a drop of seawater by using electrokinetic trapping, and their determination by surface-enhanced Raman scattering.

The authors have developed a method for simultaneous quantification of several charged pesticides (as shown for amitrole, simazine, trichlorfon and bisultap). It is based on the use of a reduced graphene oxide-modified screen-printed electrode (RGO-SPE) and combines electrokinetic trapping (EKT) and surface-enhanced Raman scattering (SERS). When a 50 μL droplet containing negatively charged RGO and positively charged gold nanorods is placed on the SPE, the RGO and gold nanorods are selectively attracted on the surface of the SPE during EKT.

Griess reaction-based paper strip for colorimetric/fluorescent/SERS triple sensing of nitrite.

This study demonstrates a novel strategy for colorimetric/fluorescent/surface enhanced Raman scattering (SERS) triple-mode sensing of nitrite based on Griess reaction modulated gold nanorods (GNRs)-Azo-gold nanoparticles (GNPs) (GNRs-Azo-GNPs) assembly. The p-aminothiophenol (PATP)-capped GNRs (GNRs@PATP) and 1,8-diaminonaphthalene (DAP)-modified GNPs (GNPs@DAP) are first synthesized through Au-S and Au-N bonds, respectively. Upon being excited at 365nm, the dispersion of GNRs-GNPs (GNRs@PATP and GNPs@DAP) emits cyan fluorescence.