•Developing a facile synthesis method to CH2-substituted phosphonate pSer mimetic.•Applying phosphonate pSer mimetic in SPPS synthesis of 14-3-3 ζ substrate.•The phosphatase-resistant substrate peptide retains 14-3-3 ζ binding efficacy.Phosphatase-inert peptidomimetics containing phosphonate pSer analogue have been developed as valuable biological tools for probing and regulating pSer-dependent protein-protein interactions (PPIs) in cellular context. Herein, we report a facile and efficient synthesis route of Fmoc-protected phosphonate pSer mimetic and also present the application of this building block in the solid-phase synthesis of a phosphatase-resistant substrate peptide of 14-3-3 ζ, retaining 14-3-3 ζ binding efficacy similar to the parent pSer-containing peptide.Download high-res image (98KB)Download full-size image

A site-specific dual-color labeled ubiquitin for sensing deubiquitinase's activity was prepared by consecutively using chemoselective native chemical ligation reactions in a facile and efficient way. The prepared sensor was applied to establish a sensitive FRET-based assay for UCH-L3.

A new type of –NH– bridged azacalix[2]arene[2]carbazoles has been synthesized by aromatic nucleophilic substitution reaction via one pot and/or fragment coupling strategy. Both symmetric and unsymmetric macrocycles are obtained. X-ray single crystal analysis reveals 1,3-alternation conformation of the macrocycle. The spectroscopic and electrochemical properties of the macrocycles are also explored.

•Phosphorylation at P3 tyrosine hinders the recognition of TEV protease to the substrate.•A facile method was developed to regulate the cleavage capability of TEV protease.•A mutual quenching pair FAM-pyrene was used in the peptide-based protease sensor.TEV protease is of great importance for in vitro and in vivo site-specific cleavage of proteins. The proteolytic efficiency of TEV protease is often regulated by mutation of the substrate, which is irreversible and hard to be modulated. Herein, a facile and reversible method, based on phosphorylation in the substrate, is developed to regulate the cleavage capability of TEV protease. Phosphorylation at P3 tyrosine hinders the recognition of TEV protease to the substrate by using a robust fluorescent protease sensor. Moreover, the phosphate group can be easily removed by alkaline phosphatases for recovering the proteolytic efficiency of TEV protease. Additionally, 5(6)-carboxyfluorescein and pyrene have been used as high-efficiency mutual fluorophore-quencher pair in the peptide-based protease sensor for the first time, which provides a chance to simultaneously monitor the cleavage process in two respective fluorescence channels. Further studies indicated both dynamic and static components contributing to the mutual quenching system. The phosphorylation-regulated TEV protease proteolysis system can be used in conditional cleavage of protein or peptide tag.We determined that phosphorylation at P3 tyrosine severely hinders the recognition of TEV protease to the substrate using a robust fluorescent protease sensor. Moreover, the phosphate group can be easily removed by alkaline phosphatase from calf intestinal (CIP) for recovering the proteolytic efficiency of TEV protease, which fulfills conditional cleavage of peptide sequence. In addition, 5(6)-carboxyfluorescein (FAM) and pyrene (Pyr) have been used as a high-efficiency mutual fluorophore-quencher pair in the peptide-based protease sensor, which provides a chance to simultaneously monitor the cleavage process in two respective fluorescence channels.

Promoting clearance of intracellular excessive tau is a potential therapeutic strategy for treating Alzheimer's disease. In this work, we designed and synthesized a cyclen-hybrid artificial ‘hydrolase’ I1-Cu(II) to cleave tau in vitro. Furthermore, a cell-permeable ‘hydrolase’ I2-Cu(II), derived from I1-Cu(II), was also synthesized to cleave intracellular tau proteins.

HIV entry is mediated by the envelope glycoproteins gp120 and gp41. The gp41 subunit contains several functional domains: the N-terminal heptad repeat (NHR) domains fold a triple stranded coiled-coil forming a meta-stable prefusion intermediate. C-terminal heptad repeat (CHR) subsequently folds onto the hydrophobic grooves of the NHR coiled-coil to form a stable 6-helix bundle, which juxtaposes the viral and cellular membranes for fusion. The C34 which has 34 amino acid residues is known as the core structure in CHR. A highly anti-HIV peptide inhibitor derived from C34 was designed. An artificial salt bridge was added in the 6-helical bundle by substitution of lysine for Ile646. With a cholesterol modification at C-terminal, the inhibitor containing I646K mutation represented higher anti-viral activity than C34–cholesterol combination without mutation.A salt bridge was added in the 6-helical bundle by substitution of lysine for Ile646. The new inhibitor has been tested for antiviral activity.