[BIO-19]Gold-based agents as promising metallo-β-lactamase inhibitors

Investigation of Gold(I)-based agents as B2 subclass metallo-β-lactamase inhibitors was performed. We demonstrated that several Au(I)-based agents, such as auranofin and auromalate, exhibited antimicrobial activity towards both CphA and Sfh-I positive bacteria in vitro when co-treated with meropenem. The bactericidal activity of meropenem could be restored effectively by Au(I). The synergistic effect was due to the inhibition of enzyme activity by Au(I) with competitive inhibition. Release of Zn(II) was observed upon Au(I) treatment, indicating that the inhibition was achieved by the removal of Zn(II) from the protein active site. Results proved Au(I)-based agents are potential inhibitors of B2 subclass MBLs.

Continue reading

[BIO-18]Chemical synthesis of LAIR1 protein cytoplasmic tail

Both native and phosphorylated LAIR1 cytoplasmic tail were achieved by chemical synthesis, with Cysteine Ligation and NCL (Native chemical ligation). Herein, cysteine ligation was followed by one-pot conversion of thiozolidine to cysteine, and formyl group removal on Tryptophan, which was not accessible with oxidized hydrazide method. Moreover, phosphorylated LAIR1 cytoplasmic tail was also successfully synthesized by this strategy. The study in vitro is under process.

Continue reading

[BIO-17] Emerging tools to interrogate metalloenzymes that uphold DNA repair processes

Iron sulfur cluster is an evolutionary-conserved protein cofactor that is crucial in human DNA metabolism due to their presence in major DNA repairment proteins. Aberrant functioning of DNA repairment proteins can lead to abnormal cellular behaviour, which in the extreme case the cell will proceed to neoplastic state. A searching method is applied to interrogate iron sulfur proteins that are associated to human somatic alterations. Input parameter for data selection from web-based protein structural portals included iron sulfur protein signature sequence and typical cysteine geometry. Lists of protein candidates generated was compared with somatic mutation information from online databases.

Continue reading

[BIO-16]Chemical protein synthesis of protein 2B4

Natural killer cell receptor 2B4 is a natural killer (NK) cell activation receptor that can provide a co-stimulatory signal to other activation receptors. Its signal transduction may be closely related to the phosphorylation of the immunoreceptor tyrosine-based switch motif (ITSM) sequence of the 2B4. However, protein 2B4 with PTM could not be prepared by biologically controlled methods, limiting the study of the acting models of protein 2B4 in the cell. In this work, we successfully synthesized the protein 2B4 and its different phosphorylation combinations by combining chemical ligation method of serine/threonine ligation (STL) and cysteine/penicillamine ligation (CPL) for further investigation.

Continue reading

[BIO-15]Substrate profiling of non-canonical ubiquitinase SdeA using modified ubiquitin probes

Natural killer cell receptor 2B4 is a natural killer (NK) cell activation receptor that can provide a co-stimulatory signal to other activation receptors. Its signal transduction may be closely related to the phosphorylation of the immunoreceptor tyrosine-based switch motif (ITSM) sequence of the 2B4. However, protein 2B4 with PTM could not be prepared by biologically controlled methods, limiting the study of the acting models of protein 2B4 in the cell. In this work, we successfully synthesized the protein 2B4 and its different phosphorylation combinations by combining chemical ligation method of serine/threonine ligation (STL) and cysteine/penicillamine ligation (CPL) for further investigation.

Continue reading

[BIO-11]Chemical synthesis of glycosylated spike RBD peptides

The emergence and wide spreading of novel coronavirus SARS-CoV-2 represent a serious threat to global human health. There is surely an urgent need to develop a vaccine to halt the viral infection and curb the pandemic. To solve the heterogeneity problem of glycopeptides/proteins obtained from biological systems, we aim to develop a chemical synthesis strategy to generate structure-defined glycosylated peptides derived from the spike protein, with which to develop vaccine candidates for SARS-CoV-2. Chemical synthesis of a complex glycopeptide/protein involves solid-phase peptide synthesis (SPPS), Ser/Thrligation (STL) and Cys/Pen ligation (CPL).

Continue reading