Small-Molecule Modulated Affinity-Tunable Semisynthetic Protein Switches.

Engineered protein switches have been widely applied in cell-based protein sensors and point-of-care diagnosis for the rapid and simple analysis of a wide variety of proteins, metabolites, nucleic acids, and enzymatic activities. Currently, these protein switches are based on two main types of switching mechanisms to transduce the target binding event to a quantitative signal, through a change in the optical properties of fluorescent molecules and the activation of enzymatic activities. In this paper, we introduce a new affinity-tunable protein switch strategy in which the binding of a small-molecule target with the protein activates the streptavidin-biotin interaction to generate a readout signal. In the absence of a target, the biotinylated protein switch forms a closed conformation where the biotin is positioned in close proximity to the protein, imposing a large steric hindrance to prevent the effective binding with streptavidin. In the presence of the target molecule, this steric hindrance is removed, thereby exposing the biotin for streptavidin binding to produce strong fluorescent signals. With this modular sensing concept, various sulfonamide, methotrexate, and trimethoprim drugs can be selectively detected on the cell surface of native and genetically engineered cells using different fluorescent dyes and detection techniques.

Systematic Elucidation of the Potential Mechanism of Erzhi Pill against Drug-Induced Liver Injury via Network Pharmacology Approach.

OBJECTIVE: The purpose of this work was to investigate the bioactive compounds, core genes, and pharmacological mechanisms and to provide a further research orientation of Erzhi pill (EZP) on drug-induced liver injury (DILI). METHODS: At first, we collected information of bioactive compounds of EZP from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and previous studies. And then, the targets related to bioactive compounds and DILI were obtained from 4 public databases. At last, Cytoscape was used to establish a visual network. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and network analysis were performed to investigate potential mechanism of EZP against DILI. RESULTS: A total of 23 bioactive compounds and 89 major proteins of EZP were screened out as potential players against DILI. Association for bioactive compounds, core targets, and related pathways was analyzed, implying that core targets related to these pathways are ALB, AKT1, MAPK1, EGFR, SRC, MAPK8, IGF1, CASP3, HSP90AA1, and MMP9, and potential mechanisms of EZP acting on DILI are closely related to negative regulation of apoptosis process, improvement of lipid metabolism, and positive regulation of liver regeneration process. CONCLUSION: This study demonstrated the multicompound, multitarget, and multichannel characteristics of EZP, which provided a novel approach for further research the mechanism of EZP in the treatment of DILI.