Related Experiment Video
Updated: Dec 14, 2025
Live Imaging and Quantification of Viral Infection in K18 hACE2 Transgenic Mice Using Reporter-Expressing Recombinant SARS-CoV-2
Published on: November 5, 2021
Discovery of M Protease Inhibitors Encoded by SARS-CoV-2
Hui-Chen Hung1, Yi-Yu Ke1, Sheng Yu Huang2
1Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, Taiwan.
Abstract:
The coronavirus (CoV) disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is a health threat worldwide. Viral main protease (Mpro, also called 3C-like protease [3CLpro]) is a therapeutic target for drug discovery. Herein, we report that GC376, a broad-spectrum inhibitor targeting Mpro in the picornavirus-like supercluster, is a potent inhibitor for the Mpro encoded by SARS-CoV-2, with a half-maximum inhibitory concentration (IC50) of 26.4 ± 1.1 nM. In this study, we also show that GC376 inhibits SARS-CoV-2 replication with a half-maximum effective concentration (EC50) of 0.91 ± 0.03 μM. Only a small portion of SARS-CoV-2 Mpro was covalently modified in the excess of GC376 as evaluated by mass spectrometry analysis, indicating that improved inhibitors are needed. Subsequently, molecular docking analysis revealed that the recognition and binding groups of GC376 within the active site of SARS-CoV-2 Mpro provide important new information for the optimization of GC376. Given that sufficient safety and efficacy data are available for GC376 as an investigational veterinary drug, expedited development of GC376, or its optimized analogues, for treatment of SARS-CoV-2 infection in human is recommended.
Insights
GC376 effectively inhibits SARS-CoV-2 replication by targeting the viral main protease (Mpro). Further optimization of GC376 is recommended for human therapeutic development against COVID-19.
Area of Science:
- Virology
- Drug Discovery
- Biochemistry
Background:
- The COVID-19 pandemic, caused by SARS-CoV-2, poses a significant global health challenge.
- The viral main protease (Mpro) is a critical therapeutic target for developing antiviral drugs.
- Picornavirus-like supercluster Mpro inhibitors offer a potential avenue for SARS-CoV-2 drug development.
Purpose of the Study:
- To evaluate the efficacy of GC376, a broad-spectrum Mpro inhibitor, against SARS-CoV-2.
- To investigate the inhibitory mechanism and potential for optimization of GC376 for human use.
Main Methods:
- In vitro assays to determine the half-maximum inhibitory concentration (IC50) of GC376 against SARS-CoV-2 Mpro.
- Cell-based assays to measure the half-maximum effective concentration (EC50) of GC376 against SARS-CoV-2 replication.
- Mass spectrometry to analyze the covalent modification of SARS-CoV-2 Mpro by GC376.
- Molecular docking to understand the binding interactions of GC376 within the Mpro active site.
Main Results:
- GC376 demonstrated potent inhibition of SARS-CoV-2 Mpro with an IC50 of 26.4 ± 1.1 nM.
- GC376 effectively inhibited SARS-CoV-2 replication with an EC50 of 0.91 ± 0.03 μM.
- Mass spectrometry revealed limited covalent modification of Mpro by GC376, suggesting room for improvement.
- Molecular docking provided insights into GC376's binding mode, guiding optimization strategies.
Conclusions:
- GC376 is a potent inhibitor of SARS-CoV-2 Mpro and exhibits antiviral activity.
- Further optimization of GC376 or its analogues is warranted for enhanced efficacy and covalent modification.
- Given its existing safety profile as a veterinary drug, expedited development of GC376 for human COVID-19 treatment is recommended.
More Related Videos
07:53A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation
Published on: January 9, 2019
10:25Detection of SARS-CoV-2 Neutralizing Antibodies using High-Throughput Fluorescent Imaging of Pseudovirus Infection
Published on: June 5, 2021
Related Concept Videos
01:05Single Nucleotide Polymorphisms-SNPs
02:50Conjugated Proteins
Nucleoproteins are protein complexes that contain nucleic acids, categorized as deoxyribonucleoproteins (DNPs) or ribonucleoproteins (RNPs) respectively. The nucleosome is a typical example of a DNP where nuclear DNA is associated with histone proteins. The major antigen for the Covid-19 virus SARS-CoV is an RNP that is critical...