Article
作者: Ye, Xianlong ; Xu, Fangfang ; Liu, Longying ; Zhou, Liangliang ; Wang, Jixia ; Hou, Tao ; Liang, Xinmiao ; Liu, Yanfang ; Tang, Hongming ; Liu, Liangji ; Zhang, Tianyu ; Wang, Pan ; Zhou, Han
Introduction::The coronavirus 3C-like protease (3CLpro) is essential for
SARS-CoV-2 replication, making it a key target for antiviral drug development. Natural
products represent a valuable source of bioactive compounds. This study aimed to identify
novel 3CLpro inhibitors from natural compounds through a combination of virtual
screening and experimental validation.
Methods::Recombinant 3CLpro was expressed, purified, and evaluated for enzymatic activity
using Fluorescence Resonance Energy Transfer (FRET) assays under optimized
conditions. Out of 583 virtually screened compounds, 30 were selected for experimental
validation. Epitheaflagallin 3-O-gallate (ETFGg) was further analyzed for binding interactions
using Molecular Dynamics (MD) simulations.
Results::ETFGg exhibited strong binding affinity (−66.90 kcal/mol) and inhibitory activity
(IC50 = 8.73 ± 2.30 μM) against 3CLpro. MD simulations revealed stable interactions
with key residues (HIE163, THR190, GLN192) in the 3CLpro active site.
Discussion::Our findings demonstrate that ETFGg is a potent and stable inhibitor of
SARS-CoV-2 3CLpro, with a binding profile distinct from known inhibitors such as ebselen.
The substrate inhibition kinetics observed suggest a novel allosteric mechanism,
which may provide a new strategy for targeting 3CLpro. This study supports the value
of natural product libraries combined with computational and FRET-based screening for
discovering antiviral leads.
Conclusion::ETFGg was identified as a promising 3CLpro inhibitor with high binding
stability, highlighting its potential as a lead compound for the development of anti--
COVID-19 drugs.
