Molecular Dynamics of SARS-CoV-2 Main Protease Inhibitors

The SARS-CoV-2 main protease (Mpro, also called 3CLpro) is a pivotal enzyme in viral replication, cleaving polyproteins into functional components. Molecular dynamics (MD) simulations have become indispensable for understanding how small-molecule inhibitors engage the flexible active site of Mpro, revealing transient conformations, energetic pathways of binding and unbinding, and the influence of mutations on inhibitor efficacy. By capturing time-resolved atomic motions, MD complements static crystallographic snapshots, guiding the optimisation of binding affinity, selectivity and pharmacokinetic properties. Computational screening pipelines now integrate high-throughput docking, MD-based free energy calculations and enhanced-sampling techniques to prioritise lead compounds before synthesis. This multiscale approach accelerates the rational design of both covalent and noncovalent inhibitors, anticipates potential resistance mutations and informs structure-driven medicinal chemistry with dynamic insights into enzyme–ligand interactions under near-physiological conditions.

Research from Nature Portfolio

Recent studies have advanced the dynamic and structural understanding of Mpro inhibition. A 2024 investigation of an α-ketoamide peptidomimetic inhibitor revealed that covalent binding to the catalytic cysteine is accompanied by unusually slow dissociation kinetics, as determined by enzyme-inhibition assays and supported by MD-inspired analyses of the binding pocket. This compound exhibited potent in vitro activity against SARS-CoV-2 variants and improved pharmacokinetics in animal models, suggesting that kinetic stability in the binding site can reduce or eliminate the need for pharmacokinetic boosters. In 2023, the development of an orally bioavailable 3C-like protease inhibitor arose from structure-based optimisation of an existing antiviral scaffold. Thermodynamic profiling indicated an enthalpy-driven binding signature, and complementary dynamic simulations helped rationalise the inhibitor’s broad activity against divergent coronavirus proteases, high selectivity and favourable safety profile in preclinical species. Another report explored the emergence of resistance to a leading oral Mpro inhibitor through in vitro viral passaging. Multiple mutational pathways were mapped, and structural modelling coupled with MD sampling identified how individual and combined amino-acid substitutions perturb inhibitor binding and restore enzymatic function, thereby informing designs for next-generation compounds less susceptible to resistance.

Molecular Dynamics of SARS-CoV-2 Main Protease Inhibitors publication trend

The graph below shows the total number of articles in molecular dynamics of sars-cov-2 main protease inhibitors across all publications each year (not limited to Nature Index journals).

Technical terms

Molecular dynamics (MD): Computational simulation of atomic motions over time to study conformational changes and binding interactions.

Main protease (Mpro, 3CLpro): Viral cysteine protease essential for processing SARS-CoV-2 polyproteins into functional units.

α-Ketoamide inhibitor: Small-molecule inhibitor featuring a ketoamide group that forms a covalent bond with the catalytic cysteine of Mpro.

Peptidomimetic: Molecule that mimics the peptide substrate of an enzyme to inhibit its activity.

Binding free energy: Thermodynamic quantity describing the favourability of ligand–protein association.

References

1. Preclinical evaluation of the SARS-CoV-2 Mpro inhibitor RAY1216 shows improved pharmacokinetics compared with nirmatrelvir. Nature Microbiology (2024).
2. Structure-based development and preclinical evaluation of the SARS-CoV-2 3C-like protease inhibitor simnotrelvir. Nature Communications (2023).
3. Open science discovery of potent noncovalent SARS-CoV-2 main protease inhibitors. Science (2023).
4. Structural plasticity of SARS-CoV-2 3CL Mpro active site cavity revealed by room temperature X-ray crystallography. Nature Communications (2020).
5. Crystal structure of SARS-CoV-2 main protease provides a basis for design of improved α-ketoamide inhibitors. Science (2020).
6. Structure-based design of antiviral drug candidates targeting the SARS-CoV-2 main protease. Science (2020).
7. Multiple pathways for SARS-CoV-2 resistance to nirmatrelvir. Nature (2022).