Identification of potent food constituents as SARS-CoV-2 papain-like protease modulators through advanced pharmacoinformatics approaches

The current ongoing pandemic of COVID-19 urges immediate treatment measures for controlling the highly contagious SARS-CoV-2 infections. The papain-like protease (PLpro), which is released from nsp3, is presently being evaluated as a significant anti-viral drug target for COVID-19 therapy development. Particularly, PLpro is implicated in the cleavage of viral polyproteins and antagonizes the host innate immune response through its deubiquitinating and deISGylating actions, thus making it a high-profile antiviral therapeutic target. The present study reports a few specific food compounds that can bind tightly with the SARS-CoV-2 PLpro protein identified through extensive computational screening techniques. Precisely, extensive advanced computational approaches combining target-based virtual screening, particularly employing sub-structure based similarity search, molecular docking, molecular dynamics (MD) simulations, and MM-GBSA based binding free energy calculations have been employed for the identification of the most promising food compounds with substantial functional implications as SARS-CoV-2 PLpro protein inhibitors/modulators. Observations from the present research investigation also provide a deeper understanding of the binding modes of the proposed four food compounds with SARS-CoV-2 PLpro protein. In docking analyses, all compounds have established essential inter-molecular interaction profiles at the active site cavity of the SARS-CoV-2 PLpro protein. Similarly, the long-range 100 ns conventional MD simulation studies also provided an in-depth understanding of probable interactions and dynamic behaviour of the SARS-CoV-2 PLpro protein-food compound complexes. Binding free energies of all molecular systems revealed a strong interaction affinity of food compounds towards the SARS-CoV-2 PLpro protein. Moreover, clear-cut comparative analyses against the known standard inhibitor also suggest that proposed food compounds may act as potential active chemical entities for modulating the action of the SARS-CoV-2 PLpro protein.