Why Are Lopinavir and Ritonavir Effective against COVID-19?

What is it about?

Since 2020, researchers have been working towards developing vaccines and drugs against coronavirus SARS-CoV-2, or COVID-19. Existing antiviral drugs were tested for their efficacy against this coronavirus. Two such anti-HIV drugs, lopinavir and ritonavir, were of particular interest for their potential role in inhibiting an important SARS-CoV-2 protease, 3CLpro. What is this protease? 3CLpro is a nonstructural protein responsible for a very significant biological process in SARS-CoV-2—viral replication and maturation. Understandably, 3CLpro could be a viable target for drugs that aim to treat COVID-19. But for drugs to act against a virus, they need to be able to bind with its viral proteins. This study describes how authors used molecular modelling and quantum chemical techniques to elucidate the three-dimensional binding interactions of lopinavir and ritonavir with the SARS-CoV-2 proteinase 3CLpro. They determined the stability of drug-proteinase interactions, by measuring the strength of the hydrogen bonds and atom contacts, as well as the energies of these interactions. Both drugs could interact and bind to the active site of 3CLpro. Ritonavir, however, displayed stronger interactions with the proteinase than lopinavir, on account of its residue pattern.

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Photo by Glen Carrie on Unsplash

Photo by Glen Carrie on Unsplash

Why is it important?

The simulations developed by these researchers not only provide information about current drugs and how efficacious they might be, but also provided additional information, which could allow for specific modifications that help improve drug efficacy and be used to accelerate future drug development. KEY TAKEAWAY: The in silico techniques and simulations developed by these authors are useful tools for studying the efficacy of candidate drugs in treatment of SARS-CoV-2 infections, and in the future for newer therapies.