Physiological models to study the effect of molecular crowding on multi-drug bound proteins: insights from SARS-CoV-2 main protease.

Molecular Dynamics simulations are often used in drug design. However, such simulations do not account for the physiological environment of the receptor; hence overlook its impact on biomolecular interactions. To address this lacuna, we identified three objectives to pursue - develop models of physiological environment, study a drug-receptor complex in such environments, and identify methods to analyze these complicated simulations. Two novel physiological models were developed and studied. The first, called 'm10', comprises of 10 of the most abundant cytoplasmic metabolites at physiological concentrations. The second, called 'phy', supplements m10 with an additional crowder protein to elicit macromolecular crowding effect. The main protease (Mpro) of SARS-CoV-2, being essential for viral replication, is an attractive drug target for COVID-19. Hence, we chose Mpro docked with multiple drugs as our model drug-receptor system. With a plethora of compounds, physiological systems can be exceedingly large and complex. A novel Spark-based software (SparkTraj) was developed to rapidly analyze non-specific contacts and water interactions. Our study shows that crowding enhances the difference in the dynamics of apo- vs drug-bound complexes. Metabolites, at times as a cluster, were seen interacting with the protease, drugs, and binding sites in drug-free receptor. Except one that crawled to an adjacent pocket in phy, the drugs remained in their respective pockets in all simulations. Given these observations, we hope that the models and approach presented here would help the optimization, evaluation, and selection of potential drugs. Generic biomolecular dynamics could also benefit from such models and tools.Communicated by Ramaswamy H. Sarma.

Targeting allosteric pockets of SARS-CoV-2 main protease Mpro.

Repurposing of antivirals is an attractive therapeutic option for the treatment of COVID-19. Main protease (Mpro), also called 3 C-like protease (3CLpro) is a key protease of SARS-CoV-2 involved in viral replication, and is a promising drug target for antivirals. A major challenge to test the efficacy of antivirals is the conformational plasticity of Mpro and its future mutation prone flexibility. Suitable choice of drugs in catalytic and allosteric pockets appear to be essential for combination therapy. Current study, based on docking and extensive set of MD simulations, finds the combination of Elbasvir, Glecaprevir and Ritonavir to be a viable candidate for further experimental drug testing/pharmacophore design for Mpro.Communicated by Ramaswamy H. Sarma.

Targeting Allosteric Pockets of SARS-CoV-2 Main Protease Mpro (preprint)

Repurposing of antivirals is an attractive therapeutic option for the treatment of COVID-19. M pro (also called 3CL pro ) is a key protease of SARS-CoV-2 involved in viral replication, and is a promising drug target for testing the existing antivirals. A major challenge to test the efficacy of antivirals is the conformational plasticity of M pro and its future mutation prone flexibility. To address this, we hereby propose combination therapy by drugging two specific additional pockets of M pro probed in our studies. Long scale Molecular Dynamics (MD) simulations provide evidence of these additional sites being allosteric. Suitable choice of drugs in catalytic and allosteric pockets appear to be essential for combination therapy. Current study, based on docking and extensive set of MD simulations, finds the combination of Elbasvir, Glecaprevir, Ritonavir to be a viable candidate for further experimental drug testing/pharmacophore design for M pro .