Targeting SARS-CoV-2 nucleocapsid oligomerization: Insights from molecular docking and molecular dynamics simulations

Abstract

The outbreak of COVID-19 caused by SARS-CoV-2 virus continually led to infect a large population worldwide. Currently, there is no specific viral protein-targeted therapeutics. The Nucleocapsid (N) protein of the SARS-CoV-2 virus is necessary for viral RNA replication and transcription. The C-terminal domain of N protein (CTD) involves in the self-assembly of N protein into a filament that is packaged into new virions. In this study, the CTD (PDB ID: 6WJI) was targeted for the identification of possible inhibitors of oligomerization of N protein. Herein, multiple computational approaches were employed to explore the potential mechanisms of binding and inhibitor activity of five antiviral drugs toward CTD. The five anti-N drugs studied in this work are 4E1RCat, Silmitasertib, TMCB, Sapanisertib, and Rapamycin. Among the five drugs, 4E1RCat displayed highest binding affinity (-10.95 kcal/mol), followed by rapamycin (-8.91 kcal/mol), silmitasertib (-7.89 kcal/mol), TMCB (-7.05 kcal/mol), and sapanisertib (-6.14 kcal/mol). Subsequently, stability and dynamics of the protein-drug complex were examined with molecular dynamics (MD) simulations. Overall, drug binding increases the stability of the complex with maximum stability observed in the case of 4E1RCat. The CTD-drug complex systems behave differently in terms of the free energy landscape and showed differences in population distribution. Overall, the MD simulation parameters like RMSD, RMSF, Rg, hydrogen bonds analysis, PCA, FEL, and DCCM analysis indicated that 4E1RCat and TMCB complexes were more stable as compared to silmitasertib and sapanisertib and thus could act as effective drug compounds against CTD.

Communicated by Ramaswamy H. Sarma

Keywords:

• COVID-19
• nucleocapsid
• C-terminal domain
• anti-N drugs
• molecular docking
• molecular dynamics simulation

Acknowledgements

S.A is thankful for Research Associate, supported by the Indian Council of Medical Research, India, for financial assistance (2019-6039 File No. ISRM/11(83)/2019). D.G is endowed with funding by the Department of Biotechnology, Government of India (Grant No. BT/BI/04/001/2018).

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

V.K. conceptualized and designed the study. S.A performed the experiments and calculations. V.K. and S.A analyzed the data. V.K. wrote the manuscript with the contributions from D.G and S.A.