Potential efficacy of existing drug molecules against severe fever with thrombocytopenia syndrome virus: an in silico study.

Severe fever with thrombocytopenia syndrome (SFTS) is a zoonotic disease caused by the SFTS virus (SFTSV). SFTS can be considered a life-threatening notifiable infectious disease. The unavailability of specific therapeutics encourages the investigation of potential efficacy of existing drugs against this infection. Drug repurposing was done by performing  virtual screening of already established drug molecules followed by 100 ns molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area-based binding-energy calculation by targeting the SFTS L protein. On the basis of binding energy and protein-ligand interactions, top 10 promising hits were identified, showing stable binding with SFTS L protein. Further 100 ns atomistic MD simulation refined the hits from top 10 to top 4 with docking-based binding energy lesser than -8.0 kcal/mol toward the SFTS L protein and engaged in π-π interactions with pivotal amino acid residues. Various parameters and binding affinity of top 4 ligands towards L protein was computed. Ligand zaltoprofen exhibited best binding energy -220.095 kJ/mol. The present work is the first in silico study to assess bromfenac, cinchophen, elliptinium, and zaltoprofen; four promising hits against SFTS. Nonetheless, further proper biological evaluation is necessary to determine their efficacy against SFTS.