Computational Screening of FDA Approved Drugs from ZINC Database for Potential Inhibitors of Zika Virus NS2B/NS3 Protease: A Molecular Docking and Dynamics Simulation Study

Zika virus is a mosquito borne pathogen with a single strand RNA genome. Human infection with this virus is usually asymptomatic, however outbreaks reported in both Pacific region and Latin America have been associated with increase in frequency of microcephaly in newborns and fetuses of infected mothers. Also, the incidence of Guillain-Barré syndrome had also increased among adults with Zika virus infection. Currently, neither vaccine nor antiviral drug has been developed against Zika virus. Structure based virtual screening can be employed, through drug repurposing strategy, to accelerate the identification of potential anti-Zika virus candidates. As such, virtual screening of approved drugs against Zika virus NS2B/NS3 protease can help to recognize new hits capable of hindering viral ability to replicate and evade immune system of the host. In this computational study, we have screened 1615 FDA approved drugs against NS2B/NS3 protease enzyme of Zika virus by using both molecular docking and dynamics simulation. Our virtual screening results indicate that the anti-muscarinic agent Darifenacin and the anti-diarrheal agent Loperamide may have a promising capacity to inhibit Zika virus NS2B/NS3 protease. According to molecular docking and dynamics simulation, these two approved drugs have good binding capacity to NS2B/NS3 as reported by docking energy of binding and MM-PBSA binding energy. In addition, both Darifenacin and Loperamide were able to maintain close proximity to protease crystal throughout simulation period. However, invitro evaluation of these two drugs against Zika virus NS2B/NS3 protease is required to confirm these computational results.