Polysaccharides like pentagalloylglucose, parishin a and stevioside inhibits the viral entry by binding the Zika virus envelope protein.

ZIKV belongs to a flavivirus family in which class II fusion proteins involve a low pH-dependent membrane fusion leading to infection of host cells. Envelope (E) protein is primarily responsible for the viral host membrane fusion and is the major target for inhibiting viral entry. Our findings reveal that compounds like PGG, Parishin A, and Stevioside have shown a high affinity for E protein and found to be active against various other viral infections. The binding of these molecules to E protein was found to decrease the RMSD and RMSF values of the ligand protein complex and restricted the Radius of Gyration in molecular dynamics simulation analysis. Further, the binding free energy calculations suggested the stability of complexes throughout simulations trajectory that could reduce the flexibility of the linker so as to block the folding back event of membrane fusion. A recent study has shown that PGG inhibits the early stages of viral entry in HCV and ZIKV. Therefore, we propose that PGG inhibits the entry of virion via binding the E protein and restricting the conformational rearrangement during membrane fusion.Communicated by Ramaswamy H. Sarma.