Exploring interaction mechanisms of the inhibitor binding to the VP35 IID region of Ebola virus by all atom molecular dynamics simulation method.

Ebola viruses (EBOVs) cause an acute and serious illness which is often fatal if untreated, and there is no effective vaccine until now. Multifunctional VP35 is critical for viral replication, RNA silencing suppression and nucleocapsid formation, and it is considered as a future target for the molecular biology technique. In the present work, the binding of inhibitor pyrrole-based compounds (GA017) to wild-type (WT), single (K248A, K251A, and I295A), and double (K248A/I295A) mutant VP35 were investigated by all-atom molecular dynamic (MD) simulations and Molecular Mechanics Generalized Born surface area (MM/GBSA) energy calculation. The calculated results indicate that the binding with GA017 makes the binding pocket more stable and reduces the space of the binding pocket. Moreover, the electrostatic interactions (ΔEele) and VDW energy (ΔEvdw) provide the major forces for affinity binding, and single mutation I295A and double mutation K248A/I295A have great influence on the conformation of the VP35 binding pocket. Interestingly, the residues R300-G301-D302 of I295A form a new helix and the sheet formed by the residues V294-I295-H296-I297 disappears in the double mutation K248A/I295A as compared with WT. Moreover, the binding free energy calculations show that I295A and K248A/I295A mutations decrease of absolute binding free energies while K248A and K251A mutations increase absolute binding free energy. Our calculated results are in good agreement with the experimental results that K248A/I295A double mutant results in near-complete loss of compound binding. The obtained information will be useful for design effective inhibitors for treating Ebola virus.