Inhibition of Primed Ebola Virus Glycoprotein by Peptide Compound Conjugated to HIV-1 Tat Peptide Through a Virtual Screening Approach

A higher prevalence of Ebola hemorrhagic fever is caused by Ebola virus (EBOV). It enters into the host cell through macropinocytosis mechanism. During the entry process, the primed viral glycoprotein (GPcl) interacts with a lysosomal cholesterol transporter, Niemann Pick C1 (NPC1), leading to the fusion of the viral envelope and the host endosomal membrane. Hence, disrupting the interaction between EBOV GPcl and host NPC1 is a promising way to prevent the viral nucleocapsid content entering the cytoplasm. In this study, a virtual screening approach has been used to investigate peptide compounds conjugated to HIV-1 Tat peptide as drug lead candidate inhibiting EBOV GPcl. About 50,261 peptides from NCBI PubChem database, which acts as ligands, were subjected to initial toxicological screening to omit ligands with undesired properties. The remaining ligands underwent a pharmacophore search, rigid docking, and flexible docking simulation to discover ligands with favorable inhibition activities. Calfluxin, SNF 8906, grgesy, phosphoramidon, and endothelin (16-21) were five ligands which have lower ΔG_binding value compared to the standard ligand. The chosen ligands were subjected to absorption, distribution, metabolism, excretion, and toxicity (ADME-Tox) analysis, which was accomplished by pkCSM software. Subsequently, they were conjugated to HIV-1 Tat peptide to accumulate them inside the endosome. The inhibition activity was reevaluated by the second flexible molecular docking simulation. As a result, only C-Calfluxin showed improved affinity while managing minimal conformational changes in protein-peptide interaction compared to its respective unconjugated ligand.