Computational identification of novel entry inhibitor scaffolds mimicking primary receptor CD4 of HIV-1 gp120

Virtual screening of novel entry inhibitor scaffolds mimicking primary receptor CD4 of HIV-1 gp120 was carried out in conjunction with evaluation of their potential inhibitory activity by molecular modeling. To do this, pharmacophore models presenting different sets of the hotspots of cellular receptor CD4 for its interaction with gp120 were generated. These models were used as the templates for identification of CD4-mimetic candidates by the pepMMsMIMIC screening platform. Complexes of these candidates with gp120 were built by high-throughput ligand docking and their stability was estimated by molecular dynamics simulations and binding free energy calculations. As a result, five top hits that exhibited strong attachment to the two well-conserved hotspots of the gp120 CD4-binding site were selected for the final analysis. In analogy to CD4, the identified compounds make hydrogen bonds with Asp-368gp120 and multiple van der Waals contacts with the gp120 residues that bind to Phe43(CD4), resulting in destruction of the critical interactions of gp120 with Phe-43(CD4) and Arg-59(CD4). The complexes of the CD4-mimetic candidates with gp120 show relative conformational stability within the molecular dynamics simulations and expose the high percentage occupancies of intermolecular hydrogen bonds, in line with the data on the binding free energy calculations. In light of these findings, the identified compounds are considered as good scaffolds for the development of new functional antagonists of viral entry with broad HIV-1 neutralization.