Structural optimization and de novo design of dengue virus entry inhibitory peptides.

Viral fusogenic envelope proteins are important targets for the development of inhibitors of viral entry. We report an approach for the computational design of peptide inhibitors of the dengue 2 virus (DENV-2) envelope (E) protein using high-resolution structural data from a pre-entry dimeric form of the protein. By using predictive strategies together with computational optimization of binding "pseudoenergies", we were able to design multiple peptide sequences that showed low micromolar viral entry inhibitory activity. The two most active peptides, DN57opt and 1OAN1, were designed to displace regions in the domain II hinge, and the first domain I/domain II beta sheet connection, respectively, and show fifty percent inhibitory concentrations of 8 and 7 microM respectively in a focus forming unit assay. The antiviral peptides were shown to interfere with virus:cell binding, interact directly with the E proteins and also cause changes to the viral surface using biolayer interferometry and cryo-electron microscopy, respectively. These peptides may be useful for characterization of intermediate states in the membrane fusion process, investigation of DENV receptor molecules, and as lead compounds for drug discovery.

In vitro inhibition of dengue virus entry by p-sulfoxy-cinnamic acid and structurally related combinatorial chemistries.

The anti-adhesive compound p-sulfoxy-cinnamic acid, zosteric acid (ZA), is derived from the temperate marine eelgrass, Zostera marina. ZA and five combinatorial chemistries based on ZA were evaluated for their anti-viral properties against dengue virus in a focus forming unit reduction assay. None of the compounds showed evidence of toxicity to the monkey kidney cell line LLCMK-2 over the concentration ranges tested. ZA showed a modest IC(50) of approximately 2.3 mM against DENV-2. Three other compounds showed IC(50) values of 2.5, 2.4, 0.3 mM, with a fourth not achieving a 50% inhibitory concentration against DENV-2. The most active compound, CF 238, showed IC(50) values of 24, 46, 14 and 47 microM against DENV-1, DENV-2, DENV-3 and DENV-4, respectively. CF 238 showed evidence of inhibition at an entry step in the viral life cycle and enhanced virus:cell binding as evidenced by a quantitative RT-PCR assay system. CF 238 may promote inappropriate virus:cell attachments common to all DENV strains that interfere with receptor interactions required for viral entry. These and other related chemistries may be useful as reagents for studying DENV entry, capturing and detecting DENV, and development of pharmaceuticals.