Peptide inhibitors of dengue virus and West Nile virus infectivity

Abstract

Viral fusion proteins mediate cell entry by undergoing a series of conformational changes that result in virion-target cell membrane fusion. Class I viral fusion proteins, such as those encoded by influenza virus and human immunodeficiency virus (HIV), contain two prominent alpha helices. Peptides that mimic portions of these alpha helices inhibit structural rearrangements of the fusion proteins and prevent viral infection. The envelope glycoprotein (E) of flaviviruses, such as West Nile virus (WNV) and dengue virus (DENV), are class II viral fusion proteins comprised predominantly of beta sheets. We used a physio-chemical algorithm, the Wimley-White interfacial hydrophobicity scale (WWIHS) [1] in combination with known structural data to identify potential peptide inhibitors of WNV and DENV infectivity that target the viral E protein. Viral inhibition assays confirm that several of these peptides specifically interfere with target virus entry with 50% inhibitory concentration (IC50) in the 10 µM range. Inhibitory peptides similar in sequence to domains with a significant WWIHS scores, including domain II (IIb), and the stem domain, were detected. DN59, a peptide corresponding to the stem domain of DENV, inhibited infection by DENV (>99% inhibition of plaque formation at a concentrations of <25 µM) and cross-inhibition of WNV fusion/infectivity (>99% inhibition at <25 µM) was also demonstrated with DN59. However, a potent WNV inhibitory peptide, WN83, which corresponds to WNV E domain IIb, did not inhibit infectivity by DENV. Additional results suggest that these inhibitory peptides are noncytotoxic and act in a sequence specific manner. The inhibitory peptides identified here can serve as lead compounds for the development of peptide drugs for flavivirus infection.

Identification of novel target sites and an inhibitor of the dengue virus E protein

“…Top right, site 2 shown in surface representation; residues conserved in at least 80% of DENV sequences are highlighted in magenta. Bottom right, site 2 shown in surface representation, highlighting amino acid types as in bottom left inhibitors such as mycophenolic acid, ribavirin and 6-azauridine [11], suppressors of viral RNA synthesis such as triaryl pyrazoline [12], nucleoside analogues [13] and tetraaldehyde [14] inhibitors of NS3 protein helicase and protease activities, peptides that mimic the conserved protein cleavage sites [15], host alpha-glucosidase inhibitors suppressing virion secretion and infectivity such as castanospermine [16,17] and deoxynojirimycin [18], c-Src protein kinase inhibitors that inhibit the assembly and maturation of DENV [19], monoclonal antibodies [20][21][22][23], domain III of the fusion protein [24], RNA silencing [25][26][27], peptides targeting the E protein [28,29], and polyanions preventing host cell receptor binding [30].…”

Hepatitis C Virus Is Primed by CD81 Protein for Low pH-dependent Fusion

“…Knowledge of the mechanism by which E1E2 is activated to mediate fusion is essential for designing urgently needed antiviral strategies, which have been successfully implemented for other viruses (see for example Refs. [35][36][37]. Enveloped viruses have evolved diverse strategies to respond to cellular cues and initiate fusion at desired sites.…”

MEPPitope: spatial, electrostatic and secondary structure perturbations in the post-fusion Dengue virus envelope protein highlights known epitopes and conserved residues in the Zika virus

“…The membranotropic α 3 and α 4 in DENV4 67 has been studied extensively through mutational studies of the hydrophobic face 60, 61 . Another strategy using peptide mimetic (residues 412 to 444, named DN59) derived from these helices showed inhibition of flaviviruses by releasing genomic RNA 70, 71 . A similar study based on peptide mimetic of residues 419-447 (comprising the conserved stretch following α 3 and α 4) inhibited viral entry 72 .…”

“…The Edmundson wheel shows the amphipathic cationic nature of the stem helices. The hydrophobicity of residues in the hydrophobic face is an important determinant of virulence 61, 70, 71 . The conservation of the charged face of α 4 ( c and d ) is in contrast to several differences in the hydrophobic face.…”