Our previous study reported that both
glycoproteins gB and gH of the herpesvirus
Marek's disease virus (MDV) contain eleven potential heptad repeat domains. These domains overlap with α-helix-enriched hydrophobic regions, including the gH-derived HR1 (gHH1) and HR3 (gHH3) and gB-derived HR1 (gBH1) regions, which demonstrate effective
antiviral activity, with 50% inhibitory concentrations (IC(50)) of less than 12 µM. Plaque formation and chicken embryo
infection assays confirmed these results. In this study, biochemical and biophysical analyses detected potential interactions between these
peptides. gHH1, gHH3, and gBH1 were found to interact with each other in pairs. The complex formed by gHH3 and gBH1 showed the most stable interaction at a molar ratio of 1:3, the binding between gHH1 and gBH1 was relatively weak, and no interaction was observed between the three HR
peptides. These results indicate that gHH3 and gBH1 are likely the key contributors to the interaction between gB and gH. Furthermore, each HR
peptide from herpesvirus
glycoproteins did not effectively inhibit
virus infection compared with
peptides from a class I enveloped virus. In this report, the HR mimic
peptide modified with a double
glutamic acid (EE) or a double
lysine (KK) at the non-interactive sites (i.e.,
solvent-accessible sites) did not noticeably affect the
antiviral activity compared with the wild-type HR
peptide, whereas tandem
peptides from gH-derived gHH1 and gB-derived gBH1 (i.e., gBH1-Linker-gHH1) produced efficient
antiviral effects, unlike the individual
peptides. The proposed interpretation of inhibition of entry has been addressed. Our results support the hypothesis that the interaction domain between
glycoproteins gH and gB is a critical target in the design of inhibitors of
herpesvirus infection.