Potent anti-HIV-1 activity of N-HR-derived peptides including a deep pocket-forming region without antagonistic effects on T-20

Background: Enfuvirtide (T-20), a C-terminal heptad repeat (C-HR)-derived peptide of HIV-1 glycoprotein, gp41, effectively suppresses HIV-1 replication through a putative mechanism that involves it acting as a decoy and binding to the N-terminal heptad repeat (N-HR) of the virus. In this study, we address whether the anti-HIV-1 activity of T-20 is antagonized by a variety of N-HR-de-rived peptides. Methods: Multinuclear activation of galactosidase indicator assays were used to evaluate T-20 activity in the presence of N-HR-derived peptides. The gp41-derived peptides were chemically synthesized. Results: We demonstrate additive anti-HIV activity when T-20 is used in combination with N-HR-derived pep-tides that do not have a putative binding region for the tryptophan-rich domain in T-20. The presence of a deep pocket-forming region in the N-HR-derived peptides enhanced their anti-HIV-1 activity, but had little effect on the activity of T-20. Conclusions: These results indicate that T-20-based antiviral therapies can be combined with N-HR-derived peptides.