C-terminal Octylation Rescues an Inactive T20 Mutant

Abstract

T20, a synthetic peptide corresponding to a C-terminal segment of the envelope glycoprotein (gp41) of human and simian immunodeficiency viruses, is a potent inhibitor of viral infection. We report here that C-terminal octylation of simian immunodeficiency virus gp41-derived T20 induces a significant increase in its inhibitory potency. Furthermore, when C-terminally octylated, an otherwise inactive mutant in which the C-terminal residues GNWF were replaced by ANAA has potency similar to that of the wild type T20. This effect cannot be explained by a trivial inhibitory effect of the octyl group added to the peptides, because the N-terminally octylated peptides have the same activity as the non-octylated parent peptides. The effects caused by octylation on the oligomerization, secondary structure, and membrane-interaction properties of the peptides were investigated. Our results shed light on the mechanism of inhibition by T20 and provide experimental support for the existence of a pre-hairpin intermediate.

Different from the HIV Fusion Inhibitor C34, the Anti-HIV Drug Fuzeon (T-20) Inhibits HIV-1 Entry by Targeting Multiple Sites in gp41 and gp120

“…The gp120 an inhibitory potency similar to that of the wild-type T-20 (62). In the present study, we found that C-terminal octylation can also rescue a low inhibitory activity of HIV-1 IIIB gp41-derived T-20-ANAA mutant ( Fig.…”

“…It has been reported that the T-20 analog with mutations in the tryptophan-rich domain, T-20-ANAA, has no HIV-1 fusion inhibitory activity, but the membrane-anchoring T-20-ANAA has similar anti-HIV-1 activity as the wild-type T-20 (61). C-terminal octylation rescue the inactive ANAA mutant of T-20-like peptide derived from the SIV gp41 (62). These suggest that interaction of T-20 and the target membrane is necessary for T-20-mediated membrane fusion inhibitory activity.…”

HIV gp41 C-terminal Heptad Repeat Contains Multifunctional Domains

“…They have also reported that the ability of T20 to inhibit membrane fusion at a post-lipid mixing stage is correlated with its activity to bind and oligomerize on the membrane surfaces (35). It was proven that the C-terminal WNWF motif of T20 is important for its anti-HIV-1 activity, because deletion of this motif or substitution of WNWF with ANAA results in loss of anti-HIV-1 activity, and octylation of ANAA mutant rescues T20-mediated fusion inhibitory activity (22,24,36). von Laer and co-workers (37) have demonstrated that the wild-type T20 and the ANAA mutant T20 have similar anti-HIV-1 activities when both peptides are anchored to the target cell membrane by fusion to a transmembrane domain.…”

“…Veiga et al (38) have shown that T-1249, an analogous peptide of T20, and its C-terminal peptide inhibit HIV-1 fusion by interacting with lipid bilayers. The tryptophan-rich (or lipid-binding) domain in the membrane proximal region of gp41 was shown to play important roles in HIV-1 fusion (22,36,39), because it may bind to the membrane surface (40) and participate in oligomerization of gp41 to form fusion pores in the membrane (23,35,41,42). Shnaper et al (43) have shown that the ordered and cholesterol-rich membranes can be destabilized by the gp41 CHR region.…”

Interactions of HIV-1 Inhibitory Peptide T20 with the gp41 N-HR Coiled Coil

“…We initially focused on the last four residues of T20: the WNWF sequence known to play a critical role in HIV-1 inhibition. Substituting Ala residues for the three aromatic amino acids (WNWF 3 ANAA) functionally ablates the potent antiviral activity of the peptide (1,24,25). However, recent studies suggest that the WNWF sequence may not directly bind the gp41 N-HR (38).…”