Schematic illustration of HIV-1 gp41 and peptide fusion inhibitors.

<p>A. View of the gp41 functional regions. The residue numbers of each region correspond to their positions in gp160 of HIV-1_HXB2. FP, fusion peptide; NHR, N-terminal heptad repeat; CHR, C-terminal heptad repeat; TM, transmembrane domain. B. Sequence of CHR-derived anti-HIV-1 peptides. ABT is engineered with three amino acids different from C34 (marked in bold). The 13th residue serine (S) of C34 was changed to lysine (K) which allows a single modification by 3-maleimidopropionic acid (MPA).