This peptide C34, also known as HR2, belongs to the helical region of gp41 of HIV, C-terminal heptad repeat 2 (HR2) defined as C helix or C-peptide. This peptide is biotinylated through 6-aminohexanoate (LC) as a spacer. HIV-1 enters cells by membrane fusion, gp41. C-peptides are potent inhibitors of HIV-1 fusion.