Schematic diagram of HIV-1 gp41 and sequences of NHR or CHR-derived peptides. The gp41 numbering of HIV-1HXB2 is used. FP, fusion peptide; NHR, N-terminal heptad repeat; CHR, C-terminal heptad repeat; TM, transmembrane domain; CT, cytoplasmic tail. The sequences corresponding to the NHR pocket region are marked in blue; The sequences corresponding to the CHR pocket-binding domain are marked in red; The position and sequence for the M-T hook structure are marked in green. Z in the SC34EK sequence indicates an artificial amino acid, norleucine. The possible electrostatic interactions are indicated by lines and correlating amino acids.