HIV-1 variants with a single-point mutation in the gp41 pocket region exhibiting different susceptibility to HIV fusion inhibitors with pocket- or membrane-binding domain

► T20 contains membrane-binding domain (MBD) but lacks pocket-binding domain (PBD). ► We constructed pseudoviruses with mutations of A67 in gp41 NHR pocket region. ► These mutants are sensitive to T20 lacking PBD but resistant to C34 that contains PBD. ► Combining T20 & C34 lead to synergistic effect against T20- & C34-resistant mutants. ► These suggest that T20 and C34 inhibit HIV-1 fusion by binding to different targets.