S2C3 is a small molecule HIV-1 fusion inhibitor, targets the membrane proximal external region (MPER) of HIV-1 envelope spike.S2C3 interacted with gp41-inter with an affinity of 2.0 uM.S2C3 has been shown to effectively block binding to the intact HIV-1 Env expressed on the cell surface by soluble CD4 but not by CD4 binding the sitedirected NAb VRC01, or the prefusion conformation-specific NAb PG16.S2C3 targets a site in the HIV-1 Env distinct from sites targeted by small-molecule entry inhibitors that have been identified so far.S2C3 could stabilize HIV-1 Env in the prefusion conformation, making it potentially useful in a vaccine preparation to reduce the conformational flexibility of Env.
