ERVW-1 and HIV-1 infection: Here, we propose that this free thiol may mimic the functionality of native redox enzymes that cause disulfide exchange in the normal course of HIV-1 infection (11, –, 14), and that the IXW pharmacophore acts as an activating component to Env, inducing a temporary activated state that can then be triggered for further conformational rearrangement by disulfide exchange.