Figure 1 . Examples of potential forms of HIV-1 envelope on the viral surface.(A) Intact envelope spikes consist of three non-covalently bound gp120/gp41 heterodimers embedded in the viral membrane via a transmembrane domain and a cytoplasmic tail. (B) Free monomeric gp120, released through envelope shedding. (C) Shaved gp41 stumps on the viral surface.
