Envelope

The HIV envelope is synthesized from the env gene as a glycoprotein (gp) 160 polyprotein precursor, which is subsequently processed by a host cellular protease to form the two structural envelope components: surface envelope glycoprotein (gp120) and transmembrane envelope glycoprotein (gp41). The gp120 protein has approximately 480 amino acids and is structurally arranged with an outer domain, inner domain, and a bridging sheet. The surface of the gp120 is coated with 80-90 glycans that make up an immunoprotective glycan shield. The gp41 subunit has approximately 345 amino acids divided into three domains: ectodomain (in the extracellular region), the transmembrane domain (spans the HIV membrane), and the cytoplasmic tail (inside the HIV membrane