Gene and post-translational modifications
Gp41 is coded with gp120 as one gp160 by the env gene of HIV. Gp160 is then extensively glycosylated and proteolytically cleaved by furin, a host cellular protease. The high glycosylation of the env coded glycoproteins allows them to escape the human body's immune system. In contrast to gp120, however, gp41 is less glycosylated and more conserved (less prone to genetic variations). Once gp160 has been cleaved into its individual subunits, the subunits are then associated non-covalently on the surface of the viral envelope.