In
virology, a protein covering that packages the virus's genetic information. The outer coat, or envelope, of HIV is composed of two layers of fat-like molecules called lipids taken from the membranes of human cells. Embedded in the envelope are numerous cellular protein, as well as mushroom-shaped HIV
proteins that protrude from the surface. Each mushroom is thought to consist of a cap made of four
glycoprotein molecules called
gp120 and a stem consisting of four
gp41 molecules embedded in the envelope. The
virus uses these
proteins to attach to and infect cells. See also
Glycoprotein;
gp41;
gp120;
Lipid.