Transmembrane domains
Transmembrane domains are stretches of residues of integral membrane proteins that span across the membrane bilayer. They are key in a wide range of integral membrane proteins including receptors for Growth factors and Hormones, channel proteins and two-way membrane transporters. Most transmembrane domains span the membrane 1-17 times, the most common being 1, 4 or 7 (G-protein linked receptor for example).