P-glycoprotein is made up of a large number of Alpha helicies. The most important, are the 12 transmembrane alpha helices that hold the protein in the membrane. Beta sheets are also present but are more common around the ATP binding sites.
P-glycoprotein forms a large clamp. It is made up of two homologous units which are linked together by a flexible region. Each unit contains 6 alpha helices and an ATP binding site. The flexible linker region is essential for function and allows the two units to work together.