Protein nanotube. Molecular model of a nanotube made up of thermosome protein subunits from the bacterium Thermoplasma acidophilum. This is a chaperonin heat shock protein, one that protects the bacterium from damage by high temperatures. The protein is made up of two chains (red and green). Eight pairs of these chains form a ring, and several rings are stacked to form this tube. Nanotubes such as this could have many uses in nanotechnology, using their structural and conductive properties.