TRAPped Structures: Making Artificial Cages with a Ring Protein

Protein cages are hollow containers typically made from multiple copies of a small number of protein subunits. They occur extensively in nature and morphologies can vary but typically they are close to spherical in shape and have diameters in the nanometers to tens of nanometers range. Because central cavities of protein cages are bounded, they offer possibilities for use as nanoreactors or as transport systems in vivo and in fields as diverse as materials science and medicine. It is now possible to produce artificial cage proteins, thus widening their potential further. Here we consider in brief natural and artificial protein cages before focusing on the development of a ring-shaped protein (TRAP) leading up to and including its use as a component of an artificial protein cage.