The cell's protein-building complex has inspired the development of a molecular machine that links amino acids together.

David Leigh at the University of Manchester, UK, and his colleagues based their 'nanomachine' on the ribosome, a complex of proteins and RNA that translates the genetic code into proteins. But, compared with the ribosome, their machine is primitive and slow, and can assemble only very short protein chains called peptides. The nanomachine is based on a rotaxane, which is a large molecular ring threaded onto a molecule that acts as an axle. In the experiment, the axle is lined with three amino acids, and a chain of three amino acids hangs from the outer edge of the ring. When the machine is heated, an amino acid from the axle is transferred to the end of the hanging chain. The ring can then move along the axle, repeating the reaction.

Running about 1018 molecular machines at once produces tens of milligrams of peptide.

Science 339, 189–193 (2013)