The origin of such various functions of living organisms as energy and material metabolism, self-multiplication, environmental adaptability and extremely complex information processing is the flow of energy, signal and material through the complex and dynamic networks formed by macromolecules such as proteins and nucleic acids. An enormous number of those macromolecules play each role just like purposefully designed machines and maintain the complex network activities. They are nanomachines and have characteristics quite different from human-made machines in the following aspects: 

(1) Designed and built with individual atoms as functional parts precisely in place in three-dimension.

(2) Self-organize the structure at the right time and place in the cellular organization

(3) Have flexibility and adaptability because of weak interactions of hydrogen bonding that forms the structure 

The bacterial flagellum is a protein nanomachine that propels the active movements of bacteria for their tactic behaviors. It is built with a few to tens of thousands copies each of about 25 different proteins, each responsible for various aspects of the functions of the flagellum for its dynamic movements, switching and self-assembly. Through the detailed study on the structures and functions of various parts of the bacterial flagellum, we have demonstrated that proteins and their complexes have high precisions down to sub Å scale and yet certain amount of flexibilities that allows them to function dynamically. We believe that this dual nature is one of the key features to their ability to deal with signal and energy at a level of thermal noise.  Because of the natural ability of proteins to self-organize their three-dimensional structures and self-assemble into complex nanomachines, the technology for mass production, which is the most difficult yet the key step in industrial applications of nanotechnology, is already well established. By learning the design principle of bio-molecular nanomachines from their structural architectures and dynamic functions, it would be possible to design and produce nano-scale devices for various applications, such as information processing and energy transduction, or tools for nano-scale material processing. Bio-nanotechnology has thus high potential in future industrial applications.