The human being was not the first to invent the engine, this is the Nature! And more specifically it is the bacteria that did it more than 2 billion years ago, with the flagellum. Surprising for such small organisms, isn’t it? It turns out they are not as simple as you think!
The flagellum, corresponding to a long and rigid filament incorporated into the bacterial membrane, has an engine enabling a large number of bacteria to move within their environment.
The engine of the flagella is one of the most amazing living molecular machine! Extremely complex, it consists of 30 to 40 proteins assembled into a movable part, the rotor, and a static part, the stator.
The rotor is composed of a large disc surmonted by smaller discs able to turn in both directions allowing the bacterium to change direction.
The stator consists of fixed tubes secure to the bacterial membrane, ensuring the stability of the whole flagellum structure. Thus, more the engine circular elements are wide, more the power shift is important.
The rotation of the flagellum is caused by a proton flow in the stator, which alters the protein structure of the rotor-stator complex responsible for the motility of flagella. The bacterium moves in a helical manner and can travel nearly 200 times its size in one second.
According to the type of bacteria, this engine has variations depending on the species but also the constraints of environment.
Another incredible aspect, the flagellum builds and repairs itself! 20 minutes are enough to build this new machine.
LC
