Amazing! New study finds bacteria have an engine-like "motor" in their flagella that can turn 2400 times per second

Most people are unfamiliar with the world of bacteria because they can not be seen directly by the human eye, but, in the world of living things, the bacteria domain occupies a fairly large category, and the reality is almost everywhere. Many bacteria have a very magical ability, for example, recently scientists have discovered that the flagellum of bacteria has a motor similar to an aircraft engine, its speed is very fast, up to thousands of revolutions per second, amazing or not?

According to "Science and Technology Daily" reported on April 21, China's Zhejiang University Institute of Life Sciences Professor Zhu Yongqun's team in cooperation with Professor Zhang Xing's team at the School of Medicine, for the first time systematically revealed the assembly and torque transmission mechanism of the flagellar motor of Salmonella, decoding the mechanism of movement of this bacterium.

Seventy percent of bacteria have flagella as an organ, and these bacteria also mainly rely on the oscillation of flagella to move. Previously, scientists did not seriously study the structure of flagella as an organ, thinking that it moves purely by oscillation, but the team of Prof. Yongqun Zhu and Prof. Xing Zhang discovered through high magnification electron microscopy that flagella are composed of a motor on the bacterial membrane, an extracellular junction device, and a flagellar filament. One of the flagellar motors is particularly amazing, it looks like a turbofan engine on a fighter-type aircraft, but instead of spewing things outward, it can rotate very fast, 300-2400 revolutions per second, which is faster than the speed of most machines that can rotate, such as the punching machines we usually use.

Life can not be separated from cars and other vehicles with wheels, bearings, and runners are almost indispensable machinery for our human society, in the plant and animal kingdom, no one organism has evolved with bearing mechanical principle that can rotate the organ, did not expect that in the bacterial kingdom, most of the bacteria have this structure, this is a very surprising discovery.

Previously, scientists were not clear about the detailed structure of bacterial flagellar motor, component situation, operation mechanism, etc., and did not know the working principle of the flagellar motor (how to achieve efficient torque transmission and thus drive the flagellar filament high-speed operation), the above-mentioned scientists in China through a detailed targeted study, solved these mysteries - in conducting this In this study, the researchers devised a very gentle flagellar motor purification procedure, obtained a complete and stable sample of the flagellar motor-joint device complex, and then applied Zhejiang University's 300 kV cryoelectron microscope platform to finally clearly observe the different components of the flagellar motor.

Just like the piles needed to drive a car, the flagellar motor has a set of components including a linkage rod, outer membrane ring, periplasmic ring, inner membrane ring, secretion device, junction device, etc. This set of components is perfectly configured on the flagellar motor of only 26 nm, creating a structure like an aircraft engine, so it is very appropriate to call it a "motor "The "motor" consists of 175 protein subunits with a molecular mass of about 6.3 MDA (very small molecular weight unit), which is a small but complex structure.

And by observing the movement of bacteria and bacterial flagellum can also be found, the bacterial flagellum is also through the flagellar motor rotation to generate power, and then through the torque transmission to the joint device, and then drive the flagellar filament movement, so that the whole flagellum will be like a propeller to push the bacteria forward, in comparison, its speed is also quite fast, 1 second can run a distance equivalent to dozens of times its length, if we humans have such a speed, then the 100-meter race will only take a second to run, it can be seen that the flagellar motor power of bacteria is very strong.

In this way, a bacteria can also be said to be a machine, but it is small to the level of the nanometer level, specifically, it is a supramolecular protein machine, and the flagellar motor is the engine of its movement power source. So how does the flagellar motor start and move? What force or energy excites the flagellar motor's high number of rotations? Through observation and analysis, the research team found that it contains a proton pump, which can drive the rotation of the proton pump by transferring hydrogen ions, which is equivalent to transforming chemical energy into mechanical energy so that the torque can be transmitted to the inner membrane ring of the flagellar motor, contributing to the rotation of the inner membrane ring up, Zhang Xing, one of the leading members of the research team, also said: "(flagellar motor) internal structural components The interplay between the various structural elements (of the flagellar motor) is very delicate so that the flagellar motor can quickly transmit the mechanical energy obtained from the proton pump to the flagellar filament to promote its high-speed rotation. Isn't this very clever?

The paper related to this study was published in the top international journal "Cell" recently. The article reveals part of the principles of bacterial motility in the microscopic world, revealing the structure and working principle of the flagellar motor from the atomic level, pointing out a new direction for cytological research, as well as for life science and biological evolution theory. New evidence and topics are provided, and new ideas for the design of future antibiotics are offered.