Research groups at Nagoya University, Osaka University, and Nagahama Institute of Biosciences have elucidated that the structural dynamics of one of the proteins, FliG, plays a dominant role in determining the direction of rotation in the motor organ "bristles motor" possessed by bacteria. ..
Bacteria generate propulsion and swim in water by rotating a spiral-shaped fibrous motor organ called flagella like a screw.At the base of the flagella, there is a rotary motor (“flagellar motor”), which is said to rotate at an ultra-high speed comparable to the engine speed of an F1 machine.
If the tongue motor rotates clockwise, it can move backward, and if it rotates counterclockwise, it can move forward. It is thought that the tongue motor plays the role of a clutch in this rotation direction control. One of the constituent proteins, FliG.However, its detailed molecular mechanism has not been elucidated.
In this study, using FliG of marine vibrio, a mutation that causes abnormal rotation direction control was introduced by gene recombination technology, and the relationship between the structural change of FliG and the rotation direction control mechanism was investigated.As a result, it was found that when a mutation is introduced into a region that acts like a hinge in the structure of FliG, the direction of rotation is fixed clockwise or counterclockwise.It was also found that when a mutation that causes an abnormality in the response performance of the chemotactic signal from the FliM protein that interacts with FliG is introduced, the rotation direction switching occurs excessively and it cannot proceed from the spot.
From this, it was clarified that the structural characteristics of FliG and the interaction with FliM play an important role in determining and switching the rotation direction of the flagellar motor.Based on this knowledge, if the rotation direction control mechanism peculiar to living organisms is clarified, it will be possible to design artificial nanomachines that freely control the direction, and it is expected that it can be applied to various fields.
Paper information:[Scientific reports] Rotational direction of flagellar motor from the conformation of FliG middle domain in marine Vibrio