Species name： Escherichia coli
The Hakubi Center for Advanced Research Masayoshi NISHIYAMA
Application of pressure changes the intermolecular interaction between protein and water molecules. It is possible to control the structure and function of protein molecules. We developed a high-pressure microscope, and then observed the rotation of E. coli flagellar motors at high-pressure conditions. A single flagellar filament from E. coli that lack the switch-inducing protein CheY was tethered directly to the observation window of the high-pressure chamber. At ambient pressure condition, All of the cells rotated exclusively in a counter-clockwise direction under ambient conditions. As shown in the movie (120 MPa), on the other hand, several motors started to rotate in a clockwise direction (red). Likewise, we found that many other cells still rotated in the counter-clockwise direction (blue), changed direction frequently (fluctuated), or stopped rotation completely. It seems that hydration of the motor at high pressure induces structural changes similar to those caused by the binding of CheY-P. Therefore, s a result, the motor could rotate in a direction should never turn in ambient conditions.
High Hydrostatic Pressure Induces Counterclockwise to Clockwise Reversals of the Escherichia coli Flagellar Motor (Journal of Bacteriology, 195(8) 1809-1814 (2013))
バクテリア・べん毛モーターが高圧力下で逆向きに回り出す！？（生物物理 53(5) 264-265 (2013)）
(2014.02.27)