Abstract
The torque-speed relationship of the Na+-driven flagellar motor of Vibrio alginolyticus was investigated. The rotation rate of the motor was measured by following the position of a bead, attached to a flagellar filament, using optical nanometry. In the presence of 50mM NaCl, the generated torque was relatively constant (∼3800pNnm) at lower speeds (speeds up to ∼300Hz) and then decreased steeply, similar to the H+-driven flagellar motor of Escherichia coli. When the external NaCl concentration was varied, the generated torque of the flagellar motor was changed over a wide range of speeds. This result could be reproduced using a simple kinetic model, which takes into consideration the association and dissociation of Na+ onto the motor. These results imply that for a complete understanding of the mechanism of flagellar rotation it is essential to consider both the electrochemical gradient and the absolute concentration of the coupling ion.
Original language | English |
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Pages (from-to) | 1043-1051 |
Number of pages | 9 |
Journal | Journal of Molecular Biology |
Volume | 327 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2003 Apr 11 |
Externally published | Yes |
Keywords
- Energy transduction
- Flagella
- Molecular machine
- Rotary motor
- Vibrio
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology