Abstract
Rotation of the Na+-driven flagellar motor of Vibrio alginolyticus was investigated under the influence of inhibitors specific to the motor, amiloride and phenamil. The rotation rate of a single flagellum on a cell stuck to a glass slide was examined using laser dark-field microscopy In the presence of 50 mM NaCl, the average rotation rate (ω̄) was about 600 r.p.s. with a standard deviation (σ(ω)) of 9% of ω̄. When ω̄ was decreased to about 200 r.p.s. by the presence of 1.5 mM amiloride, σ(ω) increased to 15% of ω̄. On the other hand, when ω̄ was decreased to about 200 r.p.s. by the addition of 0.6 μM phenamil, a large increase in σ(ω) up to 50% of ω̄ was observed. Similarly large fluctuations were observed at other concentrations of phenamil. These observations suggest that dissociation of phenamil from the motor was much slower than that of amiloride. A very low concentration of phenamil caused a transient but substantial reduction in rotation rate. This might suggest that binding of only a single molecule of phenamil strongly inhibits the torque generation in the flagellar motor.
Original language | English |
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Pages (from-to) | 687-695 |
Number of pages | 9 |
Journal | Journal of Molecular Biology |
Volume | 259 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1996 Jun 21 |
Externally published | Yes |
Keywords
- Amiloride
- Flagella
- Laser dark-field microscopy
- Phenamil
- Vibrio
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Molecular Biology