Dynamics of the bacterial flagellar motor with multiple stators

Details Dynamics of the bacterial flagellar motor with multiple stators Dynamics of the bacterial flagellar motor with multiple stators

2009-01-07

arxiv.org/abs/0901.0936v1

PNAS 106 (2009) 3746-3751

Biology

Quantitative Biology

Subcellular Processes

18 pages, 6 figures, to be published in PNAS

Scientific paper

10.1073/pnas.0809929106

The bacterial flagellar motor drives the rotation of flagellar filaments and enables many species of bacteria to swim. Torque is generated by interaction of stator units, anchored to the peptidoglycan cell wall, with the rotor. Recent experiments [Yuan, J. & Berg, H. C. (2008) PNAS 105, 1182-1185] show that near zero load the speed of the motor is independent of the number of stators. Here, we introduce a mathematical model of the motor dynamics that explains this behavior based on a general assumption that the stepping rate of a stator depends on the torque exerted by the stator on the rotor. We find that the motor dynamics can be characterized by two time scales: the moving-time interval for the mechanical rotation of the rotor and the waiting-time interval determined by the chemical transitions of the stators. We show that these two time scales depend differently on the load, and that their crossover provides the microscopic explanation for the existence of two regimes in the torque-speed curves observed experimentally. We also analyze the speed fluctuation for a single motor using our model. We show that the motion is smoothed by having more stator units. However, the mechanism for such fluctuation reduction is different depending on the load. We predict that the speed fluctuation is determined by the number of steps per revolution only at low load and is controlled by external noise for high load. Our model can be generalized to study other molecular motor systems with multiple power-generating units.

Affiliated with

Also associated with

No associations

Rating

Dynamics of the bacterial flagellar motor with multiple stators does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dynamics of the bacterial flagellar motor with multiple stators, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamics of the bacterial flagellar motor with multiple stators will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-61935