Science / Technology - Colloquium
Monday, January 28, 2008
4:00 PM-5:00 PM
Olin Hall
107
The flagellar motor of bacteria is a nearly-stoichiometric rotary molecular machine, perhaps the most elaborate engineered by evolution. It harnesses the chemical energy associated with a proton gradient for its rotation (typically hundreds of Hz), while, at longer time scales, stochastically switching between clockwise (CW) and counterclockwise (CCW) rotations. And while the switching of the rotational direction of the flagellar motor plays a crucial role in bacterial chemotaxis, its mechanism remains poorly understood. Here, I'll present recent work on the switch statistics of the flagellar motor of Caulobacter crescentus. I'll show how the interval distribution of the CW and CCW rotation provides insight into the switching, and describe a model that combines first-passage-time theory and dynamic binding to explain the switching mechanism. The model accounts for the motor's dependence on CheYp concentration, and predicts that dynamic binding of CheYp to the switch-complex proteins is the key to the signal amplification of the motor.
Cost: FREE
Sponsored by: WPI Physics Department, Dr. Stephan Koehler
Suggested Audiences: College
E-mail:
sak@wpi.edu
Phone: 508-831-5090
Last Modified: January 22, 2008 at 10:25 AM
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