Hidden stochastic nature of a single bacterial motor

Phys Rev Lett. 2006 Feb 10;96(5):058105. doi: 10.1103/PhysRevLett.96.058105. Epub 2006 Feb 7.


The rotary flagellar motor of Escherichia coli bacterium switches stochastically between the clockwise (CW) and counterclockwise (CCW) direction. We found that the CW and CCW intervals could be described by a gamma distribution, suggesting the existence of hidden Markov steps preceding each motor switch. Power spectra of time series of switching events exhibited a peaking frequency instead of the Lorentzian profile expected from standard kinetic two-state models. Our analysis indicates that the number of hidden steps may be a key dynamical parameter underlying the switching process in a single bacterial motor as well as in large cooperative molecular systems.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology
  • Bacterial Translocation
  • Escherichia coli / physiology*
  • Flagella / physiology*
  • Markov Chains
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology
  • Methyl-Accepting Chemotaxis Proteins
  • Models, Biological*
  • Molecular Motor Proteins / physiology*
  • Mutation


  • Bacterial Proteins
  • Membrane Proteins
  • Methyl-Accepting Chemotaxis Proteins
  • Molecular Motor Proteins