Flagellar motor models

FIGURE 17. 33 A model of the flagellar motor assembly of Escherichia coli. The M ring carries an array of about 100 motB proteins at its periphery. These juxtapose with motA proteins in the protein complex that snrronnds the ring assembly. Motion of protons throngh the motA/motB complexes drives the rotation of the rings and the associated rod and helical filament. 

Explain the role of proton-motive force in flagellar rotation. Present a model that explains the production of rotary motion from the effects of a proton gradient on the transmembrane flagellar motor. 

Atsumi, T. (2001). An ultrasonic motor model for bacterial flagellar motors. ]. Theor. Biol. 213, 31-51. 

Berry, R.M. (1993). Torque and switching in the bacterial flagellar motor. An electrostatic model. Biophys. J. 64, 961-973. 

Walz, D. and Caplan, S.R. (1998). An electrostatic model of the bacterial flagellar motor. Bioelectrochem. Bioenerg. 47, 19-24. 

Fig. 8 A power stroke model for a bacterial flagellar motor that has been described in terms of two asymmetric sawtooth potentials whose spatial periods are out of phase with one another. In the original depiction [24], only the long green arrows pointing downward in the shaded reaction windows were drawn for the chemical (proton binding and release) transitions, but this approximation represents a logically impossible limit...

Fig. 1 Images of the cell interior, (a) Illustration of a cross-section oiaa Escherichia coli cell generated based on available biochemical, structural, and microscopic data. A flagellar motor is shown at the upper right (From The Machinery of Life, 2nd ed, scheduled for release in late 2008 through Springer-Verlag). (b) Three-dimensional model of pancreatic p cells derived by electron tomography from thin sections of plastic-embedded freeze-substituted cells. The Golgi complex with seven cistema (C1-C7) is at the center (From [2])...

H. C. Berg. 2000. Constraints on models for the flagellar rotary motor Philos. Trans. R. Soc. Lond. B Biol. Sci. 355 491-501. (PubMedl... 

It is interesting that Peter Mitchell also conceived of the correct model for bacterial flagellar motion as being driven by a rotating proton motor, a concept later applied to the mechanism of the F,Fo ATPase. 

Schmitt R. 2003. Helix rotation model of the flagellar rotary motor. Biophys. J. 85 843-852. 

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