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. 1999 Jan;76(1 Pt 1):580–587. doi: 10.1016/S0006-3495(99)77226-7

Torque generated by the flagellar motor of Escherichia coli while driven backward.

R M Berry 1, H C Berg 1
PMCID: PMC1302548  PMID: 9876171

Abstract

The technique of electrorotation was used to apply torque to cells of the bacterium Escherichia coli tethered to glass coverslips by single flagella. Cells were made to rotate backward, that is, in the direction opposite to the rotation driven by the flagellar motor itself. The torque generated by the motor under these conditions was estimated using an analysis that explicitly considers the angular dependence of both the viscous drag coefficient of the cell and the torque produced by electrorotation. Motor torque varied approximately linearly with speed up to over 100 Hz in either direction, placing constraints on mechanisms for torque generation in which rates of proton transfer for backward rotation are limiting. These results, interpreted in the context of a simple three-state kinetic model, suggest that the rate-limiting step in the torque-generating cycle is a powerstroke in which motor rotation and dissipation of the energy available from proton transit occur synchronously.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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