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. 1995 Jul;69(1):280–286. doi: 10.1016/S0006-3495(95)79900-3

Mechanical limits of bacterial flagellar motors probed by electrorotation.

R M Berry 1, L Turner 1, H C Berg 1
PMCID: PMC1236246  PMID: 7669906

Abstract

We used the technique of electrorotation to apply steadily increasing external torque to tethered cells of the bacterium Escherichia coli while continuously recording the speed of cell rotation. We found that the bacterial flagellar motor generates constant torque when rotating forward at low speeds and constant but considerably higher torque when rotating backward. At intermediate torques, the motor stalls. The torque-speed relationship is the same in both directional modes of switching motors. Motors forced backward usually break, either suddenly and irreversibly or progressively. Motors broken progressively rotate predominantly at integral multiples of a unitary speed during the course of both breaking and subsequent recovery, as expected if progressive breaking affects individual torque-generating units. Torque is reduced by the same factor at all speeds in partially broken motors, implying that the torque-speed relationship is a property of the individual torque-generating units.

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Selected References

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

  1. Berg H. C. Dynamic properties of bacterial flagellar motors. Nature. 1974 May 3;249(452):77–79. doi: 10.1038/249077a0. [DOI] [PubMed] [Google Scholar]
  2. Berg H. C., Turner L. Torque generated by the flagellar motor of Escherichia coli. Biophys J. 1993 Nov;65(5):2201–2216. doi: 10.1016/S0006-3495(93)81278-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Berry R. M. Torque and switching in the bacterial flagellar motor. An electrostatic model. Biophys J. 1993 Apr;64(4):961–973. doi: 10.1016/S0006-3495(93)81462-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Blair D. F., Berg H. C. Restoration of torque in defective flagellar motors. Science. 1988 Dec 23;242(4886):1678–1681. doi: 10.1126/science.2849208. [DOI] [PubMed] [Google Scholar]
  5. Blair D. F. The bacterial flagellar motor. Semin Cell Biol. 1990 Apr;1(2):75–85. [PubMed] [Google Scholar]
  6. Block S. M., Berg H. C. Successive incorporation of force-generating units in the bacterial rotary motor. 1984 May 31-Jun 6Nature. 309(5967):470–472. doi: 10.1038/309470a0. [DOI] [PubMed] [Google Scholar]
  7. Conley M. P., Berg H. C. Chemical modification of Streptococcus flagellar motors. J Bacteriol. 1984 Jun;158(3):832–843. doi: 10.1128/jb.158.3.832-843.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Coulton J. W., Murray R. G. Cell envelope associations of Aquaspirillum serpens flagella. J Bacteriol. 1978 Dec;136(3):1037–1049. doi: 10.1128/jb.136.3.1037-1049.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Francis N. R., Sosinsky G. E., Thomas D., DeRosier D. J. Isolation, characterization and structure of bacterial flagellar motors containing the switch complex. J Mol Biol. 1994 Jan 28;235(4):1261–1270. doi: 10.1006/jmbi.1994.1079. [DOI] [PubMed] [Google Scholar]
  10. Jones C. J., Aizawa S. The bacterial flagellum and flagellar motor: structure, assembly and function. Adv Microb Physiol. 1991;32:109–172. doi: 10.1016/s0065-2911(08)60007-7. [DOI] [PubMed] [Google Scholar]
  11. Khan S., Dapice M., Humayun I. Energy transduction in the bacterial flagellar motor. Effects of load and pH. Biophys J. 1990 Apr;57(4):779–796. doi: 10.1016/S0006-3495(90)82598-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Khan S., Dapice M., Reese T. S. Effects of mot gene expression on the structure of the flagellar motor. J Mol Biol. 1988 Aug 5;202(3):575–584. doi: 10.1016/0022-2836(88)90287-2. [DOI] [PubMed] [Google Scholar]
  13. Khan S., Meister M., Berg H. C. Constraints on flagellar rotation. J Mol Biol. 1985 Aug 20;184(4):645–656. doi: 10.1016/0022-2836(85)90310-9. [DOI] [PubMed] [Google Scholar]
  14. Macnab R. M. Genetics and biogenesis of bacterial flagella. Annu Rev Genet. 1992;26:131–158. doi: 10.1146/annurev.ge.26.120192.001023. [DOI] [PubMed] [Google Scholar]
  15. Maeda K., Imae Y., Shioi J. I., Oosawa F. Effect of temperature on motility and chemotaxis of Escherichia coli. J Bacteriol. 1976 Sep;127(3):1039–1046. doi: 10.1128/jb.127.3.1039-1046.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Manson M. D., Tedesco P. M., Berg H. C. Energetics of flagellar rotation in bacteria. J Mol Biol. 1980 Apr 15;138(3):541–561. doi: 10.1016/s0022-2836(80)80017-9. [DOI] [PubMed] [Google Scholar]
  17. Meister M., Caplan S. R., Berg H. C. Dynamics of a tightly coupled mechanism for flagellar rotation. Bacterial motility, chemiosmotic coupling, protonmotive force. Biophys J. 1989 May;55(5):905–914. doi: 10.1016/S0006-3495(89)82889-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Meister M., Lowe G., Berg H. C. The proton flux through the bacterial flagellar motor. Cell. 1987 Jun 5;49(5):643–650. doi: 10.1016/0092-8674(87)90540-x. [DOI] [PubMed] [Google Scholar]
  19. Mizuno T., Imae Y. Conditional inversion of the thermoresponse in Escherichia coli. J Bacteriol. 1984 Jul;159(1):360–367. doi: 10.1128/jb.159.1.360-367.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Okino H., Isomura M., Yamaguchi S., Magariyama Y., Kudo S., Aizawa S. I. Release of flagellar filament-hook-rod complex by a Salmonella typhimurium mutant defective in the M ring of the basal body. J Bacteriol. 1989 Apr;171(4):2075–2082. doi: 10.1128/jb.171.4.2075-2082.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Schuster S. C., Khan S. The bacterial flagellar motor. Annu Rev Biophys Biomol Struct. 1994;23:509–539. doi: 10.1146/annurev.bb.23.060194.002453. [DOI] [PubMed] [Google Scholar]
  22. Silverman M., Simon M. Flagellar rotation and the mechanism of bacterial motility. Nature. 1974 May 3;249(452):73–74. doi: 10.1038/249073a0. [DOI] [PubMed] [Google Scholar]

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