This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schmitt, R. Search for Related Content PubMed PubMed Citation Articles by Schmitt, R.

Helix Rotation Model of the Flagellar Rotary Motor

Institute of Biochemistry, Genetics, and Microbiology, University of Regensburg, D-93040 Regensburg, Germany

Correspondence: Address reprint requests to Dr. Rüdiger Schmitt, Lehrstuhl für Genetik, University of Regensburg, D-93040 Regensburg, Germany. Tel.: 49-941-9433162; Fax: 49-941-9433163; E-mail: rudy.schmitt@biologie.uni-regensburg.de.

A new model of the flagellar motor is proposed that is based on established dynamics of the KcsA potassium ion channel and on known genetic, biochemical, and biophysical facts, which accounts for the mechanics of torque generation, force transmission, and reversals of motor rotation. It predicts that proton (or in some species sodium ion) flow generates short, reversible helix rotations of the MotA-MotB channel complex (the stator) that are transmitted by Coulomb forces to the FliG segments at the rotor surface. Channels are arranged as symmetric pairs, S and T, that swing back and forth in synchrony. S and T alternate in attaching to the rotor, so that force transmission proceeds in steps. The sense of motor rotation can be readily reversed by conformationally switching the position of charged groups on the rotor so that they interact with the stator during the reverse rather than forward strokes. An elastic device accounts for the observed smoothness of rotation and a prolonged attachment of the torque generators to the rotor, i.e., a high duty ratio of each torque-generating unit.

This article has been cited by other articles:

				K. A. Morehouse, I. G. Goodfellow, and R. E. Sockett A Chimeric N-Terminal Escherichia coli-C-Terminal Rhodobacter sphaeroides FliG Rotor Protein Supports Bidirectional E. coli Flagellar Rotation and Chemotaxis J. Bacteriol., March 1, 2005; 187(5): 1695 - 1701. [Abstract] [Full Text] [PDF]

				H. Fukuoka, T. Yakushi, and M. Homma Concerted Effects of Amino Acid Substitutions in Conserved Charged Residues and Other Residues in the Cytoplasmic Domain of PomA, a Stator Component of Na+-Driven Flagella J. Bacteriol., October 15, 2004; 186(20): 6749 - 6758. [Abstract] [Full Text] [PDF]

				V. Braun and C. Herrmann Point Mutations in Transmembrane Helices 2 and 3 of ExbB and TolQ Affect Their Activities in Escherichia coli K-12 J. Bacteriol., July 1, 2004; 186(13): 4402 - 4406. [Abstract] [Full Text] [PDF]