Bacterial translocation motors investigated by single molecule techniques


  • Jean-Francois Allemand,

    1. Ecole Normale Supérieure, Laboratoire de Physique Statistique and Département de Biologie, UMR CNRS-ENS 8550, Universités Paris 6 et 7, Paris, France
    2. Institut Universitaire de France, Paris, France
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  • Berenike Maier

    1. Biology Department, Westfälische Wilhelms Universität, Münster, Germany
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  • Editor: Tone Tonjum

Correspondence: Berenike Maier, Biology Department, Westfälische Wilhelms Universität, Schlossplatz 5, 48149 Münster, Germany. Tel.: +49 251 832 3920; fax: +49 251 832 4723; e-mail:


Translocation of DNA and protein fibers through narrow constrictions is a ubiquitous and crucial activity of bacterial cells. Bacteria use specialized machines to support macromolecular movement. A very important step toward a mechanistic understanding of these translocation machines is the characterization of their physical properties at the single molecule level. Recently, four bacterial transport processes have been characterized by nanomanipulation at the single molecule level, DNA translocation by FtsK and SpoIIIE, DNA import during transformation, and the related process of a type IV pilus retraction. With all four processes, the translocation rates, processivity, and stalling forces were remarkably high as compared with single molecule experiments with other molecular motors. Although substrates of all four processes proceed along a preferential direction of translocation, directionality has been shown to be controlled by distinct mechanisms.