title: Measurements of the Rotation of the Flagellar Motor by Bead Assay.
abstract: The bacterial flagellar motor is a reversible rotary nano-machine powered by the ion flux across the cytoplasmic membrane. Each motor rotates a long helical filament that extends from the cell body at several hundreds revolutions per second. The output of the motor is characterized by its generated torque and rotational speed. The torque can be calculated as the rotational frictional drag coefficient multiplied by the angular velocity. Varieties of methods, including a bead assay, have been developed to measure the flagellar rotation rate under various load conditions on the motor. In this chapter, we describe a method to monitor the motor rotation through a position of a 1 μm bead attached to a truncated flagellar filament.
authors.affiliation: Department of Frontier Bioscience, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo, 184-8584, Japan.|Research Center for Micro-Nano Technology, Hosei University, 3-11-15 Midori-cho, Koganei, Tokyo, 184-0003, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Kasai
authors.affiliation: Department of Frontier Bioscience, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo, 184-8584, Japan. ysowa@hosei.ac.jp.|Research Center for Micro-Nano Technology, Hosei University, 3-11-15 Midori-cho, Koganei, Tokyo, 184-0003, Japan. ysowa@hosei.ac.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sowa
mesh_terms: D001419:Bacteria / Q000737:chemistry; D001681:Biological Assay / Q000379:methods; D005407:Flagella / Q000737:chemistry*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000737:chemistry*; D012399:Rotation; D019415:Torque
chemical_list: D020409:Molecular Motor Proteins
keywords: Bacterial flagellar motor; High-speed camera; Microsphere; Rotation speed; Torque