Torque Generation in the Bacterial Flagellar Motor

The bacterial flagellar motor is a powerful, ion-driven molecular motor. Situated in the cell wall of swimming bacteria such as E. coli or Salmonella, the motor drives helical flagellar filaments propelling the bacteria through the liquid environments they inhabit. The torque-generating stator units are composed of the proteins MotA and MotB in proton-driven motors and PomA and PomB in sodium-driven motors. Units are anchored to the cell wall and use the ion-motive force across the cell membrane to apply torque to the central rotor. This thesis demonstrates control of the number of torque generators in a motor by induction from plasmids. The number of units in a full motor is determined and the dependence of motor properties on torque generator number is investigated. An assay is developed in order to study stepping in the rotation of the motor with fluorescent photodamage complications removed