title: The flagellar motor ofCaulobacter crescentusgenerates more torque when a cell swims backward.
abstract: Caulobacter crescentus, a monotrichous bacterium, swims by rotating a single right-handed helical filament. CW motor rotation thrusts the cell forward1, a mode of motility known as thepushermode; CCW motor rotation pulls the cell backward, a mode of motility referred to as thepullermode2. The situation is opposite inE. coli, a peritrichous bacterium, where CCW rotation of multiple left-handed filaments drives the cell forward. The flagellar motor inE. coligenerates more torque in the CCW direction than the CW direction in swimming cells3,4. However, monotrichous bacteria includingC. crescentusswim forward and backward at similar speeds, prompting the assumption that motor torques in the two modes are the same5,6. Here, we present evidence that motors inC. crescentusdevelop higher torques in the puller mode than in the pusher mode, and suggest that the anisotropy in torque-generation is similar in two species, despite the differences in filament handedness and motor bias (probability of CW rotation).
authors: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station TX 77843-3122; Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138.
authors: Pushkar P
authors: PP
authors: Lele
authors: Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138.
authors: Thibault
authors: T
authors: Roland
authors: Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138.
authors: Abhishek
authors: A
authors: Shrivastava
authors: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station TX 77843-3122.
authors: Yihao
authors: Y
authors: Chen
authors: Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138.
authors: Howard C
authors: HC
authors: Berg