title: Modeling torque versus speed, shot noise, and rotational diffusion of the bacterial flagellar motor.
abstract: We present a minimal physical model for the flagellar motor that enables bacteria to swim. Our model explains the experimentally measured torque-speed relationship of the proton-driven E. coli motor at various pH and temperature conditions. In particular, the dramatic drop of torque at high rotation speeds (the "knee") is shown to arise from saturation of the proton flux. Moreover, we show that shot noise in the proton current dominates the diffusion of motor rotation at low loads. This suggests a new way to probe the discreteness of the energy source, analogous to measurements of charge quantization in superconducting tunnel junctions.
authors.affiliation: Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA.
authors.forename: Thierry
authors.initials: T
authors.lastname: Mora
authors.forename: Howard
authors.initials: H
authors.lastname: Yu
authors.forename: Ned S
authors.initials: NS
authors.lastname: Wingreen
mesh_terms: D004058:Diffusion; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D012399:Rotation; D019415:Torque
chemical_list: D029968:Escherichia coli Proteins; D020409:Molecular Motor Proteins