Load-dependent adaptation near zero load in the bacterial flagellar motor. Issue 159 (31st October 2019)

• Record Type: Journal Article
• Authors: Nirody, Jasmine A.; Nord, Ashley L.; Berry, Richard M.
• Is Part Of: Journal of the Royal Society interface. Volume 16:Issue 159(2019)
• Publication Date: 2019-10-31
• Subjects: bacterial flagellar motor -- molecular motors -- mechanobiology; Physical sciences -- Research -- Periodicals; Life sciences -- Research -- Periodicals; Interdisciplinary research -- Periodicals; 570.5
• DOI: 10.1098/rsif.2019.0300
• Languages: English
• ISSNs: 1742-5689

Abstract

Abstract : The bacterial flagellar motor is an ion-powered transmembrane protein complex which drives swimming in many bacterial species. The motor consists of a cytoplasmic 'rotor' ring and a number of 'stator' units, which are bound to the cell wall of the bacterium. Recently, it has been shown that the number of functional torque-generating stator units in the motor depends on the external load, and suggested that mechanosensing in the flagellar motor is driven via a 'catch bond' mechanism in the motor's stator units. We present a method that allows us to measure—on a single motor—stator unit dynamics across a large range of external loads, including near the zero-torque limit. By attaching superparamagnetic beads to the flagellar hook, we can control the motor's speed via a rotating magnetic field. We manipulate the motor to four different speed levels in two different ion-motive force (IMF) conditions. This framework allows for a deeper exploration into the mechanism behind load-dependent remodelling by separating out motor properties, such as rotation speed and energy availability in the form of IMF, that affect the motor torque.