In solution characterisation of a soluble coiled coil stabilised chimeric variant of the integral membrane motor protein <em>H. pylori</em> MotB. — ASN Events
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  2. Session 5: Poster Session A
  3. In solution characterisation of a soluble coiled coil stabilised chimeric variant of the integral membrane motor protein H. pylori MotB.

In solution characterisation of a soluble coiled coil stabilised chimeric variant of the integral membrane motor protein H. pylori MotB. (#155)

Daniel Andrews 1 , Matthew Wilce 1 , Yuri Nesmelov 2 , Anna Roujeinikova 1
  1. Monash University, Clayton , VIC, Australia
  2. Physics, University of North Carolina , Charlotte, North Carolina, USA

H. pylori flagellar motors are powered by the stator complex which forms a proton conduction channel to transfer protons across the cytoplasmic membrane. A cell wall anchored stator ring, that contains 11 stator complexes, assembles around the rotor to produce a proton influx which is converted into mechanical work, required for rotary torque to turn the motor. The stator complex contains the integral membrane motility proteins MotA and MotB in a 4:2 ratio. Here we propose that the conformation of MotB that allows insertion into the rotor is induced by the dimeric coiled coil formed by the plug helix. A dimeric N‑terminal coiled coil MotB chimera was created by directly replacing the single transmembrane helix from each subunit with a GCN4 zipper from Saccharomyces cerevisiae1 . A peptidoglycan pull-down assay revealed that chimera and the MotB C-terminal domain variant2  associate with H. pylori peptidoglycan, whereas a linker stabilised MotB variant3  does not. Time resolved fluorescence resonance energy transfer and small angle X-ray scattering of chimera revealed that the C-terminal domain, linker and plug regions adopt conformations expected for the active stator. A model for stator activation and assembly into the rotor has been proposed that incorporates the arrangement of the MotB structure in chimera. 

  1. O'Neill, J., M. Xie, et al. (2011). Acta crystallographica. Section D, Biological crystallography 67(Pt 12): 1009-1016.
  2. Roujeinikova, A. (2008). Proc Natl Acad Sci U S A 105(30): 10348-10353.
  3. O'Neill, J., M. Xie, et al. (2011). 67(Pt 12): 1009-1016.