Scientists from MBB unravel the cap structure of the “propeller” in bacterial pathogens

  • Research from the University of Sheffield has discovered how the cap of the bacterial propeller (flagellum) works
  • The bacterium Campylobacter jejuni is a common cause of food poisoning and is often resistant to antibiotics.
  • The work used cryo-Electron Microscopy to reveal the overall structure of the cap protein and suggest a model for how the flagellum can grow. 

Bacterial flagellum cap complexThe flagellum is a motor that rotates and acts as a propeller in many bacteria. It is associated with virulence in many human pathogens including Campylobacter jejuni, a bacterium carried by chickens and cattle which is the leading cause of gastroenteritis worldwide.

The research, published in the journal Nature Communications, used cryo-Electron Microscopy to reveal the structure of a protein in C. jejuni and other pathogens called FliD that acts as a “cap” on the flagellar filament and is essential for its growth by elongation. The structure has suggested a mechanism by which FliD can facilitate the addition of new flagellin subunits at the growing tip.

A new high resolution structure of the flagellar filament itself was also obtained. FliD interacts with host cells and the new insights this work provides will help in finding ways to stop this interaction, which could yield new therapeutics to prevent infection.

Professor Dave Kelly from the Department of Molecular Biology and Biotechnology commented:

“This paper was the result of a collaboration with Dr Julien Bergeron (formerly of MBB and now at Kings College London) and the great work of PhD student Natalie Al-Otaibi and postdoc Dr Aidan Taylor. Their results show how FliD functions as well as allowing an overall model for flagellum growth to be formulated. The work will provide a strong basis for developing vaccine candidates for pathogens like Campylobacter.”

Read the full paper here.