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Updated: Jul 5, 2026
11:33
Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Twin ushers guide pili across the bacterial outer membrane.
Robert Daniels1, Staffan Normark
1Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden.
Cell
|May 20, 2008
Summary
The chaperone/usher pathway assembles bacterial pili. New crystal structures reveal the PapC usher translocation domain and FimD usher with a pilus, offering the first detailed view of this bacterial assembly machine in action.
Area of Science:
- Microbiology
- Structural Biology
- Bacteriology
Background:
- The chaperone/usher pathway is crucial for assembling adhesive pili on gram-negative pathogenic bacteria.
- Pili are essential virulence factors involved in bacterial adhesion and infection.
Purpose of the Study:
- To elucidate the structural mechanisms of the chaperone/usher pathway.
- To provide a detailed view of the usher protein's function in pilus assembly.
Main Methods:
- X-ray crystallography was used to determine the structure of the PapC usher translocation domain.
- Cryo-electron microscopy (cryo-EM) was employed to visualize the FimD usher bound to a pilus translocation intermediate.
Main Results:
- The crystal structure of the PapC usher translocation domain was successfully determined.
- Images of the FimD usher complexed with a pilus translocation intermediate were obtained.
- These structures offer unprecedented atomic-level detail of the usher translocase in action.
Conclusions:
- The presented structures provide the first detailed mechanistic insights into the chaperone/usher pathway.
- Understanding this pathway is critical for developing novel antibacterial strategies targeting bacterial adhesion.
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