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Integrative Structure and Function of the Vibrio cholerae Competence Pilus Machine
Stefano Maggi1, Stefan Kreida2, Lixinhao Yang3
1Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84604, USA.
Biorxiv : the Preprint Server for Biology
|November 24, 2025
Summary
This study reveals the detailed structure of the Vibrio cholerae competence pilus machine (CPM), crucial for DNA uptake. The findings uncover unique architectural features and dynamic mechanisms essential for natural transformation in bacteria.
Area of Science:
- Microbiology
- Structural Biology
- Molecular Biology
Background:
- Type IV pili are surface polymers essential for bacterial functions.
- The competence pilus (CP) facilitates natural transformation, enabling DNA acquisition.
- Understanding the structure of the competence pilus machine (CPM) is key to deciphering bacterial genetic exchange.
Purpose of the Study:
- To determine the high-resolution structure of the Vibrio cholerae competence pilus (CP) and its associated machine (CPM).
- To elucidate the in-situ architecture and unique features of the CPM.
- To generate a pseudoatomic model and simulate its dynamics under physiological conditions.
Main Methods:
- Purification of the Vibrio cholerae CP.
- Electron cryo-microscopy (cryo-EM) for fiber reconstruction.
- Electron cryo-tomography (cryo-ET) for in-situ architecture.
- Integrative modeling and molecular dynamics (MD) simulations.
Main Results:
- A 3.3 Å cryo-EM map of the CP fiber was obtained.
- Cryo-ET revealed unique CPM features: multiple conformational states, a PilQ C-terminal domain ring, and a double cytoplasmic ATPase ring.
- Integrative modeling yielded a full-length pseudoatomic CPM model.
- MD simulations confirmed structural integrity and revealed gate-opening mechanisms in PilQ during pilus translocation.
Conclusions:
- The study provides unprecedented structural insights into the Vibrio cholerae CPM.
- Unique features of the CPM suggest specialized mechanisms for natural transformation.
- Simulations validate the model and reveal dynamic aspects of pilus function and DNA translocation.
Keywords:
Cryo-electron tomographyMD simulationT4PType IV pilusVibrio Choleraecompetencecryo-ETmolecular dynamics simulationMore Related Videos
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