Structure and Dynamics of Type 4a Pili and Type 2 Secretion System Endopili
Nadia Izadi-Pruneyre1, Yasaman Karami2, Michael Nilges3
1Bacterial Transmembrane Systems Unit, Institut Pasteur, Université Paris Cité, CNRS UMR, Paris, France.
Sub-Cellular Biochemistry
|July 4, 2024
Summary
This review explores the structure and dynamics of type IVa pili (T4aP) and type 2 secretion system (T2SS) filaments in bacteria. Integrative structural biology methods reveal conserved features and differences, crucial for understanding their distinct functions.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Type four filament (TFF) superfamily includes type IVa pili (T4aP) and type 2 secretion system (T2SS) in diderm bacteria.
- T4aP extend beyond the outer membrane, while T2SS endopili are periplasmic, despite sequence similarities.
Purpose of the Study:
- To review methods for studying the structure and dynamics of T4aP and T2SS endopili.
- To understand how structural features enable divergent functions within the TFF superfamily.
- To highlight conserved features and differences between T4aP and T2SS.
Main Methods:
- Integrative structural biology approaches.
- Cryo-electron microscopy (cryo-EM).
- Molecular dynamics simulations.
Main Results:
- Discusses conserved features and differences between T4aP and T2SS.
- Highlights the non-helical stretch in the N-terminal helix of TFF members.
- Examines the impact of calcium on filament structure, function, and dynamics.
Conclusions:
- High-resolution structure determination is challenged by filament dynamics.
- Integrative structural biology, cryo-EM, and simulations are key to understanding TFFs.
- Calcium plays a significant role in the structure and function of these bacterial filaments.
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