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Updated: Aug 31, 2025
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Single-Molecule Diffusion and Assembly on Polymer-Crowded Lipid Membranes
Published on: July 19, 2022
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Single-molecule tracking of perfringolysin O assembly and membrane insertion uncoupling.
Michael J T Senior1, Carina Monico1,2, Eve E Weatherill1,2
1Chemistry Research Laboratory, Department of Chemistry, University of Oxford, UK.
The FEBS Journal
|August 22, 2022
Summary
Researchers tracked the assembly of Perfringolysin O (PFO) using advanced microscopy. They discovered PFO monomers can insert into membranes and assemble into pores, supporting a stepwise addition model.
Area of Science:
- Biophysics
- Molecular Biology
- Nanotechnology
Background:
- Cholesterol-dependent cytolysins (CDCs) are pore-forming toxins implicated in various infections.
- Understanding the assembly mechanism of CDCs like Perfringolysin O (PFO) is crucial for developing therapeutics.
Purpose of the Study:
- To elucidate the step-by-step assembly pathway and pore formation of Perfringolysin O.
- To investigate the role of individual PFO complexes during membrane insertion and oligomerization.
Main Methods:
- Utilized single-molecule tracking (SMT) for high-resolution observation of PFO assembly.
- Employed optical single channel recording in droplet interface bilayers (DIBs) to monitor pore formation.
- Achieved 60 ms temporal resolution and 20 nm spatial precision in tracking PFO complexes.
Main Results:
- Observed individual nascent PFO complexes inserting into the lipid membrane.
- Demonstrated that assembly can continue actively after membrane insertion.
- Determined the stoichiometry and diffusion of PFO complexes throughout the assembly process.
Conclusions:
- The data support a model of stepwise, irreversible PFO assembly primarily driven by monomer addition.
- Infrequent assembly events involving larger partial complexes were also observed.
- This study provides critical insights into the dynamic mechanism of CDC pore formation.
