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Updated: Jan 23, 2026
08:17
Deciphering the Molecular Mechanism and Function of Pore-Forming Toxins Using Leishmania major
Published on: October 28, 2022
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Membrane perforation by the pore-forming toxin pneumolysin
Martin Vögele1, Ramachandra M Bhaskara1, Estefania Mulvihill2
1Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.
Summary
Pneumolysin (PLY) forms pores in cell membranes by oligomerizing into rings. Simulations reveal two pathways for pore formation: lipid efflux or membrane buckling, clarifying the mechanism of this bacterial toxin.
Area of Science:
- Biophysics
- Microbiology
- Molecular Biology
Background:
- Pneumolysin (PLY) is a key virulence factor from *Streptococcus pneumoniae*.
- PLY interacts with cholesterol-rich membranes, forming pores through a complex mechanism.
- Existing structural data define prepore and pore states but lack mechanistic detail.
Purpose of the Study:
- To elucidate the detailed mechanism of pneumolysin-mediated membrane pore formation.
- To investigate the structural transitions and molecular interactions during pore assembly.
- To identify key intermediates and pathways involved in PLY pore formation.
Main Methods:
- Atomistic and coarse-grained molecular dynamics simulations.
- Analysis of critical PLY membrane-binding sites.
- Correlation with electron cryo-microscopy (cryo-EM) and atomic force microscopy data.
Main Results:
- Simulations confirmed previously identified PLY membrane-binding sites.
- Transmembrane β-hairpins form a stable β-sheet, driving lipid clearance and pore expansion.
- Two pore formation pathways identified: lipid efflux and membrane buckling, influenced by lipid plug dynamics.
- Mammalian membranes facilitate spontaneous plug buckling due to PLY ring size.
Conclusions:
- Molecular dynamics simulations provide a mechanistic view of PLY pore formation.
- Lipid efflux and membrane buckling represent distinct, yet interconnected, pathways for pore completion.
- The findings offer insights into the pathogenesis of *Streptococcus pneumoniae* infections.
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