CryoEM structures of membrane pore and prepore complex reveal cytolytic mechanism of Pneumolysin
- Max Planck Institute of Biophysics, Germany
Abstract
Many pathogenic bacteria produce pore-forming toxins to attack and kill human cells. We have determined the 4.5 Å structure of the ~2.2 MDa pore complex of pneumolysin, the main virulence factor of Streptococcus pneumoniae, by cryoEM. The pneumolysin pore is a 400 Å ring of 42 membrane-inserted monomers. Domain D3 of the soluble toxin refolds into two ~85 Å β-hairpins that traverse the lipid bilayer and assemble into a 168-strand β-barrel. The pore complex is stabilized by salt bridges between β-hairpins of adjacent subunits and an internal α-barrel. The apolar outer barrel surface with large sidechains is immersed in the lipid bilayer, while the inner barrel surface is highly charged. Comparison of the cryoEM pore complex to the prepore structure obtained by electron cryo-tomography and the x-ray structure of the soluble form reveals the detailed mechanisms by which the toxin monomers insert into the lipid bilayer to perforate the target membrane.
Data availability
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Crystal structure of pneumolysin D168A mutantPublicly available at the RCSB Protein Data Bank (accession no: 5AOE).
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Crystal structure of pneumolysin deletion mutant Delta146_147Publicly available at the RCSB Protein Data Bank (accession no: 5AOF).
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CryoEM structure of the membrane pore complex of Pneumolysin at 4.5APublicly available at the EMBL-EBI Protein Data Bank (accession no: 5LY6).
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CryoEM structure of the membrane pore complex of Pneumolysin at 4.5APublicly available at the EMBL-EBI Protein Data Bank (accession no: EMD-4118).
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Crystal structure of wild type pneumolysin.Publicly available at the RCSB Protein Data Bank (accession no: 5AOD).
Article and author information
Author details
Funding
Max-Planck-Gesellschaft (DepartmentSB)
- Katharina van Pee
- Alexander Neuhaus
- Edoardo D'Imprima
- Deryck J Mills
- Werner Kühlbrandt
- Özkan Yildiz
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, van Pee et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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CryoEM structures of membrane pore and prepore complex reveal cytolytic mechanism of Pneumolysin
eLife 6:e23644.
https://doi.org/10.7554/eLife.23644
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