caa a22 4500 569250595 20190930031028.0 cr unu---uuuuu 190725e20190702xx s 000 0 eng 10.3929/ethz-b-000353684 doi 10.1073/pnas.1904304116 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/353684 Membrane perforation by the pore-forming toxin pneumolysin [Elektronische Daten] [Martin Vögele, Ramachandra M. Bhaskara, Estefania Mulvihill, Katharina van Pee, Özkan Yildiz, Werner Kühlbrandt, Daniel J.; id_orcid 0000-0003-3075-0665 Müller, Gerhard Hummer] Proc Natl Acad Sci U S A Open access ethresearch Pneumolysin (PLY), a major virulence factor of Streptococcus pneumoniae, perforates cholesterol-rich lipid membranes. PLY protomers oligomerize as rings on the membrane and then undergo a structural transition that triggers the formation of membrane pores. Structures of PLY rings in prepore and pore conformations define the beginning and end of this transition, but the detailed mechanism of pore formation remains unclear. With atomistic and coarse-grained molecular dynamics simulations, we resolve key steps during PLY pore formation. Our simulations confirm critical PLY membrane-binding sites identified previously by mutagenesis. The transmembrane β-hairpins of the PLY pore conformation are stable only for oligomers, forming a curtain-like membrane-spanning β-sheet. Its hydrophilic inner face draws water into the protein-lipid interface, forcing lipids to recede. For PLY rings, this zone of lipid clearance expands into a cylindrical membrane pore. The lipid plug caught inside the PLY ring can escape by lipid efflux via the lower leaflet. If this path is too slow or blocked, the pore opens by membrane buckling, driven by the line tension acting on the detached rim of the lipid plug. Interestingly, PLY rings are just wide enough for the plug to buckle spontaneously in mammalian membranes. In a survey of electron cryo-microscopy (cryo-EM) and atomic force microscopy images, we identify key intermediates along both the efflux and buckling pathways to pore formation, as seen in the simulations. Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0 ethresearch Pore-forming toxin ethresearch Cholesterol-dependent cytolysin ethresearch Pneumolysin ethresearch Membrane pore ethresearch Vögele Martin joint author Bhaskara Ramachandra M. joint author Mulvihill Estefania joint author van Pee Katharina joint author Yildiz Özkan joint author Kühlbrandt Werner joint author Müller Daniel J.; id_orcid 0000-0003-3075-0665 joint author Hummer Gerhard joint author Proceedings of the National Academy of Sciences of the United States of America Washington, DC : National Academy of Sciences 116 (27), pp. 13352-13357 0027-8424 http://hdl.handle.net/20.500.11850/353684 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/353684 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Vögele Martin joint author ETHRESEARCH 700 1- Bhaskara Ramachandra M. joint author ETHRESEARCH 700 1- Mulvihill Estefania joint author ETHRESEARCH 700 1- van Pee Katharina joint author ETHRESEARCH 700 1- Yildiz Özkan joint author ETHRESEARCH 700 1- Kühlbrandt Werner joint author ETHRESEARCH 700 1- Müller Daniel J.; id_orcid 0000-0003-3075-0665 joint author ETHRESEARCH 700 1- Hummer Gerhard joint author ETHRESEARCH 773 0- Proceedings of the National Academy of Sciences of the United States of America Washington, DC : National Academy of Sciences 116 (27), pp. 13352-13357 0027-8424 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access