title: Stepwise visualization of membrane pore formation by suilysin, a bacterial cholesterol-dependent cytolysin.
abstract: Membrane attack complex/perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins constitute a major superfamily of pore-forming proteins that act as bacterial virulence factors and effectors in immune defence. Upon binding to the membrane, they convert from the soluble monomeric form to oligomeric, membrane-inserted pores. Using real-time atomic force microscopy (AFM), electron microscopy (EM), and atomic structure fitting, we have mapped the structure and assembly pathways of a bacterial CDC in unprecedented detail and accuracy, focussing on suilysin from Streptococcus suis. We show that suilysin assembly is a noncooperative process that is terminated before the protein inserts into the membrane. The resulting ring-shaped pores and kinetically trapped arc-shaped assemblies are all seen to perforate the membrane, as also visible by the ejection of its lipids. Membrane insertion requires a concerted conformational change of the monomeric subunits, with a marked expansion in pore diameter due to large changes in subunit structure and packing.
authors.affiliation: London Centre for Nanotechnology, University College London, London, United Kingdom.
authors.forename: Carl
authors.initials: C
authors.lastname: Leung
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Natalya V
authors.initials: NV
authors.lastname: Dudkina
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Natalya
authors.initials: N
authors.lastname: Lukoyanova
authors.affiliation: London Centre for Nanotechnology, University College London, London, United Kingdom.
authors.forename: Adrian W
authors.initials: AW
authors.lastname: Hodel
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Irene
authors.initials: I
authors.lastname: Farabella
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Arun P
authors.initials: AP
authors.lastname: Pandurangan
authors.affiliation: Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Jahan
authors.affiliation: Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Mafalda
authors.initials: M
authors.lastname: Pires Damaso
authors.affiliation: London Centre for Nanotechnology, University College London, London, United Kingdom.
authors.forename: Dino
authors.initials: D
authors.lastname: Osmanović
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia.
authors.forename: Cyril F
authors.initials: CF
authors.lastname: Reboul
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Dunstone
authors.affiliation: Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Andrew
authors.affiliation: Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Rana
authors.initials: R
authors.lastname: Lonnen
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Maya
authors.initials: M
authors.lastname: Topf
authors.affiliation: Department of Crystallography, Birkbeck College, London, United Kingdom.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Saibil
authors.affiliation: London Centre for Nanotechnology, University College London, London, United Kingdom.
authors.forename: Bart W
authors.initials: BW
authors.lastname: Hoogenboom
mesh_terms: D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002784:Cholesterol / Q000378:metabolism*; D003199:Computer Systems; D020285:Cryoelectron Microscopy; D004058:Diffusion; D004220:Disulfides / Q000378:metabolism; D006460:Hemolysin Proteins / Q000378:metabolism*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D016624:Negative Staining; D054353:Perforin / Q000378:metabolism*; D052899:Pore Forming Cytotoxic Proteins / Q000378:metabolism*; D055503:Protein Multimerization
chemical_list: D004220:Disulfides; D006460:Hemolysin Proteins; D052899:Pore Forming Cytotoxic Proteins; C104760:suilysin; D054353:Perforin; D002784:Cholesterol
keywords: S. suis; bacterial toxins; biophysics; cholesterol-dependent cytolysins; membrane pore formation; pore-forming proteins; structural biology