Modeling the bacterial protein toxin, pneumolysin, in its monomeric and oligomeric form

P J Morgan, S C Hyman, O Byron, P W Andrew, T J Mitchell, A J Rowe

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)


Pneumolysin is a member of the family of related bacterial thiol-activated toxins, which share structural similarities and a proposed common cytolytic mechanism. Currently the molecular mechanism of membrane damage caused by these toxins remains a matter of controversy. A prerequisite for defining this mechanism is a detailed knowledge of the monomeric and oligomeric pneumolysin structures. We present for the first time details of the monomeric structure of a thiol-activated toxin, pneumolysin. Electron microscope images of metal-shadowed pneumolysin monomers show an asymmetric molecule composed of four domains. We have studied the conformation of pneumolysin monomer by low resolution hydrodynamic bead modeling procedures. The bead model dimensions and shape are derived solely from the electron micrographs. The bead model has been evaluated in terms of the predicted solution properties, which in turn have been compared to the experimental values of the sedimentation coefficient, s(20,w)0, obtained by analytical ultracentrifugation and the intrinsic viscosity, [eta]. Pneumolysin oligomers, observed as ring- and arc-shaped structures, were also examined by electron microscopy. Metal shadowing and negative staining methods were used to establish the overall dimensions of the oligomer and were used to produce a morphological model for the oligomer, incorporating monomer subunits based on the hydrodynamic bead model.

Original languageEnglish
Pages (from-to)25315-20
Number of pages6
JournalJournal of Biological Chemistry
Issue number41
Publication statusPublished - 14 Oct 1994


  • Animals
  • Bacterial Proteins
  • Cytotoxins
  • Erythrocyte Membrane
  • Image Enhancement
  • Microscopy, Electron
  • Models, Structural
  • Protein Conformation
  • Shadowing (Histology)
  • Sheep
  • Streptolysins
  • Viscosity


Dive into the research topics of 'Modeling the bacterial protein toxin, pneumolysin, in its monomeric and oligomeric form'. Together they form a unique fingerprint.

Cite this