E. coli hemolysin E (HlyE, ClyA, SheA): X-ray crystal structure of the toxin and observation of membrane pores by electron microscopy

Cell. 2000 Jan 21;100(2):265-76. doi: 10.1016/s0092-8674(00)81564-0.


Hemolysin E (HlyE) is a novel pore-forming toxin of Escherichia coli, Salmonella typhi, and Shigella flexneri. Here we report the X-ray crystal structure of the water-soluble form of E. coli HlyE at 2.0 A resolution and the visualization of the lipid-associated form of the toxin in projection at low resolution by electron microscopy. The crystal structure reveals HlyE to be the first member of a new family of toxin structures, consisting of an elaborated helical bundle some 100 A long. The electron micrographs show how HlyE oligomerizes in the presence of lipid to form transmembrane pores. Taken together, the data from these two structural techniques allow us to propose a simple model for the structure of the pore and for membrane interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / ultrastructure
  • Bacterial Toxins / chemistry*
  • Conserved Sequence
  • Crystallography, X-Ray
  • Escherichia coli / chemistry
  • Escherichia coli Proteins*
  • Hemolysin Proteins / chemistry*
  • Hemolysin Proteins / ultrastructure
  • Lipids / chemistry
  • Membrane Proteins / chemistry
  • Membrane Proteins / ultrastructure
  • Microscopy, Electron
  • Molecular Sequence Data
  • Porins / chemistry*
  • Porins / ultrastructure
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Salmonella typhi / chemistry
  • Sequence Homology, Amino Acid
  • Shigella flexneri / chemistry


  • Bacterial Proteins
  • Bacterial Toxins
  • Escherichia coli Proteins
  • Hemolysin Proteins
  • Hlya protein, E coli
  • Lipids
  • Membrane Proteins
  • Porins
  • hlyE protein, E coli

Associated data

  • GENBANK/AF200955