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Updated: Jul 7, 2026

Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification
Published on: May 6, 2018
The formation and structure of Escherichia coli K-12 haemolysin E pores
Stuart Hunt1, Arthur J G Moir1, Svetomir Tzokov1
1Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
Abstract:
Some enteric bacteria synthesize a pore-forming toxin, HlyE, which is cytolytic and cytotoxic to host cells. Measurement of HlyE binding to erythrocyte ghosts and the kinetics of HlyE-mediated erythrocyte lysis suggests that interaction with target membranes is not the rate-limiting step in the formation of HlyE pores, but that there is a temperature-dependent lag phase before a functional pore is formed. Circular dichroism and fluorescence energy transfer analyses show that HlyE protomers retain an alpha-helical structure when oligomerized to form a pore consisting of parallel HlyE protomers. Comparison of the proteolytic sensitivities of the water-soluble and oligomeric forms of HlyE identifies inner and outer surfaces of the pore. This new information has been used to constrain a model of the HlyE pore, which allows a more detailed interpretation of previous low-resolution 3D reconstructions and suggests a novel mechanism for insertion of HlyE into target membranes.
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