Haemolysin E

Haemolysin E (HlyE) is a protein family that consists of several enterobacterial haemolysin (HlyE) proteins. Hemolysin E (HlyE) is a novel pore-forming toxin of "Escherichia coli", "Salmonella typhi", and "Shigella flexneri". 
HlyE is unrelated to the well characterised pore-forming "E. coli" hemolysins of the RTX family, haemolysin A.
HlyE is a protein of 34 kDa that is expressed during anaerobic growth of "E. coli". Anaerobic expression is controlled by the transcription factor, FNR, such that, upon ingestion and entry into the anaerobic mammalian intestine, HlyE is produced and may then contribute to the colonisation of the host.