Bacillus cereus hemolysin binding component B (HblB), and similar proteins
This model includes Bacillus cereus hemolysin binding component B (HblB or HBL-B) of the diarrheal enterotoxin hemolysin BL (HBL), and is a member of the cytolysin A (ClyA) family of alpha pore-forming toxins (alpha-PFTs). HBL is composed of three distinct protein components, B, L1, and L2, which together possess hemolytic, cytotoxic, dermonecrotic, and vascular permeability activities in B. cereus. Although all three HBL components can individually bind to the membrane, it requires the three components to form a complex to form a pore. Structure of HblB shows an elongated, almost entirely alpha-helical protein, except for a short hydrophobic beta-hairpin known as the beta-tongue. HBL from Bacillus toyonensis BV-17 (a strain isolated from feces samples of healthy donors) has antitumor activity both in vitro and in vivo and may have potential as a treatment for colon cancer. For B. toyonesis HBL, combining HBL-B and HBL-L2 had no cytotoxicity but combining HBL-B and HBL-L1 does.
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