Abstract
Botulinum neurotoxins (BoNTs), which are produced by Clostridium botulinum, are the most potent toxins, and cause the highly lethal food poisoning. BoNTs are produced as the assemblies with non-toxic components. Hemagglutinin (HA), one of the non-toxic components, has three biological activities: one is protecting BoNT from degradation in gastrointestinal tract, another is binding activity to carbohydrates and the other is disrupting of the epithelial barrier by direct binding to E-cadherin, which are critical for oral toxicity of BoNT. Here, we review the study on the crystal structure of type B whole HA. This structure reveals whole HA to be a huge triskelion-shaped molecule composed of 12 subcomponents, and biochemical data show that these functions of HA are employed at distinct sites.
