Structure-Function Relationship of Clostridial Neurotoxins

Botulinum neurotoxins are a unique group of metalloproteases which catalyze single site cleavage of specific proteins involved in the docking and fusion of synaptic vesicles with plasma membrane for neurotransmitter release. Seven serotypes of botulinum neurotoxins share a common molecular mode of action, with remarkable difference in their primary amino acid sequences and protein substrates in neuronal cells. the neurotoxins are large water soluble proteins (150 kDa) with distinct domains associated with different biochemical functions during the toxicogenesis process. In this review, we have focused on the description of the role of specific protein segments in the binding, translocation and endopeptidase activity of the toxin molecules.