Patent ID: 7192596

Claim:
A single chain polypeptide consisting essentially of first and second domains, wherein: said first domain is a clostridial neurotoxin light chain or a fragment or a variant thereof, wherein said first domain cleaves one or more vesicle or plasma membrane associated proteins essential to exocytosis; and said second domain is a clostridial neurotoxin heavy chain H N portion or a fragment or a variant thereof wherein said second domain (i) translocates the polypeptide into a cell or (ii) increases the solubility of the polypeptide compared to the solubility of the first domain on its own or (iii) both translocates the polypeptide into a cell and increases the solubility of the polypeptide compared to the solubility of the first domain on its own; and wherein the second domain lacks a functional C-terminal part of a clostridial neurotoxin heavy chain designated H C thereby rendering the polypeptide incapable of binding to cell surface receptors that are the natural cell surface receptors to which native clostridial neurotoxin binds.