This invention relates to novel recombinant clostridial neurotoxins exhibiting increased
duration of effect and to methods for the manufacture of such recombinant clostridial neurotoxins. These novel recombinant clostridial neurotoxins comprise (i) at least two
random coil domains, or (ii) at least two domains having a polyproline II
helix conformation, and the methods comprise the steps of inserting at least two
nucleic acid sequences each coding for (i) a
random coil domain, or (ii)
a domain having a polyproline II
helix conformation, into a
nucleic acid sequence coding for a parental
clostridial neurotoxin and expression of the recombinant
nucleic acid sequence comprising (i) the
random coil domain-coding sequences, or (ii) the sequences encoding the domains having a polyproline II
helix conformation in a host
cell. The invention further relates to novel recombinant single-chain precursor clostridial neurotoxins used in such methods, nucleic acid sequences encoding such recombinant single-chain precursor clostridial neurotoxins, and pharmaceutical compositions comprising the recombinant
clostridial neurotoxin with increased
duration of effect.