Method of preparing botulinum neurotoxin type E light chain
The present invention provides a preparation of botulinum toxin light chain type A or E, wherein the preparation is both catalytically active and soluble. Preferably, the preparation consists essentially of amino acid residues 1 through 425 of the botulinum toxin light chain type A. A method of screening inhibitors is also provided, wherein the method comprises exposing a test inhibitor to the preparation of botulinum toxin light chain type A and evaluating the biological activity of the preparation. In another embodiment, a method of providing a catalytically active, soluble preparation of botulinum toxin light chain, type A is provided, wherein the method comprises obtaining an expression vector comprising a DNA sequence encoding amino acid residues 1-425 and expressing a polypeptide.
1. A preparation of a catalytically active botulinum toxin light chain consisting of amino acid residues selected from the group consisting of 1-407, 1-408 and 1-409 of botulinum toxin light chain E from Clostridium botulinum strains.
2. The preparation of claim 1 wherein the preparation consists of amino acid residues 1-408 of botulinum toxin light chain E from Clostridium botulinum strains.
3. A method of providing a catalytically active, soluble preparation of botulinum toxin light chain E, from Clostridium botulinum strains comprising:
(a) obtaining an expression vector comprising a DNA sequence encoding an amino acid sequence consisting of residues selected from the group of 1 through 407, 1 through 408 and 1 through 409 of light chain type E from Clostridium botulinum strains, and
(b) expressing a polypeptide.