IDENTIFICATION OF SPECIFIC DOMAINS IN BOTULINUM AND TETANUS NEUROTOXINS

Specific domains of botulinum and tetanus neurotoxins have been identified by computing the bias in the use of Lys over Arg in their respective polypeptide chains (E. London and C. L. Luongo, Biochem. biophys. Res. Commun. 160, 333-339, 1989). A strong bias was noted in the C-terminal domain of the light chains of both the neurotoxins (bRK′, -8.0 to -12.0) suggesting that this domain could represent a 'catalytic domain' similar to that present in other dichain toxins such as diphtheria. Interestingly, this domain has a segment which has significant homology with the partial sequence of botulinum exoenzyme C3, an ADP-ribosyl transferase, implying a possible relationship with an enzymatic activity. © 1990.