Botulinum neurotoxin type F can be produced by proteolytic or non-proreolytic strains of C. botulinum, or from C. baratii. In recent years, the sequences of all toxin types except that of proteolytic type F toxin have been determined. We have cloned the neurotoxin gene from proteolytic C. botulinum (type F Langeland) as a series of overlapping PCR fragments, and determined the nucleotide sequence. The translated sequence demonstrates a toxin of 1278 amino acid residues, which has highest similarity with non-proteolytic type F toxin. Phylogenetic trees based on toxin sequences show that the type F sequences fall into a naturally distinct group, although the strains producing these toxins are not phylogenetically closely related.
Bibliographical noteFunding Information:
Acknowledgements. CAMR wishes to acknowledge the financial support of the UK Department of Health and Ministry of Defence (grant 2238/002), and the US Army Medical Research Development Command (grant DAMDI7-90-20033).
- Clostridium botulinum
- Gene sequence