The complete sequence of botulinum neurotoxin type A and comparison with other clostridial neurotoxins.
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Binz T, Kurazono H, Wille M, Frevert J, Wernars K, Niemann H
The complete sequence of botulinum neurotoxin type A and comparison with other clostridial neurotoxins.
J Biol Chem. 1990 Jun 5;265(16):9153-8.
- PubMed ID
- 2160960 [ View in PubMed]
- Abstract
The seven serologically different botulinum neurotoxins are highly potent protein toxins that inhibit neurotransmitter release from peripheral cholinergic synapses. The activated toxins consist of the toxifying A-subunits (Mr approximately 50,000) linked by a disulfide bond to the receptor-binding BC-subunits (Mr approximately 100,000). We have established the complete sequence of botulinum neurotoxin type A (BoNT/A; 1,296 amino acid residues, Mr = 149,425) and a partial sequence of botulinum neurotoxin type E (273 amino acid residues) as deduced from the corresponding nucleotide sequences of the chromosomally located structural genes. The promoter of the BoNT/A gene is inactive in Escherichia coli. Primer extension experiments indicated that initiation of transcription of the BoNT/A gene occurred 118 nucleotides upstream from the ATG codon. A comparison of the protein sequence revealed an overall identity of 33.8% to that of tetanus toxin. No significant similarity to other known proteins including ADP-ribosylating toxins could be detected. Three of the six histidine residues of the A-subunit of BoNT/A were found in the peptide sequence H223ELIHXXH230 within a domain of predicted alpha-helical secondary structure. This motif is also found in similar positions of the A-subunits of tetanus toxin and BoNT/E.