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BoNT Toxins

Physiological Groups and Serotypes   Toxin and Substrate Providers  

Physiological Groups and Serotypes

Clostridium botulinum, a spore-forming anaerobic bacterium produces seven serologically and antigenically distinct neurotoxins (A-G): A, B, C (C alpha), D, E, F, and G. Strains representing the seven serotypes are divided into four physiological groups: group I (A, B, F), group II (B, E, F), group III (C, D), and group IV (G).

While serotypes A, B, E and F are typically associated with human botulism, serotypes C and D are known to cause animal botulism. However, a few unusual cases of infant botulism caused by serotype C (Oguma et al. 1990, PMID: 1978909) and foodborne botulism caused by serotype D (Demarchi et al. 1958, PMID: 13560962) have been documented. In addition, although serotype G is not known to cause human botulism, there have been several cases of suspicious deaths where BoNT/G was isolated (Sonnabend et al. 1981, PMID: 7012244).

Each toxin targets specific proteins including synaptosomal-associated proteins (SNAP), vesicle-associated membrane proteins (VAMP), and syntaxin as described in Statens Serum Institut's BoTox illustration. Botulinum neurotoxins target and cleave proteins involved in synaptic vesicle docking resulting in descending flaccid paralysis due to the absence of acetylcholine.


Serotype
Target Proteins
Target Cleavage Site
PubMed ID
A SNAP-25 Gln197-Arg 198 PMID: 14614672
B VAMP (synaptobrevin) Gln76-Phe77 PMID: 16014431
C SNAP-25, syntaxin 1A, 1B Asn196-Gln197, Lys252-253, Lys25 PMID: 15528757
D VAMP (synaptobrevin) Lys59-Leu60, Ala67-Asp68 PMID: 6490511
E SNAP-25 Arg180-Ile181 PMID: 15498179
F VAMP (synaptobrevin) Gln58-Lys59 PMID: 6638057
G VAMP (synaptobrevin) Ala81-Ala82 PMID: 2252552

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Toxin and Substrate Providers

Toxin Providers

Substrate Providers

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