Botulinum neurotoxin type A2 (botA) is a 1296-residue protein from Clostridium botulinum (strain Kyoto / Type A2). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q45894.
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The mean pLDDT of this model is 90.6 (very high overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 73% |
| 70 to 90 | Confident: backbone generally right | 23% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 2% |
What pLDDT means and how to read it
Botulinum toxin causes flaccid paralysis by inhibiting neurotransmitter (acetylcholine) release from the presynaptic membranes of nerve terminals of eukaryotic host skeletal and autonomic nervous system, with frequent heart or respiratory failure. Precursor of botulinum neurotoxin A2 which has 2 coreceptors; complex polysialylated gangliosides found on neural tissue and specific membrane-anchored proteins found in synaptic vesicles. Receptor proteins are exposed on host presynaptic cell membrane during neurotransmitter release, when the toxin heavy chain (HC) binds to them. Upon synaptic vesicle recycling the toxin is taken up via the endocytic pathway. When the pH of the toxin-containing…
Heterodimer; disulfide-linked heterodimer of a light chain (LC) and a heavy chain (HC). Interacts with host synaptic vesicle glycoprotein 2C (SV2C) which serves as a coreceptor (PubMed:28252640). Also binds host receptor proteins SV2A and SV2B; glycosylation of host protein greatly improves the interaction (PubMed:29649119). Part of a crude toxin extract that includes BoNTA2/NTNH, P47, OrfX2 and…
Secreted, Host cytoplasm, host cytosol, Host synapse, host presynaptic cell membrane, Host cytoplasmic vesicle, host secretory vesicle, host synaptic vesicle membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1E1H | X-ray | 1.8 Å | A/C=10-250, B/D=251-416 |
| 2G7N | X-ray | 1.9 Å | A=3-426 |
| 6ES1 | X-ray | 2.0 Å | A=874-1296 |
| 2G7P | X-ray | 2.3 Å | A/B=3-426 |
| 5MOY | X-ray | 2.3 Å | A=871-1296 |
| 2G7Q | X-ray | 2.41 Å | A/B=3-426 |
| 2G7K | X-ray | 2.8 Å | A/B=3-426 |
| 8JLE | EM | 2.82 Å | B=871-1296 |
| 8JLG | EM | 2.87 Å | B=871-1296 |
| 8JLC | EM | 2.88 Å | B=871-1296 |
| 8JS8 | EM | 2.88 Å | B=871-1296 |
| 8JLH | EM | 2.9 Å | B/D=871-1296 |
| 8JLF | EM | 3.01 Å | B=871-1296 |
| 8JS9 | EM | 3.01 Å | B=871-1296 |
| 8K77 | EM | 3.11 Å | B=871-1296 |
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