Toxin B (tcdB) is a 2367-residue protein from Clostridioides difficile. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q9EXR0.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 82.3 (confident 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 | 24% |
| 70 to 90 | Confident: backbone generally right | 64% |
| 50 to 70 | Low: treat with caution | 9% |
| Below 50 | Very low: often disordered regions | 3% |
What pLDDT means and how to read it
Precursor of a cytotoxin that targets and disrupts the colonic epithelium, inducing the host inflammatory and innate immune responses and resulting in diarrhea and pseudomembranous colitis. TcdB constitutes the main toxin that mediates the pathology of C.difficile infection, an opportunistic pathogen that colonizes the colon when the normal gut microbiome is disrupted. Compared to TcdA, TcdB is more virulent and more important for inducing the host inflammatory and innate immune responses. This form constitutes the precursor of the toxin: it enters into host cells and mediates autoprocessing to release the active toxin (Glucosyltransferase TcdB) into the host cytosol. Targets colonic…
Interacts with host FZD1. Interacts with host FZD2; interaction promotes toxin entry into host cell and occupies the binding site for Wnt-adducted palmitoleate in FZD2, leading to prevent Wnt-binding and downstream Wnt signaling. Interacts with host FZD7. Interacts with host CSPG4. Interacts with host NECTIN3/PVRL3
Secreted, Host endosome membrane, Host cytoplasm, host cytosol, Host cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 7S0Z | X-ray | 2.34 Å | A/B=1-541 |
| 8Y9C | EM | 3.0 Å | B=1-2367 |
| 7V1N | EM | 3.2 Å | A=1-2367 |
MolViewer loads the AlphaFold model straight from AlphaFold DB into your browser. Show it as a cartoon, color by pLDDT, measure distances and angles, and load a PDB structure next to it to compare.