Cell invasion protein SipA (sipA) is a 685-residue protein from Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P0CL52.
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The mean pLDDT of this model is 62.1 (low 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 | 19% |
| 70 to 90 | Confident: backbone generally right | 32% |
| 50 to 70 | Low: treat with caution | 6% |
| Below 50 | Very low: often disordered regions | 44% |
What pLDDT means and how to read it
Actin-binding protein that interferes with host cell actin cytoskeleton. It stimulates actin polymerization and counteracts F-actin destabilizing proteins. Potentiates SipC activity; both are required for an efficient bacterial internalization. In vitro, forms a complex with host cell protein T-plastin increasing actin bundling. It inhibits ADF/cofilin-directed depolymerization both by preventing binding of ADF and cofilin and by displacing them from F-actin. Also protects F-actin from gelsolin-directed severing and reanneals gelsolin-severed F-actin fragments
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1Q5Z | X-ray | 1.8 Å | A=497-670 |
| 2FM9 | X-ray | 2.0 Å | A=49-263 |
| 2FM8 | X-ray | 2.2 Å | C=23-262 |
| 8UEE | EM | 3.2 Å | A/B/C/D=425-685 |
| 8VFM | EM | 3.6 Å | A/B/C/I=1-685 |
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