Periplasmic chaperone Spy (spy) is a 161-residue protein from Escherichia coli (strain K12). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P77754.
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The mean pLDDT of this model is 76.4 (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 | 47% |
| 70 to 90 | Confident: backbone generally right | 15% |
| 50 to 70 | Low: treat with caution | 20% |
| Below 50 | Very low: often disordered regions | 19% |
What pLDDT means and how to read it
An ATP-independent periplasmic chaperone, decreases protein aggregation and helps protein refolding. Binds substrate over a large region of its convex inner surface (PubMed:21317898, PubMed:24497545). Substrate protein folds while it is bound to chaperone (PubMed:26619265). Increasing Spy flexibility increases its substrate affinity and overall chaperone activity (shown for 3 different substrates) (PubMed:24497545). Protects proteins in vitro against tannin inactivation; tannins have antimicrobial activity (PubMed:21317898). Overexpression enhances the stability of otherwise unstable periplasmic proteins (PubMed:21317898)
Homodimer
Periplasm
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 5WO2 | X-ray | 1.77 Å | A/B=52-147 |
| 6BIE | X-ray | 1.77 Å | A/B=52-147 |
| 5WNW | X-ray | 1.79 Å | A/B=52-147 |
| 5WO1 | X-ray | 1.87 Å | A/B=52-147 |
| 5WO3 | X-ray | 1.87 Å | A/B=52-147 |
| 6OWZ | X-ray | 2.05 Å | A/B=52-147 |
| 6OWX | X-ray | 2.06 Å | A/B=52-147 |
| 6OWY | X-ray | 2.07 Å | A/B=52-147 |
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