Staphylococcal complement inhibitor (scn) is a 116-residue protein from Staphylococcus aureus (strain Mu50 / ATCC 700699). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q931M7.
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The mean pLDDT of this model is 81.6 (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 | 63% |
| 70 to 90 | Confident: backbone generally right | 9% |
| 50 to 70 | Low: treat with caution | 6% |
| Below 50 | Very low: often disordered regions | 22% |
What pLDDT means and how to read it
Involved in countering the first line of host defense mechanisms. Efficiently inhibits opsonization, phagocytosis and killing of S.aureus by human neutrophils. Acts by binding and stabilizing human C3 convertases (C4b2a and C3bBb), leading to their inactivation. The convertases are no longer able to cleave complement C3, therefore preventing further C3b deposition on the bacterial surface and phagocytosis of the bacterium. Also prevents C5a-induced neutrophil responses (By similarity)
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 3L3O | X-ray | 3.4 Å | M/P=32-116 |
| 3OHX | X-ray | 3.5 Å | M/P=32-116 |
| 3NMS | X-ray | 4.1 Å | M=32-116 |
| 6RUV | X-ray | 6.15 Å | N/Q=31-116 |
| 3L5N | X-ray | 7.54 Å | M=32-116 |
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