Protein S100-B (S100b) is a 92-residue protein from Rattus norvegicus. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P04631.
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The mean pLDDT of this model is 92.7 (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 | 84% |
| 70 to 90 | Confident: backbone generally right | 12% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Small zinc- and- and calcium-binding protein that is highly expressed in astrocytes and constitutes one of the most abundant soluble proteins in brain (PubMed:14621986, PubMed:15823027, PubMed:18949447, PubMed:20351179). Weakly binds calcium but binds zinc very tightly-distinct binding sites with different affinities exist for both ions on each monomer (PubMed:15823027). Physiological concentrations of potassium ion antagonize the binding of both divalent cations, especially affecting high-affinity calcium-binding sites (By similarity). Acts as a neurotrophic factor that promotes astrocytosis and axonal proliferation (By similarity). Involved in innervation of thermogenic adipose tissue by…
Dimer of either two alpha chains, or two beta chains, or one alpha and one beta chain (By similarity). The S100B dimer binds two molecules of STK38 (By similarity). Interacts with CACYBP in a calcium-dependent manner (PubMed:12042313). Interacts with ATAD3A; this interaction probably occurs in the cytosol prior to ATAD3A mitochondrial targeting (PubMed:20351179). Interacts with S100A6 (By…
Cytoplasm, Nucleus, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1B4C | NMR | A/B=1-92 | |
| 1DT7 | NMR | A/B=1-92 | |
| 1MWN | NMR | A/B=1-92 | |
| 1QLK | NMR | A/B=1-92 | |
| 1SYM | NMR | A/B=1-92 | |
| 1XYD | NMR | A/B=1-92 | |
| 2K7O | NMR | A/B=2-92 |
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