Interleukin-18 (IL18) is a 193-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q14116.
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The mean pLDDT of this model is 89.0 (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 | 68% |
| 70 to 90 | Confident: backbone generally right | 19% |
| 50 to 70 | Low: treat with caution | 11% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Pro-inflammatory cytokine primarily involved in epithelial barrier repair, polarized T-helper 1 (Th1) cell and natural killer (NK) cell immune responses (PubMed:10653850). Upon binding to IL18R1 and IL18RAP, forms a signaling ternary complex which activates NF-kappa-B, triggering synthesis of inflammatory mediators (PubMed:14528293, PubMed:25500532, PubMed:37993714). Synergizes with IL12/interleukin-12 to induce IFNG synthesis from T-helper 1 (Th1) cells and natural killer (NK) cells (PubMed:10653850). Involved in transduction of inflammation downstream of pyroptosis: its mature form is specifically released in the extracellular milieu by passing through the gasdermin-D (GSDMD) pore…
Forms a ternary complex with ligand-binding receptor subunit IL18R1 and signaling receptor subunit IL18RAP at the plasma membrane (PubMed:14528293, PubMed:25261253, PubMed:25500532, PubMed:37993714). Mature IL18 first binds to IL18R1 forming a low affinity binary complex, which then interacts with IL18RAP to form a high affinity ternary complex that signals inside the cell (PubMed:14528293,…
Cytoplasm, cytosol, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2VXT | X-ray | 1.49 Å | I=37-193 |
| 9OD9 | X-ray | 1.6 Å | A=37-193 |
| 4EKX | X-ray | 1.75 Å | B/D=37-193 |
| 7AL7 | X-ray | 1.8 Å | B=36-193 |
| 9OD7 | X-ray | 1.9 Å | A=37-193 |
| 4XFS | X-ray | 1.91 Å | A/B=37-193 |
| 3F62 | X-ray | 2.0 Å | B=37-193 |
| 4XFT | X-ray | 2.0 Å | A/B=37-193 |
| 4HJJ | X-ray | 2.1 Å | A=37-192 |
| 3WO2 | X-ray | 2.33 Å | A/B/C/D=37-193 |
| 4EEE | X-ray | 2.71 Å | B/D=37-193 |
| 4R6U | X-ray | 2.8 Å | B/D=37-193 |
| 4XFU | X-ray | 2.85 Å | A/B=37-193 |
| 3WO3 | X-ray | 3.1 Å | A/C/E/G/I/K=37-193 |
| 3WO4 | X-ray | 3.1 Å | A=37-193 |
| 8J6K | X-ray | 3.12 Å | B=1-193 |
| 8SPB | EM | 3.2 Å | C/c=6-193 |
| 8SV1 | EM | 3.5 Å | C/c=6-193 |
| 1J0S | NMR | A=37-193 | |
| 8URV | NMR | A=1-193 |
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