Interleukin-23 subunit alpha (IL23A) is a 189-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q9NPF7.
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The mean pLDDT of this model is 80.6 (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 | 52% |
| 70 to 90 | Confident: backbone generally right | 17% |
| 50 to 70 | Low: treat with caution | 24% |
| Below 50 | Very low: often disordered regions | 6% |
What pLDDT means and how to read it
Associates with IL12B to form the pro-inflammatory cytokine IL-23 that plays different roles in innate and adaptive immunity (PubMed:11114383). Released by antigen-presenting cells such as dendritic cells or macrophages, binds to a heterodimeric receptor complex composed of IL12RB1 and IL23R to activate JAK2 and TYK2 which then phosphorylate the receptor to form a docking site leading to the phosphorylation of STAT3 and STAT4 (PubMed:29287995, PubMed:32474165, PubMed:33606986). This process leads to activation of several pathways including p38 MAPK or NF-kappa-B and promotes the production of pro-inflammatory cytokines such as interleukin-17A/IL17A (PubMed:12023369). In turn, participates…
Heterodimer with IL12B; disulfide-linked (PubMed:11114383, PubMed:18680750). The heterodimer is known as interleukin IL-23 (PubMed:11114383, PubMed:18680750). Interacts with IL23R; this interaction enables recruitment of IL12RB1 (PubMed:29287995, PubMed:33606986)
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 5MJ3 | X-ray | 1.74 Å | B=20-189 |
| 3D85 | X-ray | 1.9 Å | C=20-189 |
| 8CR8 | X-ray | 2.0 Å | B=22-189 |
| 3DUH | X-ray | 2.3 Å | C/D=20-189 |
| 8UUI | X-ray | 2.43 Å | B=20-189 |
| 5MXA | X-ray | 2.5 Å | B=1-189 |
| 4GRW | X-ray | 2.55 Å | A/C=1-189 |
| 6UIB | X-ray | 2.74 Å | A=20-189 |
| 5MZV | X-ray | 2.8 Å | B=1-189 |
| 3D87 | X-ray | 2.9 Å | A/C=20-189 |
| 3QWR | X-ray | 3.25 Å | B=20-189 |
| 5MJ4 | X-ray | 3.4 Å | B=20-189 |
| 6WDQ | X-ray | 3.4 Å | B=28-189 |
| 8OE4 | EM | 3.6 Å | B=20-189 |
| 5NJD | X-ray | 3.9 Å | B/D/F/H/J/L=1-189 |
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