Coagulation factor IX (F9) is a 461-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P00740.
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The mean pLDDT of this model is 80.3 (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 | 51% |
| 70 to 90 | Confident: backbone generally right | 25% |
| 50 to 70 | Low: treat with caution | 13% |
| Below 50 | Very low: often disordered regions | 12% |
What pLDDT means and how to read it
Factor IX is a vitamin K-dependent plasma protein that participates in the intrinsic pathway of blood coagulation by converting factor X to its active form in the presence of Ca(2+) ions, phospholipids, and factor VIIIa (PubMed:8295821, PubMed:2592373, PubMed:20121197, PubMed:20121198, PubMed:1730085, PubMed:19846852, PubMed:39880037)
Heterodimer of a light chain and a heavy chain; disulfide-linked (PubMed:20080729, PubMed:20121197, PubMed:20121198). Interacts (inactive and activated) with F11 (activated) in calcium-dependent manner (PubMed:22961984). Interacts with SERPINC1 (PubMed:20080729). Interacts (activated) with iripin-8, a serine protease inhibitor from Ixodes ricinus saliva (PubMed:34502392). Interacts (inactive and…
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 5JB9 | X-ray | 1.3 Å | E=134-191, S=227-461 |
| 6MV4 | X-ray | 1.37 Å | H=227-461, L=132-185 |
| 5JBA | X-ray | 1.4 Å | E=134-191, S=227-461 |
| 5TNT | X-ray | 1.4 Å | A=227-461, B=130-191 |
| 4YZU | X-ray | 1.41 Å | A=227-461, B=130-191 |
| 4Z0K | X-ray | 1.41 Å | A=227-461, B=130-191 |
| 5JB8 | X-ray | 1.45 Å | E=134-191, S=227-461 |
| 1EDM | X-ray | 1.5 Å | B/C=92-130 |
| 2WPH | X-ray | 1.5 Å | E=133-191, S=227-461 |
| 5TNO | X-ray | 1.54 Å | A=227-461, B=130-191 |
| 5JBB | X-ray | 1.56 Å | E=134-191, S=227-461 |
| 2WPJ | X-ray | 1.6 Å | E=133-191, S=227-461 |
| 6RFK | X-ray | 1.6 Å | E=130-191, S=227-461 |
| 4WMA | X-ray | 1.62 Å | D=92-130 |
| 3KCG | X-ray | 1.7 Å | H=227-461, L=130-188 |
| 2WPL | X-ray | 1.82 Å | E=133-191, S=227-461 |
| 5EGM | X-ray | 1.84 Å | A=227-461, B=130-191 |
| 4ZAE | X-ray | 1.86 Å | A=227-461, B=130-191 |
| 4WMI | X-ray | 1.87 Å | D=92-130 |
| 8EPH | X-ray | 1.88 Å | A/C=93-190, B/D=227-461 |
Showing 20 of 56 experimental structures (best resolution first).
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