Ubiquitin-like protein ISG15 (Isg15) is a 161-residue protein from Mus musculus. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q64339.
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The mean pLDDT of this model is 88.8 (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 | 65% |
| 70 to 90 | Confident: backbone generally right | 30% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 3% |
What pLDDT means and how to read it
Ubiquitin-like protein which plays a key role in the innate immune response to viral infection either via its conjugation to a target protein (ISGylation) or via its action as a free or unconjugated protein. ISGylation involves a cascade of enzymatic reactions involving E1, E2, and E3 enzymes which catalyze the conjugation of ISG15 to a lysine residue in the target protein. Its target proteins include SERPINA3G/SPI2A, JAK1, MAPK3/ERK1, PLCG1, TRIM25, STAT5A, MAPK1/ERK2 and globin. Isgylation of the viral sensor IFIH1/MDA5 promotes IFIH1/MDA5 oligomerization and triggers activation of innate immunity against a range of viruses, including coronaviruses, flaviviruses and picornaviruses. Can…
Homodimer; disulfide-linked (By similarity). Interacts with, and is conjugated to its targets by the UBE1L (E1 enzyme) and UBE2E2 (E2 enzyme) (By similarity). Interacts with NEDD4 (By similarity). Interacts with PARP12; this interaction inhibits PINK1/Parkin-dependent mitophagy (By similarity)
Cytoplasm, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 5CHW | X-ray | 2.1 Å | A/B/C/D/E/F/G/H/I/J=1-155 |
| 5CHF | X-ray | 2.3 Å | A/B/C/D/E=1-155 |
| 5TL7 | X-ray | 2.44 Å | A/C=78-155 |
| 5JZE | X-ray | 2.47 Å | B/D=79-154 |
| 6J62 | X-ray | 2.49 Å | A=1-153 |
| 5CHV | X-ray | 3.0 Å | C/D=1-155 |
| 6YVA | X-ray | 3.18 Å | C=1-161 |
| 5TLA | X-ray | 3.24 Å | A/B/C/D/E/F/G/H/I/J=1-150 |
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