Complement C4-A (C4A) is a 1744-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P0C0L4.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 83.4 (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 | 44% |
| 70 to 90 | Confident: backbone generally right | 43% |
| 50 to 70 | Low: treat with caution | 6% |
| Below 50 | Very low: often disordered regions | 7% |
What pLDDT means and how to read it
Precursor of non-enzymatic components of the classical, lectin and GZMK complement pathways, which consist in a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system
Complement circulates in blood as a disulfide-linked trimer of an alpha, beta and gamma chain
Secreted, Synapse, Cell projection, axon, Cell projection, dendrite, Cell surface
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1HZF | X-ray | 2.3 Å | A=957-1323 |
| 6YSQ | X-ray | 3.3 Å | C/D=757-1446 |
| 7B2M | EM | 3.39 Å | A=20-675, B=680-1446, C=1454-1744 |
| 7B2P | EM | 3.43 Å | A=20-675, B=680-1446, C=1454-1744 |
| 5JTW | X-ray | 3.5 Å | A/D=20-675, B/E=757-1446, C/F=1454-1744 |
| 9QJ5 | EM | 3.5 Å | A/B/C=1-1744 |
| 9QK2 | EM | 3.5 Å | A/B/C=1-1744 |
| 5JPN | X-ray | 3.6 Å | A=20-675, B=680-1446, C=1455-1744 |
| 5JPM | X-ray | 3.75 Å | A/D=20-675, B/E=680-1446, C/F=1454-1744 |
| 7B2Q | EM | 3.76 Å | A=20-675, B=680-1446, C=1454-1744 |
| 9QJ4 | EM | 3.9 Å | A/B/C=1-1744 |
| 9QPY | EM | 4.3 Å | A/B/C=1-1744 |
MolViewer loads the AlphaFold model straight from AlphaFold DB into your browser. Show it as a cartoon, color by pLDDT, measure distances and angles, and load a PDB structure next to it to compare.