Complement C5 (C5) is a 1676-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01031.
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The mean pLDDT of this model is 81.6 (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 | 26% |
| 70 to 90 | Confident: backbone generally right | 60% |
| 50 to 70 | Low: treat with caution | 11% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Precursor of the C5a anaphylatoxin and complement C5b components of the 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 (PubMed:12878586, PubMed:18204047, PubMed:30643019, PubMed:6554279). Activated downstream of classical, alternative, lectin and GZMK complement pathways (PubMed:12878586, PubMed:18204047, PubMed:30643019, PubMed:39914456, PubMed:39814882, PubMed:6554279)
In absence of complement activation, the C5 precursor is first processed by the removal of 4 basic residues, forming two chains, beta and alpha, linked by a disulfide bond
Secreted, Target cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9Y6C | X-ray | 2.0 Å | A=982-1305 |
| 5B71 | X-ray | 2.11 Å | E/F=20-124 |
| 4UU9 | X-ray | 2.12 Å | C/D=678-751 |
| 7AD7 | X-ray | 2.3 Å | A/B=1-1676 |
| 4P39 | X-ray | 2.4 Å | A/B/C/D=678-747 |
| 5B4P | X-ray | 2.4 Å | B/D=678-751 |
| 7OP0 | X-ray | 2.57 Å | A=678-1676, B=19-675 |
| 3HQA | X-ray | 2.59 Å | A/B=679-750 |
| 5HCC | X-ray | 2.59 Å | A=679-1676, B=19-674 |
| 6RPT | X-ray | 2.7 Å | A/C/E=348-460 |
| 7AD6 | X-ray | 2.75 Å | A/B=1-1676 |
| 7Y64 | EM | 2.9 Å | E=678-751 |
| 5HCD | X-ray | 2.98 Å | A=679-1676, B=19-674 |
| 8B0F | EM | 3.0 Å | A=1-1676 |
| 8HK5 | EM | 3.0 Å | B=678-751 |
| 3CU7 | X-ray | 3.1 Å | A/B=1-1676 |
| 9KX6 | EM | 3.11 Å | D=678-750 |
| 5HCE | X-ray | 3.12 Å | A=679-1676, B=19-674 |
| 8IA2 | EM | 3.21 Å | D=678-751 |
| 3HQB | X-ray | 3.3 Å | A/B=679-750 |
Showing 20 of 42 experimental structures (best resolution first).
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