Complement factor B (CFB) is a 764-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P00751.
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The mean pLDDT of this model is 86.3 (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 | 64% |
| 70 to 90 | Confident: backbone generally right | 24% |
| 50 to 70 | Low: treat with caution | 5% |
| Below 50 | Very low: often disordered regions | 7% |
What pLDDT means and how to read it
Precursor of the catalytic component of the C3 and C5 convertase complexes of the alternative pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system (PubMed:3638964, PubMed:624565, PubMed:6554279, PubMed:6919543, PubMed:9748277). The alternative complement pathway acts as an amplification loop that enhances other complement pathways (classical, lectin and GZMK) by promoting formation of additional C3 and C5 convertases (PubMed:3638964, PubMed:624565, PubMed:6554279, PubMed:6919543, PubMed:9748277). CFB is cleaved and activated by CFD to generate Ba and Bb chains; Bb chain…
Monomer (PubMed:19574954). Interacts with complement C3b; this interaction is dependent on the presence of Mg(2+) (PubMed:28264884, PubMed:31507604)
Secreted, Cell surface
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6QSW | X-ray | 1.64 Å | AAA/BBB/CCC=474-764 |
| 6RAV | X-ray | 1.7 Å | AAA/BBB=474-764 |
| 6T8W | X-ray | 1.7 Å | AAA/BBB=474-764 |
| 6QSX | X-ray | 1.77 Å | AAA/BBB=474-764 |
| 1Q0P | X-ray | 1.8 Å | A=254-476 |
| 1RRK | X-ray | 2.0 Å | A=268-764 |
| 1DLE | X-ray | 2.1 Å | A/B=470-764 |
| 3HRZ | X-ray | 2.2 Å | D=26-764 |
| 6T8V | X-ray | 2.29 Å | AAA/BBB=474-764 |
| 1RTK | X-ray | 2.3 Å | A=268-764 |
| 2OK5 | X-ray | 2.3 Å | A=24-764 |
| 1RS0 | X-ray | 2.6 Å | A=268-764 |
| 9U62 | EM | 2.7 Å | B=260-764 |
| 6T8U | X-ray | 2.84 Å | AAA/BBB/CCC=474-764 |
| 3HS0 | X-ray | 3.0 Å | D/I=26-764 |
| 7JTN | X-ray | 3.1 Å | A/C=1-764 |
| 8ENU | EM | 3.22 Å | D=2-764 |
| 2XWB | X-ray | 3.49 Å | F/H=35-764 |
| 7JTQ | X-ray | 3.5 Å | A/C=1-764 |
| 8EOK | EM | 3.53 Å | D=2-764 |
Showing 20 of 26 experimental structures (best resolution first).
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