Cobra venom factor is a 1642-residue protein from Naja kaouthia. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q91132.
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The mean pLDDT of this model is 80.2 (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 | 24% |
| 70 to 90 | Confident: backbone generally right | 60% |
| 50 to 70 | Low: treat with caution | 11% |
| Below 50 | Very low: often disordered regions | 6% |
What pLDDT means and how to read it
Complement-activating protein in cobra venom. It is a structural and functional analog of complement component C3b, the activated form of C3. It binds factor B (CFB), which is subsequently cleaved by factor D (CFD) to form the bimolecular complex CVF/Bb. CVF/Bb is a C3/C5 convertase that cleaves both complement components C3 and C5. Structurally, it resembles the C3b degradation product C3c, which is not able to form a C3/C5 convertase. Unlike C3b/Bb, CVF/Bb is a stable complex and completely resistant to the actions of complement regulatory factors H (CFH) and I (CFI). Therefore, CVF continuously activates complement resulting in the depletion of complement activity
Heterotrimer of alpha, beta and gamma chains; disulfide-linked. Is active with factor B in the presence of factor D
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 3HRZ | X-ray | 2.2 Å | A=23-649, B=733-984, C=1264-1642 |
| 3FRP | X-ray | 2.61 Å | A=23-649, B=1264-1642, G=733-984 |
| 3HS0 | X-ray | 3.0 Å | A/F=23-649, B/G=733-984, C/H=1264-1642 |
| 8AYH | EM | 3.35 Å | B=1-1642 |
| 3PRX | X-ray | 4.3 Å | B/D=1-1642 |
| 3PVM | X-ray | 4.3 Å | B/D=1-1642 |
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