Complement C1r subcomponent (C1R) is a 705-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P00736.
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The mean pLDDT of this model is 87.0 (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 | 7% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Serine protease component of the complement C1 complex, a multiprotein complex that initiates the classical 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:17996945, PubMed:19473974, PubMed:29449492). C1R catalyzes the first enzymatic step in the classical complement pathway: it is activated by the C1Q subcomplex of the C1 complex, which associates with IgG or IgM immunoglobulins complexed with antigens to form antigen-antibody complexes on the surface of pathogens (PubMed:29449492, PubMed:34155115). Immunoglobulin-binding promotes the autocatalytic cleavage and…
Core component of the complement C1 complex, a calcium-dependent complex composed of 1 molecule of the C1Q subcomplex, 2 molecules of C1R and 2 molecules of C1S (PubMed:19473974, PubMed:28104818, PubMed:29311313, PubMed:2988513, PubMed:2989825, PubMed:34155115, PubMed:6952210). The C1Q subcomplex is composed 18 subunits: 3 chains of C1QA, C1QB, and C1QC trimerize to form 6 collagen-like triple…
Secreted, Cell surface
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6F1D | X-ray | 1.95 Å | A=191-307 |
| 2QY0 | X-ray | 2.6 Å | A/C=309-463, B/D=464-705 |
| 1MD8 | X-ray | 2.8 Å | A=375-703 |
| 1GPZ | X-ray | 2.9 Å | A/B=307-705 |
| 9EKE | X-ray | 3.1 Å | C/D=308-705 |
| 1MD7 | X-ray | 3.2 Å | A=375-702 |
| 9EKD | X-ray | 3.28 Å | C/D=308-705 |
| 7MZT | X-ray | 4.07 Å | A=300-463, B=464-705 |
| 6F1C | X-ray | 4.2 Å | A/C=18-308 |
| 6F1H | X-ray | 4.5 Å | A/C=18-308 |
| 6F39 | X-ray | 5.8 Å | A/B=22-306 |
| 1APQ | NMR | A=140-192 |
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