Complement receptor type 2 (CR2) is a 1033-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P20023.
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The mean pLDDT of this model is 74.9 (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 | 2% |
| 70 to 90 | Confident: backbone generally right | 71% |
| 50 to 70 | Low: treat with caution | 21% |
| Below 50 | Very low: often disordered regions | 6% |
What pLDDT means and how to read it
Serves as a receptor for various ligands including complement component CD3d, HNRNPU OR IFNA1 (PubMed:1849076, PubMed:21527715, PubMed:7753047). When C3d is bound to antigens, attaches to C3d on B-cell surface and thereby facilitates the recognition and uptake of antigens by B-cells (PubMed:21527715). This interaction enhances B-cell activation and subsequent immune responses. Forms a complex with several partners on the surface of B-cells including CD19, FCRL5 and CD81, to form the B-cell coreceptor complex that plays a crucial role in B-cell activation and signaling (PubMed:1383329, PubMed:30107486). Also induces specific intracellular signaling separately from the BCR and CD19 by…
Interacts (via Sushi domain 1 and 2) with C3 (PubMed:11387479, PubMed:21527715). Interacts with CD19 (PubMed:1702139). Part of a complex composed of CD19, CR2/CD21, CD81 and IFITM1/CD225 in the membrane of mature B-cells (PubMed:1383329). Interacts (via Sushi domain 1 and 2) with FCER2 (via the C-terminus). Interacts with CD23 (PubMed:1386409). Interacts with FCRL5 (PubMed:30107486). Interacts…
Cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 8SM0 | X-ray | 1.68 Å | C=21-149 |
| 1LY2 | X-ray | 1.8 Å | A=22-148 |
| 1GHQ | X-ray | 2.04 Å | B/C=21-153 |
| 3OED | X-ray | 3.16 Å | C/D=19-153 |
| 8ZNI | EM | 3.29 Å | A=1-971 |
| 1W2R | X-ray | A=20-153 | |
| 1W2S | X-ray | B=20-153 | |
| 2ATY | X-ray | A/B=21-153 | |
| 2GSX | X-ray | A=21-971 |
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