Low affinity immunoglobulin gamma Fc region receptor III-B (FCGR3B) is a 233-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: O75015.
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The mean pLDDT of this model is 88.6 (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 | 73% |
| 70 to 90 | Confident: backbone generally right | 12% |
| 50 to 70 | Low: treat with caution | 12% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Receptor for the Fc region of immunoglobulins gamma. Low affinity receptor. Binds complexed or aggregated IgG and also monomeric IgG. Contrary to III-A, is not capable to mediate antibody-dependent cytotoxicity and phagocytosis. May serve as a trap for immune complexes in the peripheral circulation which does not activate neutrophils
Monomer. Interacts with INPP5D/SHIP1 (By similarity). Interacts with the Fc region of IgGs with a preference for IgG1 and IgG3 isotypes
Cell membrane, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1FNL | X-ray | 1.8 Å | A=19-192 |
| 6EAQ | X-ray | 2.22 Å | C=19-193 |
| 1E4J | X-ray | 2.5 Å | A=18-193 |
| 1T83 | X-ray | 3.0 Å | C=19-194 |
| 1E4K | X-ray | 3.2 Å | C=18-193 |
| 1T89 | X-ray | 3.5 Å | C=19-194 |
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