Immunoglobulin J chain (JCHAIN) is a 159-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01591.
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The mean pLDDT of this model is 87.1 (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 | 60% |
| 70 to 90 | Confident: backbone generally right | 31% |
| 50 to 70 | Low: treat with caution | 9% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
Serves to link two monomer units of either IgM or IgA. In the case of IgM, the J chain-joined dimer is a nucleating unit for the IgM pentamer, and in the case of IgA it induces dimers and/or larger polymers. It also helps to bind these immunoglobulins to secretory component
Part of the secretory IgA (sIgA) complex that consists of two, four or five IgA monomers, and two additional non-Ig polypeptides, namely the JCHAIN and the secretory component (the proteolytic product of PIGR) (PubMed:32029686). Part of the secretory IgM (sIgM) complex that consists of five IgM monomers, and two additional non-Ig polypeptides, namely the JCHAIN and the secretory component (the…
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6UE7 | EM | 2.9 Å | D=23-159 |
| 6UE9 | EM | 2.9 Å | D=23-159 |
| 6UE8 | EM | 3.0 Å | D=23-159 |
| 6UEA | EM | 3.0 Å | D=23-159 |
| 8SKV | EM | 3.1 Å | J=23-159 |
| 6LX3 | EM | 3.15 Å | J=1-159 |
| 7YSG | EM | 3.18 Å | J=24-159 |
| 8SKU | EM | 3.2 Å | J=23-159 |
| 6LXW | EM | 3.27 Å | J=1-159 |
| 7K0C | EM | 3.3 Å | D=23-159 |
| 7YG2 | EM | 3.32 Å | J=24-159 |
| 7YTC | EM | 3.39 Å | J=24-159 |
| 8WYR | EM | 3.39 Å | J=1-159 |
| 6KXS | EM | 3.4 Å | J=24-159 |
| 8WYS | EM | 3.41 Å | J=1-159 |
| 8BPF | EM | 3.5 Å | J=1-159 |
| 7Y0H | EM | 3.56 Å | J=24-159 |
| 8R83 | EM | 3.57 Å | J=1-159 |
| 8GZN | EM | 3.6 Å | J=24-159 |
| 8R84 | EM | 3.6 Å | J=1-159 |
Showing 20 of 30 experimental structures (best resolution first).
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