Immunoglobulin heavy constant alpha 1 (IGHA1) is a 398-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01876.
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The mean pLDDT of this model is 81.9 (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 | 51% |
| 70 to 90 | Confident: backbone generally right | 30% |
| 50 to 70 | Low: treat with caution | 7% |
| Below 50 | Very low: often disordered regions | 13% |
What pLDDT means and how to read it
Constant region of immunoglobulin heavy chains. Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:20176268, PubMed:22158414). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light…
Immunoglobulins are composed of two identical heavy chains and two identical light chains; disulfide-linked (PubMed:20176268). Monomeric or polymeric (PubMed:2241915). 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)
Secreted, Cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9R2E | X-ray | 2.54 Å | P/Q=123-333 |
| 9OFR | X-ray | 2.65 Å | A/B/E/G=123-333 |
| 6UE7 | EM | 2.9 Å | A/B/F/G=123-333 |
| 1OW0 | X-ray | 3.1 Å | A/B=122-333 |
| 8SKV | EM | 3.1 Å | A/B/C/D=1-333 |
| 6LX3 | EM | 3.15 Å | A/B/C/D=122-333 |
| 2QEJ | X-ray | 3.2 Å | A/B=123-333 |
| 8SKU | EM | 3.2 Å | A/B/C/D=1-333 |
| 6LXW | EM | 3.27 Å | A/B/C/D=122-333 |
| 7UVL | EM | 3.56 Å | A/B=123-331 |
| 6XJA | EM | 4.0 Å | A/B=122-331 |
| 1IGA | X-ray | A/B=1-333 | |
| 2ESG | X-ray | A/B=1-333 | |
| 3CHN | X-ray | A/B/C/D=1-333 |
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