Beta-2-microglobulin (B2M) is a 118-residue protein from Bos taurus. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01888.
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The mean pLDDT of this model is 94.3 (very high 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 | 81% |
| 70 to 90 | Confident: backbone generally right | 13% |
| 50 to 70 | Low: treat with caution | 6% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system
Heterodimer of an alpha chain and a beta chain. Beta-2-microglobulin is the beta-chain of major histocompatibility complex class I molecules (PubMed:23613577). Forms a heterotrimer with MR1 and a metabolite antigen (By similarity)
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2XFX | X-ray | 1.9 Å | B=20-118 |
| 3L9R | X-ray | 2.3 Å | B/D/F/H=21-118 |
| 4F7E | X-ray | 2.4 Å | B=21-118 |
| 1BMG | X-ray | 2.5 Å | A=21-118 |
| 3PWV | X-ray | 2.7 Å | B/E=21-118 |
| 4F7C | X-ray | 2.86 Å | B/D=21-118 |
| 4IIQ | X-ray | 2.86 Å | C=21-118 |
| 4L8S | X-ray | 2.9 Å | C=21-118 |
| 4LCC | X-ray | 3.26 Å | C=21-118 |
| 4L9L | X-ray | 3.4 Å | C=21-118 |
| 7RNO | NMR | B=21-118 |
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