Beta-2-microglobulin (B2m) is a 119-residue protein from Rattus norvegicus. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P07151.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 94.5 (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 | 86% |
| 70 to 90 | Confident: backbone generally right | 12% |
| 50 to 70 | Low: treat with caution | 3% |
| 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. Forms a heterotrimer with MR1 and a metabolite antigen
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1KJV | X-ray | 1.48 Å | B=21-119 |
| 3FRU | X-ray | 2.2 Å | B/D/F=21-119 |
| 1KJM | X-ray | 2.35 Å | B=21-119 |
| 1ED3 | X-ray | 2.55 Å | B/E=21-119 |
| 1I1A | X-ray | 2.8 Å | B=21-119 |
| 6NF7 | X-ray | 2.9 Å | B/E/H/K/N=21-119 |
| 1FRT | X-ray | 4.5 Å | B=21-119 |
MolViewer loads the AlphaFold model straight from AlphaFold DB into your browser. Show it as a cartoon, color by pLDDT, measure distances and angles, and load a PDB structure next to it to compare.