HLA class II histocompatibility antigen, DR beta 3 chain (HLA-DRB3) is a 266-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P79483.
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The mean pLDDT of this model is 88.4 (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 | 71% |
| 70 to 90 | Confident: backbone generally right | 14% |
| 50 to 70 | Low: treat with caution | 12% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
A beta chain of antigen-presenting major histocompatibility complex class II (MHCII) molecule. In complex with the alpha chain HLA-DRA, displays antigenic peptides on professional antigen presenting cells (APCs) for recognition by alpha-beta T cell receptor (TCR) on HLA-DRB3-restricted CD4-positive T cells. This guides antigen-specific T-helper effector functions, both antibody-mediated immune response and macrophage activation, to ultimately eliminate the infectious agents and transformed cells. Typically presents extracellular peptide antigens of 10 to 30 amino acids that arise from proteolysis of endocytosed antigens in lysosomes (PubMed:16148104, PubMed:19531622, PubMed:19830726,…
Heterotrimer that consists of an alpha chain HLA-DRA, a beta chain HLA-DRB1 and a peptide (peptide-MHCII) (PubMed:17583734, PubMed:18697946). Newly synthesized alpha and beta chains forms a heterodimer (MHCII) that associates with the CD74/invariant chain (Ii) in the endoplasmic reticulum (ER). Ii is a trimer composed of three subunits and each subunit interacts with one MHCII dimer, blocking…
Cell membrane, Endoplasmic reticulum membrane, Lysosome membrane, Late endosome membrane, Autolysosome membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 3C5J | X-ray | 1.8 Å | B=30-219 |
| 2Q6W | X-ray | 2.25 Å | B/E=30-219 |
| 4H1L | X-ray | 3.3 Å | B/E=35-217 |
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