P01909: HLA class II histocompatibility antigen, DQ alpha 1 chain (HLA-DQA1)

HLA class II histocompatibility antigen, DQ alpha 1 chain (HLA-DQA1) is a 254-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P01909.

Gene
HLA-DQA1
Organism
Homo sapiens
Length
254 residues
Mean pLDDT
87.9
Model
AF-P01909-F1 v6
Model created
1 Aug 2025
PDB structures
28

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Model confidence (pLDDT)

The mean pLDDT of this model is 87.9 (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 bandMeaningShare of residues
Above 90Very high: backbone and side chains are usually accurate67%
70 to 90Confident: backbone generally right19%
50 to 70Low: treat with caution12%
Below 50Very low: often disordered regions2%

What pLDDT means and how to read it

Function

Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route, where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules, and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to…

Subunit structure

Heterodimer of an alpha and a beta subunit; also referred as MHC class II molecule. In the endoplasmic reticulum (ER) it forms a heterononamer; 3 MHC class II molecules bind to a CD74 homotrimer (also known as invariant chain or HLA class II histocompatibility antigen gamma chain). In the endosomal/lysosomal system; CD74 undergoes sequential degradation by various proteases; leaving a small…

Subcellular location

Cell membrane, Endoplasmic reticulum membrane, Golgi apparatus, trans-Golgi network membrane, Endosome membrane, Lysosome membrane

Experimental structures in the PDB

Compare the prediction with experimentally determined structures of the same protein:

PDB IDMethodResolutionChains and residues
1UVQX-ray1.8 ÅA=24-218
6U3MX-ray1.9 ÅA/C=24-206
5KSAX-ray2.0 ÅA=24-206
6MFGX-ray2.0 ÅA/C=24-206
2NNAX-ray2.1 ÅA=24-206
8W84X-ray2.1 ÅC=24-206
5KSVX-ray2.19 ÅA=24-216
9EJGX-ray2.2 ÅA=24-206
1S9VX-ray2.22 ÅA/D=24-216
8W86X-ray2.24 ÅC/G=24-206
1JK8X-ray2.4 ÅA=27-206
6XP6X-ray2.4 ÅA/D=24-206
9EJHX-ray2.45 ÅA=24-206
6MFFX-ray2.6 ÅA=24-206
4OZFX-ray2.7 ÅA=24-206
5KSUX-ray2.73 ÅA/D=24-216
8W85X-ray2.77 ÅC/G=24-206
4OZHX-ray2.8 ÅA/C=24-206
6U3NX-ray2.8 ÅA=24-206
8W83X-ray2.82 ÅC/G/K/O=24-206

Showing 20 of 28 experimental structures (best resolution first).

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