The Molecular Basis of the Increased Recognition ofDQ8-glia-α1 by HLA-DQ8
Bhuvi Vahi (1)
(1) MIT Vishwashanti Gurukul
Celiac disease (CeD) is an autoimmune disorder triggered by gluten, affecting about 1 in 100 people worldwide. The antigen HLA-DQ8 is found in approximately 5-10% of people who are affected by celiac disease. Its role in the autoimmune response is binding to gluten molecules and presenting them to immune cells, which will initiate an autoimmune response against said gluten molecules. This paper will investigate HLA-DQ8’s variant amino acids at its binding site to the gluten molecule DQ8-glia-α1, using HLA-DQ6.2 as a reference molecule. It will also investigate how these variants could affect HLA-DQ8’s binding affinity to DQ8-glia-α1. The tools consulted for this study are Uniprot, SWISSMODEL, PDB, HDOCK, PyMOL, and PRODIGY. First, the variant amino acids in HLA-DQ8 with reference to HLA-DQ6.2 were manually established. PRODIGY was used to find the binding affinity for the HLA-DQ8-DQ8-glia-α1 and HLA-DQ6.2-DQ8-glia-α1 complexes. These complexes were mapped in PyMOL, and the binding sites to DQ8-glia-α1 were determined. Finally, the overlap between the mutated amino acids and binding sites was determined. HLA-DQ8 displayed a greater binding affinity for DQ8-glia-α1 than HLA-DQ6.2, but the difference could be insignificant considering the computational model used. The five variant amino acids that could play a role in binding to DQ8-glia-α1 on HLA-DQ8 are ALA157, ASN214, GLU118, THR121 and THR122. Thus, these five amino acids could be the cause of HLA-DQ8’s increased binding affinity to DQ8-glia-α1. Understanding why HLA-DQ8 has a greater binding affinity to DQ8-glia-α1 would open new possibilities for the applications of gene editing to prevent celiac disease.
Keywords: Antigen HLA-DQ8, DQ8-glia-α1 peptide, binding site, binding affinity, mutations
Article Type: Original Research
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