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Class II major histocompatibility complex (MHCII) molecules present antigens to CD4(+) T cells. In addition to the most commonly studied human MHCII isotype, HLA-DR, whose beta chain is encoded by the HLA-DRB1 locus, several other isotypes that use the same alpha chain but have beta chains encoded by other genes. These other DR molecules also are expressed in antigen-presenting cells and are known to participate in peptide presentation to T cells and to be recognized as alloantigens by other T cells. Like some of the HLA-DRB1 alleles, several of these alternate DR molecules have been associated with specific autoimmune diseases and T cell hypersensitivity. Here we present the structure of an HLA-DR molecule (DR52c) containing one of these alternate beta chains (HLA-DRB3*0301) bound to a self-peptide derived from the Tu elongation factor. The molecule shares structurally conserved elements with other MHC class II molecules but has some unique features in the peptide-binding groove. Comparison of the three major HLA-DBR3 alleles (DR52a, b, and c) suggests that they were derived from one another by recombination events that scrambled the four major peptide-binding pockets at peptide positions 1, 4, 6, and 9 but left virtually no polymorphisms elsewhere in the molecules.

The structure of HLA-DR52c: comparison to other HLA-DRB3 alleles., Dai S, Crawford F, Marrack P, Kappler JW, Proc Natl Acad Sci U S A. 2008 Aug 19;105(33):11893-7. Epub 2008 Aug 12. PMID:18697946

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Categories: Homo sapiens | Dai, S. | Kappler, J W. | Elongation factor | Glycoprotein | Gtp-binding | Hla | Immune response | Membrane | Membrane protein | Methylation | Mhc class ii | Mhc ii | Nucleotide-binding | Nucleus | Phosphoprotein | Polymorphism | Protein biosynthesis | Transmembrane