The protein encoded by this gene belongs to the HLA class II beta chain paralogues. The class II molecule is a heterodimer consisting of an alpha (DRA) and a beta chain (DRB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages).
The beta chain is approximately 26-28 kDa. It is encoded by 6 exons, exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, exon 4 encodes the transmembrane domain and exon 5 encodes the cytoplasmic tail. Within the DR molecule the beta chain contains all the polymorphisms specifying the peptide binding specificities. Hundreds of DRB1 alleles have been described and typing for these polymorphisms is routinely done for bone marrow and kidney transplantation.
DRB1 is expressed at a level five times higher than its paralogues DRB3, DRB4 and DRB5. DRB1 is present in all individuals. Allelic variants of DRB1 are linked with either none or one of the genes DRB3, DRB4 and DRB5. The presence of DRB5 is linked with allelic variants of DRB1, otherwise it is omitted. There are 4 related pseudogenes: DRB2, DRB6, DRB7, DRB8 and DRB9.
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1aqd: HLA-DR1 (DRA, DRB1 0101) HUMAN CLASS II HISTOCOMPATIBILITY PROTEIN (EXTRACELLULAR DOMAIN) COMPLEXED WITH ENDOGENOUS PEPTIDE
1d5m: X-RAY CRYSTAL STRUCTURE OF HLA-DR4 COMPLEXED WITH PEPTIDE AND SEB
1dlh: CRYSTAL STRUCTURE OF THE HUMAN CLASS II MHC PROTEIN HLA-DR1 COMPLEXED WITH AN INFLUENZA VIRUS PEPTIDE
1fv1: STRUCTURAL BASIS FOR THE BINDING OF AN IMMUNODOMINANT PEPTIDE FROM MYELIN BASIC PROTEIN IN DIFFERENT REGISTERS BY TWO HLA-DR2 ALLELES
1fyt: CRYSTAL STRUCTURE OF A COMPLEX OF A HUMAN ALPHA/BETA-T CELL RECEPTOR, INFLUENZA HA ANTIGEN PEPTIDE, AND MHC CLASS II MOLECULE, HLA-DR1
1h15: X-RAY CRYSTAL STRUCTURE OF HLA-DRA1*0101/DRB5*0101 COMPLEXED WITH A PEPTIDE FROM EPSTEIN BARR VIRUS DNA POLYMERASE
1hqr: CRYSTAL STRUCTURE OF A SUPERANTIGEN BOUND TO THE HIGH-AFFINITY, ZINC-DEPENDENT SITE ON MHC CLASS II
1hxy: CRYSTAL STRUCTURE OF STAPHYLOCOCCAL ENTEROTOXIN H IN COMPLEX WITH HUMAN MHC CLASS II
1j8h: Crystal Structure of a Complex of a Human alpha/beta-T cell Receptor, Influenza HA Antigen Peptide, and MHC Class II Molecule, HLA-DR4
1jwm: Crystal Structure of the Complex of the MHC Class II Molecule HLA-DR1(HA peptide 306-318) with the Superantigen SEC3
1jws: Crystal Structure of the Complex of the MHC Class II Molecule HLA-DR1 (HA peptide 306-318) with the Superantigen SEC3 Variant 3B1
1jwu: Crystal Structure of the Complex of the MHC Class II Molecule HLA-DR1 (HA peptide 306-318) with the superantigen SEC3 Variant 3B2
1kg0: Structure of the Epstein-Barr Virus gp42 Protein Bound to the MHC class II Receptor HLA-DR1
1klg: Crystal structure of HLA-DR1/TPI(23-37, Thr28-->Ile mutant) complexed with staphylococcal enterotoxin C3 variant 3B2 (SEC3-3B2)
1klu: Crystal structure of HLA-DR1/TPI(23-37) complexed with staphylococcal enterotoxin C3 variant 3B2 (SEC3-3B2)
1lo5: Crystal structure of the D227A variant of Staphylococcal enterotoxin A in complex with human MHC class II
1pyw: Human class II MHC protein HLA-DR1 bound to a designed peptide related to influenza virus hemagglutinin, FVKQNA(MAA)AL, in complex with staphylococcal enterotoxin C3 variant 3B2 (SEC3-3B2)
1r5i: Crystal structure of the MAM-MHC complex
1seb: COMPLEX OF THE HUMAN MHC CLASS II GLYCOPROTEIN HLA-DR1 AND THE BACTERIAL SUPERANTIGEN SEB
1sje: HLA-DR1 complexed with a 16 residue HIV capsid peptide bound in a hairpin conformation
1sjh: HLA-DR1 complexed with a 13 residue HIV capsid peptide
1t5w: HLA-DR1 in complex with a synthetic peptide (AAYSDQATPLLLSPR)
1t5x: HLA-DR1 in complex with a synthetic peptide (AAYSDQATPLLLSPR) and the superantigen SEC3-3B2
1zgl: Crystal structure of 3A6 TCR bound to MBP/HLA-DR2a
2g9h: Crystal Structure of Staphylococcal Enterotoxin I (SEI) in Complex with a Human MHC class II Molecule
2iam: Structural basis for recognition of mutant self by a tumor-specific, MHC class II-restricted TCR
2ian: Structural basis for recognition of mutant self by a tumor-specific, MHC class II-restricted TCR
2icw: Crystal structure of a complete ternary complex between TCR, superantigen, and peptide-MHC class II molecule
2ipk: Crystal Structure of the MHC Class II Molecule HLA-DR1 in Complex with the Fluorogenic Peptide, AcPKXVKQNTLKLAT (X=3-[5-(dimethylamino)-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl]-L-alanine) and the Superantigen, SEC3 Variant 3B2
2oje: Mycoplasma arthritidis-derived mitogen complexed with class II MHC molecule HLA-DR1/HA complex in the presence of EDTA