3b3i
From Proteopedia
Citrullination-dependent differential presentation of a self-peptide by HLA-B27 subtypes
Structural highlights
Disease[1B27_HUMAN] Defects in HLA-B are a cause of susceptibility to spondyloarthropathy type 1 (SPDA1) [MIM:106300]. It is a chronic rheumatic disease with multifactorial inheritance. It includes a spectrum of related disorders comprising ankylosing spondylitis, a subset of psoriatic arthritis, reactive arthritis (e.g. Reiter syndrome), arthritis associated with inflammatory bowel disease and undifferentiated spondyloarthropathy. These disorders may occur simultaneously or sequentially in the same patient, probably representing various phenotypic expressions of the same disease. Ankylosing spondylitis is the form of rheumatoid arthritis affecting the spine and is considered the prototype of seronegative spondyloarthropathies. It produces pain and stiffness as a result of inflammation of the sacroiliac, intervertebral, and costovertebral joints. Note=In the Greek Cypriot population, a restricted number of HLA-B27 subtypes are associated with ankylosing spondylitis and other B27-related diseases and an elevated frequency of the B*2702 allele in ankylosing spondylitis patients is identified. The allele B*2707 seems to have a protective role in this population because it was found only in the healthy controls.[1] [B2MG_HUMAN] Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:241600]. Affected individuals show marked reduction in serum concentrations of immunoglobulin and albumin, probably due to rapid degradation.[2] Note=Beta-2-microglobulin may adopt the fibrillar configuration of amyloid in certain pathologic states. The capacity to assemble into amyloid fibrils is concentration dependent. Persistently high beta(2)-microglobulin serum levels lead to amyloidosis in patients on long-term hemodialysis.[3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] Function[1B27_HUMAN] Involved in the presentation of foreign antigens to the immune system. [VIPR1_HUMAN] This is a receptor for VIP. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase. The affinity is VIP = PACAP-27 > PACAP-38.[16] [B2MG_HUMAN] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedInflammatory processes are accompanied by the posttranslational modification of certain arginine residues within proteins to yield citrulline, although it is largely unknown how this modification influences antigen presentation. We employed crystallographic and functional studies to investigate whether the exchange of arginine to citrulline affects the display of a peptide by two human major histocompatibility antigen class I subtypes, HLA-B(*)2705 and HLA-B(*)2709. Both differ only in residue 116 within the peptide binding groove despite their differential association with ankylosing spondylitis, an inflammatory rheumatic disorder. The crystal structures described here show that a modified self-peptide, pVIPR-U5 (RRKWURWHL; U = citrulline), is presented by the two HLA-B27 molecules in distinct conformations. These binding modes differ not only drastically from each other but also from the conformations exhibited by the non-citrullinated peptide in a given subtype. The differential reactivity of HLA-B27-restricted cytotoxic T cells with modified or unmodified pVIPR supports the structural findings and shows that the presentation of citrullinated peptides has the potential to influence immune responses. Citrullination-dependent differential presentation of a self-peptide by HLA-B27 subtypes.,Beltrami A, Rossmann M, Fiorillo MT, Paladini F, Sorrentino R, Saenger W, Kumar P, Ziegler A, Uchanska-Ziegler B J Biol Chem. 2008 Oct 3;283(40):27189-99. Epub 2008 Jul 23. PMID:18650441[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Beltrami, A | Fiorillo, M T | Kumar, P | Paladini, F | Rossmann, M | Saenger, W | Sorrentino, R | Uchanska-Ziegler, B | Ziegler, A | Ankylosing spondylitis | Disease mutation | G-protein coupled receptor | Glycation | Glycoprotein | Hla-b2709 | Host-virus interaction | Immune response | Immune system | Immunoglobulin domain | Membrane | Mhc i | Phosphorylation | Protein binding | Pyrrolidone carboxylic acid | Receptor | Secreted | Transducer | Transmembrane
