5def
From Proteopedia
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==Crystal structure of B*27:04 complex bound to the pVIPR peptide== | ==Crystal structure of B*27:04 complex bound to the pVIPR peptide== | ||
<StructureSection load='5def' size='340' side='right' caption='[[5def]], [[Resolution|resolution]] 1.60Å' scene=''> | <StructureSection load='5def' size='340' side='right' caption='[[5def]], [[Resolution|resolution]] 1.60Å' scene=''> | ||
Revision as of 17:29, 10 May 2016
Crystal structure of B*27:04 complex bound to the pVIPR peptide
Structural highlights
Disease[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.[1] 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.[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Function[B2MG_HUMAN] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Publication Abstract from PubMedOBJECTIVE: Dissimilarities in antigen processing and presentation are known to contribute to the differential association of HLA-B*27 subtypes with the inflammatory rheumatic disease ankylosing spondylitis (AS). In support of this contention, previous X-ray crystallographic data showed that peptides can be displayed by almost identical HLA-B*27 molecules in a subtype-dependent manner, allowing cytotoxic T lymphocytes to distinguish between these subtypes. For example, the human self-peptide pVIPR (RRKWRRWHL) is displayed in a single conformation by B*27:09 (not AS-associated), while B*27:05 (AS-associated) presents the peptide in a dual binding mode. In addition, differences in conformational flexibility between these subtypes might affect their stability or antigen presentation capability. We investigated B*27:04 and B*27:06, another pair of minimally distinct HLA-B*27 subtypes, to assess whether dual peptide conformations or structural dynamics could play a role in the initiation of AS. METHODS: Using X-ray crystallography, we solved the structures of pVIPR-B*27:04 and pVIPR-B*27:06 and employed isotope-edited infrared (IR) spectroscopy to probe the dynamics of these HLA-B*27 subtypes. RESULTS: As opposed to B*27:05 and B*27:09, B*27:04 (AS-associated) displays pVIPR conventionally and B*27:06 (not AS-associated) presents the peptide in a dual conformation. On the other hand, the comparison of the four HLA-B*27 subtypes using IR spectroscopy revealed that B*27:04 and B*27:05 exhibit elevated molecular dynamics when compared to the non-associated subtypes B*27:06 and B*27:09. CONCLUSION: Our results demonstrate that an increase in conformational flexibility characterizes the disease-associated subtypes B*27:04 and B*27:05. This article is protected by copyright. All rights reserved. Increased conformational flexibility characterizes HLA-B*27 subtypes associated with ankylosing spondylitis.,Loll B, Fabian H, Huser H, Hee CS, Ziegler A, Uchanska-Ziegler B, Ziegler A Arthritis Rheumatol. 2016 Jan 8. doi: 10.1002/art.39567. PMID:26748477[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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