| 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
[1B35_HUMAN] Involved in the presentation of foreign antigens to the immune system. [BZLF1_EBVB9] Plays a key role in the switch from latent infection to lytic cycle producing new virions. Acts as a transcription factor, inducing early lytic cycle genes, and as a origin binding protein for genome replication. BZLF1 activates the promoter of another EBV gene (BSLF2+BMLF1).[15] [16] [17] [18] [19] [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 PubMed
Thousands of potentially antigenic peptides are encoded by an infecting pathogen; however, only a small proportion induce measurable CD8(+) T cell responses. To investigate the factors that control peptide immunogenicity, we have examined the cytotoxic T lymphocyte (CTL) response to a previously undefined epitope ((77)APQPAPENAY(86)) from the BZLF1 protein of Epstein-Barr virus (EBV). This peptide binds well to two human histocompatibility leukocyte antigen (HLA) allotypes, HLA-B*3501 and HLA-B*3508, which differ by a single amino acid at position 156 ((156)Leucine vs. (156)Arginine, respectively). Surprisingly, only individuals expressing HLA-B*3508 show evidence of a CTL response to the (77)APQPAPENAY(86) epitope even though EBV-infected cells expressing HLA-B*3501 process and present similar amounts of peptide for CTL recognition, suggesting that factors other than peptide presentation levels are influencing immunogenicity. Functional and structural analysis revealed marked conformational differences in the peptide, when bound to each HLA-B35 allotype, that are dictated by the polymorphic HLA residue 156 and that directly affected T cell receptor recognition. These data indicate that the immunogenicity of an antigenic peptide is influenced not only by how well the peptide binds to major histocompatibility complex (MHC) molecules but also by its bound conformation. It also illustrates a novel mechanism through which MHC polymorphism can further diversify the immune response to infecting pathogens.
The immunogenicity of a viral cytotoxic T cell epitope is controlled by its MHC-bound conformation.,Tynan FE, Elhassen D, Purcell AW, Burrows JM, Borg NA, Miles JJ, Williamson NA, Green KJ, Tellam J, Kjer-Nielsen L, McCluskey J, Rossjohn J, Burrows SR J Exp Med. 2005 Nov 7;202(9):1249-60. PMID:16275762[20]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wani MA, Haynes LD, Kim J, Bronson CL, Chaudhury C, Mohanty S, Waldmann TA, Robinson JM, Anderson CL. Familial hypercatabolic hypoproteinemia caused by deficiency of the neonatal Fc receptor, FcRn, due to a mutant beta2-microglobulin gene. Proc Natl Acad Sci U S A. 2006 Mar 28;103(13):5084-9. Epub 2006 Mar 20. PMID:16549777 doi:10.1073/pnas.0600548103
- ↑ Gorevic PD, Munoz PC, Casey TT, DiRaimondo CR, Stone WJ, Prelli FC, Rodrigues MM, Poulik MD, Frangione B. Polymerization of intact beta 2-microglobulin in tissue causes amyloidosis in patients on chronic hemodialysis. Proc Natl Acad Sci U S A. 1986 Oct;83(20):7908-12. PMID:3532124
- ↑ Argiles A, Derancourt J, Jauregui-Adell J, Mion C, Demaille JG. Biochemical characterization of serum and urinary beta 2 microglobulin in end-stage renal disease patients. Nephrol Dial Transplant. 1992;7(11):1106-10. PMID:1336137
- ↑ Momoi T, Suzuki M, Titani K, Hisanaga S, Ogawa H, Saito A. Amino acid sequence of a modified beta 2-microglobulin in renal failure patient urine and long-term dialysis patient blood. Clin Chim Acta. 1995 May 15;236(2):135-44. PMID:7554280
- ↑ Cunningham BA, Wang JL, Berggard I, Peterson PA. The complete amino acid sequence of beta 2-microglobulin. Biochemistry. 1973 Nov 20;12(24):4811-22. PMID:4586824
- ↑ Haag-Weber M, Mai B, Horl WH. Isolation of a granulocyte inhibitory protein from uraemic patients with homology of beta 2-microglobulin. Nephrol Dial Transplant. 1994;9(4):382-8. PMID:8084451
- ↑ Trinh CH, Smith DP, Kalverda AP, Phillips SE, Radford SE. Crystal structure of monomeric human beta-2-microglobulin reveals clues to its amyloidogenic properties. Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9771-6. Epub 2002 Jul 15. PMID:12119416 doi:10.1073/pnas.152337399
- ↑ Stewart-Jones GB, McMichael AJ, Bell JI, Stuart DI, Jones EY. A structural basis for immunodominant human T cell receptor recognition. Nat Immunol. 2003 Jul;4(7):657-63. Epub 2003 Jun 8. PMID:12796775 doi:10.1038/ni942
- ↑ Kihara M, Chatani E, Iwata K, Yamamoto K, Matsuura T, Nakagawa A, Naiki H, Goto Y. Conformation of amyloid fibrils of beta2-microglobulin probed by tryptophan mutagenesis. J Biol Chem. 2006 Oct 13;281(41):31061-9. Epub 2006 Aug 10. PMID:16901902 doi:10.1074/jbc.M605358200
- ↑ Eakin CM, Berman AJ, Miranker AD. A native to amyloidogenic transition regulated by a backbone trigger. Nat Struct Mol Biol. 2006 Mar;13(3):202-8. Epub 2006 Feb 19. PMID:16491088 doi:10.1038/nsmb1068
- ↑ Iwata K, Matsuura T, Sakurai K, Nakagawa A, Goto Y. High-resolution crystal structure of beta2-microglobulin formed at pH 7.0. J Biochem. 2007 Sep;142(3):413-9. Epub 2007 Jul 23. PMID:17646174 doi:10.1093/jb/mvm148
- ↑ Ricagno S, Colombo M, de Rosa M, Sangiovanni E, Giorgetti S, Raimondi S, Bellotti V, Bolognesi M. DE loop mutations affect beta2-microglobulin stability and amyloid aggregation. Biochem Biophys Res Commun. 2008 Dec 5;377(1):146-50. Epub 2008 Oct 1. PMID:18835253 doi:S0006-291X(08)01866-4
- ↑ Esposito G, Ricagno S, Corazza A, Rennella E, Gumral D, Mimmi MC, Betto E, Pucillo CE, Fogolari F, Viglino P, Raimondi S, Giorgetti S, Bolognesi B, Merlini G, Stoppini M, Bolognesi M, Bellotti V. The controlling roles of Trp60 and Trp95 in beta2-microglobulin function, folding and amyloid aggregation properties. J Mol Biol. 2008 May 9;378(4):887-97. Epub 2008 Mar 8. PMID:18395224 doi:10.1016/j.jmb.2008.03.002
- ↑ Ricagno S, Raimondi S, Giorgetti S, Bellotti V, Bolognesi M. Human beta-2 microglobulin W60V mutant structure: Implications for stability and amyloid aggregation. Biochem Biophys Res Commun. 2009 Mar 13;380(3):543-7. Epub 2009 Jan 25. PMID:19284997 doi:10.1016/j.bbrc.2009.01.116
- ↑ Packham G, Economou A, Rooney CM, Rowe DT, Farrell PJ. Structure and function of the Epstein-Barr virus BZLF1 protein. J Virol. 1990 May;64(5):2110-6. PMID:2157874
- ↑ Kouzarides T, Packham G, Cook A, Farrell PJ. The BZLF1 protein of EBV has a coiled coil dimerisation domain without a heptad leucine repeat but with homology to the C/EBP leucine zipper. Oncogene. 1991 Feb;6(2):195-204. PMID:1847997
- ↑ Schepers A, Pich D, Hammerschmidt W. A transcription factor with homology to the AP-1 family links RNA transcription and DNA replication in the lytic cycle of Epstein-Barr virus. EMBO J. 1993 Oct;12(10):3921-9. PMID:8404860
- ↑ Wen W, Iwakiri D, Yamamoto K, Maruo S, Kanda T, Takada K. Epstein-Barr virus BZLF1 gene, a switch from latency to lytic infection, is expressed as an immediate-early gene after primary infection of B lymphocytes. J Virol. 2007 Jan;81(2):1037-42. Epub 2006 Nov 1. PMID:17079287 doi:10.1128/JVI.01416-06
- ↑ McDonald CM, Petosa C, Farrell PJ. Interaction of Epstein-Barr virus BZLF1 C-terminal tail structure and core zipper is required for DNA replication but not for promoter transactivation. J Virol. 2009 Apr;83(7):3397-401. doi: 10.1128/JVI.02500-08. Epub 2009 Jan 14. PMID:19144704 doi:10.1128/JVI.02500-08
- ↑ Tynan FE, Elhassen D, Purcell AW, Burrows JM, Borg NA, Miles JJ, Williamson NA, Green KJ, Tellam J, Kjer-Nielsen L, McCluskey J, Rossjohn J, Burrows SR. The immunogenicity of a viral cytotoxic T cell epitope is controlled by its MHC-bound conformation. J Exp Med. 2005 Nov 7;202(9):1249-60. PMID:16275762 doi:http://dx.doi.org/10.1084/jem.20050864
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