| Structural highlights
Disease
[MTAP_HUMAN] Defects in MTAP are the cause of diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMSMFH) [MIM:112250]. An autosomal dominant bone dysplasia characterized by pathologic fractures due to abnormal cortical growth and diaphyseal medullary stenosis. The fractures heal poorly, and there is progressive bowing of the lower extremities. Some patients show a limb-girdle myopathy, with muscle weakness and atrophy. Approximately 35% of affected individuals develop an aggressive form of bone sarcoma consistent with malignant fibrous histiocytoma or osteosarcoma. Note=DMSMFH causing mutations found in MTAP exon 9 result in exon skipping and dysregulated alternative splicing of all MTAP isoforms (PubMed:22464254).[1] Note=Loss of MTAP activity may play a role in human cancer. MTAP loss has been reported in a number of cancers, including osteosarcoma, malignant melanoma and gastric cancer.[HAMAP-Rule:MF_03155] [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
[1B41_HUMAN] Involved in the presentation of foreign antigens to the immune system. [MTAP_HUMAN] Catalyzes the reversible phosphorylation of S-methyl-5'-thioadenosine (MTA) to adenine and 5-methylthioribose-1-phosphate. Involved in the breakdown of MTA, a major by-product of polyamine biosynthesis. Responsible for the first step in the methionine salvage pathway after MTA has been generated from S-adenosylmethionine. Has broad substrate specificity with 6-aminopurine nucleosides as preferred substrates.[16] [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 PubMed
Abstract Background. Polymorphic differences between human leucocyte antigen (HLA) molecules affect the specificity and conformation of their bound peptides and lead to differential selection of the T-cell repertoire. Mismatching during allogeneic transplantation can therefore lead to immunological reactions. Design and methods. We investigated the structure-function relationships of six members of the HLA-B*41 allelic group that differ by six polymorphic amino acids, including positions 80, 95, 97 and 114 within the antigen binding cleft. Peptide-binding motifs for B*4101, *4102, *4103, *4104, *4105 and *4106 were determined by sequencing self-peptides from recombinant B*41 molecules by ESI-MS-MS fragmentation. The crystal structures of HLA-B*4103 bound to a natural 16-mer self-ligand (AEMYGSVTEHPSPSPL) and HLA-B*4104 bound to a natural 11-mer self-ligand (HEEAVSVDRVL) were solved. Results. Peptide analysis revealed that all B*41 alleles have an identical p2 anchor (Glu), but differ in their choice of C-terminal p_anchor (Pro, Val, Leu). Additionally, B*4104 displayed a greater preference for long peptides (>10 residues) when compared to the other B*41 allomorphs, while the longest peptide to be eluted from the allelic group (a 16mer) was obtained from B*4103. The crystal structures of HLA-B*4103 and HLA-B*4104 revealed that both alleles interact in a highly conserved manner with the terminal regions of their respective ligands, while micropolymorphism-induced changes in the steric and electrostatic properties of the Ag-binding cleft account for differences in peptide repertoire and auxiliary anchoring. Conclusions. Differences in peptide repertoire, and peptide length specificity reflect the significant functional evolution of these closely related allotypes and signal their importance in allogeneic transplantation, especially B*4103 and B*4104, which accommodate longer peptides, creating structurally distinct pHLA-I (peptide-HLA) ligands.
The impact of human leucocyte antigen (HLA) micropolymorphism on ligand specificity within the HLA-B*41 allotypic family.,Bade-Doeding C, Theodossis A, Gras S, Kjer-Nielsen L, Eiz-Vesper B, Seltsam A, Huyton T, Rossjohn J, McCluskey J, Blasczyk R Haematologica. 2010 Oct 7. PMID:20934997[17]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Camacho-Vanegas O, Camacho SC, Till J, Miranda-Lorenzo I, Terzo E, Ramirez MC, Schramm V, Cordovano G, Watts G, Mehta S, Kimonis V, Hoch B, Philibert KD, Raabe CA, Bishop DF, Glucksman MJ, Martignetti JA. Primate genome gain and loss: a bone dysplasia, muscular dystrophy, and bone cancer syndrome resulting from mutated retroviral-derived MTAP transcripts. Am J Hum Genet. 2012 Apr 6;90(4):614-27. doi: 10.1016/j.ajhg.2012.02.024. Epub, 2012 Mar 29. PMID:22464254 doi:10.1016/j.ajhg.2012.02.024
- ↑ 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
- ↑ Della Ragione F, Carteni-Farina M, Gragnaniello V, Schettino MI, Zappia V. Purification and characterization of 5'-deoxy-5'-methylthioadenosine phosphorylase from human placenta. J Biol Chem. 1986 Sep 15;261(26):12324-9. PMID:3091600
- ↑ Bade-Doeding C, Theodossis A, Gras S, Kjer-Nielsen L, Eiz-Vesper B, Seltsam A, Huyton T, Rossjohn J, McCluskey J, Blasczyk R. The impact of human leucocyte antigen (HLA) micropolymorphism on ligand specificity within the HLA-B*41 allotypic family. Haematologica. 2010 Oct 7. PMID:20934997 doi:10.3324/haematol.2010.030924
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