| Structural highlights
5whk is a 4 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | EDO, NHE |
| Gene: | FCGRT, FCRN (HUMAN), B2M, CDABP0092, HDCMA22P (HUMAN) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
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. [FCGRN_HUMAN] Binds to the Fc region of monomeric immunoglobulins gamma. Mediates the uptake of IgG from milk. Possible role in transfer of immunoglobulin G from mother to fetus.
Publication Abstract from PubMed
The neonatal Fc receptor FcRn plays a critical role in the trafficking of IgGs across tissue barriers and in retaining high circulating concentrations of both IgG and albumin. Although generally beneficial from an immunological perspective in maintaining IgG populations, FcRn can contribute to the pathogenesis of autoimmune disorders when an abnormal immune response targets normal biological components. We previously described a monoclonal antibody (DX-2507) that binds to FcRn with high affinity at both neutral and acidic pH, prevents the simultaneous binding of IgG, and reduces circulating IgG levels in preclinical animal models. Here, we report a 2.5 A resolution X-ray crystal structure of an FcRn-DX-2507 Fab complex, revealing a nearly complete overlap of the IgG-Fc binding site in FcRn by complementarity-determining regions in DX-2507. This overlap explains how DX-2507 blocks IgG binding to FcRn and thereby shortens IgG half-life by preventing IgGs from recycling back into circulation. Moreover, the complex structure explains how the DX-2507 interaction is pH-insensitive unlike normal Fc interactions and how serum albumin levels are unaffected by DX-2507 binding. These structural studies could inform antibody-based therapeutic approaches for limiting the effects of IgG-mediated autoimmune disease.
Structural basis for pH-insensitive inhibition of immunoglobulin G recycling by an anti-neonatal Fc receptor antibody.,Kenniston JA, Taylor BM, Conley GP, Cosic J, Kopacz KJ, Lindberg AP, Comeau SR, Atkins K, Bullen J, TenHoor C, Adelman BA, Sexton DJ, Edwards TE, Nixon AE J Biol Chem. 2017 Oct 20;292(42):17449-17460. doi: 10.1074/jbc.M117.807396. Epub , 2017 Sep 6. PMID:28878017[15]
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
- ↑ Kenniston JA, Taylor BM, Conley GP, Cosic J, Kopacz KJ, Lindberg AP, Comeau SR, Atkins K, Bullen J, TenHoor C, Adelman BA, Sexton DJ, Edwards TE, Nixon AE. Structural basis for pH-insensitive inhibition of immunoglobulin G recycling by an anti-neonatal Fc receptor antibody. J Biol Chem. 2017 Oct 20;292(42):17449-17460. doi: 10.1074/jbc.M117.807396. Epub , 2017 Sep 6. PMID:28878017 doi:https://dx.doi.org/10.1074/jbc.M117.807396
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