1lds
From Proteopedia
Crystal Structure of monomeric human beta-2-microglobulin
Structural highlights
DiseaseB2MG_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] FunctionB2MG_HUMAN Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDissociation of human beta-2-microglobulin (beta(2)m) from the heavy chain of the class I HLA complex is a critical first step in the formation of amyloid fibrils from this protein. As a consequence of renal failure, the concentration of circulating monomeric beta(2)m increases, ultimately leading to deposition of the protein into amyloid fibrils and development of the disorder, dialysis-related amyloidosis. Here we present the crystal structure of a monomeric form of human beta(2)m determined at 1.8-A resolution that reveals remarkable structural changes relative to the HLA-bound protein. These involve the restructuring of a beta bulge that separates two short beta strands to form a new six-residue beta strand at one edge of this beta sandwich protein. These structural changes remove key features proposed to have evolved to protect beta sheet proteins from aggregation [Richardson, J. & Richardson, D. (2002) Proc. Natl. Acad. Sci. USA 99, 2754-2759] and replaces them with an aggregation-competent surface. In combination with solution studies using (1)H NMR, we show that the crystal structure presented here represents a rare species in solution that could provide important clues about the mechanism of amyloid formation from the normally highly soluble native protein. Crystal structure of monomeric human beta-2-microglobulin reveals clues to its amyloidogenic properties.,Trinh CH, Smith DP, Kalverda AP, Phillips SE, Radford SE Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9771-6. Epub 2002 Jul 15. PMID:12119416[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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