Human beta two microglobulin
From Proteopedia
Human Beta two microglobulin (b2m)
Beta two microglubulin in human class I major histocompatibility complex
Human β2-Microglobulin (b2m) is the non-covalently bound light chain of the human class I major histocompatibility complex (MHC-I). its function is to ensure proper folding and cell-surface expression of MHC-1. The natural turnover of MHC-I gives rise to the release of b2m into plasmatic fluids at ~0.1 um and to its catabolism in the kidney. In case of renal dysfunction, b2m concentration increases up to 60-fold, giving rise to pathogenic accumulation of filamentous structures, displaying the typical properties of amyloid fibrils, principally in the joints and connective tissue.
Monomeric human b2m
The first crystal structure of monomeric human b2m (Mhb2m) is solved in 2002. The protein is 99 residue in length and has a seven-stranded β sandwich fold typical of the Immunoglobulin superfamily. β strands A,B,D and E comprise one β sheet, and whereas β strands C,F,G form the second β sheet. The protein is stabilized by a single disulfide bond between Cys-25 and Cys-80, which links the two β sheets.
