A.E.P.-A. observed by fluorescence spectroscopy. Isothermal calorimetry titration showed that Cu(II) binds to the protein with micromolar affinity. His99 may be one of the main Cu(II) conversation sites, as observed by nuclear magnetic resonance spectroscopy. The binding of Cu(II) to His99 induces larger fluctuations of the CDR1 and loop C, as shown by molecular dynamics simulations. Thus, Cabergoline Cu(II) binding may be inducing the loss of interactions between CDR3 and CDR1, making the protein less stable and more prone to form amyloid fibers. This study provides insights into the Cabergoline mechanism of metal-induced aggregation of the 6aJL2-R24G protein and sheds light around the bio-inorganic understanding of AL disease. Introduction Light-chain amyloidosis (AL) is usually a fatal degenerative disease characterized by the extracellular deposition of insoluble aggregates of antibody light chain (LC) proteins. Plasma cells normally produce a small excess of LCs over heavy chains, and these LCs are cleared by the kidneys,1 but occasionally, free LCs aggregate into pathological forms.2?4 LCs misfold and aggregate,5 depositing in tissues in the form of amyloid fibrils, among other types of aggregates.6,7 The LC gene consists of three segments, the variable (V), junction (J), and constant (C) segments. The functional gene is a combination of different VJC genes,8 which result in a protein with two domains, the variable (VL) and constant (CL) domain name. Structurally, the variable domain contains the V and J segments and consists of eight -strands (ABCCDEFG), forming two -linens of four strands. The linens are joined by a disulfide bridge.9 In vitro studies have shown that this VL domain forms amyloid fibers more readily than the CL domain,10 and there are some LC genes preferentially associated with AL,11?16 in particular, V6, the gene that encodes 6 proteins.17 The recombinant protein 6aJL2-R24G contains the 6a and JL2 germline genes and also contains the Arg24 by Gly substitution. This mutation is present in 25% of all amyloid-associated 6 LC cases.18 6aJL2-R24G protein is less stable and more prone to form amyloid fibers in vitro than the germline protein 6aJL2,19 while maintaining a similar three-dimensional structure.9,20 6aJL2-R24G is a -sandwich domain name formed by 111 residues and has a conserved tryptophan residue at position 36, which is quenched in the native state by the nearby conserved disulfide bridge.21 Copper is an essential trace element present in all organs and cells. It is involved in several biological processes, participating as an enzyme cofactor in neurotransmitter biosynthesis, peptide maturation, antioxidant defense, cellular respiration, and pigmentation, among others.22 The normal range of serum copper in the adult is 11C24 M.23 In blood, most of the copper is Cabergoline associated with ceruloplasmin, around 15% to albumin, 10% to transcuprein, and small amounts to small peptides and amino acids.24,25 A common feature of degenerative diseases is the aggregation of partially folded or misfolded proteins,26,27 and an increasing quantity of systems involving aggregation have been shown to be affected by the presence of metal ions, including prion diseases,28 Alzheimer,29 Parkinson,30,31 and type II diabetes,32 among others. Thus, metal ions have emerged as important players in protein aggregation. Therefore, understanding the properties of the binding and Cabergoline the molecular details of proteinCmetal complex formation may provide important insights into the pathogenic processes. However, the Rabbit polyclonal to Receptor Estrogen alpha.ER-alpha is a nuclear hormone receptor and transcription factor.Regulates gene expression and affects cellular proliferation and differentiation in target tissues.Two splice-variant isoforms have been described. effect of metal ions in LC and comparable proteins is relatively unexplored, as well as the presence of metal ions in the AL patients. The conversation of 2-microglobulin (2m), a protein from dialysis-related amyloidosis, with metal ions showed that Cu(II) induces amyloid fibril formation, Zn(II) induces oligomerization but not amyloid fibril formation, and Ni(II) does not induce oligomerization or aggregation of the protein.33,34 Also, it has been reported that a recombinant kIV LC (SMA) aggregates when incubated with Cu(II), both in vitro and under high copper concentration conditions within cells.35 Although there are no direct evidences of the role of metal ions in the development of this disease, it has been reported that.