Clusterin His Recombinant Protein

Source : Escherichia Coli. Clusterin Human Recombinant produced in E.Coli is a single, non-glycosylated polypeptide chain containing 463 amino acids (23-449 a.a.) & having a molecular mass of 54.1kDa. Clusterin is fused to a 36 amino acid His-tag at N-terminus & purified by proprietary chromatographic techniques. Clusterin also named Apolipoprotein J (APO-J) is a 75-80 kD disulfide-linked heterodimeric protein containing about 30% of N-linked carbohydrate rich in sialic acid but truncated forms targeted to the nucleus have also been identified.The precursor polypeptide chain is cleaved proteolytically to remove the 22-mer secretory signal peptide & subsequently between residues 227/228 to generate the a & b chains. These are assembled in anti-parallel to give a heterodimeric molecule in which the cysteine-rich centers are linked by five disulfide bridges & are flanked by two predicted coiled-coil a-helices & three predicted amphipathic a-helices.Across a broad range of species clusterin shows a high degree of sequence homology ranging from 70% to 80%. It is nearly ubiquitously expressed in most mammalian tissues & can be found in plasma, milk, urine, cerebrospinal fluid & semen.It is able to bind & form complexes with numerous partners such as immunoglobulins, lipids, heparin, bacteria, complement components, paraoxonase, beta amyloid, leptin & others. Clusterin has been ascribed a plethora of functions such as phagocyte recruitment, aggregation induction, complement attack prevention, apoptosis inhibition, membrane remodeling, lipid transport, hormone transport &/or scavenging, matrix metalloproteinase inhibition.A genuine function of clusterin has not been defined. One tempting hypothesis says that clusterin is an extracellular chaperone protecting cells from stress induced insults caused by degraded & misfolded protein precipitates.Clusterin is up- or down regulated on the mRNA or protein level in many pathological & clinically relevant situations including cancer, organ regeneration, infection, Alzheimer disease, retinitis pigmentosa, myocardial infarction, renal tubular damage, autoimmunity & others.