Recombinant Human Complement Factor H-related 2 His-tag, CF

Complement factor H-related protein 2 (CFHR2) is a ~30 kDa secreted, primarily homodimeric member of the factor H family of glycoproteins (1). CFHR2 is produced by hepatocytes and circulates as two differentially glycosylated isoforms (2). The human complement factor H protein family consists of the complement and immune regulators factor H, the factor H-like protein 1 (FHL-1) and five factor H-related proteins (CFHR-1 to -5) (3). The genes of this family are located on human chromosome 1q32, which is known as the regulator of complement activation (RCA) gene clusters (4). CFHRs are exclusively composed of individually folded protein domains termed short consensus repeats (SCRs) or complement control modules. CFHR2 contains 4 SCRs. Although considered group 1 CFHRs based on conserved N-termini (1), compared to CFHR2, human CFHR1 and CFHR5 show 67.5% and 34.5% aa identity, respectively. All CFHRs are capable of binding complement factor C3b, discriminate between self and non-self cell surfaces, and have been proposed to deregulate complement activation (3). CFHR2 inhibits the C3 convertase cleavage amplification loop by inhibiting terminal complement complex assembly (5). CFHR2 polymorphisms and deficiency were identified to correlate with risk of age-related macular degeneration (AMD) (6-8) implicating CFHR2 in human disease.