In the complement factor H family, there are five CFHR proteins have been identified, which are divided into two major groups, Group I and Group II, based on their conserved domains. Complement factor H-related protein 1 (CFHR1), a member of Group I CFHR proteins, is a plasma protein circulating in two glycosylated forms at the concentration of 70 to 100 μg/mL. CFHR1 is composed of five short consensus repeat (SCR) domains or complement control protein (CCP) domains.
The N-terminal two SCRs, SCR1 and SCR2, exhibit sequence homology to SCR6 and SCR7 of CFH, and share high amino acid identity to SCR1 and SCR2 of CFHR2 and CFHR5. CFHR1 has a dimerization domain at the N-terminus that can form heterodimers with CFHR2 and CFHR5. The sequence of C-terminal SCR3, SCR4, and SCR5 are almost identical to the SCR18-20 of CFH, except for two amino acid differences.
Learn more: CFHR1 Protein