Functional recombinant human complement C1q with different affinity tags

Complement C1q is a multifunctional protein able to sense pathogens and immune molecules such as immunoglobulins pentraxins, trigger the classical complement pathway through activation of its two associated proteases, C1r C1s. multimeric composed three homologous yet distinct polypeptide chains A, B, C, each an N-terminal collagen-like sequence C-terminal globular gC1q module, that assemble into six heterotrimeric (A-B-C) subunits. This hexameric structure exhibits characteristic shape bouquet flowers, comprising triple helices, terminating in trimeric head. We have produced previously functional recombinant full-length stably transfected HEK 293-F cells, with FLAG tag inserted at end C1qC chain. report here generation additional proteins, fused C-terminus C1qA or C1qB chains, N-terminus Two other variants harboring Myc 6-His were also produced. show all variants, except for His-tagged protein, can be comparable yields are bind similar affinities either IgM, ligand regions, C1r2-C1s2 tetramer, IgM-mediated serum activation. These new provide tools investigate multiple functions C1q.