Ficolin 2, Recombinant, Human (Ficolin-B, Ficolin beta, L-ficolin)

Human Ficolin 2 is a member of the ficolin family of secreted pattern recognition proteins that participate in the lectin complement activation pathway. Ficolin 2 is expressed in the liver and released into the circulation. The 35-40kD, 313 amino acid (aa) human Ficolin-2 contains a 25 aa signal sequence, an N-terminal collagen domain and a C-terminal fibrinogen-like domain that includes a calcium binding site and two potential N-glycosylation sites. The collagen domain mediates trimer formation. Larger homo-multimers are formed by disulfide links at the N-terminus, the most prominent of which is a 12 subunit oligomer. Ficolin 2 binds microbial ligands that contain acetylated compounds. Notably, this includes N-acetyl glucosamine in compounds such as lipoteichoic acid in gram-positive bacteria. It also binds fungal 1,3-beta-D-glucan. Pathogen recognition by Ficolin-2 initiates an immune response that involves calcium-dependent interaction of Ficolin 2 with the MBL-associated serine protease (MASP) complex. This complex cleaves C4 to activate the complement pathway. In a secondary role, Ficolin 2 is known to bind late apoptotic and necrotic cells, probably through the recognition of exposed DNA. This also activates the complement cascade that assists in clearance of cells. Mature human Ficolin-2 shares 70%, 72%, 76% and 78% aa identity with mouse, rat, cow and pig Ficolin 2, respectively. It shares 84% and 52% aa identity with human ficolin 1 and ficolin 3, respectively. Single nucleotide polymorphisms are common in human Ficolin 2. Some affect serum concentration, while others can increase or decrease ligand binding. Recombinant protein corresponding to Leu26-Ala313 from human Ficolin 2, with a C-terminal 10-His tag, expressed in NSO cells (Q15485). , Activity: Measured by its ability to bind biotinylated N-Acetylglucosamine-Polyacrylamide in a functional ELISA type binding assay. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.