Affinity purification of human factor H on polypeptides derived from streptococcal m protein: enrichment of the Y402 variant.

Affinity purification of human factor H on polypeptides derived from streptococcal m protein: enrichment of the Y402 variant.

Blog Article

Recent studies indicate that defective activity of complement factor H (FH) is associated with several human diseases, suggesting that pure FH may be used for therapy.Here, we describe a simple method to isolate human FH, based on the specific interaction between FH and the hypervariable region (HVR) of certain Streptococcus pyogenes M Skateboards proteins.Special interest was focused on the FH polymorphism Y402H, which is associated with the common eye disease age-related macular degeneration (AMD) and has also been implicated in the binding to M protein.Using a fusion protein containing two copies of the M5-HVR, we found that the Y402 and H402 variants of FH could be efficiently purified by single-step affinity chromatography from human serum containing the corresponding protein.

Different M proteins vary in their binding properties, and the M6 and M5 proteins, but not the Hayward Commercial White Goods M18 protein, showed selective binding of the FH Y402 variant.Accordingly, chromatography on a fusion protein derived from the M6-HVR allowed enrichment of the Y402 protein from serum containing both variants.Thus, the exquisite binding specificity of a bacterial protein can be exploited to develop a simple and robust procedure to purify FH and to enrich for the FH variant that protects against AMD.