Affinity purification of human factor h on polypeptides derived from streptococcal m protein: enrichment of the y402 variant.

Summary, in English

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 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 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.

• Author: Rickard O Nilsson; Jonas Lannergård; B Paul Morgan; Gunnar Lindahl; Mattias Gustafsson
• Department/s: Division of Medical Microbiology
• Publishing year: 2013
• Language: English
• Publication/Series: PLoS ONE
• Volume: 8
• Issue: 11
• Full text: - 864 kB; Download statistics
• Links: http://www.ncbi.nlm.nih.gov/pubmed/24278416?dopt=Abstract; http://dx.doi.org/10.1371/journal.pone.0081303
• Document type: Journal article
• Publisher: Public Library of Science (PLoS)
• Topic: Microbiology in the medical area
• Status: Published
• ISBN/ISSN/Other: ISSN: 1932-6203