Single-step purification of human C4b-binding protein (C4BP) by affinity chromatography on a peptide derived from a streptococcal surface protein.

Research output: Contribution to journalArticle


Many Gram-positive bacteria express surface proteins that bind human plasma proteins. These bacterial proteins, and derivatives of them, are of interest for analysis of bacterial pathogenesis and as immunochemical tools. Well-characterized examples include the IgG-binding reagents staphylococcal protein A and streptococcal protein G, and the recently described streptococcal IgA-binding peptide Sap. Here, we show that a peptide derived from the streptococcal M22 protein can be used for single-step affinity purification of the human complement regulator Cob-binding protein (C4BP). Binding of C4BP was strongly enhanced by dimerization of the peptide via a C-terminal cysteine residue not present in the intact M22 protein. The purified C4BP had the expected binding characteristics, and acted as a cofactor for factor I in the degradation of Cob. Passage of serum through a peptide column under non-saturating conditions resulted in binding of > 99.5% of serum C4BP, implying that such a column can be used to deplete serum of C4BP. These data indicate that the C4BP-binding peptide is a versatile tool that can be used for simple and rapid purification of biologically active human C4BP or for removal of C4BP from serum. (c) 2005 Elsevier B.V. All rights reserved.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Immunology in the medical area


  • depletion, peptide, streptococcal M protein, protein purification, C4BP
Original languageEnglish
Pages (from-to)83-95
JournalJournal of Immunological Methods
Issue number1-2
Publication statusPublished - 2005
Publication categoryResearch