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