TY - JOUR
T1 - Protein H — a surface protein of Streptococcus pyogenes with separate binding sites for lgG and albumin
AU - Frick, Inga‐Maria ‐M
AU - Åkesson, Per
AU - Cooney, Jakki
AU - Sjöbring, Ulf
AU - Schmidt, Karl‐Hermann ‐H
AU - Gomi, Hideyuki
AU - Hattori, Shizuo
AU - Tagawa, Chiaki
AU - Kishimoto, Fumitaka
AU - Björck, Lars
PY - 1994/4
Y1 - 1994/4
N2 - Protein H, a molecule expressed at the surface of some strains of Streptococcus pyogenes, has affinity for the constant (lgGFc) region of immunoglobulin (lg) G. In absorption experiments with human plasma, protein H–sepharose could absorb not only lgG but also albumin from plasma. The affinity constant for the reaction between albumin and protein H was 7.8 × 109M−1, which is higher than the affinity between lgG and protein H (Ka= 1.6 × 109 M−1). Fragments of protein H were generated with deletion plasmids and polymerase chain reaction (PCR) technology. Using these fragments in various protein–protein interaction assays, the binding of albumin was mapped to three repeats (C1–C3) in the C‐terminal half of protein H. On the albumin molecule, the binding site for protein H was found to overlap the site for protein G, another albumin‐ and lgGFc‐binding bacterial surface protein. Aiso lgGFc‐binding could be mapped with the protein H fragments and the region was found N‐terminally of the C repeats. A synthetic peptide (25 amino acid residues long) based on a sequence in this region was shown to inhibit the binding of protein H to immobilized lgG or lgGFc. This sequence was not found in previously described lgGFc‐binding proteins. However, two other cell surface proteins of S. pyogenes exhibited highly homologous regions. The results identify lgGFc‐ and albumin binding regions of protein H and further define and emphasize the convergent evolution among bacterial surface proteins interacting with human plasma proteins.
AB - Protein H, a molecule expressed at the surface of some strains of Streptococcus pyogenes, has affinity for the constant (lgGFc) region of immunoglobulin (lg) G. In absorption experiments with human plasma, protein H–sepharose could absorb not only lgG but also albumin from plasma. The affinity constant for the reaction between albumin and protein H was 7.8 × 109M−1, which is higher than the affinity between lgG and protein H (Ka= 1.6 × 109 M−1). Fragments of protein H were generated with deletion plasmids and polymerase chain reaction (PCR) technology. Using these fragments in various protein–protein interaction assays, the binding of albumin was mapped to three repeats (C1–C3) in the C‐terminal half of protein H. On the albumin molecule, the binding site for protein H was found to overlap the site for protein G, another albumin‐ and lgGFc‐binding bacterial surface protein. Aiso lgGFc‐binding could be mapped with the protein H fragments and the region was found N‐terminally of the C repeats. A synthetic peptide (25 amino acid residues long) based on a sequence in this region was shown to inhibit the binding of protein H to immobilized lgG or lgGFc. This sequence was not found in previously described lgGFc‐binding proteins. However, two other cell surface proteins of S. pyogenes exhibited highly homologous regions. The results identify lgGFc‐ and albumin binding regions of protein H and further define and emphasize the convergent evolution among bacterial surface proteins interacting with human plasma proteins.
UR - http://www.scopus.com/inward/record.url?scp=0028362183&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2958.1994.tb01003.x
DO - 10.1111/j.1365-2958.1994.tb01003.x
M3 - Article
C2 - 8057834
AN - SCOPUS:0028362183
SN - 0950-382X
VL - 12
SP - 143
EP - 151
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 1
ER -