Staphylococcal protein A consists of five IgG‐binding domains

• Published in: European journal of biochemistry Vol. 156; no. 3; pp. 637 - 643
• Main Authors: MOKS, Tomas, ABRAHMSÉN, Lars, NILSSON, Björn, HELLMAN, Ulf, SJÖQUIST, John, UHLÉN, Mathias
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-05-1986; Blackwell
• Subjects: Amino Acids - analysis; Applied sciences; Cloning, Molecular; Escherichia coli - genetics; Escherichia coli - metabolism; Exact sciences and technology; Genes, Bacterial; immunoglobulins; Other techniques and industries; Peptide Fragments - genetics; Plasmids; protein A; Protein Biosynthesis; Protein Sorting Signals - analysis; Receptors, IgG; Receptors, Immunologic - genetics; Staphylococcal Protein A - genetics; Staphylococcus - genetics; Transformation, Bacterial; Staphylococcus aureus
• ISSN: 0014-2956; 1432-1033
• DOI: 10.1111/j.1432-1033.1986.tb09625.x

A genetic approach is described to clarify the IgG‐binding properties of the N‐terminal portion of staphylococcal protein A (region E). Several gene fragments, encoding region E or B or protein A, have been cloned and expressed in Escherichia coli. The gene products were purified by IgG‐affinity chromatography and subjected to structural and functional analyses. Both fragments can be efficiently purified using this method, suggesting that region B as well as region E has Fc‐binding activity. In addition, gene fusions were assembled giving fragments EB and EE, which both showed a divalent Fc‐binding. These results demonstrate that protein A consists of five IgG‐binding domains. The implications of these findings for the structure of protein‐A‐immunoglobulin‐G complexes are discussed.