Open AccessAll individual domains of staphylococcal protein A show Fab binding
Author(s) -
Jansson Birger,
Uhlén Mathias,
Nygren PerÅke
Publication year - 1998
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.1998.tb01112.x
Subject(s) - polyclonal antibodies , recombinant dna , escherichia coli , cysteine , alanine , biology , biochemistry , immunoglobulin fab fragments , antibody , protein engineering , microbiology and biotechnology , amino acid , binding site , peptide sequence , enzyme , gene , complementarity determining region , genetics
The interactions between the individual domains (E, D, A, B and C) of staphylococcal protein A (SPA) and Fc and Fab regions of human immunoglobulins were studied using real‐time biospecific interaction analysis. An engineered domain Z, similar to fragment B but with a single glycine to alanine amino acid substitution, was also included in the study. The domains were expressed in Escherichia coli , affinity purified and immobilised onto sensor chip surfaces in a directed manner using a unique C‐terminal cysteine residue engineered into the recombinant proteins. All domains bound to a recombinant human IgG1 Fc fragment with similar strength. For the first time, binding to human Fab was demonstrated for all native SPA domains, using both polyclonal F(ab′) 2 and a recombinant scFv fragment as reagents. Interestingly, the engineered Z domain showed a considerably lower affinity for Fab as compared to the native domains.