Gene for an immunoglobulin-binding protein from a group G streptococcus.

AUTOR(ES)

Fahnestock, S R

RESUMO

The gene (spg) for an immunoglobulin G (IgG)-binding protein from a Streptococcus clinical isolate of Lancefield group G was cloned and expressed in Escherichia coli. The complete nucleotide sequence of the gene and 5'-flanking sequences was determined. The DNA sequence includes an open reading frame which encodes a hypothetical protein of 448 amino acid residues (Mr = 47,595). The 5' end of this open reading frame encodes a sequence resembling a typical secretion signal sequence, and the remainder of the encoded protein has features reminiscent of staphylococcal protein A and of streptococcal M6 protein, including repeated sequences and a similar C-terminal structure. Aside from this C-terminal structure, the encoded protein has little direct amino acid sequence homology to either protein A or M6 protein. In E. coli, the cloned gene directs the synthesis of a protein which binds to immunoglobulins, including rabbit immunoglobulin, goat IgG, and human IgG3(lambda). Its binding properties are similar to those of the protein G described by Björck and Kronvall (L. Björck and G. Kronvall, J. Immunol. 133:969-974, 1984), a type III Fc receptor from a group G streptococcus.

Documentos Relacionados

• Cloning and expression of the gene for an immunoglobulin G Fc receptor protein from a group A streptococcus.
• Immunoglobulin-binding structure on bovine group G streptococci different from type III Fc receptors on human group G streptococci.
• Protein L, a bacterial immunoglobulin-binding protein and possible virulence determinant.
• Escherichia coli strains with nonimmune immunoglobulin-binding activity.
• Colloidal gold immunolabeling of immunoglobulin-binding sites and beta antigen in group B streptococci.