Open AccessCloning and Expression of an Adhesin Antigen of Streptococcus sanguis G9B in Escherichia coli
Author(s) -
Burton Rosan,
Carol T. Baker,
Genevieve M. Nelson,
Richard Berman,
Richard J. Lamont,
Donald R. Demuth
Publication year - 1989
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-135-3-531
Subject(s) - bacterial adhesin , escherichia coli , polyclonal antibodies , fusion protein , recombinant dna , microbiology and biotechnology , antigen , expression vector , biology , molecular cloning , cloning (programming) , antibody , streptococcus , clone (java method) , peptide sequence , bacteria , gene , biochemistry , genetics , computer science , programming language
A genomic library of Streptococcus sanguis, strain G9B, was constructed and expressed in Escherichia coli using a lambda gt11 expression vector. The amplified library was probed with polyclonal anti-G9B IgG and 13 antigen-positive clones were isolated. A lysate of one clone, designated PP39, absorbed the adhesion-inhibitory activity of anti-G9B IgG. This clone contained an insert of approximately 2000 bp and expressed unique 200 and 53 kDa proteins that reacted with monospecific anti-adhesin antibody. The 200 kDa protein also reacted with anti-beta-galactosidase IgG, indicating that it is a fusion protein of which 84 kDa represents the streptococcal adhesin. The 84 and 53 kDa proteins are similar in size to the major polypeptides in a streptococcal antigen complex which is associated with the adhesion of G9B to saliva-coated hydroxyapatite. The 53 kDa fragment may result from post-translational cleavage of the recombinant polypeptide.