title: Cloning and expression of an adhesin antigen of Streptococcus sanguis G9B in Escherichia coli.
abstract: 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.
authors.affiliation: University of Pennsylvania, School of Dental Medicine, Department of Microbiology, Philadelphia 19104.
authors.forename: B
authors.initials: B
authors.lastname: Rosan
authors.forename: C T
authors.initials: CT
authors.lastname: Baker
authors.forename: G M
authors.initials: GM
authors.lastname: Nelson
authors.forename: R
authors.initials: R
authors.lastname: Berman
authors.forename: R J
authors.initials: RJ
authors.lastname: Lamont
authors.forename: D R
authors.initials: DR
authors.lastname: Demuth
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000276:immunology*; D003001:Cloning, Molecular; D004926:Escherichia coli; D005798:Genes, Bacterial; D015151:Immunoblotting; D007074:Immunoglobulin G; D008970:Molecular Weight; D015183:Restriction Mapping; D013298:Streptococcus sanguis / Q000235:genetics / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G