title: Characterization of a gene coding for a type IIo bacterial IgG-binding protein.
abstract: Two antigenic classes of non-immune IgG-binding proteins can be expressed by group A streptococci. One antigenic group of proteins is recognized by an antibody prepared against the product of a cloned fcrA gene (anti-FcRA). In this study, the immunogen used to prepare the antibody that defines the second antigenic class was shown to be the product of the emm-like (emmL) gene of M serotype 55 group A isolate, A928. The emmL55 gene expressed in E. coli produced an M(r) approximately 58,000 molecule which bound human IgG1, IgG2, IgG3 and IgG4, as well as horse, rabbit and pig IgG in a non-immune fashion. These properties are characteristic of the previously described type IIo IgG-binding protein isolated from this strain. In addition, the recombinant protein was reactive with human serum albumin and fibrinogen. The emmL 55 gene sequence was analysed and found to have the organization and sequence characteristics of a typical class I emm-like gene.
authors.affiliation: Department of Microbiology, Medical College of Ohio, Toledo 43699-0008, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Boyle
authors.forename: J
authors.initials: J
authors.lastname: Weber-Heynemann
authors.forename: R
authors.initials: R
authors.lastname: Raeder
authors.forename: A
authors.initials: A
authors.lastname: Podbielski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007132:Immunoglobulin Isotypes / Q000378:metabolism; D008969:Molecular Sequence Data; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C095209:Emm55 protein, Streptococcus pyogenes; C034284:IgG Fc-binding protein, Streptococcus; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes