title: A second IgG-binding protein in Staphylococcus aureus.
abstract: Most strains of Staphylococcus aureus express IgG-binding activity and this binding has been considered to be solely mediated by protein A. However, the existence of a second gene in S. aureus strain 8325-4 encoding an IgG-binding polypeptide was recently reported. This novel IgG-binding polypeptide was found after panning a shotgun phage display library, made from chromosomal DNA, against immobilized human IgG. The complete gene (sbi) encoding this novel IgG-binding protein, denoted protein Sbi, has now been cloned and sequenced. Analysis of other S. aureus strains showed that this gene is not unique for strain 8325-4. The protein consists of 436 amino acids and exhibits an immunoglobulin-binding specificity similar to protein A. Furthermore, it is shown that Sbi is highly expressed in strain Newman 4, which shows that IgG-binding activity in S. aureus can be mediated by proteins other than protein A.
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, S-750 07 Uppsala, Sweden.
authors.forename: Lihong
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, S-750 07 Uppsala, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Jacobsson
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, S-750 07 Uppsala, Sweden.
authors.forename: Jozsef
authors.initials: J
authors.lastname: Vasi
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, S-750 07 Uppsala, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Lindberg
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, S-750 07 Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Frykberg
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D001426:Bacterial Proteins; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C112405:Sbi protein, Staphylococcus aureus