title: The serine-aspartate repeat (Sdr) protein family in Staphylococcus epidermidis.
abstract: Staphylococcus epidermidis can express three different cell-surface-associated proteins, designated SdrF, SdrG and SdrH, that contain serine-aspartate dipeptide repeats. Proteins SdrF and SdrG are similar in sequence and structural organization to the Sdr proteins of Staphylococcus aureus and comprise unique 625- and 548-residue A regions at their N termini, respectively, followed by 110-119-residue B-repeat regions and SD-repeat regions. The C termini contain LPXTG motifs and hydrophobic amino acid segments characteristic of surface proteins covalently anchored to peptidoglycan. In contrast, SdrH has a short 60-residue A region at its N terminus followed by a SD-repeat region, a unique 277-residue C region and a C-terminal hydrophobic segment. SdrH lacks a LPXTG motif. Recombinant proteins representing the A regions of SdrF, SdrG and SdrH were expressed and purified from Escherichia coli. Antisera specific to these proteins were raised in rabbits and used to identify Sdr proteins expressed by S. epidermidis. Only SdrF was released from lysostaphin-generated protoplasts of cells grown to late-exponential phase. SdrG and SdrH remained associated with the protoplast fraction and thus appear to be ineffectively sorted along the conventional pathway used for cell-wall-anchored proteins. In Southern hybridization analyses, the sdrG and sdrH genes were present in all 16 strains tested, whilst sdrF was present in 12 strains. Antisera from 16 patients who had recovered from S. epidermidis infections contained antibodies that reacted with recombinant A regions of SdrG and SdrH, suggesting that these proteins can be expressed during infection.
authors.affiliation: Institute of Biosciences and Technology, Texas Medical Center, 2121 West Holcombe Boulevard, Houston, TX 77030-3303, USA1.
authors.forename: Kirk W
authors.initials: KW
authors.lastname: McCrea
authors.affiliation: Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland2.
authors.forename: Orla
authors.initials: O
authors.lastname: Hartford
authors.affiliation: Institute of Biosciences and Technology, Texas Medical Center, 2121 West Holcombe Boulevard, Houston, TX 77030-3303, USA1.
authors.forename: Stacey
authors.initials: S
authors.lastname: Davis
authors.affiliation: Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland2.
authors.forename: Deirdre Nı
authors.initials: DN
authors.lastname: Eidhin
authors.affiliation: EA1655, Faculté Laennec, 69372 Lyon Cedex 08, France3.
authors.forename: Gerard
authors.initials: G
authors.lastname: Lina
authors.affiliation: Department of Biochemistry, University of Pavia, 27100 Pavia, Italy4.
authors.forename: Pietro
authors.initials: P
authors.lastname: Speziale
authors.affiliation: Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland2.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Foster
authors.affiliation: Institute of Biosciences and Technology, Texas Medical Center, 2121 West Holcombe Boulevard, Houston, TX 77030-3303, USA1.
authors.forename: Magnus
authors.initials: M
authors.lastname: Höök
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015139:Blotting, Southern; D015153:Blotting, Western; D003001:Cloning, Molecular; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D008248:Lysostaphin / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides; D011994:Recombinant Proteins / Q000378:metabolism; D013211:Staphylococcus aureus / Q000235:genetics; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D017931:DNA Primers; D007106:Immune Sera; D008565:Membrane Proteins; D010455:Peptides; D011994:Recombinant Proteins; D008248:Lysostaphin