title: Identification of a novel collagen-like protein, SclC, in Streptococcus equi using signal sequence phage display.
abstract: Strangles is a serious disease in horses caused by Streptococcus equi subspecies equi. In this study, genes encoding putative extracellular proteins in this subspecies have been identified using signal sequence phage display. Among these, one showed similarities to the SclB protein, a member of the collagen-like proteins of Streptococcus pyogenes. The novel gene denoted sclC encodes a protein, SclC, of 302 amino acids, containing typical features found in cell wall-anchored proteins in Gram-positive bacteria. Based on similarities to the S. pyogenes collagen-like proteins the mature SclC protein can be divided into various domains: an N-terminal non-repetitive region (A), a highly repetitive collagen-like region (CL), and a C-terminal proline-rich wall-associated region (W). Using PCR, the sclC gene was detected in all studied strains of S. equi subsp. equi and S. equi subsp. zooepidemicus. Further, antibodies against recombinant SclC were detected in a collection of sera from horses with no history of strangles as well as horses previously infected with S. equi subsp. equi. Interestingly, the sera from convalescence horses were found to have significantly increased antibody titers against the SclC protein indicating that this protein is expressed during infection of S. equi subsp. equi.
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, 750 07 Uppsala, Sweden. asa.karlstrom@mikrob.slu.se
authors.forename: Asa
authors.initials: A
authors.lastname: Karlström
authors.forename: Karin
authors.initials: K
authors.lastname: Jacobsson
authors.forename: Margareta
authors.initials: M
authors.lastname: Flock
authors.forename: Jan-Ingmar
authors.initials: JI
authors.lastname: Flock
authors.forename: Bengt
authors.initials: B
authors.lastname: Guss
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D003094:Collagen / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006734:Horse Diseases / Q000382:microbiology; D006736:Horses; D008969:Molecular Sequence Data; D016415:Sequence Alignment / Q000662:veterinary; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary; D018502:Streptococcus equi / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D003094:Collagen