SclC is a member of a novel family of collagen-like proteins in Streptococcus equi subspecies equi that are recognised by antibodies against SclC.
Previously we have reported on a cell surface collagen-like protein, called SclC, from Streptococcus equi subspecies equi. In the present study we show that this protein is a member of a family of seven collagen-like proteins, called SclC-SclI in this subspecies. All proteins contain an N-terminal signal sequence, followed by a unique non-repetitive region called A, a highly repetitive collagen-like region (CL) consisting of Glycine-Xaa-Yaa-triplet repeats. Following the CL-region a C-terminal proline-rich putative wall spanning region (W) preceding an LPXTG-motif and a hydrophobic transmembrane region (M) are found, typical features of cell surface exposed proteins in Gram-positive bacteria. The nucleotide and amino acid sequences, were analysed to investigate the similarities between them, and recombinant proteins encoding different domains (A- and CL-regions) were expressed and purified. Although the novel collagen-like proteins display differences in amino acid sequences, affinity purified antibodies against SclC were found to cross react with the other members of the novel collagen-like proteins. Furthermore, in sera from horses previously diagnosed having strangles, antibodies against these proteins were detected suggesting that these proteins are expressed during the infection.
Karlström
Asa
A
Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, 750 07 Uppsala, Sweden.
Jacobsson
Karin
K
Guss
Bengt
B
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D003094:Collagen / Q000145:classification / Q000235:genetics / Q000276:immunology*; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D015870:Gene Expression; D023061:Gene Order / Q000235:genetics; D006734:Horse Diseases / Q000276:immunology / Q000382:microbiology; D006736:Horses; D007098:Imino Acids / Q000032:analysis; D008565:Membrane Proteins / Q000096:biosynthesis / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
D000907:Antibodies, Bacterial; D017931:DNA Primers; D007098:Imino Acids; D008565:Membrane Proteins; D011994:Recombinant Proteins; D003094:Collagen